{"id":909,"date":"2021-12-19T01:45:07","date_gmt":"2021-12-18T17:45:07","guid":{"rendered":"https:\/\/blog.cauchyschwarz.com\/?p=909"},"modified":"2021-12-19T01:50:08","modified_gmt":"2021-12-18T17:50:08","slug":"hpbn%e8%af%bb%e4%b9%a6%e7%ac%94%e8%ae%b0%e4%b9%8bwireless-networks","status":"publish","type":"post","link":"https:\/\/blog.cauchyschwarz.com\/?p=909","title":{"rendered":"HPBN\u8bfb\u4e66\u7b14\u8bb0\u4e4bWireless Networks"},"content":{"rendered":"\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_82_2 ez-toc-wrap-right counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-69e0ada051521\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-69e0ada051521\" checked aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Chapter_5_Introduction_to_Wireless_Networks\" >Chapter 5 Introduction to Wireless Networks<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#%E6%97%A0%E7%BA%BF%E7%BD%91%E7%BB%9C%E7%9A%84%E7%B1%BB%E5%9E%8B%E6%8C%89%E8%B7%9D%E7%A6%BB%E5%88%92%E5%88%86%EF%BC%9A\" >\u65e0\u7ebf\u7f51\u7edc\u7684\u7c7b\u578b(\u6309\u8ddd\u79bb\u5212\u5206)\uff1a<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#%E8%AE%A1%E7%AE%97%E4%BF%A1%E9%81%93%E5%AE%B9%E9%87%8F%E7%9A%84%E5%85%AC%E5%BC%8F%E4%B8%8D%E6%98%8E%E8%A7%89%E5%8E%89%EF%BC%9A\" >\u8ba1\u7b97\u4fe1\u9053\u5bb9\u91cf\u7684\u516c\u5f0f(\u4e0d\u660e\u89c9\u5389)\uff1a<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Measuring_Real-World_Wireless_Performance\" >Measuring Real-World Wireless Performance<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Chapter_6_WiFi\" >Chapter 6 WiFi<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#From_Ethernet_to_a_Wireless_LAN\" >From Ethernet to a Wireless LAN<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#%E4%BB%A5%E5%A4%AA%E7%BD%91%E5%92%8CWifi%E5%AF%B9%E9%80%9A%E4%BF%A1%E8%80%85%E5%92%8C%E9%80%9A%E4%BF%A1%E6%97%B6%E6%9C%BA%E7%9A%84%E8%B0%83%E5%BA%A6\" >\u4ee5\u592a\u7f51\u548cWifi\u5bf9\u901a\u4fe1\u8005\u548c\u901a\u4fe1\u65f6\u673a\u7684\u8c03\u5ea6<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#WiFi%E6%A0%87%E5%87%86%E5%8F%8A%E5%85%B6%E7%89%B9%E6%80%A7\" >WiFi\u6807\u51c6\u53ca\u5176\u7279\u6027<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Measuring_and_Optimizing_WiFi_Performance\" >Measuring and Optimizing WiFi Performance<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Chapter_7_Mobile_Networks\" >Chapter 7 Mobile Networks<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Brief_Historynof_the_Gs\" >Brief Historynof the G&#8217;s<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#First_Data_Services_with_2G\" >First Data Services with 2G<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#3GPP_and_3GPP2_Partnerships\" >3GPP and 3GPP2 Partnerships<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Evolution_of_3G_Technologies\" >Evolution of 3G Technologies<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Evolution_of_3GPP_technologies\" >Evolution of 3GPP technologies<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Evolution_of_3GPP2_technologies\" >Evolution of 3GPP2 technologies<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#IMT-Advanced_4G_Requirements\" >IMT-Advanced 4G Requirements<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Long_Term_EvolutionLTE\" >Long Term Evolution(LTE)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#HSPA_is_Leading_Worldwide_4G_Adoption\" >HSPA+ is Leading Worldwide 4G Adoption<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Building_for_the_Multigeneration_Future\" >Building for the Multigeneration Future<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Device_Features_and_Capabilities\" >Device Features and Capabilities<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#User_Equipment_Category\" >User Equipment Category<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Radio_Resource_ControllerRRC\" >Radio Resource Controller(RRC)<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-24\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#3G4G_and_WiFi_Power_Requierments\" >3G,4G, and WiFi Power Requierments<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-25\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#LTE_RRC_State_Machine\" >LTE RRC State Machine<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-26\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#HSPA_and_HSPAUMTSRRC_State_Machine\" >HSPA and HSPA+(UMTS)RRC State Machine<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-27\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#EV-DOCDMA_RRC_State_Machine\" >EV-DO(CDMA) RRC State Machine<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-28\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Inefficiency_of_Periodic_Transfers\" >Inefficiency of Periodic Transfers<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-29\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#End-to-End_Carrier_Architecture\" >End-to-End Carrier Architecture<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-30\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Radio_Access_NetworkRAN\" >Radio Access Network(RAN)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-31\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Core_NetworkCN\" >Core Network(CN)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-32\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Backhaul_Capacity_and_Latency\" >Backhaul Capacity and Latency<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-33\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Packet_Flow_in_a_Mobile_Network\" >Packet Flow in a Mobile Network<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-34\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Initiating_a_Request\" >Initiating a Request<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-35\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Inbound_Data_Flow\" >Inbound Data Flow<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-36\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Heterogeneous_NetworksHetNets\" >Heterogeneous Networks(HetNets)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-37\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Real-World_3G_4G_and_WiFi_Performance\" >Real-World 3G, 4G and WiFi Performance<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-38\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Chapter_8_Optimizing_for_Mobile_Networks\" >Chapter 8 Optimizing for Mobile Networks<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-39\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Preserve_Battery_Power\" >Preserve Battery Power<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-40\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Eliminate_Periodic_and_Inefficient_Data_Transfer\" >Eliminate Periodic and Inefficient Data Transfer<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-41\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Eliminate_Unnecessary_Application_Keepalives\" >Eliminate Unnecessary Application Keepalives<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-42\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Anticipate_Network_Latency_Overhead\" >Anticipate Network Latency Overhead<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-43\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Account_for_RRC_State_Transitions\" >Account for RRC State Transitions<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-44\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Decouple_User_Interactions_from_Network_Communication\" >Decouple User Interactions from Network Communication<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-45\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Design_for_Variable_Network_Interface_Availability\" >Design for Variable Network Interface Availability<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-46\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Burst_Your_Data_and_Return_to_Idle\" >Burst Your Data and Return to Idle<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-47\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Offload_to_WiFi_Networks\" >Offload to WiFi Networks<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-48\" href=\"https:\/\/blog.cauchyschwarz.com\/?p=909\/#Apply_Protocol_and_Applicationo_Best_Practices\" >Apply Protocol and Applicationo Best Practices<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1 class=\"wp-block-heading\" id=\"chapter-5-introduction-to-wireless-networks\"><span class=\"ez-toc-section\" id=\"Chapter_5_Introduction_to_Wireless_Networks\"><\/span>Chapter 5 Introduction to Wireless Networks<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"%E6%97%A0%E7%BA%BF%E7%BD%91%E7%BB%9C%E7%9A%84%E7%B1%BB%E5%9E%8B%E6%8C%89%E8%B7%9D%E7%A6%BB%E5%88%92%E5%88%86\"><span class=\"ez-toc-section\" id=\"%E6%97%A0%E7%BA%BF%E7%BD%91%E7%BB%9C%E7%9A%84%E7%B1%BB%E5%9E%8B%E6%8C%89%E8%B7%9D%E7%A6%BB%E5%88%92%E5%88%86%EF%BC%9A\"><\/span>\u65e0\u7ebf\u7f51\u7edc\u7684\u7c7b\u578b(\u6309\u8ddd\u79bb\u5212\u5206)\uff1a<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Type<\/th><th>Range<\/th><th>Applications<\/th><th>Standards<\/th><\/tr><\/thead><tbody><tr><td>Personal area network(PAN)<\/td><td>Within reach of person<\/td><td>Cable replacement for peripherals<\/td><td>Bluetooth, ZigBee, NFC<\/td><\/tr><tr><td>Local area network(LAN)<\/td><td>Within a building or campus<\/td><td>Wireless extension of wired network<\/td><td>IEEE 802.11(WiFi)<\/td><\/tr><tr><td>Metropolitan area network(MAN)<\/td><td>Within a city<\/td><td>Wireless inter-network connectivity<\/td><td>IEEE 802.15(WiMAX)<\/td><\/tr><tr><td>Wide area network(WAN)<\/td><td>Worldwide<\/td><td>Wireless network access<\/td><td>Cellular(UMTS, LTE, etc)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"%E8%AE%A1%E7%AE%97%E4%BF%A1%E9%81%93%E5%AE%B9%E9%87%8F%E7%9A%84%E5%85%AC%E5%BC%8F%E4%B8%8D%E6%98%8E%E8%A7%89%E5%8E%89\"><span class=\"ez-toc-section\" id=\"%E8%AE%A1%E7%AE%97%E4%BF%A1%E9%81%93%E5%AE%B9%E9%87%8F%E7%9A%84%E5%85%AC%E5%BC%8F%E4%B8%8D%E6%98%8E%E8%A7%89%E5%8E%89%EF%BC%9A\"><\/span>\u8ba1\u7b97\u4fe1\u9053\u5bb9\u91cf\u7684\u516c\u5f0f(\u4e0d\u660e\u89c9\u5389)\uff1a<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\\( C=BW \\times \\log{2}{(1+\\frac{S}{N})} \\)<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>C<\/strong>&nbsp;is the channel capacity and is measured in bits persecond<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>BW<\/strong>&nbsp;is the available bandwidth, and is measured in hertz<\/li><li><strong>S<\/strong>&nbsp;is signal and&nbsp;<strong>N<\/strong>&nbsp;is noise, and they are measured in watts<\/li><\/ul>\n\n\n\n<p>\u5bf9\u4e8e\u4e0a\u8ff0\u516c\u5f0f\u4e2d\u51e0\u4e2a\u53d8\u91cf\u7684\u8fdb\u4e00\u6b65\u89e3\u91ca\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Bandwidth<\/strong><br>\u65e0\u7ebf\u7f51\u7edc\u901a\u8fc7\u7535\u78c1\u6ce2\u901a\u4fe1\uff0c\u901a\u4fe1\u8005\u9700\u8981\u5728\u901a\u4fe1\u524d\u7ea6\u5b9a\u597d\u901a\u4fe1\u7684\u9891\u7387\uff0c\u6bd4\u5982802.11b\u548c802.11g\u6807\u51c6\u4f7f\u75282.4-2.GHz\u9891\u6bb5\u3002\u7f8e\u56fd\u8054\u90a6\u901a\u4fe1\u59d4\u5458\u4f1a(Federal Communications Commission, FCC)\u8d1f\u8d23\u5212\u5206\u5404\u9891\u6bb5\u7684\u7528\u9014\u3002\u5982\u4e0a\u9762\u7684\u9999\u519c\u516c\u5f0f\u6240\u793a\uff0c\u901a\u4fe1\u9891\u6bb5\u7684\u5e26\u5bbd(bandwidth)\u4e0e\u4fe1\u9053\u4f20\u8f93\u901f\u7387\u6210\u6b63\u6bd4\u5173\u7cfb\uff0c802.11n\u5c31\u662f\u901a\u8fc7\u5c06\u4fe1\u9053\u5e26\u5bbd\u4ece20 MHz\u63d0\u5347\u523040 MHz\u628a\u6570\u636e\u4f20\u8f93\u901f\u7387\u52a0\u500d\u3002<br>\u4e0d\u540c\u9891\u7387\u7684\u65e0\u7ebf\u7535\u4fe1\u53f7\u6709\u7740\u4e0d\u540c\u7684\u7279\u6027\uff0c\u4f4e\u9891\u7387\u65e0\u7ebf\u7535\u4fe1\u53f7\u4f20\u64ad\u66f4\u8fdc\uff0c\u4f46\u662f\u9700\u8981\u66f4\u5927\u7684\u5929\u7ebf(\u6765\u4ea7\u751f\u4f4e\u9891\u7387\u65e0\u7ebf\u7535\u6ce2)\uff0c\u800c\u4e14(\u7531\u4e8e\u4f20\u8f93\u8303\u56f4\u66f4\u8fdc)\u4e0d\u540c\u901a\u4fe1\u8005\u4e4b\u95f4\u76f8\u4e92\u5e72\u6270\u7684\u6982\u7387\u52a0\u5927\u3002\u9ad8\u9891\u7387\u65e0\u7ebf\u7535\u4fe1\u53f7\u5c31\u6b63\u597d\u76f8\u53cd\u3002<br>\u4e0b\u56fe\u663e\u793a\u4e86FCC\u5212\u5b9a\u76842300-3000MHz\u65e0\u7ebf\u7535\u6ce2\u7684\u7528\u9014\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"1282\" class=\"wp-image-910\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/ISM.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/ISM.png 889w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/ISM-199x300.png 199w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/ISM-679x1024.png 679w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/ISM-768x1158.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/ISM-670x1011.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><br>\u4e0d\u540c\u56fd\u5bb6\u5bf9\u65e0\u7ebf\u7535\u9891\u7387\u7528\u9014\u5212\u5206\u53ef\u80fd\u4e0d\u540c\uff0c\u4f46\u662fISM(industrial, scientific, and medical)\u9891\u6bb5\u662f\u56fd\u9645\u901a\u7528\u7684\uff0c\u4e8e1947\u5e74\u901a\u8fc7International Telecommunications Conference\u786e\u5b9a\uff0cWiFi\u4f7f\u7528\u7684\u9891\u6bb5\u5c31\u662fISM\u9891\u6bb5\u7684\u4e00\u90e8\u5206\u3002ISM\u9891\u6bb5\u662f\u4efb\u4f55\u4eba\u53ef\u4ee5\u81ea\u7531\u4f7f\u7528\u7684\uff0c\u53ea\u8981\u9075\u5faa\u4e00\u4e9b\u6280\u672f\u9650\u5236(\u6bd4\u5982\u53d1\u5c04\u529f\u7387\u7684\u9650\u5236)\u3002<\/li><li><strong>Signal Power<\/strong><br>\u60f3\u8981\u63d0\u9ad8\u4fe1\u566a\u6bd4\uff0c\u90a3\u4e48\u8981\u4e48\u63d0\u9ad8\u53d1\u5c04\u529f\u7387\uff0c\u8981\u4e48\u51cf\u5c0f\u901a\u4fe1\u8005\u4e4b\u95f4\u7684\u8ddd\u79bb\uff0c\u6216\u8005\u51cf\u5c11\u4f7f\u7528\u901a\u9891\u6bb5\u65e0\u7ebf\u7535\u901a\u4fe1\u7684\u7528\u6237\u6570\u3002<\/li><li><strong>Modulation<\/strong><br>\u9891\u6bb5\u5e26\u5bbd\u548c\u4fe1\u566a\u6bd4\u662f\u4fe1\u9053\u5bb9\u91cf\u7684\u4e24\u4e2a\u4e3b\u8981\u7269\u7406\u5f71\u54cd\u56e0\u7d20\uff0c\u4f46\u662f\u901a\u4fe1\u8005\u4e4b\u95f4\u7684\u7f16\u7801\u4f20\u8f93\u4fe1\u53f7\u7684\u7b97\u6cd5\u4e5f\u5bf9\u4fe1\u9053\u5bb9\u91cf\u8d77\u7740\u91cd\u8981\u5f71\u54cd\u4f5c\u7528\u3002<br>\u6bd4\u5982\uff1a<ul><li>\u7535\u78c1\u6ce2\u4fe1\u53f7\u7684\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u6bcf\u79d2\u53ef\u4ee5\u5904\u74061000\u6b21\u7535\u78c1\u8109\u51b2\u4fe1\u53f7(modulation alphabets, baud)\uff1b<\/li><li>\u6bcf\u4e2a\u7535\u78c1\u8109\u51b2\u4fe1\u53f7\u4ee3\u8868\u4e00\u4e2a2\u4f4d\u7684alphabet\uff1b<\/li><li>\u90a3\u4e48\u8fd9\u4e2a\u4fe1\u9053\u7684\u5bb9\u91cf\u5c31\u662f1000x2bits\u6bcf\u79d2\uff0c\u53732000bps\uff1b \u60f3\u63d0\u9ad8\u6bcf\u4e2a\u7535\u78c1\u8109\u51b2\u4fe1\u53f7alphabet\u4ee3\u8868\u7684\u4fe1\u606f\u91cf\uff0c\u9700\u8981\u66f4\u9ad8\u7ea7\u7684\u8bbe\u5907\uff0c\u4f46\u4e5f\u4f1a\u5bfc\u81f4\u5bf9\u566a\u97f3\u7684\u6297\u5e72\u6270\u80fd\u529b\u53d8\u5f31\u3002<\/li><\/ul><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"measuring-real-world-wireless-performance\"><span class=\"ez-toc-section\" id=\"Measuring_Real-World_Wireless_Performance\"><\/span>Measuring Real-World Wireless Performance<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u5f71\u54cd\u4f60\u6b63\u5728\u4f7f\u7528\u7684\u65e0\u7ebf\u7f51\u7edc\u6027\u80fd\u7684\u4e00\u4e9b\u56e0\u7d20\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Amount of distance between receiver and sender<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Amount of background noise in current location<\/li><li>Amount of interference from users in the same network(intra-cell)<\/li><li>Amount of interference from users in other, nearby networks(inter-cell)<\/li><li>Amount of available transmit power, both at receiver and sender<\/li><li>Amount of processing power and the choosen modulation scheme<\/li><\/ul>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"chapter-6-wifi\"><span class=\"ez-toc-section\" id=\"Chapter_6_WiFi\"><\/span>Chapter 6 WiFi<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"from-ethernet-to-a-wireless-lan\"><span class=\"ez-toc-section\" id=\"From_Ethernet_to_a_Wireless_LAN\"><\/span>From Ethernet to a Wireless LAN<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>802.11\u7684ISO\u4e03\u5c42\u6a21\u578b\u793a\u610f\u56fe\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"433\" class=\"wp-image-911\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model.png 2474w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model-300x153.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model-1024x522.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model-768x391.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model-1536x782.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model-2048x1043.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_iso_wifi_model-670x341.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"%E4%BB%A5%E5%A4%AA%E7%BD%91%E5%92%8Cwifi%E5%AF%B9%E9%80%9A%E4%BF%A1%E8%80%85%E5%92%8C%E9%80%9A%E4%BF%A1%E6%97%B6%E6%9C%BA%E7%9A%84%E8%B0%83%E5%BA%A6\"><span class=\"ez-toc-section\" id=\"%E4%BB%A5%E5%A4%AA%E7%BD%91%E5%92%8CWifi%E5%AF%B9%E9%80%9A%E4%BF%A1%E8%80%85%E5%92%8C%E9%80%9A%E4%BF%A1%E6%97%B6%E6%9C%BA%E7%9A%84%E8%B0%83%E5%BA%A6\"><\/span>\u4ee5\u592a\u7f51\u548cWifi\u5bf9\u901a\u4fe1\u8005\u548c\u901a\u4fe1\u65f6\u673a\u7684\u8c03\u5ea6<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u4ee5\u592a\u7f51\u534f\u8bae\u548cWifi\u534f\u8bae\u90fd\u5c06\u4f20\u8f93\u5a92\u4ecb\u5f53\u4f5c<strong>random access channel<\/strong>\uff0c\u5373\u6ca1\u6709\u4e00\u4e2a\u4e2d\u5fc3\u6765\u8c03\u5ea6\u63a7\u5236\u6bcf\u65f6\u6bcf\u523b\u54ea\u4e2a\u901a\u4fe1\u8005\u53ef\u4ee5\u5728\u8fd9\u4e2a\u5171\u4eab\u7684\u4f20\u8f93\u4ecb\u8d28\u4e0a\u4f20\u8f93\u6570\u636e\u3002\u4ee5\u592a\u7f51\u4f7f\u7528\u4e86CSMA(a probabilistic carrier sense multiple access)\u534f\u8bae\u6765\u8c03\u5ea6\u6bcf\u65f6\u6bcf\u523b\u7531\u7f51\u7edc\u4e2d\u7684\u54ea\u4e00\u4e2a\u8bbe\u5907\u6765\u4f20\u8f93\u6570\u636e\uff0c\u7b80\u8a00\u4e4b\u5c31\u662f&#8221;listen before you speak&#8221;\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Check whether anyone else is transmitting<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>if the channel is busy, listen until it is free<\/li><li>When the channel is free, transmit data immediately<\/li><\/ul>\n\n\n\n<p>\u7531\u4e8e\u4fe1\u53f7\u4f20\u8f93\u9700\u8981\u65f6\u95f4\uff0c\u6240\u4ee5\u4ecd\u7136\u5b58\u5728\u591a\u4e2a\u901a\u4fe1\u8005\u540c\u65f6\u4f20\u8f93\u6570\u636e\u53d1\u9001collision\u7684\u60c5\u51b5\uff0c\u6240\u4ee5\u4ee5\u592a\u7f51\u4e5f\u5f15\u5165\u4e86collision detection(CSMA\/CD)\uff0c\u5f53collision\u53d1\u751f\u7684\u65f6\u5019\uff0c\u540c\u65f6\u4f20\u8f93\u6570\u636e\u7684\u901a\u4fe1\u8005\u90fd\u7acb\u5373\u505c\u6b62\u4f20\u8f93\uff0c\u968f\u673a\u7b49\u5f85\u4e00\u6bb5\u65f6\u95f4(\u7ed3\u5408\u6307\u6570\u56de\u9000\u7684\u7b56\u7565)\u518d\u53d1\u9001\u6570\u636e\u3002<br>WiFi\u7f51\u7edc\u7c7b\u4f3c\uff0c\u4f46\u662fWiFi\u505a\u4e0d\u4e86collision detection\uff0c\u53ea\u80fd\u641ecollision avoidance(CSMA\/CA)\u3002WiFi\u4e2d\u7684\u901a\u4fe1\u8bbe\u5907\u6bcf\u6b21\u53d1\u9001\u4e00\u5e27\uff0c\u6536\u5230\u5176ack\u4e4b\u540e\u624d\u4f1a\u7ee7\u7eed\u53d1\u9001\u4e0b\u4e00\u5e27\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>In practice, the probabilistic access model works very well for lightly loaded networks. In fact, we won\u2019t show the math here, but we can prove that to get good channel utilization (minimize number of collisions), the channel load must be kept below 10%. If the load is kept low, we can get good throughput without any explicit coordination or scheduling. However, if the load increases, then the number of collisions will quickly rise, leading to unstable performance of the entire network.<\/p><\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"wifi%E6%A0%87%E5%87%86%E5%8F%8A%E5%85%B6%E7%89%B9%E6%80%A7\"><span class=\"ez-toc-section\" id=\"WiFi%E6%A0%87%E5%87%86%E5%8F%8A%E5%85%B6%E7%89%B9%E6%80%A7\"><\/span>WiFi\u6807\u51c6\u53ca\u5176\u7279\u6027<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>802.11 protocol<\/th><th>Release<\/th><th>Freq(GHz)<\/th><th>Bandwidth(MHz)<\/th><th>Data rate per stream<\/th><th>MAX MIMO streams<\/th><\/tr><\/thead><tbody><tr><td>b<\/td><td>Sep 1999<\/td><td>2.4<\/td><td>20<\/td><td>1,2,5.5,11<\/td><td>1<\/td><\/tr><tr><td>g<\/td><td>Jun 2003<\/td><td>2.4<\/td><td>20<\/td><td>6,9,12,18,24,36,48,54<\/td><td>1<\/td><\/tr><tr><td>n<\/td><td>Oct 2009<\/td><td>2.4<\/td><td>20<\/td><td>7.2,14.4,21.7,28.9,43.3,57.8,65,72.2<\/td><td>4<\/td><\/tr><tr><td>n<\/td><td>Oct 2009<\/td><td>5<\/td><td>40<\/td><td>15,30,45,60,90,120,135,150<\/td><td>4<\/td><\/tr><tr><td>ac<\/td><td>~2014<\/td><td>5<\/td><td>20,40,80,160<\/td><td>up to 866.7<\/td><td>8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>WiFi\u7684\u53d1\u5c04\u529f\u7387\u88ab\u9650\u5236\u5728200mW\u3002<br>\u6240\u4ee5\u60f3\u8981\u63d0\u9ad8WiFi\u7f51\u7edc\u7684\u6027\u80fd\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u4f7f\u7528\u9891\u6bb5\u5e26\u5bbd\u66f4\u5927\u7684\u4fe1\u9053(n,ac\u4e24\u4e2a\u6807\u51c6\u5c06\u4fe1\u9053\u5e26\u5bbd\u4ece20MHz\u63d0\u5347\u5230\u4e8640MHz)<\/li><li>\u4f7f\u7528\u66f4nb\u7684modulation(\u8ba9\u53d1\u9001\u7684\u6bcf\u4e2a\u4fe1\u53f7\u643a\u5e26\u66f4\u591a\u7684\u4fe1\u606f)<\/li><li>\u540c\u65f6\u4f7f\u7528\u591a\u4e2a\u6d41(MIMO\uff0c\u8c8c\u4f3c\u9700\u8981WiFi\u6709\u591a\u4e2a\u5929\u7ebf\u540c\u65f6\u5728\u591a\u4e2a\u4fe1\u9053\u8fdb\u884c\u901a\u4fe1\u624d\u53ef\u4ee5)<br>\u4e0a\u9762\u8fd9\u4e9b\u90fd\u505a\u5230\u4e86\uff0c\u90a3\u4e48\u5c06\u53ef\u4ee5\u83b7\u5f97Gbps\u7ea7\u522b\u7684\u65e0\u7ebf\u7f51\u7edc\u4f20\u8f93\u901f\u7387\u3002<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"measuring-and-optimizing-wifi-performance\"><span class=\"ez-toc-section\" id=\"Measuring_and_Optimizing_WiFi_Performance\"><\/span>Measuring and Optimizing WiFi Performance<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4e0b\u9762\u7684\u4e24\u5f20\u56fe\u663e\u793a\u4e86\u67d0\u4e2a\u529e\u516c\u73af\u5883\u6216\u8005\u90fd\u5e02\u73af\u5883\u4e0b\u7684wifi\u626b\u63cf\u7ed3\u679c\u548cwifi\u901a\u4fe1\u7684\u9891\u6bb5\u3002\u4f7f\u7528\u540c\u4e00\u9891\u6bb5\u901a\u4fe1\u7684wifi\u4e4b\u95f4\u4e92\u4e92\u76f8\u5e72\u6270\u3002<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"302\" class=\"wp-image-912\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_inssider.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_inssider.png 953w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_inssider-300x107.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_inssider-768x273.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_inssider-670x238.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"205\" class=\"wp-image-913\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels.png 2487w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels-300x72.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels-1024x247.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels-768x186.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels-1536x371.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels-2048x495.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_wifi_channels-670x162.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<p>\u5728Android\u4e0a\u53ef\u4ee5\u4f7f\u7528WiFi Analyzer\u4e4b\u7c7b\u7684\u5e94\u7528\u83b7\u53d6\u8fd9\u79cd\u4fe1\u606f\uff1b\u800c\u5728Linux\u4e0a\uff0c\u53ef\u4ee5\u901a\u8fc7\u6267\u884c<code>nmcli d wifi<\/code>\u83b7\u53d6\u8fd9\u4e9b\u4fe1\u606f(nmcli\u770b\u8d77\u6765\u4e5f\u662f\u4e00\u4e2a\u5f88\u6709\u8da3\u7684\u547d\u4ee4)\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>WiFi\u4e0b\u7684\u4e22\u5305<br>\u867d\u7136WiFi\u7684CSMA\/CA\u7b56\u7565\u5728\u4fe1\u9053\u62e5\u6324\u7684\u65f6\u5019\u4f1a\u9020\u6210\u8f83\u591a\u7684collision\uff0c\u4f46\u662f\u8fd9\u5e76\u4e0d\u610f\u5473\u7740WiFi\u4e0b\u7684TCP\u4f20\u8f93\u4e00\u5b9a\u4f1a\u8868\u73b0\u51fa\u66f4\u9ad8\u7684\u4e22\u5305\u7387\uff0c\u56e0\u4e3aWiFi\u4e0b\u7684\u6570\u636e\u94fe\u8def\u5c42\u548c\u7269\u7406\u5c42\u6709\u81ea\u5df1\u7684\u91cd\u4f20\u673a\u5236\u548cerror correction\u673a\u5236\u3002<\/li><li>WiFi\u4e0b\u7684latency<br>\u540c\u4e0a\u8ff0\u7406\u7531\uff0cWiFi\u4e0b\u7684latency(\u5c24\u5176\u662f\u7528\u6237\u5230ap\u7684\u8fd9\u4e00\u8df3)\u662f\u5bb9\u6613\u56e0\u4e3a\u4fe1\u9053\u7684\u72b6\u51b5\u53d1\u751f\u53d8\u5316\u7684\uff0c\u53ef\u4ee5\u89c2\u5bdf\u5230long latency tail\u3002\u90a3\u4e48BBR\u80fd\u6b63\u786e\u5904\u7406WiFi\u7684\u8fd9\u79cdvariable latency\u7279\u6027\u5417\uff1fBBR\u4e0d\u662f\u5c06latency\u5f53\u4f5c\u6574\u4e2a\u94fe\u8def\u4e2d\u8def\u7531\u91cc\u7684\u7f13\u5b58\u961f\u5217\u957f\u5ea6\u7684\u8868\u73b0\u5417\uff1f<\/li><li>WiFi\u4e0b\u7684\u5e26\u5bbd<br>\u4ecd\u7136\u540c\u4e0a\u8ff0\u7406\u7531\uff0cWiFi\u4e0b\u7684\u5e26\u5bbd(\u7528\u6237\u5230ap\u7684\u5e26\u5bbd)\u4e5f\u662f\u5728\u4e0d\u65ad\u53d1\u751f\u53d8\u5316\u7684\u3002\u4e0d\u8fc7\u5728\u8de8\u8d8a\u6574\u4e2a\u4e92\u8054\u7f51\u7684\u4f20\u8f93\u8fc7\u7a0b\u4e2d\uff0c\u8fd9\u4e2a\u5e26\u5bbd\u5e94\u8be5\u4e0d\u81f3\u4e8e\u6210\u4e3a\u94fe\u8def\u7684\u74f6\u9888\u5e26\u5bbd\u5427\uff1f<\/li><\/ul>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"chapter-7-mobile-networks\"><span class=\"ez-toc-section\" id=\"Chapter_7_Mobile_Networks\"><\/span>Chapter 7 Mobile Networks<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"brief-historynof-the-gs\"><span class=\"ez-toc-section\" id=\"Brief_Historynof_the_Gs\"><\/span>Brief Historynof the G&#8217;s<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Generation<\/th><th>Peak data rate<\/th><th>Description<\/th><\/tr><\/thead><tbody><tr><td>1G<\/td><td>no data<\/td><td>Analog systems<\/td><\/tr><tr><td>2G<\/td><td>Kbit\/s<\/td><td>First digital systems as overlays or parallel to analog systems<\/td><\/tr><tr><td>3G<\/td><td>Mbit\/s<\/td><td>Dedicated digital networks deployed in parallel to analog systems<\/td><\/tr><tr><td>4G<\/td><td>Gbit\/s<\/td><td>Digital and packet-only networks<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Generation<\/th><th>Data rate<\/th><th>Latency<\/th><\/tr><\/thead><tbody><tr><td>2G<\/td><td>100-400Kbit\/s<\/td><td>300-1000ms<\/td><\/tr><tr><td>3G<\/td><td>0.5-5Mbit\/s<\/td><td>100-500ms<\/td><\/tr><tr><td>4G<\/td><td>1-50Mbit\/s<\/td><td>&lt;100ms<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"first-data-services-with-2g\"><span class=\"ez-toc-section\" id=\"First_Data_Services_with_2G\"><\/span>First Data Services with 2G<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>1979\u5e74\u7b2c\u4e00\u4e2a\u5546\u75281G\u7f51\u7edc\u8bde\u751f\u4e8e\u65e5\u672c\uff0c\u8fd9\u662f\u4e00\u4e2a\u6ca1\u6709\u6570\u636e\u4f20\u8f93\u80fd\u529b\u7684\u6a21\u62df\u7cfb\u7edf(analog system)\u30021991\u5e74\u7b2c\u4e00\u4e2a2G\u7f51\u7edc\u5728\u82ac\u5170\u8bde\u751f\uff0c\u57fa\u4e8eGSM(Global System for Mobile Communications, originally Groupe Special Mobile)\u6807\u51c6\uff0c\u5e76\u4e14\u5728\u65e0\u7ebf\u7535\u7f51\u7edc\u4e2d\u5f15\u5165\u4e86\u7535\u5b50\u4fe1\u53f7\u3002\u8be5\u7f51\u7edc\u7b2c\u4e00\u6b21\u63d0\u4f9b\u4e86\u57fa\u4e8ecircuit-switched\u7684\u79fb\u52a8\u6570\u636e\u670d\u52a1\uff0c\u6bd4\u5982\u77ed\u4fe1(SMS)\uff0c\u4f20\u8f93\u6570\u636e\u7684\u901f\u7387\u6700\u9ad8\u4e3a9.6Kbit\/s\u3002<br>1990\u5e74\u4ee3\u4e2d\u671f\uff0cGPRS(General Packet Radio Service)\u88ab\u5f15\u5165GSM\u6807\u51c6\uff0c\u6700\u9ad8\u53ef\u4ee5\u63d0\u4f9b172Kbit\/s\u7684\u4f20\u8f93\u901f\u7387\uff0c\u4f34\u968f\u7740\u51e0\u767ems\u7684rtt\u3002GPRS\u548c2G\u8bed\u97f3\u901a\u4fe1\u7f51\u7edc\u5408\u5728\u4e00\u8d77\u88ab\u79f0\u4e3a2.5G\u30022003\u5e74\u5728\u7f8e\u56fd\u5219\u8bde\u751f\u4e86\u7b2c\u4e00\u4e2aEDGE(Enhanced Data rates for GSM Evolution)\u7f51\u7edc\uff0c\u79f0\u4e3a2.75G\uff0c\u53ef\u4ee5\u63d0\u4f9b\u8fbe384Kbit\/s\u7684\u6570\u636e\u4f20\u8f93\u901f\u7387\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"3gpp-and-3gpp2-partnerships\"><span class=\"ez-toc-section\" id=\"3GPP_and_3GPP2_Partnerships\"><\/span>3GPP and 3GPP2 Partnerships<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>2G\u6709\u4e24\u4e2a\u6807\u51c6\uff0c\u4e00\u4e2a\u662fETSI(European Telecommunication Standards Institute)\u5236\u5b9a\uff0c\u4e00\u4e2a\u662f\u9ad8\u901a\u5236\u5b9a(IS-95\u6807\u51c6)\uff0c\u524d\u8005\u536080%-85%\u5e02\u573a\u4efd\u989d\uff0c\u540e\u8005\u5219\u5360\u4e8610%-15%\u4efd\u989d\uff0c\u5e76\u4e14\u4e3b\u8981\u662f\u5360\u9886\u4e86\u7f8e\u56fd\u5e02\u573a\u3002\u8fd9\u4e24\u4e2a\u6807\u51c6\u4e0d\u517c\u5bb9\uff0c\u5e76\u4e14\u7531\u8fd9\u4e24\u4e2a\u6807\u51c6\u51fa\u53d1\uff0c\u5206\u522b\u8bde\u751f\u4e86\u4e24\u4e2a\u4e0d\u540c\u7684\u7ec4\u7ec7\u6765\u5236\u5b9a\u66f4\u65b0\u7684\u7f51\u7edc\u901a\u4fe1\u6807\u51c6\u3002<br>\u4e0b\u56fe\u662f\u5404\u79cd\u901a\u4fe1\u6280\u672f\u7684\u5e02\u573a\u4efd\u989d\u53d8\u5316\u60c5\u51b5\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"453\" class=\"wp-image-914\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_market-share-mobile-standards.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_market-share-mobile-standards.png 957w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_market-share-mobile-standards-300x160.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_market-share-mobile-standards-768x409.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_market-share-mobile-standards-670x357.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>3rd Generation Partnership Project(3GPP)Responsible for developing the Universal Mobile Telecommunication System(UMTS), which is the 3G upgrade to GSM networks. Later, it also assumed maintenance of the GSM standard and development of the new LTE standards.<\/li><li>3rd Generation Partnership Project2(3GPP2)Responsible for developing the 3G specifications based on the CDMA2000 technology, which is a successor to the IS-95 standard developed by Qualcomm.<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Generation<\/th><th>Organization<\/th><th>Release<\/th><\/tr><\/thead><tbody><tr><td>2G<\/td><td>3GPP<\/td><td>GSM<\/td><\/tr><tr><td>2G<\/td><td>3GPP2<\/td><td>IS-95(cdmaOne)<\/td><\/tr><tr><td>2.5G,2.75G<\/td><td>3GPP<\/td><td>GPRS,EDGE(EGPRS)<\/td><\/tr><tr><td>2.5G,2.75G<\/td><td>3GPP2<\/td><td>CDMA2000<\/td><\/tr><tr><td>3G<\/td><td>3GPP<\/td><td>UMTS<\/td><\/tr><tr><td>3G<\/td><td>3GPP2<\/td><td>CDMA2000 1x EV-DO Release 0<\/td><\/tr><tr><td>3G,3.75G,3.9G<\/td><td>3GPP<\/td><td>HSPA,HSPA+,LTE<\/td><\/tr><tr><td>3G,3.75G,3.9G<\/td><td>3GPP2<\/td><td>EV-DO Revision A, EV-DO Revision B, EV-DO Advanced<\/td><\/tr><tr><td>4G<\/td><td>3GPP<\/td><td>LTE-Advanced, HSPA+ Revision 11+<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>HSPA(High Speed Packet Access network)\u662f\u6307\u540c\u65f6\u652f\u6301HSDPA(High Speed Downlink Packet Access)\u548cHSUPA(High Speed Uplink Packet Access)\u7684\u7f51\u7edc\uff0c\u901a\u5e38\u79f0\u4e4b\u4e3a3.5G\uff0c\u53ef\u4ee5\u63d0\u4f9b\u4e0aMbit\/s\u7684\u901f\u7387\u3002HSPA+\u5219\u88ab\u79f0\u4e4b\u4e3a3.75G\u3002<\/p>\n\n\n\n<p>\u5728\u79fb\u52a8\u65e0\u7ebf\u5de5\u4e1a\u754c\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>There are two dominant, deployed mobile network types around the world<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>3GPP and 3GPP2 manage the evolution of each technology<\/li><li>3GPP and 3GPP2 standards are not device interoperable<\/li><\/ul>\n\n\n\n<p>\u4e0d\u5b58\u5728\u5355\u4e00\u76844G\u62163G\u6280\u672f\uff0cITU(International Telecommunication Union)\u53ea\u4e3a\u6bcf\u4e00\u4ee3\u65e0\u7ebf\u901a\u4fe1\u6280\u672f\u8bbe\u5b9a\u6027\u80fd\u4e0a\u9700\u8981\u6ee1\u8db3\u7684\u8981\u6c42\uff0c\u800c3GPP\u548c3GPP2\u4e24\u4e2a\u7ec4\u5219\u6839\u636e\u4ed6\u4eec\u5404\u81ea\u7684\u6280\u672f\u53bb\u5236\u5b9a\u5177\u4f53\u7684\u6807\u51c6\u3002<br>\u4f7f\u7528\u4e86SIM\u5361\u7684\u624b\u673a\u662f\u5728\u4f7f\u7528GSM\u6f14\u5316\u800c\u6765\u7684\u75313GPP\u5236\u5b9a\u7684\u6280\u672f\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"evolution-of-3g-technologies\"><span class=\"ez-toc-section\" id=\"Evolution_of_3G_Technologies\"><\/span>Evolution of 3G Technologies<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>3G\u6280\u672f\u6709\u4e24\u4e2a\u4e3b\u6d41\u7684\u6807\u51c6\uff0c\u75313GPP\u53d1\u5c55\u7684UMTS\u548c\u75313GPP2\u53d1\u5c55\u7684\u57fa\u4e8eCDMA\u7684\u7f51\u7edc\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"evolution-of-3gpp-technologies\"><span class=\"ez-toc-section\" id=\"Evolution_of_3GPP_technologies\"><\/span>Evolution of 3GPP technologies<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Release<\/th><th>Date<\/th><th>Summary<\/th><\/tr><\/thead><tbody><tr><td>99<\/td><td>1999<\/td><td>First release of the UMTS standard<\/td><\/tr><tr><td>4<\/td><td>2001<\/td><td>Introduced an all-IP core network<\/td><\/tr><tr><td>5<\/td><td>2002<\/td><td>Introduced High-Speed Packet Downlink Access(HSDPA)<\/td><\/tr><tr><td>6<\/td><td>2004<\/td><td>Introduced High-Speed Packet Uplink Access(HSUPA)<\/td><\/tr><tr><td>7<\/td><td>2007<\/td><td>Introduced High-Speed Packet Access Evolution(HSPA+)<\/td><\/tr><tr><td>8<\/td><td>2008<\/td><td>Introduced new LTE System Architecture Evolution(SAE)<\/td><\/tr><tr><td>9<\/td><td>2009<\/td><td>Improvements to SAE and WiMAX interoperability<\/td><\/tr><tr><td>10<\/td><td>2010<\/td><td>Introduced 4G LTE-Advanced architecture<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"evolution-of-3gpp2-technologies\"><span class=\"ez-toc-section\" id=\"Evolution_of_3GPP2_technologies\"><\/span>Evolution of 3GPP2 technologies<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>CDMA2000 EV-DO\u6807\u51c6\u7684\u53d1\u5c55\u5386\u7a0b\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>Release<\/th><th>Date<\/th><th>Summary<\/th><\/tr><\/thead><tbody><tr><td>Rel.0<\/td><td>1999<\/td><td>First release of the 1x EV-DO standard<\/td><\/tr><tr><td>Rel.A<\/td><td>2001<\/td><td>Upgrade to peak data-rate, lower latency, and QoS<\/td><\/tr><tr><td>Rel.B<\/td><td>2004<\/td><td>Introduced multicarrier capabilities to Rev.A<\/td><\/tr><tr><td>Rel.C<\/td><td>2007<\/td><td>Improved core network efficiency and performance<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>3GPP2\u6ca1\u6709\u76f8\u5e94\u76844G\u6807\u51c6\uff0c\u56e0\u4e3a\u6700\u540e\u5168\u7403\u7684\u8fd0\u8425\u5546\u90fd\u540c\u610f\u5c063GPP LTE\u6807\u51c6\u4f5c\u4e3a\u6240\u6709\u7f51\u7edc\u8981\u91c7\u7528\u76844G\u6807\u51c6\u3002\u6362\u53e5\u8bdd\u8bf4\uff0c\u8fd0\u8425\u5546\u90fd\u9010\u6e10\u6536\u655b\u5230HSPA+\u548cLTE\u8fd9\u4e24\u4e2a\u65e0\u7ebf\u7f51\u7edc\u6807\u51c6\u4e86\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"imt-advanced-4g-requirements\"><span class=\"ez-toc-section\" id=\"IMT-Advanced_4G_Requirements\"><\/span>IMT-Advanced 4G Requirements<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u548c3G\u4e00\u6837\uff0c4G\u4e5f\u4e0d\u662f\u4e00\u79cd\u5355\u4e00\u7684\u6280\u672f\uff0c\u53ea\u8981\u6ee1\u8db3ITU\u4e8e2008\u5e74\u53d1\u5e03\u7684IMT-Advanced 4G\u6807\u51c6\u7684\u6280\u672f\u5c31\u662f4G\u3002\u8fd9\u4e2a\u6807\u51c6\u7684\u4e00\u4e9b\u8981\u6c42\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Based on an IP packet switched network<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Interoperable with previous wireless standards(3G and 2G)<\/li><li>100Mbit\/s data rate for mobile clients and Gbit\/s+ when staionary<\/li><li>Sub 100 ms control-plane latency and sub 10 ms user-plane latency<\/li><li>Dynamic allocation and sharing of network resources between users<\/li><li>Use of variable bandwidth allocation, from 5 to 20 MHz<\/li><\/ul>\n\n\n\n<p>LTE-Advanced \u662f\u4e13\u95e8\u53d1\u5c55\u51fa\u6765\u6ee1\u8db3IMT-Advanced 4G\u8981\u6c42\u7684\u6280\u672f\uff0c\u4e5f\u662f3GPP\u7684\u7b2c\u4e00\u4e2a\u6ee1\u8db34G\u6807\u51c6\u7684\u6280\u672f\u3002LTE(release 8)\u548cLTE-Advanced(release 10)\u6280\u672f\u867d\u7136\u540d\u5b57\u770b\u8d77\u6765\u5f88\u50cf\uff0c\u4f46\u5b9e\u9645\u4e0a\u662f\u4e0d\u540c\u7684\u6280\u672f\uff0cLTE(release 8)\u4ecd\u7136\u662f3G\uff0c\u6216\u8005\u53ef\u4ee5\u79f0\u4e3a\u54114G\u8fc7\u6e21\u76843.9G\u6280\u672f\u3002LTE\u548cHSPA+\u6280\u672f\u4e5f\u5e38\u88ab\u79f0\u4e3a\u201c4G\u201d\u6280\u672f\uff0c\u8fd9\u662f\u8fd0\u8425\u5546\u5728\u5e02\u573a\u8425\u9500\u4e0a\u7684\u80dc\u5229(\u8fd9\u4e24\u4e2a\u6280\u672f\u4e5f\u786e\u5b9e\u5f88\u63a5\u8fd14G)\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"long-term-evolutionlte\"><span class=\"ez-toc-section\" id=\"Long_Term_EvolutionLTE\"><\/span>Long Term Evolution(LTE)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>All IP core netwrok<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Simplified network architecture to lower costs<\/li><li>Low latencies in user(&lt;10ms) and control planes(&lt;100ms)<\/li><li>New radio interface and modulation for high throughput(100Mbps)<\/li><li>Ability to use larger bandwidth allocations and carrier aggregation<\/li><li>MIMO as a requirement for all devices<\/li><\/ul>\n\n\n\n<p>LTE\u7f51\u7edc\u7684\u90e8\u7f72\u5e76\u4e0d\u662f\u5bf93G\u7f51\u7edc\u57fa\u7840\u8bbe\u65bd\u5347\u7ea7\u8fd9\u4e48\u7b80\u5355\uff0c\u800c\u662f\u9700\u8981\u90e8\u7f72\u548c\u73b0\u67093G\u57fa\u7840\u8bbe\u65bd\u5e76\u5b58\u7684\u65b0\u7684\u57fa\u7840\u8bbe\u65bd\uff0c\u5e76\u4e14\u9700\u8981\u548c\u73b0\u67093G\u7f51\u7edc\u5de5\u4f5c\u5728\u4e0d\u540c\u7684\u9891\u6bb5\u4e0a\u3002LTE\u4f5c\u4e3aUMTS\u548cCDMA\u4e24\u79cd\u6807\u51c6\u7684\u5171\u540c\u7ee7\u4efb\u8005\uff0c\u63d0\u4f9b\u4e86\u7528\u6237\u57283G\u7f51\u7edc\u548cLTE\u4e4b\u95f4\u6765\u56de\u5207\u6362\u7684\u80fd\u529b\u3002<br>LTE\u7684\u90e8\u7f72\u662f\u4e00\u4e2a\u6f2b\u957f\u7684\u8fc7\u7a0b\uff0c\u56e0\u4e3a\u9700\u8981\u5168\u65b0\u7684\u57fa\u7840\u8bbe\u65bd\u4e0a\u7684\u6295\u5165\u3002<br>\u5bf9\u4e8e\u652f\u6301LTE\u7684\u8bbe\u5907\uff0c\u8981\u5b9e\u73b0MIMO\uff0c\u5c31\u5fc5\u987b\u5f97\u6709\u591a\u4e2a\u5929\u7ebf\uff1b2G\uff0c3G\u548cLTE\u4e5f\u9700\u8981\u4e0d\u540c\u7684\u5929\u7ebf\uff0c\u6240\u4ee5\u624b\u673a\u5982\u679c\u652f\u6301MIMO\u7684\u8bdd\uff0c\u90a3\u4e48\u624b\u673a\u4e0a\u5c31\u53ef\u80fd\u6709\u81f3\u5c114\u4e2a\u5929\u7ebf\u3002<a href=\"https:\/\/www.howtogeek.com\/394266\/what-is-4x4-mimo-and-does-my-smartphone-need-it\/\">\u5173\u4e8eMIMO\u7684\u7b80\u5355\u4ecb\u7ecd<\/a>\u3002\u9664\u4e86\u5c4f\u5e55\uff0c\u5904\u4e8eactive\u72b6\u6001\u7684\u624b\u673a\u5929\u7ebf\u662f\u7b2c\u4e8c\u8017\u7535\u5927\u6237\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"hspa-is-leading-worldwide-4g-adoption\"><span class=\"ez-toc-section\" id=\"HSPA_is_Leading_Worldwide_4G_Adoption\"><\/span>HSPA+ is Leading Worldwide 4G Adoption<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7531\u4e8eLTE\u9700\u8981\u5168\u65b0\u7684\u57fa\u7840\u8bbe\u65bd\uff0c\u5bf9\u4e8e\u8fd0\u8425\u5546\u6765\u8bf4\u9700\u8981\u7684\u6295\u5165\u5f88\u5927\u3002\u4e8e\u662f\u5728\u539f\u67093G\u7f51\u7edc\u4e0a\u8fdb\u884c\u5347\u7ea7\u7684HSPA+\u6280\u672f\u4e5f\u6210\u4e3a\u4e86\u4e3b\u6d41\u4e4b\u4e00\u3002\u5404\u79cd\u7f51\u7edc\u6280\u672f\u7684\u53d8\u5316\u8d8b\u52bf\u662f\uff1a\u57fa\u4e8eCMDA\u7684\u9010\u6e10\u51cf\u5c11\uff1bHSPA+\u6210\u4e3a\u4e00\u6bb5\u65f6\u95f4\u7684\u4e3b\u6d41\uff1bLTE\u5219\u662f\u968f\u7740\u8fd0\u8425\u5546\u5bf9\u7f51\u7edc\u57fa\u7840\u8bbe\u65bd\u7684\u6295\u5165\u4e5f\u9010\u6e10\u6210\u4e3a\u4e3b\u6d41\uff0c\u6700\u7ec8\u8d85\u8fc7HSPA+\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"building-for-the-multigeneration-future\"><span class=\"ez-toc-section\" id=\"Building_for_the_Multigeneration_Future\"><\/span>Building for the Multigeneration Future<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u867d\u71364G\u7f51\u7edc(\u5305\u542bLTE)\u5728\u4f20\u8f93IP\u6570\u636e\u5305\u65b9\u9762\u6709\u4e86\u5927\u7684\u63d0\u5347\uff0c\u4f46\u662f\u8bbd\u523a\u7684\u662f3G\u7f51\u7edc\u5374\u6bd44G\u66f4\u5584\u4e8e\u4f20\u9012\u8bed\u97f3\u901a\u4fe1\u7684\u6570\u636e\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th><\/th><th>HSPA+<\/th><th>LTE<\/th><th>LTE-Advanced<\/th><\/tr><\/thead><tbody><tr><td>Peak downlink speed(Mbit\/s)<\/td><td>168<\/td><td>300<\/td><td>3000<\/td><\/tr><tr><td>Peak uplink speed(Mbit\/s)<\/td><td>22<\/td><td>75<\/td><td>1500<\/td><\/tr><tr><td>Maximum MIMO streams<\/td><td>2<\/td><td>4<\/td><td>8<\/td><\/tr><tr><td>Idle to connected latency(ms)<\/td><td>&lt;100<\/td><td>&lt;100<\/td><td>&lt;50<\/td><\/tr><tr><td>Dormant to active latency(ms)<\/td><td>&lt;50<\/td><td>&lt;50<\/td><td>&lt;10<\/td><\/tr><tr><td>User-plane one-way latency(ms)<\/td><td>&lt;10<\/td><td>&lt;5<\/td><td>&lt;5<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><strong>User-Plane One-Way Latency<\/strong>\uff1a<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>User-plane one-way latency is the target time specified by the LTE standard for the one-way transit between a packet being available in the wireless device and the same packet being available at the radio tower. In other words, it is the one-way latency of the first wirelss hop when the device is in the high-power continuous reception state. Every application packet will incur this cost-no shortcuts.<\/p><\/blockquote>\n\n\n\n<p>\u5c31\u662f\u4e00\u4e2a\u6570\u636e\u5305\u4ece\u79fb\u52a8\u8bbe\u5907(\u8bbe\u5907\u5904\u4e8e\u6b63\u5e38\u8017\u7535\u72b6\u51b5\u4e0b)\u5230\u7b2c\u4e00\u4e2a\u57fa\u7ad9\u9700\u8981\u7684\u65f6\u95f4\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"device-features-and-capabilities\"><span class=\"ez-toc-section\" id=\"Device_Features_and_Capabilities\"><\/span>Device Features and Capabilities<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"user-equipment-category\"><span class=\"ez-toc-section\" id=\"User_Equipment_Category\"><\/span>User Equipment Category<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Sample 3GPP HSPA user Equipment(UE) categories:<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>3GPP Release<\/th><th>Category<\/th><th>MIMO, Multicell<\/th><th>Peak data rate(Mbit\/s)<\/th><\/tr><\/thead><tbody><tr><td>5<\/td><td>8<\/td><td>&#8211;<\/td><td>7.2<\/td><\/tr><tr><td>5<\/td><td>10<\/td><td>&#8211;<\/td><td>14.0<\/td><\/tr><tr><td>7<\/td><td>14<\/td><td>&#8211;<\/td><td>21.1<\/td><\/tr><tr><td>8<\/td><td>20<\/td><td>2x MIMO<\/td><td>42.2<\/td><\/tr><tr><td>8<\/td><td>21<\/td><td>Dual-cell<\/td><td>23.4<\/td><\/tr><tr><td>8<\/td><td>24<\/td><td>Dual-cell<\/td><td>42.2<\/td><\/tr><tr><td>10<\/td><td>32<\/td><td>Quad-cell + MIMO<\/td><td>168.8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>LTE user equipment(UE) categories\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th>3GPP release<\/th><th>Category<\/th><th>MIMO<\/th><th>Peak downlink(Mbit\/s)<\/th><th>Peak uplink(Mbit\/s)<\/th><\/tr><\/thead><tbody><tr><td>8<\/td><td>1<\/td><td>1x<\/td><td>10.3<\/td><td>5.2<\/td><\/tr><tr><td>8<\/td><td>2<\/td><td>2x<\/td><td>51.0<\/td><td>25.5<\/td><\/tr><tr><td>8<\/td><td>3<\/td><td>2x<\/td><td>102.0<\/td><td>51.0<\/td><\/tr><tr><td>8<\/td><td>4<\/td><td>2x<\/td><td>150.8<\/td><td>51.0<\/td><\/tr><tr><td>8<\/td><td>5<\/td><td>4x<\/td><td>299.6<\/td><td>75.4<\/td><\/tr><tr><td>10<\/td><td>6<\/td><td>2x or 4x<\/td><td>301.5<\/td><td>51.0<\/td><\/tr><tr><td>10<\/td><td>7<\/td><td>2x or 4x<\/td><td>301.5<\/td><td>102.0<\/td><\/tr><tr><td>10<\/td><td>8<\/td><td>8x<\/td><td>2998.6<\/td><td>1497.8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u60f3\u8981\u4f60\u7684\u624b\u673a\u83b7\u5f97\u597d\u7684\u7f51\u7edc\u6027\u80fd\uff0c\u90a3\u4e48\u9700\u8981\u624b\u673a\u8bbe\u5907\u7684UE\u7248\u672c\u548c\u6240\u4f7f\u7528\u7684\u7f51\u7edc\u7248\u672c\u76f8\u5339\u914d\uff0c\u4e14\u90fd\u662f\u9ad8\u7248\u672c\u624d\u884c\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"radio-resource-controllerrrc\"><span class=\"ez-toc-section\" id=\"Radio_Resource_ControllerRRC\"><\/span>Radio Resource Controller(RRC)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>Radio Resource Controller\uff1a\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"459\" class=\"wp-image-915\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController.png 2480w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController-300x162.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController-1024x552.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController-768x414.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController-1536x829.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController-2048x1105.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioResourceController-670x361.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"3g4g-and-wifi-power-requierments\"><span class=\"ez-toc-section\" id=\"3G4G_and_WiFi_Power_Requierments\"><\/span>3G,4G, and WiFi Power Requierments<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5bf9\u4e8e\u4f7f\u7528WiFi\u7684\u79fb\u52a8\u8bbe\u5907\u6765\u8bf4\uff0c\u5929\u7ebf\u7684\u529f\u7387\u7531\u8bbe\u5907\u81ea\u5df1\u51b3\u5b9a\uff0c\u901a\u5e38\u572830-200mW\u8fd9\u4e2a\u8303\u56f4\uff1b\u800c\u4f7f\u75283G\/4G\u7684\u8bbe\u5907\uff0c\u5929\u7ebf\u7684\u529f\u7387\u5219\u7531\u57fa\u7ad9\u7f51\u7edc\u6765\u51b3\u5b9a\uff0c\u5728idle\u72b6\u6001\u4e0b\u7684\u8bbe\u5907\u5929\u7ebf\uff0c\u5176\u529f\u7387\u53ef\u4ee5\u4f4e\u81f315mW\uff0c\u4f46\u662f\u5728high-power\u72b6\u6001\u4e0b\uff0c\u5176\u529f\u7387\u4e5f\u53ef\u4ee5\u8fbe\u52301000-3500mW\u3002<br>\u5728\u4f20\u8f93\u5927\u91cf\u6570\u636e\u7684\u65f6\u5019\uff0c\u5982\u679c\u4fe1\u53f7\u597d\uff0cWiFi\u66f4\u8282\u80fd\uff0c\u4f46\u662f\u5982\u679c\u8bbe\u5907\u5927\u591a\u6570\u65f6\u5019\u5904\u4e8e\u7a7a\u95f2\u72b6\u6001\uff0c\u90a3\u4e483G\/4G\u5929\u7ebf\u66f4\u8282\u80fd\u3002\u53ef\u662f\u73b0\u5728\u5e76\u6ca1\u6709\u53ef\u4ee5\u5728\u4e24\u79cd\u7f51\u7edc\u4e0b\u81ea\u7531\u5207\u6362\u4ee5\u8fbe\u5230\u8282\u80fd\u76ee\u7684\u7684\u673a\u5236\u5b58\u5728\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"lte-rrc-state-machine\"><span class=\"ez-toc-section\" id=\"LTE_RRC_State_Machine\"><\/span>LTE RRC State Machine<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>LTE RRC State Machine\uff1a\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"453\" class=\"wp-image-917\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine.png 2483w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine-300x160.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine-1024x546.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine-768x409.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine-1536x818.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine-2048x1091.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTERRCStateMachine-670x357.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><br>\u6bcf\u4e00\u4e2aLTE\u8bbe\u5907\u7684\u5929\u7ebf\u72b6\u6001\u7531\u670d\u52a1\u8be5\u8bbe\u5907\u7684\u57fa\u7ad9\u63a7\u5236\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>RRC Idle<br>Device radio is in a low-power state(&lt;15mW) and only listening to control traffic. No radio resources are assigned to the client within the carrier network.<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>RRC Connected<br>Device radio is in a high-power state(1000-3500mW) while it either transmits data or waits for data, and dedicated radio resources are allocated by the radio network.<\/li><\/ul>\n\n\n\n<p>\u8bbe\u5907\u5904\u4e8eIDLE\u72b6\u6001\u65f6\uff0c\u662f\u4e0d\u80fd\u4f20\u8f93\u6570\u636e\u7684\uff0c\u60f3\u8981\u4f20\u8f93\u6570\u636e\u9700\u8981\u548c\u57fa\u7ad9\u901a\u4fe1\u53d8\u4e3aConnected\u72b6\u6001\uff0c\u800c\u8fd9\u4e2a\u8fc7\u7a0b\u57283GPP LTE\u7f51\u7edc\u4e2d\u9700\u8981\u6700\u591a100ms\uff0c\u5728LTE-Advanced\u7f51\u7edc\u4e2d\u9700\u8981\u6700\u591a50ms\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Continuous reception<br>Highest power state, established network context, allocated network resources<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Short Discoutinuous Reception(Short DRX)<br>Established network context, no allocated network resources<\/li><li>Long Discontinuous Reception(Long DRX)<br>Established network context, no allocated network resouces<\/li><\/ul>\n\n\n\n<p>Discontinuous Reception\uff1a\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"207\" class=\"wp-image-918\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception.png 2485w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception-300x73.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception-1024x249.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception-768x187.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception-1536x374.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception-2048x499.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_DiscontinuousReception-670x163.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th><\/th><th>LTE<\/th><th>LTE-Advanced<\/th><\/tr><\/thead><tbody><tr><td>Idle to connected latency<\/td><td>&lt;100ms<\/td><td>&lt;50ms<\/td><\/tr><tr><td>DRX to connected latency<\/td><td>&lt;50ms<\/td><td>&lt;50ms<\/td><\/tr><tr><td>User-plane one-way latency<\/td><td>&lt;5ms<\/td><td>&lt;5ms<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"hspa-and-hspaumtsrrc-state-machine\"><span class=\"ez-toc-section\" id=\"HSPA_and_HSPAUMTSRRC_State_Machine\"><\/span>HSPA and HSPA+(UMTS)RRC State Machine<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>LTE\u4e4b\u524d\u7684HSPA\u548cHSPA+\u7f51\u7edc\u7684RRC\u72b6\u6001\u673a\u66f4\u52a0\u590d\u6742\uff0c\u56e0\u4e3a\u66f4\u590d\u6742\u6240\u4ee5\u4e5f\u95f4\u63a5\u5bfc\u81f4\u4e86\u66f4\u9ad8\u7684\u5ef6\u65f6\u3002<br>HSPA\u548cHSPA+\u7684RRC\u72b6\u6001\u673a\uff1a\u00a0<img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"447\" class=\"wp-image-916\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine.png 2487w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine-300x158.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine-1024x538.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine-768x404.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine-1536x807.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine-2048x1076.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_UMTS-RRC-State-Machine-670x352.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Idle<br>Similar to idle in LTE. The device radio is in a low-power state and only listening to control traffic from the network. No radio resources are assigned to the client within the carrier network.<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Cell DCH<br>Similar to connected LTE mode when in continuous reception. The device is in a high-power state, and network resources are assigned both for upstream and downstream data transfer.<\/li><li>Cell FACH<br>An intermediate power state, which consumes significantly less power then DCH. The device does not have dedicated network resources but is nonetheless able to transmit small amounts of user data through a shared low-speed channel(with speeds of typically less than 20Kbps)<\/li><\/ul>\n\n\n\n<p>FACH\u72b6\u6001\u4e0b\uff0c\u8bbe\u5907\u4ecd\u7136\u53ef\u4ee5\u4ee5\u4e00\u4e2a\u8f83\u4f4e\u7684\u7a33\u5b9a\u7684\u901f\u7387\u4f20\u8f93\u6570\u636e\u3002<\/p>\n\n\n\n<p>\u4eceDCH\u5230FACH\u7684\u72b6\u6001\u8f6c\u6362\u662f\u9760\u7684timer\uff0c\u800c\u4eceFACH\u5230DCH\u7684\u72b6\u6001\u8f6c\u6362\u5219\u662f\u5728\u8bbe\u5907\u4e2dbuffer\u4e2d\u8981\u53d1\u9001\u7684\u6570\u636e\u8fbe\u5230\u67d0\u4e2a\u9608\u503c\u4e4b\u540e\u89e6\u53d1\u3002<br>LTE\u867d\u7136\u63d0\u4f9b\u7684\u4e2d\u95f4\u72b6\u6001\u6bd4HSPA,HSPA+\u591a\uff0c\u4f46\u662f\u7531\u4e8eLTE\u63d0\u4f9b\u7684\u6570\u636e\u4f20\u8f93\u901f\u7387\u66f4\u9ad8\uff0c\u6240\u4ee5LTE\u7684\u80fd\u8017\u4ecd\u7136\u66f4\u9ad8\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"ev-docdma-rrc-state-machine\"><span class=\"ez-toc-section\" id=\"EV-DOCDMA_RRC_State_Machine\"><\/span>EV-DO(CDMA) RRC State Machine<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>CDMA RRC\u72b6\u6001\u673a\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"451\" class=\"wp-image-919\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine.png 2466w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine-300x159.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine-1024x543.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine-768x407.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine-1536x815.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine-2048x1086.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CDMA-RRC-State-Machine-670x355.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Idle<br>Similar to idle in 3GPP standards. The device radio is in a low-power state and only listening to control traffic from the network. No radio resources are assigned to the client within the carrier network.<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Connected<br>Similar to connected LTE mode and DCH in HSPA. The device is in a high-power state and network resources are assigned for both upstream and downstream data transfers.<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"inefficiency-of-periodic-transfers\"><span class=\"ez-toc-section\" id=\"Inefficiency_of_Periodic_Transfers\"><\/span>Inefficiency of Periodic Transfers<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u4e00\u79cd\u8017\u7535\u5e76\u4e14\u7528\u6237\u4f53\u9a8c\u7cdf\u7cd5\u7684\u4f20\u8f93\u6570\u636e\u7684\u6a21\u5f0f\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"321\" class=\"wp-image-920\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail.png 2488w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail-300x113.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail-1024x387.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail-768x290.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail-1536x580.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail-2048x774.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_EnergyTail-670x253.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><br>\u6839\u636eATT\u5b9e\u9a8c\u5ba4\u7684\u7814\u7a76\uff0c46%\u7684\u5929\u7ebf\u6d88\u8017\u7684\u7535\u91cf\u53ea\u7528\u6765\u4f20\u8f93\u4e860.2%\u7684\u6570\u636e\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"end-to-end-carrier-architecture\"><span class=\"ez-toc-section\" id=\"End-to-End_Carrier_Architecture\"><\/span>End-to-End Carrier Architecture<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4e0b\u9762\u4ecb\u7ecd\u4e86\u4e00\u4e2aLTE\u7f51\u7edc\u7684\u5178\u578b\u6784\u6210\uff1a<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"radio-access-networkran\"><span class=\"ez-toc-section\" id=\"Radio_Access_NetworkRAN\"><\/span>Radio Access Network(RAN)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"475\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-1024x475.png\" alt=\"\" class=\"wp-image-921\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-1024x475.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-300x139.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-768x356.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-1536x713.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-2048x951.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_RadioAccessNetwork-670x311.png 670w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>&nbsp;eNodeB\u5c31\u662f\u57fa\u7ad9\u4e86\uff0c\u4e5f\u662fRadio Resource Controller\u3002\u5f53\u7528\u6237\u4ece\u4e00\u4e2a\u90bb\u8fd1\u57fa\u7ad9\u6536\u5230\u4e86\u66f4\u5f3a\u7684\u4fe1\u53f7\u6216\u8005\u7528\u6237\u5f53\u524d\u6240\u8fde\u63a5\u7684\u57fa\u7ad9\u8fc7\u8f7d\u65f6\uff0c\u7528\u6237\u5c31\u53ef\u80fd\u88ab\u5207\u6362\u5230\u53e6\u4e00\u4e2a\u57fa\u7ad9\u3002\u8fd9\u4e2a\u5207\u6362\u7684\u8fc7\u7a0b\u5f88\u590d\u6742\uff0c\u5728LTE\u7f51\u7edc\u4e2d\u8fd9\u4e2a\u8fc7\u7a0b\u53ef\u80fd\u9700\u8981\u51e0\u767e\u6beb\u79d2\uff0c\u800c\u5728\u66f4\u65e9\u7684\u7f51\u7edc\u4e2d\u8fd9\u4e2a\u8fc7\u7a0b\u53ef\u80fd\u9700\u8981\u957f\u8fbe\u51e0\u79d2\u3002\u8fd9\u4e2a\u5207\u6362\u8fc7\u7a0b\u4e5f\u4f1a\u9020\u6210\u6570\u636e\u4f20\u8f93\u7684\u505c\u6ede\uff0c\u4f1a\u88ab\u5e94\u7528\u7a0b\u5e8f\u548c\u7528\u6237\u611f\u77e5\u3002 \u5728\u57fa\u7ad9\u5bc6\u5ea6\u5927\u7684\u5730\u533a(\u57ce\u533a\u3001\u529e\u516c\u533a)\uff0c\u7528\u6237\u53ef\u80fd\u4f1a\u6765\u56de\u4e0d\u505c\u5730\u5728\u4e0d\u540c\u7684\u57fa\u7ad9\u63a7\u5236\u533a\u57df\u91cc\u7a7f\u68ad\uff0c\u800c\u7528\u6237\u5207\u6362\u57fa\u7ad9\u7684\u65f6\u5019\uff0c\u662f\u9700\u8981\u8bbe\u5907\u548c\u57fa\u7ad9\u901a\u4fe1\u7684\uff0c\u5373\u4f7f\u8bbe\u5907\u6b63\u5904\u4e8eRRC\u91cc\u7684IDLE\u72b6\u6001\uff0c\u4e5f\u5c31\u5bfc\u81f4\u4e86\u7528\u6237\u8bbe\u5907\u6d88\u8017\u66f4\u591a\u7684\u7535\u91cf\u3002\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u591a\u4e2a\u57fa\u7ad9\u5f62\u6210\u4e00\u4e2a&#8221;tracking area&#8221;\uff0ccore network\u5e76\u4e0d\u77e5\u9053\u7528\u6237\u8fde\u7684\u662f\u54ea\u4e00\u4e2a\u57fa\u7ad9\uff0c\u800c\u53ea\u77e5\u9053\u7528\u6237\u5728\u54ea\u4e2atracking area\u91cc\uff0c\u9700\u8981\u53d1\u7ed9\u7528\u6237\u7684\u6570\u636e\u5305\u5c31\u53d1\u7ed9tracking area\uff0ctracking area\u5185\u90e8\u518d\u51b3\u5b9a\u7531\u54ea\u4e00\u4e2a\u57fa\u7ad9\u628a\u6570\u636e\u53d1\u7ed9\u7528\u6237\u3002\u8fd9\u6837\u505a\u7684\u597d\u5904\u662f\u7528\u6237\u5728tracking area\u5185\u90e8\u7684\u4e0d\u540c\u57fa\u7ad9\u8303\u56f4\u5185\u5207\u6362\u65f6\uff0c\u5904\u4e8eRRC IDLE\u72b6\u6001\u7684\u8bbe\u5907\u4e0d\u5fc5\u518d\u56e0\u4e3a\u8fd9\u4e2a\u5207\u6362\u8fc7\u7a0b\u548c\u57fa\u7ad9\u8fdb\u884c\u901a\u4fe1\u4ece\u800c\u8282\u7701\u4e86\u7535\u91cf\uff0c\u574f\u5904\u5219\u662f\u5c06\u6570\u636e\u5305\u53d1\u7ed9\u7528\u6237\u65f6\u53ef\u80fd\u9700\u8981\u66f4\u9ad8\u7684\u5ef6\u8fdf\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"core-networkcn\"><span class=\"ez-toc-section\" id=\"Core_NetworkCN\"><\/span>Core Network(CN)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Core Network\u8d1f\u8d23routing, accounting and policy management\u3002\u5728LTE\u4e2d\uff0cCore Network\u4e5f\u79f0\u4e3aEvolved Packet Core(EPC)\u3002<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"416\" class=\"wp-image-922\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork.png 2486w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork-300x147.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork-1024x502.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork-768x376.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork-1536x753.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork-2048x1003.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_CoreNetwork-670x328.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><br>Packet gateway(PGW)\u5c06\u516c\u7f51\u548cCarrier Network\u76f8\u8fde\uff0cCarrier Network\u91cc\u7684\u8bbe\u5907\u7684IP\u5730\u5740\u7531PGW\u5206\u914d\u7ba1\u7406\u3002Carrier Network\u4e2d\u7684\u6bcf\u4e2a\u8bbe\u5907\u6709\u4e00\u4e2a\u5185\u90e8\u6807\u8bc6\u7b26\uff0c\u5f53PGW\u6536\u5230\u6570\u636e\u5305\u540e\uff0cPGW\u50cfNAT\u4e00\u6837\uff0c\u627e\u5230\u9700\u8981\u63a5\u6536\u8fd9\u4e2a\u6570\u636e\u5305\u7684\u8bbe\u5907\uff0c\u7136\u540e\u8fd9\u4e2a\u6570\u636e\u5305\u5c01\u88c5\u5e76\u901a\u8fc7\u7ba1\u9053\u53d1\u9001\u7ed9\u8be5\u8bbe\u5907\u3002\u5728Carrier Network\u5185\u90e8\uff0cLTE\u4f7f\u7528SCTP(Stream Control Transmission Protocol)\u6765\u4f20\u8f93control-plane\u7684\u6570\u636e\uff0c\u7528UDP\u548cGTP(GPRS Tunneling Protocol)\u6df7\u5408\u53d1\u9001\u5176\u4ed6\u6570\u636e\u3002<br>\u5728IPV4\u60c5\u51b5\u4e0b\uff0cPGW\u7c7b\u4f3cNAT\uff0c\u53ef\u80fd\u51e0\u5341\u4e0a\u767e\u4e2a\u8bbe\u5907\u5171\u7528\u4e86\u4e00\u4e2a\u516c\u7f51IP\u5730\u5740\uff0c\u4e00\u4e2a\u8bbe\u5907\u53ef\u80fd\u4f1a\u4f7f\u7528\u4e0d\u540c\u7684IP\u5730\u5740\u548c\u670d\u52a1\u5668\u901a\u4fe1\u3002\u800c\u5728IPV6\u60c5\u51b5\u4e0b\uff0c\u6bcf\u4e2a\u8bbe\u5907\u53ef\u80fd\u6700\u7ec8\u83b7\u5f97\u5c5e\u4e8e\u81ea\u5df1\u7684\u72ec\u7acbIP\u5730\u5740\u3002<br>\u5728PGW\u548c\u5e94\u7528\u7a0b\u5e8f\u7684TCP\u534f\u8bae\u4ecd\u7136\u4fdd\u6301\u7740\u8fde\u63a5\u7684\u540c\u65f6\uff0c\u8bbe\u5907\u5e95\u5c42\u7684\u5929\u7ebf\u662f\u53ef\u4ee5\u5904\u4e8eIDLE\u72b6\u6001\u7684\uff0c\u53ea\u8981\u6ca1\u6709\u6570\u636e\u9700\u8981\u53d1\u9001\u6216\u8005\u63a5\u6536\u3002\u800c\u5728\u9700\u8981\u4f20\u8f93\u6570\u636e\u7684\u65f6\u5019\uff0c\u4fbf\u662fRRC\u72b6\u6001\u673a\u8f6c\u6362\u7684\u8fc7\u7a0b\u4e86\u3002<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>The PGW also performs all the common policy enforcement, such as packet filtering and inspection, QoS assignment, DoS protection, and more. The Policy and Charging Rules Function(PCRF) component is responsible for maintaining and evaluating these rules for the packet gateway. PCRF is a logical component, meaning it can be part of the PGW, or it can stand on its own.<\/p><\/blockquote>\n\n\n\n<p>\u5f53PGW\u4ece\u516c\u7f51\u6536\u5230\u6570\u636e\u5305\u7684\u65f6\u5019\uff0c\u5b83\u5e76\u4e0d\u77e5\u9053\u7528\u6237\u7684\u4f4d\u7f6e\u6216\u8005\u5728\u54ea\u4e2a<em>tracking area<\/em>\u91cc\uff0c\u8fd9\u662fSGW(Serving Gateway)\u548cMME(Mobility Management Entity)\u9700\u8981\u89e3\u51b3\u7684\u95ee\u9898\u3002SGW\u5176\u5b9e\u4e5f\u53ef\u80fd\u4e0d\u77e5\u9053\u7528\u6237\u5728\u54ea\u91cc\uff0c\u5b83\u9700\u8981\u4ece\u4fdd\u5b58\u3001\u8ddf\u8e2a\u8fd9\u4e9b\u4fe1\u606f\u7684\u6570\u636e\u5e93MME\u91cc\u67e5\u8be2\u3002<\/p>\n\n\n\n<p>\u65e0\u8bba\u662f\u54ea\u4e00\u4ee3\u7684\u79fb\u52a8\u6570\u636e\u7f51\u7edc\uff0c\u5927\u4f53\u7ed3\u6784\u90fd\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Data arrives at the external packet gateway, which connects the core network to the public Internet.<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>A set of routing and packet policies is applied at the packet gateway.<\/li><li>Data is routed from the public gateway to one or more serving gateways, which act as mobility anchors for the devices within the radio network.<\/li><li>A user database service performs the authentication, billing, provisioning of services, and location tracking of each user on the network.<\/li><li>Once the location of the user within the radio network is determined, the data is routed from the serving gateway to the appropriate radio tower.<\/li><li>The radio tower performs the necessary resource assignment and negotiation with the target device and then delivers the data over the radio interface.<\/li><\/ul>\n\n\n\n<p>LTE\u7684EPC\u7684\u4e00\u4e2a\u7279\u6027\u662f\uff0c\u8be5carrier network\u662f\u57fa\u4e8eIP-only\u7684\u67b6\u6784\uff0c\u5e76\u4e14\u7528\u8fd9\u4e2a\u7edf\u4e00\u7684\u7f51\u7edc\u540c\u65f6\u4f20\u8f93\u6570\u636e\u548c\u97f3\u9891\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"backhaul-capacity-and-latency\"><span class=\"ez-toc-section\" id=\"Backhaul_Capacity_and_Latency\"><\/span>Backhaul Capacity and Latency<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u90e8\u7f724G\u4e0d\u53ea\u662f\u90e8\u7f72\u57fa\u7ad9\u8fd9\u4e48\u7b80\u5355\uff0c\u4e5f\u9700\u8981\u5347\u7ea7Core Network\u624d\u80fd\u652f\u6301\u76f8\u5e94\u7684throughput\u548clatency\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"packet-flow-in-a-mobile-network\"><span class=\"ez-toc-section\" id=\"Packet_Flow_in_a_Mobile_Network\"><\/span>Packet Flow in a Mobile Network<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"initiating-a-request\"><span class=\"ez-toc-section\" id=\"Initiating_a_Request\"><\/span>Initiating a Request<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>LTE request flow latencies:<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"596\" class=\"wp-image-923\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies.png 1901w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies-300x210.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies-1024x718.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies-768x539.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies-1536x1077.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Request-Flow-Latencies-670x470.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>In summary, a user initiating a new request incurs several different latencies:<\/p><\/blockquote>\n\n\n\n<ul class=\"wp-block-list\"><li>Control-plane latency<br>Fixed, one-time latency cost incurred for RRC negotiation and state transitions:&lt;100ms for idle to active, and &lt;50ms for dormant to active.<\/li><li>User-plane latency<br>Fixed cost for every application packet transferred between the device and the radio tower:&lt;5ms.<\/li><li>Core network latency<br>Carrier dependent cost for transporting the packet from the radio tower to the packet gateway: in practice, 30-100ms.<\/li><li>Internet routing latency<br>Variable latency cost between the carrier&#8217;s packet gateway and the destination address on the public Internet.<\/li><\/ul>\n\n\n\n<p>\u524d\u4e24\u4e2a\u5ef6\u65f6\u662f\u75314G\u6807\u51c6\u505a\u4e86\u9650\u5236\uff0c<em>Core network latency<\/em>\u5219\u4e0e<em>Carrier Network<\/em>\u5177\u4f53\u76f8\u5173\uff0c<em>Internet routing latency<\/em>\u5219\u53ef\u4ee5\u901a\u8fc7\u5c06\u4f60\u7684\u670d\u52a1\u5668\u90e8\u7f72\u7684\u66f4\u9760\u8fd1\u7528\u6237\u6765\u89e3\u51b3\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"inbound-data-flow\"><span class=\"ez-toc-section\" id=\"Inbound_Data_Flow\"><\/span>Inbound Data Flow<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>LTE Inbound Flow Latencies:<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"578\" class=\"wp-image-924\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency.png 1957w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency-300x204.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency-1024x696.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency-768x522.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency-1536x1045.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_LTE-Inbound-Flow-Latency-670x456.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"heterogeneous-networkshetnets\"><span class=\"ez-toc-section\" id=\"Heterogeneous_NetworksHetNets\"><\/span>Heterogeneous Networks(HetNets)<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"real-world-3g-4g-and-wifi-performance\"><span class=\"ez-toc-section\" id=\"Real-World_3G_4G_and_WiFi_Performance\"><\/span>Real-World 3G, 4G and WiFi Performance<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4e0b\u56fe\u663e\u793a\u4e86ATT\u5b9e\u9a8c\u5ba4\u548c\u5bc6\u6b47\u6839\u5927\u5b66\u8054\u5408\u505a\u7684\u4e00\u4e2a\u5b9e\u9a8c\uff0cWiFi\u548cLTE\u4ee5\u53ca\u5176\u4ed6\u65e0\u7ebf\u7f51\u7edc\u6807\u51c6\u7684\u6027\u80fd\u6bd4\u8f83\u7ed3\u679c\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"342\" class=\"wp-image-925\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_Wireless-Standards-Comparisons.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_Wireless-Standards-Comparisons.png 1071w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_Wireless-Standards-Comparisons-300x121.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_Wireless-Standards-Comparisons-1024x412.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_Wireless-Standards-Comparisons-768x309.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_Wireless-Standards-Comparisons-670x270.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<p>\u8fd9\u81f3\u5c11\u663e\u793a\u4e86\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0cLTE\u6216\u80054G\u53ef\u4ee5\u6bd4WiFi\u7684\u6027\u80fd\u66f4\u597d\u3002<\/p>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"chapter-8-optimizing-for-mobile-networks\"><span class=\"ez-toc-section\" id=\"Chapter_8_Optimizing_for_Mobile_Networks\"><\/span>Chapter 8 Optimizing for Mobile Networks<span class=\"ez-toc-section-end\"><\/span><\/h1>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"preserve-battery-power\"><span class=\"ez-toc-section\" id=\"Preserve_Battery_Power\"><\/span>Preserve Battery Power<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u4f7f\u7528att\u7684Video Optimizer\u6765\u5e2e\u52a9\u5206\u6790\u4f18\u5316\u4f60\u7684\u89c6\u9891\u5e94\u7528\uff0c\u8be5\u5de5\u5177\u901a\u8fc7vpn\u6536\u96c6\u79fb\u52a8\u8bbe\u5907\u7684\u7f51\u7edc\u6d3b\u52a8\u8bf7\u6c42\uff0c\u5e76\u4e14\u53ef\u4ee5\u8bb0\u5f55\u8bbe\u5907RRC\u7684\u72b6\u6001\u8f6c\u6362\u8fc7\u7a0b\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"eliminate-periodic-and-inefficient-data-transfer\"><span class=\"ez-toc-section\" id=\"Eliminate_Periodic_and_Inefficient_Data_Transfer\"><\/span>Eliminate Periodic and Inefficient Data Transfer<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u65e0\u8bba\u53d1\u9001\u6570\u636e\u91cf\u6709\u591a\u5c11\uff0c\u65e0\u7ebf\u8bbe\u5907\u5728\u7528\u65e0\u7ebf\u7535\u53d1\u9001\u6570\u636e\u65f6\u7684\u8017\u7535\u529f\u7387\u603b\u662f\u76f8\u540c\u7684\u3002\u8fd9\u5c31\u5bfc\u81f4\u4ee5\u4e0b\u51e0\u70b9\u9700\u8981\u5f15\u8d77\u6211\u4eec\u7684\u6ce8\u610f\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Polling is exceptionally expensive on mobile networks; minimize it;<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>Where possible, push delivery and notifications should be used;<\/li><li>Outbound and inbound requests shold be coalesced and aggregated;<\/li><li>Noncritical requests should be deferred until the radio is active;<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"eliminate-unnecessary-application-keepalives\"><span class=\"ez-toc-section\" id=\"Eliminate_Unnecessary_Application_Keepalives\"><\/span>Eliminate Unnecessary Application Keepalives<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>TCP\/UDP\u5c42\u9762\u7684\u8fde\u63a5\u72b6\u6001\u4e0e\u901a\u4fe1\u8bbe\u5907\u4e0a\u7684\u65e0\u7ebf\u8bbe\u5907\u7684\u72b6\u6001\u662f\u65e0\u5173\u7684\uff1a<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\"><p>the radio can be in a low-power state while the connections are maintained by the carrier network. Then when a new packet arrives form the external network, the carrier radio network will notify the device, promote its radio to a connected state, and resume the data transfer.<br>The application does not need to keep the radio &#8220;active&#8221; to ensure that connections are not dropped.<br>Most mobile carriers set a 5-30 minute NAT connection timeout. Hence, you may need a periodic(5 minute) keepalive to keep an idle connection from being dropped.<\/p><\/blockquote>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"anticipate-network-latency-overhead\"><span class=\"ez-toc-section\" id=\"Anticipate_Network_Latency_Overhead\"><\/span>Anticipate Network Latency Overhead<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>RRC\uff1aRadio Resource Control<br>\u4e0b\u56fe\u663e\u793a\u4e86\u4e00\u6b21http\u8bf7\u6c42\u7684\u5ef6\u65f6\u7684\u6765\u6e90\uff1a<br><img loading=\"lazy\" decoding=\"async\" width=\"850\" height=\"90\" class=\"wp-image-926\" style=\"width: 850px;\" src=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency.png\" alt=\"\" srcset=\"https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency.png 2463w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency-300x32.png 300w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency-1024x108.png 1024w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency-768x81.png 768w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency-1536x162.png 1536w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency-2048x216.png 2048w, https:\/\/blog.cauchyschwarz.com\/wp-content\/uploads\/2021\/12\/hpbn_http-request-latency-670x71.png 670w\" sizes=\"auto, (max-width: 850px) 100vw, 850px\" \/><\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><thead><tr><th><\/th><th>3G<\/th><th>4G<\/th><\/tr><\/thead><tbody><tr><td>Control plane<\/td><td>200-2500ms<\/td><td>50-100ms<\/td><\/tr><tr><td>DNS lookup<\/td><td>200ms<\/td><td>100ms<\/td><\/tr><tr><td>TCP handshake<\/td><td>200ms<\/td><td>100ms<\/td><\/tr><tr><td>TLS handshake<\/td><td>200-400ms<\/td><td>100-200ms<\/td><\/tr><tr><td>HTTP request<\/td><td>200ms<\/td><td>100ms<\/td><\/tr><tr><td>Total latency overhead<\/td><td>200-3500ms<\/td><td>100-600ms<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"account-for-rrc-state-transitions\"><span class=\"ez-toc-section\" id=\"Account_for_RRC_State_Transitions\"><\/span>Account for RRC State Transitions<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5bf9\u4e8eRRC\u7684\u72b6\u6001\u8f6c\u6362\u9075\u5faa\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>RRC state machines are different for every wireless standard<\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li>RRC state machines are managed by the radio network for each device<\/li><li>RRC state promotions to high power occur when data must be transferred<\/li><li>RRC state demotions to lower power occur on network-configured timeouts<\/li><li>(4G)LTE state transitions can take 10 to 100 milliseconds<\/li><li>(4G)HSPA+ state transitions are competitive with LTE<\/li><li>(3G)HSPA and CDMA state transitions can take several seconds<\/li><li>Every network transfer, no matter the size, incurs an energy tail<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"decouple-user-interactions-from-network-communication\"><span class=\"ez-toc-section\" id=\"Decouple_User_Interactions_from_Network_Communication\"><\/span>Decouple User Interactions from Network Communication<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6700\u597d\u8bbe\u8ba1\u5e94\u7528\u4ea4\u4e92\u7684\u65f6\u5019\u5c31\u628a\u7b49\u5f85\u7f51\u7edc\u8bf7\u6c42\u7684\u7ed3\u679c\u548c\u7ed9\u4e88\u7528\u6237\u5373\u65f6\u53cd\u9988\u8fd9\u4e24\u4ef6\u4e8b\u60c5\u5206\u5f00\uff0c\u56e0\u4e3a\u524d\u8005\u53ef\u80fd\u4f1a\u82b1\u4e0a\u6bd4\u8f83\u957f\u7684\u65f6\u95f4\uff0c\u5f71\u54cd\u7528\u6237\u4f53\u9a8c\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"design-for-variable-network-interface-availability\"><span class=\"ez-toc-section\" id=\"Design_for_Variable_Network_Interface_Availability\"><\/span>Design for Variable Network Interface Availability<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u628a\u4f60\u7684\u7f51\u7edc\u6570\u636e\u8bf7\u6c42\u805a\u5408\u8d77\u6765\uff0c\u4ee5\u5c11\u6b21\u591a\u91cf\u7684\u65b9\u5f0f\u4f20\u8f93\u6570\u636e\uff0c\u8fd9\u6837\u4f60\u7684\u7f51\u7edc\u901a\u4fe1\u8bbe\u5907\u53ef\u4ee5\u5927\u591a\u6570\u65f6\u95f4\u5904\u4e8eIDLE\u72b6\u6001\uff0c\u589e\u52a0\u7535\u6c60\u4f7f\u7528\u65f6\u95f4\u3002\u50cfLTE,HSPA+\u8fd9\u79cd\u7f51\u7edc\uff0c\u4ed6\u4eec\u4ee51ms\u7684\u95f4\u9694\u6765\u4e3a\u7528\u6237\u8c03\u914d\u7f51\u7edc\u8d44\u6e90\uff0c\u5e76\u4e14\u7ed9\u4e88bursty data flows\u9ad8\u4f18\u5148\u7ea7\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"burst-your-data-and-return-to-idle\"><span class=\"ez-toc-section\" id=\"Burst_Your_Data_and_Return_to_Idle\"><\/span>Burst Your Data and Return to Idle<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"offload-to-wifi-networks\"><span class=\"ez-toc-section\" id=\"Offload_to_WiFi_Networks\"><\/span>Offload to WiFi Networks<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p>\u9700\u8981\u4f20\u8f93\u5927\u91cf\u6570\u636e\u65f6\uff0c\u6700\u597d\u9009\u62e9\u5728\u6709WiFi\u7684\u60c5\u51b5\u4e0b\u8fdb\u884c\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"apply-protocol-and-applicationo-best-practices\"><span class=\"ez-toc-section\" id=\"Apply_Protocol_and_Applicationo_Best_Practices\"><\/span>Apply Protocol and Applicationo Best Practices<span class=\"ez-toc-section-end\"><\/span><\/h2>\n","protected":false},"excerpt":{"rendered":"<p>Chapter 5 Introduction to Wireless Networks \u65e0\u7ebf\u7f51\u7edc\u7684\u7c7b\u578b(\u6309\u8ddd\u79bb\u5212\u5206)\uff1a Type Range Applications Standards Person&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10,6],"tags":[105,28,9],"class_list":["post-909","post","type-post","status-publish","format-standard","hentry","category-10","category-6","tag-hpbn","tag-28","tag-9"],"_links":{"self":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/909","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=909"}],"version-history":[{"count":2,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/909\/revisions"}],"predecessor-version":[{"id":929,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=\/wp\/v2\/posts\/909\/revisions\/929"}],"wp:attachment":[{"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=909"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=909"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.cauchyschwarz.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=909"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}