Licensed spectrum remains 3GPP operators’ top priority to deliver advanced services and user experience Opportunistic use of unlicensed spectrum is becoming an important complement for operators to meet the growing traffic demand Moving forward 3GPP operators will have two options to offload traffic to unlicensed spectrum: 1. WI-FI (via LTE/WI-FI interworking) 2. LTE over unlicensed It will then be up to each individual operator to choose which approach to use, which will depend on a number of factors
標(biāo)簽： 3GPP_unlicensed_Dino_Flore 2015 01
上傳時間： 2020-05-26
上傳用戶：shancjb
Wireless Fidelity (WI-FI) networks have become mainstream over the last few years. What started out as cable replacement for static desktops in indoor networks has been extended to fully mobile broadband applications involving moving vehicles, high-speed trains, and even airplanes.
標(biāo)簽： Technologies Emerging Wireless Theory LANs in
上傳時間： 2020-05-27
上傳用戶：shancjb
Following chapter introduces the mobile communication, gives a short history of wireless communication evolution, and highlights some application scenarios predestined for the use of mobile devices. Cellular and wireless based systems related to different generations of mobile communication, including GSM, IS-95, PHS, AMPS, D-AMPS, cdma2000 and WCDMA are also described by this Chapter. Much attention in this chapter is given to express the wireless based networks, such as WI-FI and WiBro/WiMax, and wireless broadcasting systems, including DMB, DVB-H, and ISDB-T. We conclude the chapter with the future vision of mobile communication evolution
標(biāo)簽： Technologies Enhanced Access Radio
上傳時間： 2020-05-27
上傳用戶：shancjb
Digital mobile wireless communication and the Internet have undergone a fantastic growth in the last few years and, despite originating from two different worlds, they are converging. This convergence corresponds to the evolution of mobile systems towards the highest broadband data transmissions (GSM, EDGE/GPRS, UMTS then HSDPA), while the computing world gets equipped with wireless technologies such as WI-FI or Wi-Max.
標(biāo)簽： Reconfigurable Systems Mobile Radio
上傳時間： 2020-06-01
上傳用戶：shancjb
Today wireless is becoming the leader in communication choices among users. It is not anymore a backup solution for nomadic travellers but really a newmoodnaturallyusedeverywhereevenwhenthewiredcommunicationsare possible. Many technologies evolve then continuously, changing the telecom- munication world. We talk about wireless local area networks (WLANs), wire- less personal area networks (WPANs), wireless metropolitan area networks (WMANs), wireless wide area networks (WWANs), mobile ad hoc networks (MANETs), wireless sensor networks (WSNs) and mesh networks. Since we can find today a multitude of wireless technologies we decided to group a numberofcomplementarytechnologiesintoonedocumenttomakeiteasierfor areadertounderstandsomeofthetechnicaldetailsofeachmedia.
標(biāo)簽： TM Bluetooth Zigbee WI-FI WiMax and
上傳時間： 2020-06-01
上傳用戶：shancjb
Although the origins of radio frequency based wireless networking can be traced back to the University of Hawaii’s ALOHANET research project in the 1970s, the key events that led to wireless networking becoming one of the fastest growing technologies of the early 21st century have been the ratification of the IEEE 802.11 standard in 1997, and the subsequent development of interoperability certification by the WI-FI Alliance (formerly WECA).
標(biāo)簽： Networking Technology Wireless
上傳時間： 2020-06-01
上傳用戶：shancjb
設(shè)計了一種基于STM32F103單片機的甲醛檢測報警儀，采用ESP8266 WI-FI模塊實現(xiàn)通信連接與數(shù)據(jù)傳遞，采用M-01傳感器實時采集室內(nèi)環(huán)境的甲醛濃度，通過LCD12864液晶模塊顯示甲醛濃度，并在甲醛濃度超標(biāo)時進(jìn)行聲光報警。該甲醛檢測報警儀成本低，精度高，可以滿足室內(nèi)環(huán)境甲醛濃度監(jiān)測的需要。
上傳時間： 2022-04-28
上傳用戶：
移動通信網(wǎng)絡(luò)由于帶寬和技術(shù)的限制，遠(yuǎn)遠(yuǎn)不能滿足人們不斷高漲的無線上網(wǎng)需求。WI-FI作為無線接入技術(shù)MLAN的主流標(biāo)準(zhǔn)口益成熟，它能夠隨時隨地高速連接到Internet，極大地滿足了用戶對無線上網(wǎng)需求，受到消費者的青睞。因而越來越多的移動終端都集成了WI-FI功能，WI-FI和藍(lán)牙樣成為移動終端的標(biāo)配。隨之而來的是WI-FI和藍(lán)牙都工作在2.4CHZz ISM頻段而引發(fā)的互相 擾問題，導(dǎo)致數(shù)據(jù)吞吐量下降，語音質(zhì)量惡化失真，極端狀況下甚至導(dǎo)致鏈路斷開而不能正常工作。因此，必須尋求有效的措施和方法，實現(xiàn)兩種技術(shù)在近距離的和諧共存，這已成為非常迫切的技術(shù)需要，也成為人們研究的一個熱點和難點。近距離WiFi和藍(lán)牙互相1擾的問題，目前已經(jīng)形成了非常多的有效解決機制，包括基于WI-FI的PTA（Packet Traffic Arbitration）、AWMA（Alternating Wireless Medium Access）和DSE（Deterministic Spectral Excision），其中PTA和AWMA機制在WI-FI側(cè)MAC層實現(xiàn)，通過協(xié)調(diào)WI-FI和藍(lán)牙的幀發(fā)射時間來避免相互干擾：而DSE是在WI-FI側(cè)物理層PHY實現(xiàn)，通過一個可編程帶阻濾波器（Notch Filter）來阻止來白藍(lán)牙的窄帶干擾。還有基于藍(lán)牙側(cè)的AFH（Adaptive Frequency Hopping），它通過跳頻，自動避開被干擾的頻點，從而大大提高了藍(lán)牙傳輸性能。
上傳時間： 2022-06-20
上傳用戶：zhanglei193
本文開展的主要工作如下：1，設(shè)計實現(xiàn)了可通過藍(lán)牙、語音和WI-FI三種方式控制的智能家居電源開關(guān)控制器。設(shè)計了元器件電路、PCB線路和Android UI界面，可應(yīng)用于Android手機、平板、藍(lán)牙程式實施進(jìn)程控制，改變了傳統(tǒng)家居布線模式，可免開關(guān)布線，也可相容已有線路布局，還可與各種智能家庭系統(tǒng)實現(xiàn)無縫連接。借助熱成像實驗測試了環(huán)境溫度對該控制器的影響，并對控制器的性能做了全面的分析和研究。2基于穩(wěn)定性、安全性、易于擴(kuò)展及便于施工的原則，規(guī)劃了整個智能家居終端控制系統(tǒng)的通信協(xié)議和組網(wǎng)方式，選用支持OpenWrt系統(tǒng)的哦耶路由器改裝成中控智能家庭網(wǎng)關(guān)。以CO傳感器監(jiān)控報警為例，實驗驗證了整個系統(tǒng)的可行性。3本文使用藍(lán)牙組網(wǎng)，相對于ZigBee功耗更低。在消費電子領(lǐng)域，藍(lán)牙具有更多優(yōu)勢，也得到了越來越多的青睞。隨著藍(lán)牙自組網(wǎng)技術(shù)（BLE Mesh）的發(fā)布，進(jìn)一步規(guī)范了基于IPv6數(shù)據(jù)包的交換設(shè)備間的藍(lán)牙通信，克服了短距離通信和限制通信拓?fù)浣Y(jié)構(gòu)的缺陷，可免疫電磁干擾。藍(lán)牙的另一大優(yōu)勢就是可直接與手機連接，必將成為近程通信發(fā)展的主要方向。注：本文第三章電源開關(guān)控制器是獨立開發(fā)準(zhǔn)備投放市場的產(chǎn)品，后來和藍(lán)牙CSR廠商有合作，其提供了CSR1010藍(lán)牙芯片及開發(fā)API，所以在架構(gòu)整個智能家居終端控制系統(tǒng)時，整個系統(tǒng)內(nèi)所選用的藍(lán)牙芯片都用的是廠商提供的CSR1010芯片，組建BLE mesh網(wǎng)絡(luò)。
上傳時間： 2022-06-23
上傳用戶：
MT7688 family integrates a 1T1R 802.11n WI-FI radio,a 580MHz MIPS? 24KEcTM CPU,1-port fast Ethernet PHY, USB2.0 host, PCIe, SD-XC,I2S/PCM and multiple slow IOs. MT7688 provides two operation modes-IoT gateway mode and IoT device mode. In IoT gateway mode, the PCI Express interface can connect to 802.1lac chipset for 1lac dual-band concurrent gateway. The high performance USB2.0 allows MT7688 to add 3G/LTE modem support or add a H.264 ISP for wireless IP camera. For the IoT device mode, MT7688 supports eMC, SD-XC and USB 2.0. MT7688 can support the Wifi high quality audio via 192Kbps/24bits I2S interface and VolP application through PCM. In IoT device mode, it further supports PWM, SPI slave,3d UARI and more GPIOs. For IoT gateway, it canl connect to touch panel and BLE, Zigbee/Z-Wave and sub-1G RF for smart home control.
上傳時間： 2022-07-24
上傳用戶：
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