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02 Nov 09

Faculty Profile - Gregory David Durgin

Who wrote the book, Space-Time Wireless Channels
I only understood the basis of MIMO communication after reading this great book!!!

www.ece.gatech.edu/...publications.php - Preview

channel-modeling mimo wireless persons favorites

  • Gregory David Durgin





    Associate Professor

    Electromagnetics
20 Oct 09

WiMedia Alliance - Wikipedia, the free encyclopedia

Standardization of Ultra-bandwidth Communication
UWB本来将通过IEEE802.15 WG进行其标准化工作，各方在IEEE通过PAR，即15.3a TG的成立许可。但究竟是使用Multi-Band OFDM还是DS UWB让各参与者渐行渐远。

一方是Multi-Band OFDM的支持者，组成了WiMedia[http://www.wimedia.org/]联盟，将近乎完整的规范已提案
[http://www.wimedia.org/imwp/idms/popups /pop_download.asp?ContentID=6516]的形式投给了IEEE802.15.3a。WiMedia的主要支持者是TI、 Intel这样的老牌芯片厂商，同时也有很多初创的小企业。

另一方则是DS UWB的支持者，组成了UWB Forum，开始与WiMedia竞争。主要players是Motorola，Freescale。Freescale也是有备而来，准备使用其的 110Mbit/s技术，以推广其XS110芯片组。其实很多学术界的人都是支持直序或脉冲方式的高速通信的，UFL的Dongliang Duan的老板就是做脉冲的。个人分析，因为大家觉得最初的无线通信方式（马可尼的电报系统）就是脉冲方式的，在使用波形调制这么多年后，从哲学的角度来说，技术是该进行一次轮回的。当然，脉冲方式是有很多实质性好处的，应该较MB-OFDM简单，使得成本更低。代价是，在这个满是波形调制的现有社会中，要使用脉冲而不让干扰波及到现有系统，是很困难的。

在IEEE Member Voting中，双方势均力敌，不可开交。于是双方决定放弃在IEEE的标准化路程，通过走向市场的de facto事实标准来竞争，让用户来决定谁是赢家。另一方面，缺少一致也被认为是技术和市场均还未成熟，进行标准化尚早，也支持了15.3a的流产。

按传闻[http://www.handheld.eet-china.com /ART_8800414008_4000001_NT_4072ae1d.HTM]，2006年4月，Freescale计划退出UWB Forum，主要厌倦了游说工作，认为太多肮脏政治超过了技术本身。Motorola是Freescale的兄长，自然也是保持一致地推出了。这样，UWB Forum元气大伤，只剩Pulse-Link高举大旗死扛。按照Wikipedia的描述，如今的UWB Forum已名存实亡。不过有趣的是当年MultiBand OFDM Alliance Special Interest Group (MBOA-SIG)的域名[multibandofdm.org]也已易主。

WiMedia则一番风顺，其输出标准于2005年被ECMA（欧洲计算机制造商协会）采纳为规范，ECMA-368[http://www.ecma- international.org/publications/standards/Ecma-368.htm]和ECMA-369[http: //www.ecma-international.org/publications/standards/Ecma-369.htm]。

ETSI（欧洲通信标准学会）采纳了ECMA的规范。

2007年ISO（国际标准组织）也采纳了ECMA的规范，作为ISO/IEC 26907:2007和ISO/IEC 26908:2007[http://standards.iso.org/ittf/PubliclyAvailableStandards /index.html]。

2009 年1月，WiMedia宣称中国信产部已批准MB-OFDM在中国的使用并准许其使用频谱。不过中国未必安心使用国外标准，众多国内芯片企业虎视眈眈。至少在DVB领域，中国就算是抄，也得抄出个自己的标准来。不过在DVB时代，中国是采纳了南北两套技术的。实验室邻座的小弟在徒手研究UWB信道建模，老板也开始过问起UWB标准，不知道是否是UWB中国大雨前的乌云。

WiMedia的思路倒是很先进的，同IEEE802.16的 Service-Specific Convergent Sub-Layer一样，WiMedia在上层支持多种payload的承载，自身以负责PHY传输技术为主，这样厂商甚至可以在WiMedia上架设私有的MAC协议。WiMedia的2008版也将Interference Avoidance纳入其设计考虑，这样在世界各地频谱使用不同的情况下推广要容易得多。

这些相似的重要战略步伐当然还是因为他们背后是同一批 Sophisticated 的棋手。

我们这帮做无线的就等着啥时候自己在家看电视时只用接电源线就了事，忽略信号线的时代了!

en.wikipedia.org/...WiMedia_Alliance - Preview

standards wireless UWB industry OFDM

  • Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM)
15 Oct 09

ath9k - Linux Wireless

  • FOSS wireless driver for all Atheros IEEE 802.11n PCI/PCI-Express and AHB WLAN based chipsets
30 Aug 09

Welcome to IEEE Xplore 2.0: Multi-cell uplink-downlink beamforming throughput duality based on Lagrangian duality with per-base station power constraints

not good

pure optimization theory
no simulation result, so the result can't be repeated.

ieeexplore.ieee.org/...abs_all.jsp - Preview

wireless multi-cell power-control duality beamforming papers ieee

  • Multi-cell uplink-downlink beamforming throughput duality based on Lagrangian duality with per-base station power constraints
28 Aug 09

Welcome to IEEE Xplore 2.0: On capacity of cognitive radio networks with average interference power constraints

  • On capacity of cognitive radio networks with average interference power constraints






    Cheng-Xiang Wang  

    Xuemin Hong  

    Hsiao-Hwa Chen  

    Thompson, J.  


    Joint Res. Inst. for Signal & Image Process., Heriot-Watt Univ., Edinburgh;







    This paper appears in: Wireless Communications, IEEE Transactions on



    Publication Date: April 2009


    Volume: 8, 

    Issue: 4



    On page(s): 1620-1625





    ISSN: 1536-1276


    INSPEC Accession Number: 10627523


    Digital Object Identifier: 10.1109/TWC.2009.071075


    <!--Start 2.5.3 code-->

    Current Version Published: 2009-05-02



    <!--End 2.5.3 code-->



















    Abstract

    Cognitive radio (CR) has been considered as a promising technology to improve the spectrum utilization. In this paper we analyze the capacity of a CR network with average received interference power constraints. Under the assumptions of uniform node placements and a simple power control scheme, the maximum transmit power of a target CR transmitter is characterized by its cumulative distribution function (CDF). We study two CR scenarios for future applications. The first scenario is called the CR based central access network, which aims at providing broadband access to CR devices. In the second scenario, the so-called CR assisted virtual multiple-input multiple-output (MIMO) network, CR is used to improve the access capability of a cellular system. The uplink ergodic channel capacities of both scenarios are derived and analyzed with an emphasis on understanding the impact of numbers of primary users and CR users on the capacity. Numerical and simulation results suggest that the CR based central access network is more suitable for less-populated rural areas where a relatively low density of primary receivers is expected; while the CR assisted virtual MIMO network performs better in urban environments with a dense population of mobile CR users.

22 Aug 09

Technology Review: TR35

  • Ashoke Ravi, 32



    Intel


    Using software to send diverse radio signals

20 Aug 09

IEEE 802.16 Task Group m (TGm)

  • IEEE 802.16 Task Group m (TGm)
  • IEEE Standard 802.16
  • 39 more annotations...
16 Jul 09

Liuqing Yang

She visits our Lab in July 23, 2009.

www.yang.ece.ufl.edu - Preview

wireless persons cognitive university america

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