iPhone. I PAD. HTC EVO 4G Phone. Palm. Windows Phone 7. MIMO. Understanding of SISO, SIMO, MISO and MIMO In radio, multiple-input and multiple-output, or MIMO (pronounced my-moh by some and me-moh by others), is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology. MIMO technology has attracted attention in wireless communications, because it offers significant increases in data throughput and link range without additional bandwidth or increased transmit power.
It achieves this goal by spreading the same total transmit power over the antennas to achieve an array gain that improves the spectral efficiency (more bits per second per hertz of bandwidth) and/or to achieve a diversity gain that improves the link reliability (reduced fading). History of MIMO[edit] First concepts[edit] The earliest ideas in this field go back to work by AR Kaye and DA George (1970), Branderburg and Wyner (1974)[1] and W. van Etten (1975, 1976).
Principle[edit] where and . 3GPP. The 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations, known as the Organizational Partners. The initial scope of 3GPP was to make a globally applicable third-generation (3G) mobile phone system specification based on evolved Global System for Mobile Communications (GSM) specifications within the scope of the International Mobile Telecommunications-2000 project of the International Telecommunication Union (ITU). The scope was later enlarged[1] to include the development and maintenance of: the Global System for Mobile Communications (GSM) including GSM evolved radio access technologies (e.g. History[edit] The 3rd Generation Partnership Project initiative eventually arose from a strategic initiative between Nortel Networks and AT&T Wireless. Organizational Partners[edit] The six 3GPP Organizational Partners are from Asia, Europe and North America.
Market Representation Partners[edit] Standards[edit] Specification groups[edit] 4G. 4G, short for fourth generation, is the fourth generation of mobile telecommunications technology succeeding 3G. A 4G system, in addition to usual voice and other services of 3G system, provides mobile ultra-broadband Internet access, for example to laptops with USB wireless modems, to smartphones, and to other mobile devices. Even though 4G is a successor technology of 3G, there can be signification issues on 3G network to upgrade to 4G as many of them were not built on forward compatibility. Conceivable applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television, and cloud computing.
Two 4G candidate systems are commercially deployed: the Mobile WiMAX standard (first used in South Korea in 2006), and the first-release Long Term Evolution (LTE) standard (in Oslo, Norway and Stockholm, Sweden since 2009). Technical understanding[edit] Background[edit] IMT-Advanced requirements[edit] System standards[edit] Bing for mobile. Cellphone Payments Offer Alternative to Cash. AT&T dropping more calls than ever. Three times as many as Verizon, according to a consumer survey released Tuesday Click to enlarge.
Source: ChangeWave Research AT&T (T) announced in January that it was spending $2 billion this year to improve its much maligned cellular network. But you wouldn't know it from the survey of smartphone customers released Tuesday by ChangeWave Research, the consumer polling division of InvestorPlace.com. In a poll that asked 4,040 smartphone users in March how many dropped calls they had experienced in the past three months, AT&T -- the exclusive U.S. carrier of Apple's (AAPL) iPhone and iPad mobile devices -- came in dead last among the country's four largest carriers. Verizon (VZ) customers reported losing only 1.5% of their calls over the past three months, the lowest in the smartphone industry and the lowest percentage for a carrier ever recorded by ChangeWave.
AT&T customers, by contrast, reported 4.5% of calls dropped in the last three months. For other recent ChangeWave reports, see: