Direct LTE受到业界大多公司力推

目前，有十几家企业，都已表态支持一项才刚刚提议的长期演进(LTE)标准，该标准将可实现装置到装置之间的链接。这些公司相信， Direct LTE 将为不适合使用 Wi-Fi Direct 和 GPS 的适地性应用，提供更具能源效益的服务。 Direct-LTE 是以500公尺的可视范围链接和20-23 dBm的讯号限制为基础，该技术能更快地找到本地使用者，而且所需的处理开销要比Wi-Fi Direct 或 GPS 要少得多，高通(Qualcomm)技术销售总监 Mahesh Makhijani 在 NGMN Alliance 大会上表示。 高通透露，在该公司的内部测试中， LTE Direct 能在0.64秒内发现多达7,200个终端，相较之下， Wi-Fi Direct 则需要82~119秒才能发现369个终端。另外，高通的测试还发现，造成 Wi-Fi Direct 可发现终端数量大幅减少的延迟，将会随着终端设备密度的提升而变严重。 然而，Makhijani表示， LTE Direct 可以和 Wi-Fi Direct 并存。例如，在某些情况下，当终端装置已经使用 LTE Direct 连接后，还是可以经由 Wi-Fi Direct 来传送资料，他说。 包括阿尔卡特朗讯、德意志电信、LG电子、NEC和诺基亚等电信业者、系统厂和芯片公司都支持这个想法。他们提出了将 Direct LTE 增添到 3GPP 组织的 LTE Release 12标准中的构想，该标准预计2015年问世。然而，为了让 Direct LTE 更容易导入产品设计，3GPP组织可能会考虑定义一个ad hoc标准。 Direct LTE可以支持“就近服务，进而为移动网络提供更多价值，”Makhijani说。 少数的新兴移动应用都采用了 FourSquare Radar 和Twitter Discovery tab 等更具环境感知能力的技术。过去一年来，投顾业者已针对上述二家业者投资了约五亿美元，Makhijani表示。 高通也在大会中展示了Direct LTE的仿真成果。在手机应用中，该技术需要升级的收发器，而这些收发器都尚未应用在目前的芯片组中。 编译： Joy Teng 本文授权编译自EE Times，版权所有，谢绝转载 本文下一页：参考英文原文：Look Ma, no network: Group drives LTE Direct ，by Rick Merritt

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{pagination} Look Ma, no network: Group drives LTE Direct Rick Merritt SAN FRANCISCO – More than a dozen companies are supporting a proposed standard for device-to-device links in Long Term Evolution handsets. They believe Direct LTE will offer capabilities and power efficiency for location-based applications not available with today’s Wi-Fi Direct and GPS links. Direct-LTE is based on line-of-sight links at a range up to 500 meters and 20-23 dBm signaling limits. The technique could discover local users more quickly with less processing overhead than Wi-Fi Direct or GPS, said Mahesh Makhijani, a director of technical marketing at Qualcomm, in a presentation at the conference here of the NGMN Alliance. Qualcomm said in its internal tests, LTE Direct discovered as many as 7,200 terminals in 0.64 seconds compared to 369 terminals found in using Wi-Fi Direct that took 82 to 119 seconds. The chip makers tests also found latency for Wi-Fi Direct discovery degraded significantly as device density increased. Nevertheless, Makhijani said LTE Direct could work with Wi-Fi Direct. For example, in some cases it might be more useful to send data via Wi-Fi Direct after devices had been found using LTE Direct, he said. A wide range of operators, system and chip companies back the idea, including Alcatel-Lucent, Deutche Telekom, LG, NEC and Nokia. They proposed adding Direct LTE to the 3GPP group’s LTE Release 12, slated to be available in 2015. However, the group may consider defining an ad hoc standard to get Direct LTE into products earlier. Direct LTE could support “proximity services that provide more value to the mobile network,” said Makhijani. A handful of emerging mobile applications are adopting the concept of ambient awareness including FourSquare Radar and the Twitter Discovery tab. Venture capitalists spent an estimates $500 million on the theme over the last year, said Makhijani. Qualcomm showed a simulation of Direct LTE at the event. The technique requires upgraded transceivers in handsets, not yet available in current chip sets.