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Methods and apparatus of providing transmit diversity in a multiple access wireless communication system

A communication method and technology of a communication system, applied in the field of providing transmit diversity, can solve the problems of inaccuracy, channel state change, base station error channel state information, etc.

Active Publication Date: 2010-12-29
QUALCOMM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Also, since the channel measurements on which the channel estimation is based have been made, sharp changes often lead to inaccurate channel estimates used to decode the received signal, since the channel state may have changed significantly
The feedback loop used between the base station and the wireless terminal (for power control and other purposes) limits the speed at which the communication channel can be changed because it is faster than the wireless terminal can measure channel state information and feed it back to the base station. Changing the channel state at a fast rate will cause the base station to have largely wrong channel state information

Method used

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  • Methods and apparatus of providing transmit diversity in a multiple access wireless communication system
  • Methods and apparatus of providing transmit diversity in a multiple access wireless communication system
  • Methods and apparatus of providing transmit diversity in a multiple access wireless communication system

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Embodiment Construction

[0042] figure 1 A typical wireless communication system 100 implemented in accordance with the present invention is shown. A typical wireless communication system 100 includes multiple base stations (BS): BS 1 102 , BS M 114 . Cell 1 104 is the wireless coverage area of ​​base station 1 102 . BS 1 102 communicates with a number of wireless terminals (WTs): WT ( 1 ) 106 , WT (N) 108 located within cell 1 104 . WT(1) 106, WT(N) 108 are connected to BS 1 102 via wireless links 110, 112, respectively. Similarly, cell M 116 is the wireless coverage area of ​​base station M 114 . BS M 114 communicates with a number of wireless terminals (WTs): WT (I′) 118 , WT (N′) 120 located within unit M 116 . WT (I') 118, WT (N') 120 are connected to BS M 114 via wireless links 122, 124, respectively. WTs (106, 108, 118, 120) may be mobile and / or stationary wireless communication devices. Mobile WTs, sometimes referred to as mobile nodes (MNs), can move around the system 100 and communicat...

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Abstract

Methods and apparatus for providing channel diversity to wireless terminal (WT) in a manner that reduces the latency between the time a WT encounters satisfactory channel conditions are described. A plurality of communications channels with different physical characteristics are maintained in a cell by a base station (BS). Each WT monitors multiple channels and maintains multiple channel estimates at the same time so that rapid switching between channels is possible. Channel quality information is conveyed from each WT to the BS. The WT or BS selects a channel based on the measured channel quality. By supporting multiple channels and by introducing periodic variations into the channels in various embodiments, the time before a WT encounters a channel with good or acceptable channel conditions is minimized even if the WT does not change location. Multiple antennas are used at the BS to support numerous channels simultaneously, e.g., by controlling antenna patterns.

Description

technical field [0001] The present invention relates to communication systems and, in particular, to methods and apparatus for providing transmit diversity in multiple access cellular communication networks. Background technique [0002] In a wireless communication system, a base station located at a fixed location communicates with a plurality of wireless terminals, such as mobile nodes, which can move around within their cell. A given base station with a single fixed antenna may have a fixed antenna radiation pattern. Consider a single base station; its antenna pattern will support variable levels of channel quality between the base station and mobile node, depending on the location of the mobile node relative to the antenna pattern. Now consider a neighboring base station with its own antenna pattern, which can cause different levels of interference at different locations. The channel quality between the base station and the mobile node will vary as the mobile node move...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04W40/12H04W88/08H04W88/02H04W88/18H04B7/06
CPCH04B7/0626
Inventor 拉加维·拉洛亚厉隽怿桑德普·兰格恩穆拉瑞·斯瑞尼瓦萨恩
Owner QUALCOMM INC