Method and apparatus for closed loop transmission

A technology of user stations and base stations, applied in the field of communication systems, can solve problems such as closed-loop transmission performance degradation, achieve low peak-to-average power ratio, high signaling efficiency, and suppress interference

Inactive Publication Date: 2007-06-13
MOTOROLA INC
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  • Abstract
  • Description
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Problems solved by technology

These problems can severely degrade the performance of closed-loop transmission in reciprocity-based systems

Method used

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  • Method and apparatus for closed loop transmission
  • Method and apparatus for closed loop transmission
  • Method and apparatus for closed loop transmission

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Embodiment Construction

[0033]Turning now to the drawings, in which like reference numerals refer to like components, FIG. 1 is a block diagram of a communication system 100 . The communication system 100 includes a plurality of cells 105 (only one shown) each having a base station (BS, or base station) 104 that communicates with a plurality of subscriber stations (SS) 101-103. If closed-loop transmissions to SS 101 are performed on the downlink, BS 104 may be referred to as a source communication unit and SS 101 may be referred to as a target communication unit. If a closed-loop transmission from SS 101 to BS 104 is performed on the uplink, SS 101 may be referred to as a source communication unit and BS 104 may be referred to as a target communication unit. In a preferred embodiment of the present invention, communication system 100 utilizes Orthogonal Frequency Division Multiplexing (OFDM) or a multi-carrier based architecture including Adaptive Modulation and Coding (AMC). The architecture can al...

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Abstract

In a wireless communication system, a method and apparatus for closed loop transmission is disclosed. In accordance with the preferred embodiment of the present invention, a time frequency portion of an uplink frame is dynamically reserved as a sounding zone for uplink channel sounding. A first message is transmitted to a first subscriber station in a downlink frame assigning a time-frequency resource within the sounding zone, and a sounding waveform. Furthermore, a signal is received from the subscriber station within the assigned time-frequency resource, a partial channel response is determined from the received sounding signal, and the subsequent transmission to the subscriber station is tailored based on the at least partial channel response.

Description

technical field [0001] The present invention relates generally to communication systems, and in particular, to a method and apparatus for closed-loop transmission. Background of the invention [0002] In mobile broadband cellular communication systems, there are several physical layer techniques that need to provide the transmitter with knowledge of the channel response between the transmitter and receiver. A transmission technique that utilizes a channel response between a transmitter and a receiver is called a closed-loop transmission technique. An example of closed-loop transmission is the use of a closed-loop transmit antenna array at the transmitter. A closed-loop transmit antenna array is an array of multiple transmit antennas, where the signal fed to each antenna is weighted in an appropriate manner in order to control the characteristics of the transmitted signal energy according to some predefined optimization strategy. Typically, a closed-loop transmit antenna ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/00H04B7/00H04B17/00H04B1/40H04J11/00H04L27/28
Inventor 弗雷德里克·W·沃克庄向阳凯文·L·鲍姆蒂莫西·A·托马斯
Owner MOTOROLA INC
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