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Wireless communication system and wireless communication method

A wireless communication system and active user technology, applied in the field of user scheduling, can solve problems such as capacity mismatch, inability to guarantee, user interference, etc.

Inactive Publication Date: 2009-07-15
FUJITSU LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although interference from other streams is considered in the CQI calculation, there is no guarantee that the user selected by the BS will actually use the precoding index determined in the CQI calculation
Therefore, the CQI calculation will still likely not match the actual capacity
[0018] In addition, the simultaneous transmission of multiple subscriber stations introduces interference between users, that is, multi-user interference that degrades system performance
Because even if the best codebook is selected, the difference between the codebook and the actual channel direction is significant in some cases, so it may not be possible to completely eliminate the multi-user interference

Method used

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  • Wireless communication system and wireless communication method
  • Wireless communication system and wireless communication method
  • Wireless communication system and wireless communication method

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no. 1 example

[0057] The overall structure of the MU-MIMO wireless communication system in the first embodiment is basically the same as figure 1 The structure shown is the same. In other words, the MU-MIMO wireless communication system in the first embodiment is applied to an OFDM (Orthogonal Frequency Division Multiplexing) system. In the following description will refer to figure 1 . However, as will be clear from the following description, the invention is not limited to OFDM systems, but can also be applied to any multiplexing scheme other than OFDM.

[0058] Such as figure 1 As shown, the MIMO wireless communication system in the first embodiment includes at least one base station ( figure 1 Only one base station is illustrated in ) and at least one user equipment, the base station has N transmit antennas, and can accommodate multiple user equipments by performing precoding based on a codebook. The base station schedules the users and determines the data rate based on the feedbac...

no. 2 example

[0134] In the first embodiment, the scheduling unit 35 judges whether the iteration ends based on the effective total SNR of the active user set, while in the second embodiment, the scheduling unit 35 determines the active user set based on the total capacity.

[0135] The second embodiment will be described in detail as follows. The structure of the SU-MIMO communication system in the second embodiment is the same as that in the first embodiment, and the difference between the second embodiment and the first embodiment lies in the scheduling process of the scheduling unit of the base station. Hereinafter, the reference numerals in the first embodiment are adopted, the description of the same parts is omitted, and the emphasis is placed on different parts.

[0136] Same as the first embodiment, each user terminal estimates its own channel state information, and then according to the maximum of the received signal-to-noise ratio (SNR) in the codebook N b Select the best precod...

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Abstract

There is provided a method for scheduling users in a multi user-multi input multi output (MU-MIMO) wireless communication system and a method for scheduling users in the system. The MU-MIMO wireless communication system comprises at least one based station and at least one user equipment, the base station is capable of accommodating plural user equipments by precoding based on a codebook, the method comprising: each of the plural user equipments conducting a channel estimation based on a pilot signal transmitted from the base station, to obtain a channel information; determining, based on the channel information, a codeword that results in the maximum signal-noise-ratio (SNR), and a channel quality indictor (CQI) value corresponding to the codeword; and feeding back the codeword and the CQI value to the base station, the base station setting up an active user set that includes at least one user allowed of downlink transmission based on the codewords and the CQI values fed back from the user equipments, so that a predetermined performance metric of the system is maximized.

Description

technical field [0001] The present invention relates generally to wireless communication and, in particular, to user scheduling in MU-MIMO (Multiple User Multiple Input Multiple Output) wireless communication systems. Background technique [0002] A communication technology that enables multiple terminals (each with one or more antennas) to simultaneously communicate with a console with multiple antennas: MU-MIMO (Multiple User-Multiple Input Multiple Output) has greatly facilitated communication in cellular wireless networks. efficient data transfer. There have been many proposals on how to support multi-user transmissions on the same MIMO channel [Documents 1-6]. [0003] Basically, these proposals can be divided into two types according to the availability of channel state information at the transmitter, one type is called "codebook based", which does not require full channel information in the transmitter, but Only the channel vector needs to be quantized (in the form ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/00
CPCH04L1/0002H04L1/06H04L1/0026H04B7/0421H04B7/0452H04B7/0632H04B7/0639H04W72/12
Inventor 张杰周华
Owner FUJITSU LTD