Method for realizing open-loop precoding in wireless communication system

Abstract

The invention provides a method for realizing open-loop precoding in a wireless communication system, which comprises the following steps that: by using the symmetry of an uplink channel and a downlink channel, a downlink precoding matrix is realized through a low-complexity algorithm under the open-loop condition; and after transmitting data is pre-coded according to different port numbers, the pre-coded transmitting data is modulated and transmitted to complete the correct demodulation of UE downlink. Because the method realizes the downlink precoding through the low-complexity algorithm instead of using the UE closed loop feedback of a user terminal, fully uses the symmetry of the uplink channel and the downlink channel of a TDD system, realizes the downlink precoding proposal under the condition of multiple ports, avoids the system performance loss caused by codebook mapping and reduces the feedback load of the system, the downlink received power and the system performance are improved effectively, and the method is favorable for realizing engineering.

Description

technical field [0001] The present invention relates to the communication field, in particular to a method for realizing open-loop precoding in TDD (Time Division Duplex, Time Division Duplex) LTE (Long Term Evolution, long-term evolution). Background technique [0002] In the LTE system, the linear spatial precoding (Precoding) technology is usually used to improve the performance of the system; the linear spatial precoding method means that when there are multiple transmitting antennas at the transmitting end, multiple Data streams are mapped to multiple antennas. Assuming that the number of antennas is N and the number of data streams is L, when the number of data streams is 1, that is, when one data stream is mapped to N antennas, this kind of linear precoding in the spatial domain can be regarded as the traditional beam assignment shape method. The principle is mainly to make the transmitted signal on the corresponding orthogonal basis of the channel matrix through pr...

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Problems solved by technology

However, considering that the uplink and downlink of the TDD system are divided according to time, the downlink feedback delay will inevitably be greater than that of the FDD system, causing the system delay, overhead loss and quantization error caused by the UE side to calculate the weight quantization and then feedback. The impact of performance will reduce the performance of the system, and since the existing protocol of the LTE system only gives the reference signal positions of up to 4 ports, how to obtain the precoding weight and ensure the UE when the number of ports is greater than 4 Correct demodulation is a problem that needs to be solved, so the measures taken by the precoding method of the prior art need to be improved

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