A method for reducing bandwidth of ir interface and distributed base station

Abstract

The present invention provides a method for reducing the bandwidth of an Ir interface, which is applied to a remote baseband system that introduces a beamforming function. The method includes: when sending downlink, the indoor baseband processing unit BBU transmits The downlink user data and downlink control signals are sent to the remote radio unit RRU, and the RRU performs downlink beamforming processing according to the downlink user data and downlink control signals; when receiving uplink, the BBU sends the uplink control signals to the RRU through the Ir interface , the RRU performs uplink equalization processing on the received uplink user data according to the uplink control signal, and sends the equalized uplink user data obtained after the uplink equalization processing to the BBU through the Ir interface. The present invention also provides a distributed base station corresponding to the above method. The application of the present invention can greatly reduce the bandwidth requirement of the Ir interface, and increase the effective data occupancy ratio of the Ir interface.

Description

technical field [0001] The invention relates to baseband remote system technology, in particular to a method for reducing Ir interface bandwidth and a distributed base station. Background technique [0002] In the 3G system, the baseband remote networking mode of BBU+RRU (indoor baseband processing unit + remote radio unit) has been applied on a large scale, and this networking mode will also be applied to LTE systems, TD-SCDMA systems, etc. . The baseband IQ signal is transmitted between the BBU and the RRU through an optical fiber. The interface between the BBU and the RRU is called an Ir interface. The bandwidth of the Ir interface depends on the transmission rate of the baseband signal. [0003] Taking the LTE system as an example, under the bandwidth of 20MHz, when the antenna configuration is 2×2 MIMO (Multiple Input Multiple Output), the Ir interface bandwidth of a single sector is calculated as follows: [0004] Ir interface bandwidth = 30.72MHz (sampling rate) × 1...

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Problems solved by technology

[0023] It can be seen from the above data that on the downlink transmitting side, the bandwidth required by the Ir interface after beamforming is doubled (increased by 4 times) compared to before beamforming, and the bandwidth efficiency of data transmission is greatly reduced (reduced to 20%, reduced by 4 times), resulting in a substantial increase in the cost of the transmission network

[0024] For the uplink receiving side, in order to estimate the user’s uplink channel for uplink equalization and downlink beamforming, the uplink receiving side also needs to use multi-antenna reception. For example, if downlink beamforming uses 8 antennas for transmission, then uplink reception also needs to use 8-antenna reception, so similar to the downlink, the bandwidth requirements of the uplink Ir interface will also increase exponentially, and the cost of the transmission network will increase significantly

[0025] It can be seen from the above that, due to the introduction of beamforming in the existing baseband remote system, the data bandwidth of the uplink and downlink Ir interfaces has increased several times, but the effective data has not increased, which has greatly increased the cost of the Ir interface bandwidth requirements, and the transmission The problem of low efficiency

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