User activity and signal joint detection method for large-scale MIMO system

Abstract

The invention discloses a user activity and signal joint detection method for a large-scale MIMO system. The method comprises the steps: enabling the number of IoT equipment to be greater than the number of antennas configured at a base station side, transmitting an M-ary quadrature amplitude modulation symbol at each time slot at each active IoT equipment of an uplink, and enabling the transmitting symbol of inactive IoT equipment to be 0 at each time slot, wherein each antenna on the base station side receives signals in each time slot; considering the condition that the noise power is unknown, estimating the noise power by utilizing unitary transformation approximate message passing, obtaining a posterior probability of transmitting symbols, and performing user activity detection according to the posterior probability and an expectation maximization algorithm, thereby finally obtaining a signal detection result, namely, estimating a matrix formed by symbols transmitted by all IoT equipment in all time slots. The method has the advantages that the noise power does not need to be known, the method better conforms to the actual situation, and the method can still have good detection performance under the condition that the number of active IoT devices is close to the number of base station side antennas.

Description

technical field [0001] The present invention relates to a user activity and signal joint detection method, in particular to a massive MIMO (Multiple-Input Multiple-Output, multiple-input multiple-output) system uplink user activity and signal joint detection method. Background technique [0002] With the rapid development of the Internet of things (IoT) and mobile Internet, the fifth-generation mobile communication system needs to cope with challenges such as high throughput, low latency, and large-scale connections. Massive Multiple-Input Multiple-Output (mMIMO) technology has become one of the key technologies of the fifth-generation mobile communication because it can improve spectrum efficiency, energy efficiency and reliability. In an mMIMO system, the base station usually configures dozens or even hundreds of antennas to serve multiple IoT devices (users). [0003] According to the traditional communication method, a handshake process is required for users to access t...

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Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a method for joint detection of user activity and signals in a massive MIMO system, which does not require known noise power, is more in line with the actual situation, and can be used when the number of active IoT devices is close to the base station side. In the case of the number of antennas, there is still good detection performance

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