Variational Bayesian Inference Clustering Based Joint User Activity and Data Detection for Grant-Free Random Access in mMTC

10/25/2022
by   Zhaoji Zhang, et al.
0

Tailor-made for massive connectivity and sporadic access, grant-free random access has become a promising candidate access protocol for massive machine-type communications (mMTC). Compared with conventional grant-based protocols, grant-free random access skips the exchange of scheduling information to reduce the signaling overhead, and facilitates sharing of access resources to enhance access efficiency. However, some challenges remain to be addressed in the receiver design, such as unknown identity of active users and multi-user interference (MUI) on shared access resources. In this work, we deal with the problem of joint user activity and data detection for grant-free random access. Specifically, the approximate message passing (AMP) algorithm is first employed to mitigate MUI and decouple the signals of different users. Then, we extend the data symbol alphabet to incorporate the null symbols from inactive users. In this way, the joint user activity and data detection problem is formulated as a clustering problem under the Gaussian mixture model. Furthermore, in conjunction with the AMP algorithm, a variational Bayesian inference based clustering (VBIC) algorithm is developed to solve this clustering problem. Simulation results show that, compared with state-of-art solutions, the proposed AMP-combined VBIC (AMP-VBIC) algorithm achieves a significant performance gain in detection accuracy.

READ FULL TEXT
research
04/10/2023

Matrix Factorization Based Blind Bayesian Receiver for Grant-Free Random Access in mmWave MIMO mMTC

Grant-free random access is promising for massive connectivity with spor...
research
04/26/2021

Joint Activity Detection and Data Decoding in Massive Random Access via a Turbo Receiver

In this paper, we propose a turbo receiver for joint activity detection ...
research
02/17/2021

Supporting More Active Users for Massive Access via Data-assisted Activity Detection

Massive machine-type communication (mMTC) has been regarded as one of th...
research
04/24/2019

Fixed-Symbol Aided Random Access Scheme for Machine-to-Machine Communications

The massiveness of devices in crowded Machine-to-Machine (M2M) communica...
research
05/17/2023

Asynchronous Grant-Free Random Access: Receiver Design with Partially Uni-Directional Message Passing and Interference Suppression Analysis

Massive Machine-Type Communications (mMTC) features a massive number of ...
research
05/22/2022

Data-aided Active User Detection with a User Activity Extraction Network for Grant-free SCMA Systems

In grant-free sparse code multiple access system, joint optimization of ...
research
03/20/2021

Multi-sequence Spreading Random Access (MSRA) for Compressive Sensing-based Grant-free Communication

The performance of grant-free random access (GF-RA) is limited by the nu...

Please sign up or login with your details

Forgot password? Click here to reset