Topic
Multi-user MIMO
About: Multi-user MIMO is a research topic. Over the lifetime, 10265 publications have been published within this topic receiving 227206 citations. The topic is also known as: multi user mimo & MU-MIMO.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: An efficient resource-allocation strategy for a multiuser multiple-input-multiple-output (MU-MIMO) rateless-coded cognitive radio network with quality-of-service (QoS) provisioning is designed.
Abstract: In this paper, we design an efficient resource-allocation strategy for a multiuser multiple-input-multiple-output (MU-MIMO) rateless-coded cognitive radio network (CRN) with quality-of-service (QoS) provisioning. We consider a limited feedback MU-MIMO CRN, where zero-forcing beamforming (ZFBF) is performed under imperfect channel state information (CSI) at a cognitive base station to mitigate both inter- and intranetwork interferences. To minimize the total feedback amount while satisfying the interference constraint and QoS requirements simultaneously, we propose to adaptively adjust the transmit power, select the transmission mode, and choose the feedback codebook size according to the interference constraint, CSI, and QoS requirements. The optimization problem is shown to be an integer programming problem, and we propose a heuristic algorithm that can provide an optimal solution for most practical scenarios. Results show that our resource-allocation strategy can decide the feedback amount and transmission mode adaptively based on the delay requirements.
57 citations
••
08 Dec 2008TL;DR: An analytical model is developed and results show that the proposed MU MAC significantly outperforms the single-user MAC.
Abstract: Multi-user multiple-input multiple-output (MIMO) systems have been emerging and attracting considerable attention recently for its potential to substantially improve system capacity via space division multiple access. In this paper, we propose a distributed multi-user (MU) medium access control (MAC) protocol for wireless local area networks (WLANs) with MIMO capability, using a leakage-based preceding scheme. By exploiting the multi-user degree of freedom in a MIMO system to allow the access point (AP) to communicate with multiple users in the same frequency band simultaneously, the proposed MU MAC can effectively minimize the AP-bottleneck effect in legacy WLANs. We then develop an analytical model to study the performance of the proposed MU MAC, in terms of the maximum number of users that can be supported and the network throughput. The analysis and simulation results show that the proposed MU MAC significantly outperforms the single-user MAC.
57 citations
••
TL;DR: In this article, a joint channel training and feedback scheme for FDD massive MIMO systems is proposed, which simultaneously reduces the overhead for downlink training and uplink feedback.
Abstract: Massive multiple-input multiple-output (MIMO) is widely recognized as a promising technology for future 5G wireless communication systems. To achieve the theoretical performance gains in massive MIMO systems, accurate channel state information at the transmitter (CSIT) is crucial. Due to the overwhelming pilot signaling and channel feedback overhead, however, conventional downlink channel estimation and uplink channel feedback schemes might not be suitable for frequency-division duplexing (FDD) massive MIMO systems. In addition, these two topics are usually separately considered in the literature. In this paper, we propose a joint channel training and feedback scheme for FDD massive MIMO systems. Specifically, we firstly exploit the temporal correlation of time-varying channels to propose a differential channel training and feedback scheme, which simultaneously reduces the overhead for downlink training and uplink feedback. We next propose a structured compressive sampling matching pursuit (S-CoSaMP) algorithm to acquire a reliable CSIT by exploiting the structured sparsity of wireless MIMO channels. Simulation results demonstrate that the proposed scheme can achieve substantial reduction in the training and feedback overhead.
57 citations
••
08 Jun 2015TL;DR: It is shown that even users located close to each other in LOS propagation conditions can be spatially separated in a massive MIMO system, the first report of fully-synchronous dynamic measurements of amassive MIMo system.
Abstract: Fully-synchronous measurements of a massive multi-user multiple-input multiple-output (MU-MIMO) radio propagation channel are presented. We evaluate the ability of a massive MIMO system to spatially separate users located close to each other in line-of-sight (LOS) propagation conditions. The system consists of a base-station (BS) antenna array equipped with 64 dual-polarized antenna elements (128 ports) arranged in a cylindrical configuration, and eight single-antenna users. The users are confined to a five-meter diameter circle and move randomly at pedestrian speeds. The BS antenna array is located on top of a 20 m tall building and has LOS to the users. We examine user separability by studying singular value spread of the MU-MIMO channel matrix for several subsets of BS antenna array ports, along with sum-rate capacity and achievable sum-rates with both zero-forcing and matched-filtering linear precoders. We also analyze the performance of the user with the lowest rate. Finally, a comparison between the performance offered by the massive MIMO system and that of a conventional MU-MIMO system is provided. To the best of our knowledge, this is the first report of fully-synchronous dynamic measurements of a massive MIMO system. Our investigation shows that even users located close to each other in LOS propagation conditions can be spatially separated in a massive MIMO system.
57 citations
••
01 Oct 2007
TL;DR: This work presents a detector based on objective information theoretic criteria (the celebrated AIC and MDL estimators) for detecting the number of transmit antennas and results derived for an ideal BLAST-like transmission demonstrate good performance already for mild SNR conditions.
Abstract: In this work we consider one of the challenges facing unauthorized receivers and cognitive radios since the appearance of MIMO system, which is detecting the number of transmit antennas. To achieves this goal, we present a detector based on objective information theoretic criteria (the celebrated AIC and MDL estimators). Numerical results derived for an ideal BLAST-like transmission demonstrate good performance already for mild SNR conditions and majority decision based on rather few independent measurements.
57 citations