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.

Closed-form blind channel identification and source separation in SDMA systems through correlative coding

Abstract: We address the problem of blind identification of multiuser multiple-input multiple-output (MIMO) finite-impulse response (FIR) digital systems. This problem arises in spatial division multiple access (SDMA) architectures for wireless communications. We present a closed-form, i.e., noniterative, consistent estimator for the MIMO channel based only on second-order statistics. To obtain this closed form we introduce spectral/correlation asymmetry between the sources by filtering each source output with adequate correlative filters. Our algorithm uses the closed form MIMO channel estimate to cancel the intersymbol interference (ISI) due to multipath propagation and to discriminate between the sources at the wireless base station receiver. Simulation results show that, for single-user channels, this technique yields better channel estimates in terms of mean-square error (MSE) and better probability of error than a well-known alternative method. Finally, we illustrate its performance for MIMO channels in the context of the global system for mobile communications (GSM) system.

Control Channel in a Wireless Communication System

Abstract: A base station receives channel state information from a wireless device. The base station transmits to the wireless device one or more data packets on a data channel employing a first precoding matrix identifier. The base station transmits one or more control packets on a control channel to the wireless device employing a second precoding matrix.

Investigation of Diagonal Antenna-Chassis Mode in Mobile Terminal LTE MIMO Antennas for Bandwidth Enhancement

Abstract: i»?A diagonal antenna–chassis mode is investigated in long-term evolution multiple-input–multiple-output (LTE MIMO) antennas. The MIMO bandwidth is defined in this paper as the overlap range of the low-envelope correlation coefficient, high total efficiency, and -6-dB impedance matching bandwidths. Utilizing the diagonal mode analysis, the MIMO bandwidth of the collocated MIMO antennas is improved efficiently at the frequencies of lower than 960 MHz. This is realized through moving the three bandwidths to the same range without the degradation of impedance bandwidth and total efficiency. The physical mechanism of the mismatch of these three bandwidth ranges is also explained. Furthermore, the diagonal antenna–chassis mode is also studied for MIMO elements in the adjacent and diagonal corner locations. As a practical example, a wideband collocated LTE MIMO antenna is proposed and measured. It covers the bands of 740–960 and 1700–2700 MHz, where the total efficiencies are better than -3.4 and -1.8 dB, with lower than 0.5 and 0.1, respectively. The measurements agree well with the simulations. Since the proposed method only needs to modify the excitation locations of the MIMO elements on the chassis, this method is valid for different types of symmetrical or asymmetrical MIMO antennas to improve the MIMO bandwidth.

A scalable massive MIMO array architecture based on common modules

Abstract: Massive MIMO is envisioned as one of the key enabling technologies for 5G wireless and beyond. While utilizing the spatial dimension to reduce interference and increase capacity in multi-user scenarios, massive MIMO base stations present several unique implementation challenges due to their large physical size and the high datarate generated by all the elements. To be cost-effective and energy efficient, practical designs must leverage the particular characteristics of massive MIMO to ensure scalability. Here, we propose an array architecture based on a common module which serves a small number of antennas with RF transceivers, data converters, and several support functions. Multiple chips are tiled into a grid and interconnected through a digital nearest-neighbor mesh network, avoiding the severe problems associated with analog signal distribution. Scalability across a wide range of array sizes is achieved by using distributed beamforming algorithms. It is demonstrated that by using this approach, the maximum backhaul datarate scales as the number of users rather than the number of antennas. Finally, we present a detailed accounting of the power consumption of the array and use the resulting optimization problem to show that per-element overhead limits the minimum achievable power consumption.