Adaptive Uniform Channel Decomposition in MU-MIMO-OFDM: Application to IEEE 802.11ac

Abstract

This work considers the design of multiuser MIMO (MU-MIMO) schemes suitable for orthogonal frequency division multiplex (OFDM) systems such as those being currently discussed within IEEE 802.11ac. A general framework is proposed showing that the singular value decomposition (SVD), the geometric mean decomposition (GMD) and the uniform channel decomposition (UCD) are all viable mechanisms on which to lay the design. Nonetheless, some striking differences in terms of performance among these three schemes are uncovered. In particular, a novel adaptive transmission scheme based on the UCD is introduced that enables multiuser MIMO-OFDM gains to be realized, clearly outperforming those obtained using the SVD or GMD counterparts while remaining fully compliant with the latest IEEE 802.11ac specification. Relying on the UCD properties, the proposed technique takes into account the availability of a finite modulation and coding set and restrictions on transmission mode selection defined within the standard, to incorporate an optimisation step in charge of selecting the number of transmitted data streams to each user to maximise the system throughput. Comprehensive simulation results in the context of IEEE 802.11ac confirm the applicability and advantage of the adaptive UCD-based design.Index Terms-MU-MIMO, OFDM, IEEE 802.11ac, geometric mean decomposition (GMD), uniform channel decomposition (UCD), zero-forcing beamforming, fast link adaptation (FLA).

Optimal Pair-Wise Sus Algorithm as Proportional Fair Algorithm for Mu-Mimo-Ofdm Systems

“…Therefore, Jain's fairness index is low for large number of users in the cell for MSUS algorithm, which was. expected [11]. It is also expected that the PF-MSUS algorithm would show a worse throughput performance than the MSUS algorithm [11], and it is confirmed through Fig.…”

“…A spacetime-frequency-selective fading channel is presented through B and E channel profile [21]. The values of parameters for FLA are taken from Table I in [11]. In this paper, unlike the work in [10] where a homogenous scenario is considered, in which all users sit on circumference centered at AP and all experience the same average SNR, a more realistic scenario is analyzed.…”

“…Moreover, the SUS algorithm in combination with ZFBF gives performance reasonably close to one achieved with DPC [6]. In open technical literature, many SUS-based algorithms have been suggested to be applied in practice: seminal SUS, simplified SUS, generalized multicarrier SUS (GMSUS), pair-wise SUS, optimal pair-wise SUS [6,[9][10][11].…”

Channel capacity and performance evaluation of precoded MIMO-OFDM system with large-size constellation

“…Owing to the popular characteristics of the orthogonal frequency division multiplexing (OFDM) in bandwidth efficiency, simple channel equalization and immunity to multipath fading channels, it has been considered for several wireless applications and standards [3,4]. It has been adopted in IEEE 802.11 a,g,and n, IEEE 802.16a, and terrestrial digital video broadcasting (DVB-T) [5].…”

Performance Analysis of Adaptive Filter Channel Estimated MIMO OFDM Communication System

“…These services require interference free transmission over frequency selective fading channels. OFDM is a promising technique for Long Term Evaluation-Advanced (LTE-A), Worldwide Interoperability for Microwave Access (Wi-MAX) systems, IEEE 802.11ac, and IEEE 802.15 [1]. A good channel estimation procedure is necessary in order to make reliable decisions and to coherently demodulate the received data.…”