User Identification for Opportunistic OFDM-Based Multiuser Wireless Communications

• Published in: IEEE transactions on vehicular technology Vol. 61; no. 4; pp. 1673 - 1684
• Main Authors: Li, Hang, Guo, Qinghua, Huang, Defeng (David), Zhang, YingJun (Angela)
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Channels; Detection, estimation, filtering, equalization, prediction; Exact sciences and technology; Frequency domain analysis; Information, signal and communications theory; Messages; Multiple-input multiple-output (MIMO); Multiplexing; multiuser diversity; Multiuser systems; OFDM; Organization and planning of networks (techniques and equipments); Orthogonal Frequency Division Multiplexing; orthogonal frequency-division multiplexing (OFDM); Scheduling; Signal and communications theory; Signal, noise; Simulation; Stations; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Throughput; Tightness; Time domain analysis; Transmission and modulation (techniques and equipments); Transmitting antennas; user identification approach (UIDA); Vectors; Wireless communication; Wireless communications; wireless local area network (WLAN); Wireless networks; Performance evaluation; Multiple-input multiple-output (MIMO); Parameter estimation; Current source converter; Base station; Wireless telecommunication; Power system economics; Information rate; Identification; user identification approach (UIDA); Channel estimation; Broadcasting; Power markets; Message transmission; User need; Fading channels; MIMO system; Multiple access; Leakproofness; multiuser diversity; Rayleigh channels; wireless local area network (WLAN); Scheduling; Information transmission; Upper bound; Orthogonal frequency division multiplexing; Wireless network; System simulation; Planning; orthogonal frequency-division multiplexing (OFDM)
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2012.2187936

Multiuser diversity can be employed in wireless communications to significantly improve system performance by scheduling the channel to the user with the best instantaneous channel-state information (CSI). Conventionally, all users' CSI must be available at the base station (BS) to achieve the benefit of multiuser diversity, thereby inducing enormous system overhead. To solve the overhead issue, we propose a user identification approach (UIDA) in a generic wireless network and demonstrate its application in the orthogonal frequency-division multiplexing (OFDM) system and the multiple-input multiple-output OFDM (MIMO-OFDM) system. In the UIDA, to find the user with the best CSI, all active users simultaneously send response messages to the BS following a broadcast probing message from the BS, and only the selected user's CSI needs to be available at the BS, thus reducing the system overhead. We present a theoretical upper bound of the throughput of the system with the UIDA over general channels, and its tightness over Rayleigh fading channels is verified by simulations. In addition, a modified UIDA is proposed to effectively trade off throughput and fairness performances, where only the active users whose signal-to-noise ratios (SNRs) are above their predetermined thresholds will send response messages. Compared with medium access diversity and multiuser diversity with capture (two alternative approaches in the literature for exploiting multiuser diversity) and with a similar system setup, simulation results show that the UIDA achieves better throughput performance when there are a reasonably large number of users.