TR2007-091

Asymmetric Cooperation Among Relays with Linear Precoding


    •  Devroye, N., Mehta, N.B., Molisch, A.F., "Asymmetric Cooperation Among Relays with Linear Precoding", IEEE Global Telecommunications Conference (GLOBECOM), November 2007, pp. 4391-4396.
      BibTeX TR2007-091 PDF
      • @inproceedings{Devroye2007nov,
      • author = {Devroye, N. and Mehta, N.B. and Molisch, A.F.},
      • title = {Asymmetric Cooperation Among Relays with Linear Precoding},
      • booktitle = {IEEE Global Telecommunications Conference (GLOBECOM)},
      • year = 2007,
      • pages = {4391--4396},
      • month = nov,
      • isbn = {978-1-4244-1043-9},
      • url = {https://www.merl.com/publications/TR2007-091}
      • }
  • Research Area:

    Communications

Abstract:

Fixed and mobile relays are used, among other applications, in the downlink of cellular communications systems. Cooperation between relays can greatly increase their benefits in terms of extended coverage, increased reliability, and improved spectral efficiency. In this paper, we introduce the fundamental notion of asymmetric cooperation. For this, we consider a two-phase transmission protocol where, in the first phase, the base station (BS) sends several available messages to the relay over wireless links. But, depending on the channel state and the duration of the BS transmission, not all relays decode all messages. In a second phase, the relays, which may now have asymmetric message knowledge, use cooperative linear precoding for the transmission to the mobile stations. We show that for many channel configurations, asymmetric cooperation, although (slightly) sub-optimum for the second phase, is optimum from a total-throughput point of view, as it requires less time and energy in the first phase. We give analytical formulations for the optimum operating parameters and the achievable throughput, and show that under typical circumstances, 20-30% throughput enhancement can be achieved over conventional systems.

 

  • Related News & Events

    •  NEWS    GLOBECOM 2007: 4 publications by Philip V. Orlik, Koon Hoo Teo, Zhifeng (Jeffrey) Tao, Jinyun Zhang and others
      Date: November 26, 2007
      Where: IEEE Global Telecommunications Conference (GLOBECOM)
      MERL Contacts: Jinyun Zhang; Philip V. Orlik
      Brief
      • The papers "Hybrid Coherent and Frequency-Shifted-Reference Ultrawideband Radio" by Liu, H., Molisch, A.F., Zhao, S., Goeckel, D. and Orlik, P., "Channel Measurements of an Indoor Office Scenario for Wireless sensor Applications" by Wyne, S., Santos, T., Tufvesson, F. and Molisch, A.F., "Asymmetric Cooperation Among Relays with Linear Precoding" by Devroye, N., Mehta, N.B. and Molisch, A. F. and "Frame Structure Design for IEEE 802.16j Mobile Multihop Relay (MMR) Networks" by Tao, Z., Li, A., Teo, K.H. and Zhang, J. were presented at the IEEE Global Telecommunications Conference (GLOBECOM).
    •