On Performance of Limited Feedback Coordinated Multipoint Transmission for Mobile Systems

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School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2016-08-25
Degree programme
97 + app. 98
Aalto University publication series DOCTORAL DISSERTATIONS, 129/2016
Mobile networks are expected provide consistent quality of experience across the service area. Yet, intercell interference is one of the main causes for the inconsistent user experience in contemporary mobile systems especially when the universal reuse of spectrum is applied. To mitigate and/or even exploit the intercell interference, coordinated multipoint (CoMP) transmission/reception has been considered as a promising technique and it is incorporated in the fourth generation mobile standard. Various CoMP techniques have been investigated in literature and practice, each offering differing trade-offs between performance and implementation requirements. Thus, effective use of various CoMP realizations requires thorough understanding of the mentioned trade-offs associated with each CoMP technique. The contribution of this thesis includes practical approaches for development of effective CoMP transmission methods. Dissertation investigates the methods from three perspectives, namely: by proposing a flexible and practical hierarchical feedback structure to effectively combine different beamforming techniques in CoMP transmission; by studying the performance degradation of CoMP systems due to channel power imbalance in practical CoMP methods with limited feedback; and by evaluating CoMP performance gains in realistic urban deployment scenarios using deterministic 3D propagation models. Performance results reveal that in addition to implementation flexibility, notable performance gain can be achieved by simple limited feedback CoMP methods. Our results also demonstrate that the use of amplitude feedback – fast or slow – is important to effectively compensate the impact of channel power imbalance. Furthermore, our results show that CoMP may significantly relax the capacity gap between backhaul and access links of self-backhauled low power nodes.
Supervising professor
Hämäläinen, Jyri, Prof., Aalto University, Department of Communications and Networking, Finland
Thesis advisor
Mutafungwa, Edward, Dr., Aalto University, Department of Communications and Networking, Finland
User Experience, Intercell Interference, Coordinated Multipoint, Hierarchical Beamforming, Channel Power Imbalance, Self-backhauling, Low Power Nodes, QoE, 4.5G, CoMP, Relay, Smallcell
Other note
  • [Publication 1]: B. B. Haile and J. Hämäläinen. Performance analysis of hierarchically combined practical beamforming methods. Wireless Personal Communications, vol. 84, no. 3, pp. 1855-1875, April 2015.
    DOI: 10.1007/s11277-015-2545-5 View at publisher
  • [Publication 2]: B. B. Haile, A. Dowhuszko, J. Hämäläinen, R. Wichman and Z. Ding. On performance loss of some CoMP techniques under channel power imbalance and limited feedback. IEEE Transactions on Wireless Communications, vol. 14, no. 8, pp. 4469-4481, August 2015.
    DOI: 10.1109/TWC.2015.2421898 View at publisher
  • [Publication 3]: B. B. Haile, J. Hämäläinen and Z. Ding. Power imbalance induced BER performance loss under limited feedback CoMP techniques. submitted to EURASIP Journal on Communications and Networking.
  • [Publication 4]: B. B. Haile, E. Mutafungwa and J. Hämäläinen. Coordinated multipoint transmission for LTE-Advanced networks in dense informal settlements. In IEEE AFRICON 2013, Pointe-Aux-Piments, pp. 1-5, September 2013.
    DOI: 10.1109/AFRCON.2013.6757791 View at publisher
  • [Publication 5]: B. B. Haile, E. Mutafungwa and J. Hämäläinen. Coordinated multipoint transmission for relaxation of self-backhauling bottlenecks in heterogeneous networks. EURASIP Journal on Wireless Communications and Networking, vol. 2015, no. 1, March 2015.
  • [Publication 6]: B. B. Haile, E. Mutafungwa and J. Hämäläinen. Use of coordinated multipoint transmission for relaxation of relay link bottlenecks. In IEEE 79th Vehicular Technology Conference Spring (VTC-Spring 2014), Seoul, pp. 1-5, May 2014.
    DOI: 10.1109/VTCSpring.2014.7023136 View at publisher
  • [Publication 7]: B. B. Haile, E. Mutafungwa and J. Hämäläinen. LTE-Advanced enhancements for self-backhauled LTE-U small cells: An addis ababa case study. In IEEE AFRICON 2015, Addis Ababa, pp. 1-5, September 2015.
    DOI: 10.1109/AFRCON.2015.7332025 View at publisher