Coordinated Multipoint (CoMP) transmission and reception has been suggested as a key enabling technology of future cellular systems. To understand different CoMP configurations and to facilitate the configuration selection (and thus determine channel state information (CSI) feedback and data sharing requirements), performance benchmarks are needed to show what performance gains are possible. A unified approach is also needed to enable the cluster of cooperating cells to systematically take care of the transceiver design. To address these needs, the generalized iterative approach (GIA) is proposed as a unified approach for the minimum mean square error (MMSE) transceiver design of general multiple-transmitter multiple-receiver multiple-input-multiple-output (MIMO) systems subject to general linear power constraints. Moreover, the optimum decoder covariance optimization approach is proposed for downlink systems. Their optimality and relationships are established and shown numerically. Five CoMP configurations (Joint Processing-Equivalent Uplink, Joint Processing-Equivalent Downlink, Joint Processing-Equivalent Single User, Noncoordinated Multipoint, and Coordinated Beamforming) are studied and compared numerically. Physical insights, performance benchmarks, and some guidelines for CoMP configuration selection are presented. 1. Introduction Though cellular has many challenges such as multipath fading, cell edge interference, and scarce spectrum, there is a demand for even better cellular performance than what is achieved today. In order to meet this demand, revolutionary ideas are needed. Coordinated Multipoint (CoMP) transmission and reception, a type of Network MIMO (multiple-input and multiple-output) in Long-Term Evolution-Advanced (LTE-A) [1], is one of those ideas and is a key enabling technology of future cellular systems. It, being a MIMO technique, actually exploits the multipath fading. Furthermore, it lowers the cell edge interference by having potential interfering cells cooperate. And lastly, its lowering of the interference allows for better spectrum reuse and, therefore, better use of the scarce spectrum. Since there are various levels of cell cooperation, there are various CoMP configurations [1–4]. As such, the following three categories of configurations are generally considered. The first category is Noncoordinated Multipoint (Non-CoMP) and does not use CoMP at all. In it, each base station (BS) communicates with its own user(s) and does so without cooperating with the other cells in data sharing or channel state information (CSI)
References
[1]
“Further advancements for E-UTRA,” 3GPP TR36.814, 2009.
[2]
F. Zheng, M. Wu, and H. Lu, “Coordinated multi-point transmission and reception for LTE-advanced,” in Proceedings of the 5th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM '09), September 2009.
[3]
S. Parkvall, E. Dahlman, A. Furusk？r et al., “LTE-Advanced - Evolving LTE towards IMT-Advanced,” in Proceedings of the 68th Semi-Annual IEEE Vehicular Technology Conference (VTC '08), September 2008.
[4]
R. Irmer, H. Droste, P. Marsch et al., “Coordinated multipoint: concepts, performance, and field trial results,” IEEE Communications Magazine, vol. 49, no. 2, pp. 102–111, 2011.
[5]
S. Catreux, P. F. Driessen, and L. J. Greenstein, “Simulation results for an interference-limited multiple-input multiple-output cellular system,” IEEE Communications Letters, vol. 4, no. 11, pp. 334–336, 2000.
[6]
R. S. Blum, J. H. Winters, and N. R. Sollenberger, “On the capacity of cellular systems with MIMO,” IEEE Communications Letters, vol. 6, no. 6, pp. 242–244, 2002.
[7]
H. Dai and H. V. Poor, “Asymptotic spectral efficiency of multicell MIMO systems with frequency-flat fading,” IEEE Transactions on Signal Processing, vol. 51, no. 11, pp. 2976–2988, 2003.
[8]
M. Chiani, M. Z. Win, and H. Shin, “MIMO networks: the effects of interference,” IEEE Transactions on Information Theory, vol. 56, no. 1, pp. 336–349, 2010.
[9]
V. R. Cadambe and S. A. Jafar, “Interference alignment and degrees of freedom of the K-user interference channel,” IEEE Transactions on Information Theory, vol. 54, no. 8, pp. 3425–3441, 2008.
[10]
K. Gomadam, V. R. Cadambe, and S. A. Jafar, “Approaching the capacity of wireless networks Through distributed interference alignment,” in Proceedings of the IEEE Global Telecommunications Conference (GLOBECOM '08), pp. 4260–4265, December 2008.
[11]
A. ？. Zgür and D. Tse, “Achieving linear scaling with interference alignment,” in Proceedings of the IEEE International Symposium on Information Theory (ISIT '09), pp. 1754–1758, July 2009.
[12]
R. Tresch, M. Guillaud, and E. Riegler, “On the achievability of interference alignment in the K-user constant MIMO interference channel,” in Proceedings of the IEEE/SP 15th Workshop on Statistical Signal Processing (SSP '09), pp. 277–280, September 2009.
[13]
C. B. Chae, S. H. Kim, and R. W. Heath, “Linear network coordinated beamforming for cell-boundary users,” in Proceedings of the IEEE 10th Workshop on Signal Processing Advances in Wireless Communications (SPAWC '09), pp. 534–538, June 2009.
[14]
H. Dahrouj and W. Yu, “Coordinated beamforming for the multi-cell multi-antenna wireless system,” in Proceedings of the 42nd Annual Conference on Information Sciences and Systems (CISS '08), pp. 429–434, March 2008.
[15]
R. Zakhour, Z. K. M. Ho, and D. Gesbert, “Distributed beamforming coordination in multicell MIMO channels,” in Proceedings of the IEEE 69th Vehicular Technology Conference (VTC '09), April 2009.
[16]
H. Dai, A. F. Molisch, and H. V. Poor, “Downlink capacity of interference-limited MIMO systems with joint detection,” IEEE Transactions on Wireless Communications, vol. 3, no. 2, pp. 442–453, 2004.
[17]
W. Qixing, J. Dajie, L. Guangyi, and Y. Zhigang, “Coordinated multiple points transmission for LTE-advanced systems,” in Proceedings of the 5th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM '09), September 2009.
[18]
S. Shi, M. Schubert, N. Vucic, and H. Boche, “MMSE optimization with per-base-station power constraints for network MIMO systems,” in Proceedings of the IEEE International Conference on Communications (ICC '08), pp. 4106–4110, May 2008.
[19]
J. Zhang, R. Chen, J. G. Andrews, and R. W. Heath, “Coordinated multi-cell MIMO systems with cellular block diagonalization,” in Proceedings of the 41st Asilomar Conference on Signals, Systems and Computers (ACSSC '07), pp. 1669–1673, November 2007.
[20]
J. Dajie, W. Qixing, L. Jianjun, L. Guangyi, and C. Chunfeng, “Uplink coordinated multi-point reception for LTE-advanced systems,” in Proceedings of the 5th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM '09), September 2009.
[21]
A. T？lli, M. Codreanu, and M. Juntti, “Linear multiuser MIMO transceiver optimization in cooperative networks,” in Proceedings of the 2nd International Conference on Communications and Networking in China (ChinaCom '07), pp. 513–517, August 2007.
[22]
A. T？lli, H. Pennanen, and P. Komulainen, “On the value of coherent and coordinated multi-cell transmission,” in Proceedings of the IEEE International Conference on Communications Workshops (ICC '09), June 2009.
[23]
A. T？lli, H. Pennanen, and P. Komulainen, “SINR balancing with coordinated multi-cell transmission,” in Proceedings of the IEEE Wireless Communications and Networking Conference (WCNC '09), April 2009.
[24]
M. Boldi, A. T？lli, M. Olsson et al., “Coordinated MultiPoint (CoMP) Systems,” in Mobile and Wireless Communications for IMT-Advanced and Beyond, A. Osseiran, J. F. Monserrat, and W. Mohr, Eds., pp. 121–155, John Wiley & Sons, Chichester, UK, 2011.
[25]
D. P. Palomar, J. M. Cioffi, and M. A. Lagunas, “Joint Tx-Rx beamforming design for multicarrier MIMO channels: a unified framework for convex optimization,” IEEE Transactions on Signal Processing, vol. 51, no. 9, pp. 2381–2401, 2003.
[26]
A. Scaglione, P. Stoica, S. Barbarossa, G. B. Giannakis, and H. Sampath, “Optimal designs for space-time linear precoders and decoders,” IEEE Transactions on Signal Processing, vol. 50, no. 5, pp. 1051–1064, 2002.
[27]
C.-C. Weng and P. P. Vaidyanathan, “MIMO transceiver optimization with linear constraints on transmitted signal covariance components,” IEEE Transactions on Signal Processing, vol. 58, no. 1, pp. 458–462, 2010.
[28]
D. P. Palomar, “Unified framework for linear MIMO transceivers with shaping constraints,” IEEE Communications Letters, vol. 8, no. 12, pp. 697–699, 2004.
[29]
S. Serbetli and A. Yener, “Transceiver optimization for multiuser MIMO systems,” IEEE Transactions on Signal Processing, vol. 52, no. 1, pp. 214–226, 2004.
[30]
Z. Q. Luo, T. N. Davidson, G. B. Giannakis, and K. M. Wong, “Transceiver optimization for block-based multiple access through ISI channels,” IEEE Transactions on Signal Processing, vol. 52, no. 4, pp. 1037–1052, 2004.
[31]
J. Zhang, Y. Wu, S. Zhou, and J. Wang, “Joint linear transmitter and receiver design for the downlink of multiuser MIMO systems,” IEEE Communications Letters, vol. 9, no. 11, pp. 991–993, 2005.
[32]
M. Schubert, S. Shi, E. A. Jorswieck, and H. Boche, “Downlink sum-MSB transceiver optimization for linear multi-user MIMO systems,” in Proceedings of the 39th Asilomar Conference on Signals, Systems and Computers, pp. 1424–1428, November 2005.
[33]
G. Zheng, T.-S. Ng, and K. K. Wong, “Optimal beamforming for sum-MSE minimization in MIMO downlink channels,” in Proceedings of the IEEE 63rd Vehicular Technology Conference (VTC '06), pp. 1830–1834, July 2006.
[34]
A. J. Tenenbaum and R. S. Adve, “Minimizing sum-MSE implies identical downlink and dual uplink power allocations,” IEEE Transactions on Communications, vol. 59, no. 3, pp. 686–688, 2011.
[35]
S. W. Peters and R. W. Heath, “Cooperative algorithms for MIMO interference channels,” IEEE Transactions on Vehicular Technology, vol. 60, no. 1, pp. 206–218, 2011.
[36]
J. F. Sturm, “Using SeDuMi 1.02, a MATLAB toolbox for optimization over symmetric cones,” Optimization Methods and Software, vol. 11, no. 1, pp. 625–653, 1999.
[37]
J. Lofberg, “YALMIP: a toolbox for modeling and optimization in MATLAB,” in Proceedings of the IEEE International Symposium on Computer-Aided Control System Design (CACSD '04), Taipei, Taiwan, 2004.
[38]
C. M. Yetis, S. A. Jafar, and A. H. Kayran, “Feasibility conditions for interference alignment,” IEEE Transactions on Signal Processing, vol. 58, no. 9, pp. 4771–4782, 2010.
[39]
E. Lu and I-T. Lu, “Practical decentralized high-performance coordinated beamforming,” in Proceedings of the 34th IEEE Sarnoff Symposium, (SARNOFF '11), May 2011.
[40]
I-T. Lu, “Joint MMSE precoder and decoder design for downlink multiuser MIMO systems with arbitrary transmit power constraints,” in Proceedings of the IEEE Sarnoff Symposium (SARNOFF '09), April 2009.
[41]
I-T. Lu, “Joint MMSE precoder and decoder design subject to arbitrary power constraints for uplink multiuser MIMO systems,” in Proceedings of the IEEE 70th Vehicular Technology Conference Fall (VTC '09), September 2009.
[42]
I-T. Lu, J. Li, and E. Lu, “Novel MMSE precoder and decoder designs subject to per-antenna power constraint for uplink multiuser MIMO systems,” in Proceedings of the 3rd International Conference on Signal Processing and Communication Systems (ICSPCS'09), September 2009.
[43]
J. Li, I-T. Lu, and E. Lu, “Optimum mmse transceiver designs for the downlink of multicell mimo systems,” in Proceedings of the IEEE Military Communications Conference (MILCOM '09), October 2009.
[44]
J. Li, I-T. Lu, and E. Lu, “Unified framework and MMSE transceiver designs for multiple-transmitter- multiple-receiver MIMO systems,” in Proceedings of the 33rd IEEE Sarnoff Symposium, April 2010.
[45]
E. Lu, J. Li, and I-T. Lu, “Comparison of coordinated beamforming and non-coordinated multipoint using MMSE transceiver designs,” in Proceedings of the 33rd IEEE Sarnoff Symposium, April 2010.
[46]
J. Li, I-T. Lu, and E. Lu, “Novel MMSE precoder and decoder designs for single-user MIMO systems under general power constraints,” in Proceedings of the IEEE 71st Vehicular Technology Conference (VTC '10), May 2010.
[47]
J. Li, E. Lu, and I-T. Lu, “Performance benchmark for network MIMO systems: a unified approach for mmse transceiver design and performance analysis,” in Proceedings of the 53rd IEEE Global Communications Conference (GLOBECOM '10), December 2010.
