An Uplink Capacity Analysis of the Distributed Antenna System (DAS): From Cellular DAS to DAS with Virtual Cells

Performance of cellular networks is severely limited by intense inter-cell interference due to aggressive frequency reuse among cells. How to characterize the dependency of inter-cell interference on positions of BS antennas and users is a key question for the capacity analysis of cellular systems, which unfortunately remains elusive. In this paper, a comparative study on the uplink ergodic sum capacity of cellular systems is presented, where Lc BS antennas are either co-located at the cell center or uniformly distributed within each cell. With a large number of users, the inter-cell interference density is shown to be inversely proportional to Lc if the co-located antenna (CA) layout is adopted. With the distributed antenna (DA) layout, it scales in the order of Lc-α/2, where α is the path-loss factor, and is much lower than that in the CA case when Lc is large. Substantial gains on the uplink sum capacity are achieved by the DA layout thanks to the reduction of inter-cell interference level. The analysis also reveals that the inter-cell interference density of each BS antenna is sensitive to its position. With the DA layout, BS antennas at cell boundary areas suffer from much higher inter-cell interference than those at the cell center, which may exacerbate the performance disparity of users in cellular systems. To tackle the cell-edge problem, a distributed antenna system (DAS) is further considered, where L BS antennas are distributed over a wide area, and each user chooses V ≪ L surrounding BS antennas as its virtual cell, i.e., its own serving BS antenna set. A uniform inter-cell interference density is shown to be achieved thanks to the adaptive formation of virtual cells. More importantly, by the use of virtual cell, the number of users served by each BS antenna decreases with an increasing L, implying that much of the signal processing and information exchange can be performed in a local and distributed way. The uplink ergodic sum capacity and the ergodic rate with orthogonal access of DASs with V=1 are further derived, and shown to be close to each other even with a large L. It is in sharp contrast to cellular systems where a significant tradeoff between performance and complexity has to be made when the number of BS antennas is large.

[1]  Wei Feng,et al.  Downlink Capacity of Distributed Antenna Systems in a Multi-Cell Environment , 2009, 2009 IEEE Wireless Communications and Networking Conference.

[2]  Shlomo Shamai,et al.  Sum Rate Characterization of Joint Multiple Cell-Site Processing , 2007, IEEE Transactions on Information Theory.

[3]  M. J. Gans,et al.  On Limits of Wireless Communications in a Fading Environment when Using Multiple Antennas , 1998, Wirel. Pers. Commun..

[4]  V. Marčenko,et al.  DISTRIBUTION OF EIGENVALUES FOR SOME SETS OF RANDOM MATRICES , 1967 .

[5]  Huiling Zhu,et al.  Performance Comparison Between Distributed Antenna and Microcellular Systems , 2011, IEEE Journal on Selected Areas in Communications.

[6]  S. Ariyavisitakul,et al.  A radio access system with distributed antennas , 1994, 1994 IEEE GLOBECOM. Communications: The Global Bridge.

[7]  Lin Dai,et al.  Capacity analysis in CDMA distributed antenna systems , 2005, IEEE Transactions on Wireless Communications.

[8]  H. H. Xia,et al.  A CDMA-distributed antenna system for in-building personal communications services , 1996, IEEE J. Sel. Areas Commun..

[10]  Hiroyuki Ohtsuka,et al.  The New Generation of Wireless Communications Based on Fiber-Radio Technologies , 1993 .

[11]  David Tse,et al.  Multicell Downlink Capacity with Coordinated Processing , 2008, EURASIP J. Wirel. Commun. Netw..

[12]  Shlomo Shamai,et al.  Uplink Macro Diversity of Limited Backhaul Cellular Network , 2008, IEEE Transactions on Information Theory.

[13]  David Tse,et al.  Fundamentals of Wireless Communication , 2005 .

[14]  Liang Xiao,et al.  Information-theoretic capacity analysis in MIMO distributed antenna systems , 2003, The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring..

[15]  David Gesbert,et al.  Adaptation, Coordination, and Distributed Resource Allocation in Interference-Limited Wireless Networks , 2007, Proceedings of the IEEE.

[16]  Aaron D. Wyner,et al.  Shannon-theoretic approach to a Gaussian cellular multiple-access channel , 1994, IEEE Trans. Inf. Theory.

[17]  Inkyu Lee,et al.  Capacity Analysis of Distributed Antenna Systems in a Composite Fading Channel , 2012, IEEE Transactions on Wireless Communications.

[18]  Emre Telatar,et al.  Capacity of Multi-antenna Gaussian Channels , 1999, Eur. Trans. Telecommun..

[19]  Xiaohu You,et al.  Spectral Efficiency of Distributed MIMO Cellular Systems in a Composite Fading Channel , 2008, 2008 IEEE International Conference on Communications.

[20]  Wei Yu,et al.  Multi-Cell MIMO Cooperative Networks: A New Look at Interference , 2010, IEEE Journal on Selected Areas in Communications.

[21]  Jing Wang,et al.  Distributed wireless communication system: a new architecture for future public wireless access , 2003, IEEE Commun. Mag..

[22]  David Tse,et al.  Asymptotically optimal water-filling in vector multiple-access channels , 2001, IEEE Trans. Inf. Theory.

[23]  Giuseppe Caire,et al.  Multi-Cell MIMO Downlink With Cell Cooperation and Fair Scheduling: A Large-System Limit Analysis , 2010, IEEE Transactions on Information Theory.

[24]  Adel A. M. Saleh,et al.  Distributed Antennas for Indoor Radio Communications , 1987, IEEE Trans. Commun..

[25]  Liang Xiao,et al.  Spectral efficiency of distributed antenna system with random antenna layout , 2003 .

[26]  Lin Dai A Comparative Study on Uplink Sum Capacity with Co-Located and Distributed Antennas , 2011, IEEE Journal on Selected Areas in Communications.

[27]  Jeffrey G. Andrews,et al.  Downlink performance and capacity of distributed antenna systems in a multicell environment , 2007, IEEE Transactions on Wireless Communications.

[28]  Min Chen,et al.  Distributed Antenna Systems: Open Architecture for Future Wireless Communications , 2006 .

[29]  M. V. Clark,et al.  Distributed versus centralized antenna arrays in broadband wireless networks , 2001, IEEE VTS 53rd Vehicular Technology Conference, Spring 2001. Proceedings (Cat. No.01CH37202).

[30]  Antonia Maria Tulino,et al.  Capacity of multiple-transmit multiple-receive antenna architectures , 2002, IEEE Trans. Inf. Theory.

[31]  Jamie S. Evans,et al.  Scaling results on the sum capacity of cellular networks with MIMO links , 2006, IEEE Transactions on Information Theory.

[32]  Jeffrey G. Andrews,et al.  Distributed Antenna Systems with Randomness , 2008, IEEE Transactions on Wireless Communications.

[33]  Arogyaswami Paulraj,et al.  MIMO channel capacity for the distributed antenna , 2002, Proceedings IEEE 56th Vehicular Technology Conference.

[34]  Xiaohu You,et al.  Cell Edge Performance of Cellular Mobile Systems , 2011, IEEE Journal on Selected Areas in Communications.

[35]  Lin Dai,et al.  Capacity with MRC-based macrodiversity in CDMA distributed antenna systems , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.