Macrodiversity MIMO

Fig. 1: Macro-scale diversity MIMO network for multi-user uplink communication, two concurrent users communicate with three base stations [1]. Macro-scale multi-user MIMO networks are often also known as CoMP or network MIMO.

As shown in Fig. 1, macrodiversity MIMO refers to macro-scale diversity networks for mobile wireless communication. In this technology, a set of geographically distributed base stations coherently communicate, both in the uplink and in the downlink, to one or more users in the same time and frequency resource enabling highly reliable and spectrally efficient wireless mobile communication.

A network MIMO system with T transmit antennas (or users in the uplink) and R receive antennas (or base stations) in narrowband flat fading gives rise to the channel:

where y and x are the receive and transmit vectors, respectively, and H and n are the macrodiversity channel matrix and the spatially uncorrelated AWGN vector, respectively. In the uplink network MIMO system in Fig. 1, T=2 and R=3. One way to characterize macrodiversity MIMO networks is by using large scale fading information as:

where the matrix G is known as the macrodiversity gain profile matrix. One can find the average BER of the 1st data stream (or user) in the uplink in terms of the large scale fading information or G as:

Fig. 2: Link-level BER of macrodiversity MIMO networks [1].

where "Perm(.)" denotes the matrix permanent, and SNR is the receive signal-to-noise-ratio. The matrix Q is G with the first column removed, and the diagonal matrix P is:

which is made up of the large scale parameters in the 1st column of G. A detailed derivation of this result could be found in [1]. For more information on practical applications of these results, readers are also referred to [2,3]. If one needs to find the BER of the 2nd user, then the corresponding P would be made up of the large scale parameters in the 2nd column of G, and the corresponding Q would be G with the 2nd column removed.

REFERENCES

1. D. A. Basnayaka, P. J. Smith and P. A. Martin, "Performance Analysis of Macrodiversity MIMO Systems with MMSE and ZF Receivers in Flat Rayleigh Fading," in IEEE Transactions on Wireless Communications, vol. 12, no. 5, pp. 2240-2251, May 2013.

   
   

2. P. J. Smith and D. A. Basnayaka, "Multiuser scheduling for radio resource allocation," granted US patent No: 9107231, Nov. 2015.

   
   

3. Yu-An Chen, "A Low Complexity Method of Resource Allocation in Up-link Macrodiversity Systems Using Long-Term Power" Masters Thesis, University of Canterbury, Christchurch, New Zealand, Dec. 2013.