Interference mitigation techniques for clustered multicell joint decoding systems

Abstract

Multicell joint processing has originated from information-theoretic principles as a means of reaching the fundamental capacity limits of cellular networks. However, global multicell joint decoding is highly complex and in practice clusters of cooperating Base Stations constitute a more realistic scenario. In this direction, the mitigation of intercluster interference rises as a critical factor towards achieving the promised throughput gains. In this paper, two intercluster interference mitigation techniques are investigated and compared, namely interference alignment and resource division multiple access. The cases of global multicell joint processing and cochannel interference allowance are also considered as an upper and lower bound to the interference alignment scheme, respectively. Each case is modelled and analyzed using the per-cell ergodic sum-rate throughput as a figure of merit. In this process, the asymptotic eigenvalue distribution of the channel covariance matrices is analytically derived based on free-probabilistic arguments in order to quantify the sum-rate throughput. Using numerical results, it is established that resource division multiple access is preferable for dense cellular systems, while cochannel interference allowance is advantageous for highly sparse cellular systems. Interference alignment provides superior performance for average to sparse cellular systems on the expense of higher complexity.

Cognitive Interference Alignment for Spectral Coexistence

“…The DoF regions are characterized for several wireless channels such as MIMO BC, interference channels (ICs), including X and multihop ICs, and the CR channels [68]. The DoF metric has been extensively used for interference mitigation and alignment objectives in various wireless networks such as interference mitigation in multicell networks [10,31], interference mitigation in two-cell MIMO interfering BCs [63], IA in CR networks [14,34,57]. The main limitation of the DoF metric is that it does not provide much insight to optimally manage interference when all signals are not comparable, since it forces all channels to be equally strong.…”

“…In addition, authors in [64] consider the uplink of a limited-size cellular system without Multicell Joint Decoding (MJD), showing that the interference-free DoFs can be achieved as the number of User Terminals (UTs) grows large. In the same context, authors in [10] employ IA as an uplink interference mitigation technique amongst cooperating Base Station (BS) clusters for Rayleigh channels. In the context of small cells, the study in [41] extends [10] by assuming clusters of small cells which dictate the use of a Rician fading channel.…”

“…In the same context, authors in [10] employ IA as an uplink interference mitigation technique amongst cooperating Base Station (BS) clusters for Rayleigh channels. In the context of small cells, the study in [41] extends [10] by assuming clusters of small cells which dictate the use of a Rician fading channel. The IA technique has also been investigated in multicarrier systems in different settings [15,19,38,62].…”

Cognitive interference alignment between small cells and a macrocell

“…In addition, authors in [15] consider the uplink of a limited-size cellular system without MJD, showing that the interferencefree degrees of freedom (dofs) can be achieved as the number of UTs grows large. In the same context, authors in [16] employ IA as an uplink interference mitigation technique amongst cooperating BS clusters for Rayleigh channels. Coming back to small cells, the work in [17] extends [16] by assuming clusters of small cells which dictate the use of a Ricean channel.…”

“…In the same context, authors in [16] employ IA as an uplink interference mitigation technique amongst cooperating BS clusters for Rayleigh channels. Coming back to small cells, the work in [17] extends [16] by assuming clusters of small cells which dictate the use of a Ricean channel. Finally, the authors in [18] propose Vandermondesubspace Frequency Division Multiplexing for the downlink in order to null out the interference of small cells towards primary macro users.…”