MIMO Interference Alignment in Random Access Networks

Abstract

Abstract-In this paper we analyze a multiple-input-multipleoutput interference channel where nodes randomly distributed on a plane utilize interference alignment to reduce the point-topoint outage. We model the spatial distribution of the nodes as a spatial Poisson cluster point process with equal sized clusters. Each cluster uses intra-cluster interference alignment to suppress interference. We link the accuracy of channel state information to the distance between the nodes, i.e., for a fixed SNR, the quality of CSI degrades with increasing distance. Accounting for the inter-cluster unaligned interference, we compare intra-cluster interference alignment with open-loop spatial multiplexing. In our analysis we find common system setups where the benefits of using interference alignment over spatial multiplexing degrade the most due to the imperfect channel state information.

System-level performance of interference alignment

“…The spectral efficiency functionals in (24) and (26) depend, through ρ IA , on both r 0 and r K−1 and they are thus fully general-in fact unnecessarily general for the purpose of assessing the benefits of IA. For that purpose, specifying the ratio a 0 is largely sufficient, as that allows marginalizing out the network dimensions while retaining the discrimination of relative in-cluster positions.…”

MIMO interference alignment in random access networks

“…Also, the signal-tonoise-ratio (SNR) switching point between IA and TDMA+SM decreases with increasing density and mobility. Our initial work in [1] only deals with point-to-point outage probability. This paper elaborates on the claims of [1], solves for the optimum training period, finds the corresponding transmission capacity of the network, provides easier to compute bounds in several important cases, and presents new simulation results.…”

Performance Analysis of Clustered LoRa Networks

“…PCPs have attracted lots of attention in cellular networks and wireless sensor networks [27]- [33], recently. In [27], an interference alignment approach has been used for a cluster topology to address intra-cluster interference for multipleinput multiple-output (MIMO) systems, where a spatial PCP process is used to model the nodes in a random access network.…”

“…PCPs have attracted lots of attention in cellular networks and wireless sensor networks [27]- [33], recently. In [27], an interference alignment approach has been used for a cluster topology to address intra-cluster interference for multipleinput multiple-output (MIMO) systems, where a spatial PCP process is used to model the nodes in a random access network. For heterogeneous cellular networks, PCP has been adopted in [28], [29] to model nodes clustering at hot spots while taking into consideration the fact that base stations belonging to different tiers may differ in terms of transmit power, node density, and link reliability.…”