Queueing stability and CSI probing of a TDD wireless network with interference alignment

Abstract

This paper characterizes the performance of interference alignment (IA) technique taking into account the dynamic traffic pattern and the probing/feedback cost. We consider a time-division duplex (TDD) system where transmitters acquire their channel state information (CSI) by decoding the pilot sequences sent by the receivers. Since global CSI knowledge is required for IA, the transmitters have also to exchange their estimated CSIs over a backhaul of limited capacity (i.e. imperfect case). Under this setting, we characterize in this paper the stability region of the system under both the imperfect and perfect (i.e. unlimited backhaul) cases, then we examine the gap between these two resulting regions.Further, under each case, we provide a centralized probing algorithm (policy) that achieves the max stability region. These stability regions and scheduling policies are given for the symmetric system where all the path loss coefficients are equal to each other, as well as for the general system. For the symmetric system, we compare the stability region of IA with the one achieved by a time division multiple access (TDMA) system where each transmitter applies a simple singular value decomposition technique (SVD). We then propose a scheduling policy that consists in switching between these two techniques, leading the system, under some conditions, to achieve a bigger stability region. Under the general system, the adopted scheduling policy is of a high computational complexity for moderate number of pairs, consequently we propose an approximate policy that has a reduced complexity but that achieves only a fraction of the system stability region. A characterization of this fraction is provided.

Whittle Index Policy for Multichannel Scheduling in Queueing Systems

“…There are lot of works which study the problem of resource allocation in wireless networks. For instance, in [5] [6] [16] [7], the authors give a throughput optimal policy for single channel, multi-channel and multi-user MIMO contexts using max weight rule, which is known to not be delay optimal. To overcome this matter, many works have been developed in the past to minimize the average delay of the traffic of the users (e.g.…”

Using Continuous Power Modulation for Exchanging Local Channel State Information

“…While many estimation techniques or protocols to acquire local CSI (i.e., the channel gains of links from all transmitters to a given receiver) at a transmitter are available in literature (see e.g., [1] [2]), there are not many works providing techniques to acquire global CSI. The existing techniques to acquire global CSI, typically rely on the existence of inter-transmitter signaling channels (see [3] [4] [5]), which may be unavailable in practice. Remarkably, it has been shown recently in [6] that global CSI 1 can be acquired from the sole knowledge of the received signal strength indicator (RSSI) or signal-tointerference plus noise ratio (SINR), and therefore making dedicated feedback and inter-transmitter channels unnecessary.…”