Efficient wireless scheduling with limited channel feedback and performance guarantees

Abstract

It is well known that Max-Weight scheduling provides queue stability whenever this is possible. However, MaxWeight scheduling requires the complete channel state information (CSI) to make the best transmission decision at every time slot. The common assumption in this line of research assumes that the network controller has full CSI at every decision time without taking into account the overhead associated with channel probing. In practice, however, acquiring CSI is not cost-free and requires certain amount of resources. In this work, we design a Scheduling and Dynamic Feedback algorithm, named SDF, by considering the overhead of obtaining the channel state information. We first establish a bound on the achievable rate region of SDF algorithm by proving that SDF supports 1 + fraction of of the full rate region (the rate region when all users are probed) where only depends on the expected number of users which are not probed. Then, for homogenous channel, we show that when the number of users in the network is greater than 3, > 0, i.e., we guarantee to expand the rate region. We also demonstrate numerically in a realistic simulation setting that this rate region can be achieved by probing only less than 50% of all channels in a CDMA based cellular network utilizing high data rate protocol under normal channel conditions.

A traffic aware joint CQI feedback and scheduling scheme for multichannel downlink systems in TDD feedback mode

“…Z kn (t) = 1 if user k is scheduled on channel n at time slot t and zero otherwise). As mentioned in the Introduction, we will compare our scheme with the scheme of [13] applied in multiple carriers (will be referred to as "SSF" in the rest of the paper, standing for "Selective Scheduling and Feedback" [12], [13]). Variables with a tilde will be the quantities corresponding to the proposed scheme, while variables denoted with normal letters will correspond to the SSF scheme.…”

“…Based on optimal stopping theory and assuming that the distributions of the channel gains are known to the base station, the authors derive the general properties of the centralized optimal probing policy and completely characterize it in some special cases. Finally, for the same model, the authors in [12], [13] have recently propose a simple feedback scheme for a single channel system. This scheme requires no knowledge of channel and traffic statistics and is shown to guarantee greater stability region than a scheme where all channels are probed.…”

Joint Opportunistic Scheduling and Selective Channel Feedback

“…In their seminal work, Tassiulas and Ephremides have shown that opportunistic Max-Weight algorithm which schedules the user with the highest queue backlog and transmission rate product at every time slot can stabilize the network, whenever this is possible [2]. This scheme has been generalized to wireless Preliminary version of the paper was presented at the International WDN Workshop on Cooperative and Heterogeneous Cellular Networks (WDN-CN2012) co-located with IEEE PIMRC in Sydney, Australia on Sep. 2012 [1].…”

“…This value is then sent back to the base station via the reverse link data rate request channel (DRC). The channel state information is 4 bits long and it is sent back every 1.67 ms 1 . If there are 25 users in a cell, 100 bits of channel state information is sent back to the base station every 1.67 ms.…”

Traffic-Aware Scheduling and Feedback Allocation in Multichannel Wireless Networks

“…Different limitations result in such incomplete information, such as estimation error, delay and limited feedback resources, so it is important to analyze the impact of such imperfections on the system stability. For a single channel system, mainly time-division duplex (TDD), the authors in [11], [12] have proposed a feedback allocation scheme. Specifically, this scheme sets as threshold the rate of the user with the maximum queue length and requires no knowledge of channel and traffic statistic.…”