Multi-Flow Scheduling for Coordinated Direct and Relayed Users in Cellular Systems

Abstract

There are two basic principles used in wireless network coding to design throughput-efficient schemes: (1) aggregation of communication flows and (2) interference is embraced and subsequently cancelled or mitigated. These principles inspire design of many novel multi-flow transmission (MFT) schemes. Such are the Coordinated Direct/Relay (CDR) schemes, where each basic transmission involves two flows to a direct and a relayed user. Usage of MFT schemes as building blocks of more complex transmission schemes essentially changes the problem of scheduling, since some of the flows to be scheduled are coupled in a signal domain and they need to be assigned a communication resource simultaneously. In this paper we define a novel framework that can be used to analyze MFT schemes and assess the system-level gains. The framework is based on cellular wireless users with two-way traffic and it sets the basis for devising composite time-multiplexed MFT schemes, tailored to particular optimization criteria. Those criteria can be formulated by adapting well-known schedulers in order to incorporate MFT schemes. The results show rate advantages brought by the CDR schemes in pertinent scenarios. Another key contribution is the proposed framework, which can be used to evaluate any future multi-flow transmission scheme.

Five disruptive technology directions for 5G

“…Cooperative communications paradigms such as CoMP or relaying, which despite falling short of their initial hype are nonetheless beneficial [8], could require a redefinition of the functions of the different nodes. In the context of relaying, for instance, recent developments in wireless network coding [9] suggest transmission principles that would allow recovering some of the losses associated with half-duplex relays. Moreover, recent research points to the plausibility of fullduplex nodes for short-range communication in a not-so-distant future.…”

Energy efficiency of network-coding enabled mobile small cells

“…In brief, network coding allows intermediate nodes between the source and the destination to process and encode data packets from different inputs and to produce new output packets to forward [14]. Various NC schemes have been proposed for both wired and wireless networks, primarily for its ability to improve network throughput and robustness [15] [16][17] [18]. Some studies on energy savings by network coding have also been conducted.…”

Diversity-Multiplexing Trade-off for Coordinated Direct and Relay Schemes

“…Several relaying modes February 26, 2013 DRAFT have been established, such as Amplify-and-Forward (AF) [1], Decode-and-Forward (DF) [2] and Compress-and-Forward (CF) [3], etc. These modes have been used as building blocks to devise relaying techniques in relaying scenarios with one, two, or multiple communication flows [4].…”

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