arXiv subjects

Neda Aboutorab

Publications and source records attributed to Neda Aboutorab.

23 records · Page 2Linked to original sources

arXiv2014

Scheduling Advantages of Network Coded Storage in Point-to-Multipoint Networks

We consider scheduling strategies for point-to-multipoint (PMP) storage area networks (SANs) that use network coded storage (NCS). In particular, we present a simple SAN system model, two server scheduling algorithms for PMP networks, and analytical expressions for internal and external blocking probability. We point to select scheduling advantages in NCS systems under normal operating conditions, where content requests can be temporarily denied owing to finite system capacity from drive I/O access or storage redundancy limitations. NCS can lead to improvements in throughput and blocking probability due to increased immediate scheduling options, and complements other well documented NCS advantages such as regeneration, and can be used as a guide for future storage system design.

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arXiv2013

On Improving the Balance between the Completion Time and Decoding Delay in Instantly Decodable Network Coded Systems

This paper studies the complicated interplay of the completion time (as a measure of throughput) and the decoding delay performance in instantly decodable network coded (IDNC) systems over wireless broadcast erasure channels with memory, and proposes two new algorithms that improve the balance between the completion time and decoding delay of broadcasting a block of packets. We first formulate the IDNC packet selection problem that provides joint control of the completion time and decoding delay as a statistical shortest path (SSP) problem. However, since finding the optimal packet selection policy using the SSP technique is computationally complex, we employ its geometric structure to find some guidelines and use them to propose two heuristic packet selection algorithms that can efficiently improve the balance between the completion time and decoding delay for broadcast erasure channels with a wide range of memory conditions. It is shown that each one of the two proposed algorithms is superior for a specific range of memory conditions. Furthermore, we show that the proposed algorithms achieve an improved fairness in terms of the decoding delay across all receivers.

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arXiv2013

From Instantly Decodable to Random Linear Network Coding

Our primary goal in this paper is to traverse the performance gap between two linear network coding schemes: random linear network coding (RLNC) and instantly decodable network coding (IDNC) in terms of throughput and decoding delay. We first redefine the concept of packet generation and use it to partition a block of partially-received data packets in a novel way, based on the coding sets in an IDNC solution. By varying the generation size, we obtain a general coding framework which consists of a series of coding schemes, with RLNC and IDNC identified as two extreme cases. We then prove that the throughput and decoding delay performance of all coding schemes in this coding framework are bounded between the performance of RLNC and IDNC and hence throughput-delay tradeoff becomes possible. We also propose implementations of this coding framework to further improve its throughput and decoding delay performance, to manage feedback frequency and coding complexity, or to achieve in-block performance adaption. Extensive simulations are then provided to verify the performance of the proposed coding schemes and their implementations.

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arXiv2013

On Throughput and Decoding Delay Performance of Instantly Decodable Network Coding

In this paper, a comprehensive study of packet-based instantly decodable network coding (IDNC) for single-hop wireless broadcast is presented. The optimal IDNC solution in terms of throughput is proposed and its packet decoding delay performance is investigated. Lower and upper bounds on the achievable throughput and decoding delay performance of IDNC are derived and assessed through extensive simulations. Furthermore, the impact of receivers' feedback frequency on the performance of IDNC is studied and optimal IDNC solutions are proposed for scenarios where receivers' feedback is only available after and IDNC round, composed of several coded transmissions. However, since finding these IDNC optimal solutions is computational complex, we further propose simple yet efficient heuristic IDNC algorithms. The impact of system settings and parameters such as channel erasure probability, feedback frequency, and the number of receivers is also investigated and simple guidelines for practical implementations of IDNC are proposed.

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arXiv2013

Joint Optimization of Throughput and Packet Drop Rate for Delay Sensitive Applications in TDD Satellite Network Coded Systems

In this paper, we consider the issue of throughput and packet drop rate (PDR) optimization as two performance metrics for delay sensitive applications in network coded time division duplex (TDD) satellite systems with large round trip times (RTT). We adopt random linear network coding (RLNC) under two different scenarios, feedback-less and with feedback, and our goal is to jointly optimize the mean throughputs and PDRs of users in the system. For this purpose, we propose a systematic framework and start with formulating and optimizing these performance metrics for the single-user case. This framework enables us to analytically compare the performance metrics under different system parameters and settings. By comparing RLNC schemes under feedback-less and feedback scenarios for different RTTs, we show that the feedback-less schemes outperform the schemes with feedback in TDD systems with large RTTs. Then, we extend the study of feedback-less RLNC schemes to the multi-user broadcast case. Here, we consider a number of different broadcast scenarios and optimize the system parameters such that the best overall performance is achieved. Furthermore, the complicated interplay of the mean throughputs and PDRs of different users with different packet erasure conditions in each of the considered broadcast scenarios is discussed.

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