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Feedbackbased coding algorithms for broadcast erasure channels with degraded message sets
 in Proc. International Symposium on Network Coding (NetCod
, 2012
"... Abstract—We consider singlehop broadcast packet erasure channels (BPEC) with degraded message sets and instantaneous feedback regularly available from all receivers, and demonstrate that the main principles of the virtualqueuebased algorithms in [1], which were proposed for multiple unicast sessi ..."
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Abstract—We consider singlehop broadcast packet erasure channels (BPEC) with degraded message sets and instantaneous feedback regularly available from all receivers, and demonstrate that the main principles of the virtualqueuebased algorithms in [1], which were proposed for multiple unicast sessions, can still be applied to this setting and lead to capacityachieving algorithms. Specifically, we propose a generic class of algorithms and intuitively describe its rationale and properties that result in its efficiency. We then apply this class of algorithms to three examples of BPEC channels (with different numbers of users and 2 or 3 degraded message sets) and show that the achievable throughput region matches a known capacity outer bound, assuming feedback availability through a separate public channel. If the feedback channel is not public, all users can still decode their messages, albeit at some overhead which results in an achievable throughput that differs from the outer bound by O(N/L), where L is the packet length. These algorithms do not require any prior knowledge of channel statistics for their operation. I.
Article The Maximum Error Probability Criterion, Random Encoder, and Feedback, in Multiple Input Channels
, 2014
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1 A Class of Feedbackbased Coding Algorithms for Broadcast Erasure Channels with Degraded Message Sets
"... We consider singlehop broadcast erasure channels (BEC) with degraded message sets and instantaneous feedback regularly available from all receivers, and demonstrate that the main principles of the virtual queuebased algorithms in [1], which were proposed for multiple unicast sessions, can still be ..."
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We consider singlehop broadcast erasure channels (BEC) with degraded message sets and instantaneous feedback regularly available from all receivers, and demonstrate that the main principles of the virtual queuebased algorithms in [1], which were proposed for multiple unicast sessions, can still be applied to this setting and lead to capacityachieving algorithms. Specifically, we propose a generic class of algorithms and intuitively describe its rationale and properties that result in its efficiency. We then apply this class of algorithms to three examples of BEC channels (with different numbers of users and 2 or 3 degraded message sets) and show that the achievable throughput region matches a known capacity outer bound. These algorithms do not require any prior knowledge of channel statistics for their operation. I.
Retroactive AntiJamming for MISO Broadcast Channels∗
, 2014
"... Jamming attacks can significantly impact the performance of wireless communication systems. In addition to reducing the capacity, such attacks may lead to insurmountable overhead in terms of retransmissions and increased power consumption. In this paper, we consider the multipleinput singleoutput ..."
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Jamming attacks can significantly impact the performance of wireless communication systems. In addition to reducing the capacity, such attacks may lead to insurmountable overhead in terms of retransmissions and increased power consumption. In this paper, we consider the multipleinput singleoutput (MISO) broadcast channel (BC) in the presence of a jamming attack in which a subset of the receivers can be jammed at any given time. Further, countermeasures for mitigating the effects of such jamming attacks are presented. The effectiveness of these antijamming countermeasures is quantified in terms of the degreesoffreedom (DoF) of the MISO BC under various assumptions regarding the availability of the channel state information (CSIT) and the jammer state information at the transmitter (JSIT). The main contribution of this paper is the characterization of the DoF region of the two user MISO BC under various assumptions on the availability of CSIT and JSIT. Partial extensions to the multiuser broadcast channels are also presented. 1
Approximate Capacity of the TwoUser MISO Broadcast Channel with Delayed CSIT
"... Abstract—We consider the problem of the twouser multipleinput singleoutput complex Gaussian Broadcast Channel where the transmitter has access to delayed knowledge of the channel state information. We characterize the capacity region of this channel to within a constant number of bits for all val ..."
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Abstract—We consider the problem of the twouser multipleinput singleoutput complex Gaussian Broadcast Channel where the transmitter has access to delayed knowledge of the channel state information. We characterize the capacity region of this channel to within a constant number of bits for all values of the transmit power. The proposed signaling strategy utilizes the delayed knowledge of the channel state information and the previously transmitted signals, in order to create a signal of common interest for both receivers. This signal is the quantized version of the summation of the previously transmitted signals. To guarantee the independence of quantization noise and signal, we extend the framework of lattice quantizers with dither, together with an interleaving step. For converse, we use the fact that the capacity region of this problem is upperbounded by the capacity region of a physically degraded broadcast channel with no channel state information where one receiver has two antennas. We then derive an outerbound on the capacity region of this degraded broadcast channel which in turn provides an outerbound on the capacity region of the twouser multipleinput singleoutput complex Gaussian broadcast channel with delayed knowledge of the channel state information. By careful examination, we show that the achievable rate region and the outerbound are within 1.81 bits/sec/Hz per user. I.
Author manuscript, published in "NETCOOP 2010 4th Workshop on Network Control and Optimization (2010)" Multiuser broadcast erasure channel with feedback — capacity and algorithms
, 2011
"... Abstract—We consider the Nuser broadcast erasure channel where feedback from the users is fed back to the transmitter in the form of ACK messages. We first provide a generic outer bound to the capacity of this system; we then propose a coding algorithm, compute its throughput region and show that i ..."
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Abstract—We consider the Nuser broadcast erasure channel where feedback from the users is fed back to the transmitter in the form of ACK messages. We first provide a generic outer bound to the capacity of this system; we then propose a coding algorithm, compute its throughput region and show that it achieves capacity under certain conditions on channel statistics, assuming that instantaneous feedback is known to all users. Removing this assumption results in a rate region which differs from the outer bound by a factor O(N/L), where L is packet length. For the case of nonsymmetric channels, we present a modification of the previous algorithm whose achievable region is identical to the outer bound for N ≤ 3, when instant feedback is known to all users, and differs from the bound by O(N/L) when each user knows only its own ACK. The proposed algorithms do not require any prior knowledge of channel statistics. Index Terms—Broadcast erasure channels, feedbackbased coding, capacity achieving algorithms. I.
Article Network Coding for Line Networks with Broadcast Channels
, 2012
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Cooperative Networks with Channel Uncertainty
, 2012
"... In this thesis, we focus on cooperative networks where the transmitter is uncertain about the channel in operation. The main contributions are organized in three chapters. tel00765429, version 1 14 Dec 2012 In the first chapter, cooperative strategies are developed for simultaneous relay channels ..."
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In this thesis, we focus on cooperative networks where the transmitter is uncertain about the channel in operation. The main contributions are organized in three chapters. tel00765429, version 1 14 Dec 2012 In the first chapter, cooperative strategies are developed for simultaneous relay channels (SRC) which consist of a set of two single relay channels out of which the channel in operation is chosen. Provided that the channel uncertainty involves a limited number of possibilities, this problem is recognized as being equivalent to that of sending common and private information to several destinations in presence of helper relays where each channel outcome becomes a branch of the broadcast relay channel (BRC). For instance, the source can design a code with three messages (W0, W1, W2) such that (W0, W1) are decoded when the relay uses DF scheme and (W0, W2) when CF scheme is used. Inner bounds on the capacity region of the general BRC with two helper relays are derived for the cases where two relays use different variations of coding strategies. First, both relays use partially DecodeandForward (DF) scheme –DFDF region–, secondly both relays use CompressandForward
On the TwoUser MISO Broadcast Channel With Alternating CSIT: A Topological Perspective
, 2014
"... Abstract — In many wireless networks, link strengths are affected by many topological factors, such as different distances, shadowing, and intercell interference, thus resulting in some links being generally stronger than other links. From an information theoretic point of view, accounting for such ..."
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Abstract — In many wireless networks, link strengths are affected by many topological factors, such as different distances, shadowing, and intercell interference, thus resulting in some links being generally stronger than other links. From an information theoretic point of view, accounting for such topological aspects is still a novel approach, that has been recently fueled by strong indications that such aspects can crucially affect transceiver and feedback design, as well as the overall performance. This paper here takes a step in exploring this interplay between topology, feedback, and performance. This is done for the two user broadcast channel with random fading, in the presence of a simple twostate topological setting of statistically strong versus weaker links, and in the presence of a practical ternary feedback setting of alternating channel state information at the transmitter [alternating channel state information at the transmitter (CSIT)] where for each channel realization, this CSIT can be perfect, delayed, or not available. In this setting, the work derives generalized degreesoffreedom bounds and exact expressions, that capture performance as a function of feedback statistics and topology statistics. The results are based on novel topological signal management schemes that account for topology in order to fully utilize feedback. This is achieved for different classes of feedback mechanisms of practical importance, from which we identify specific feedback mechanisms that are best suited for different topologies. This approach offers further insight on how to split the effort—of channel learning and feeding back CSIT—for the strong versus for the weaker link. Further intuition is provided on the possible gains from topological spatiotemporal diversity, where topology changes in time and across users. Index Terms — Broadcast channel, channel with state, feedback, network topology, channel state information at the transmitter (CSIT), degreesoffreedom (DoF). I.