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coding-strategy
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Secrecy capacity of wiretap channel for a new scenario and designing code for wiretap channel
, Article Proceedings - 2010 18th Iranian Conference on Electrical Engineering, ICEE 2010, 11 May 2010 through 13 May 2010 ; 2010 , Pages 183-187 ; 9781424467600 (ISBN) ; Salimi, S ; Salmasizadeh, M ; Sharif University of Technology
Abstract
The concept of information theoretic security is introduced. Secrecy capacity of two receiver broadcast channel for a new scenario is derived in which it is assumed that the legitimate receiver has access to a noisy version of eavesdroppers channel outputs. Also the ideas of code designing to achieve zero error on main channel and perfect secrecy on the eavesdropper's channel, without invoking complicated capacity achieving codes are provided
Content delivery via multi-server coded caching in linear networks
, Article ITW 2015 - 2015 IEEE Information Theory Workshop, 11 October 2015 through 15 October 2015 ; 2015 , Pages 267-271 ; 9781467378529 (ISBN) ; Motahari, S. A ; Khalaj, B. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
We consider a content delivery network where multiple servers are connected to multiple cache-enabled clients. Clients request their corresponding contents from the servers and servers collaboratively transmit packets to fulfill all the requests. It is assumed that some contents are stored in the caches in off-peak time of the network without knowing the actual requests, the so called cache content placement phase. The goal is to minimize the worst case delay in the content delivery phase. Considering a random linear network, we propose a coding strategy which exploits servers' multiplexing gains as well as caches' global and local coding gains. The main idea in our coding scheme is to...
Achievable rate regions for interference channel with two relays
, Article ISITA/ISSSTA 2010 - 2010 International Symposium on Information Theory and Its Applications, 17 October 2010 through 20 October 2010 ; October , 2010 , Pages 1018-1023 ; 9781424460175 (ISBN) ; Mirmohseni, M ; Aref, M.R ; Society of Information Theory and Its Applications (SITA); National Science Council; Bureau of Foreign Trade, MOEA; Chunghwa Telecom Co., Ltd; Inf. Commun. Res. Lab. Ind. Technol ; Sharif University of Technology
2010
Abstract
In this paper, we introduce discrete memoryless Interference Channel (IFC) with two relays as two interfering transmitter-receiver pairs that are aided by two relays. We propose two different coding strategies for this channel. In the first strategy, we assume that each relay tries to mainly help one of the transmitter-receiver pairs through signal relaying and interference cancellation, while in the second strategy we assume that each relay tries to help both transmitter-receiver pairs. In our coding schemes, we employ rate-splitting, generalized block Markov coding, superposition coding and Gel'fand-Pinsker binning to cancel parts of the interference known to be experienced at the...
An achievable rate for relay networks based on compress-and-forward strategy
, Article IEEE Communications Letters ; Volume 14, Issue 4 , 2010 , Pages 279-281 ; 10897798 (ISSN) ; Ghabeli, L ; Aref, M. R ; Sharif University of Technology
Abstract
Compress-and-Forward (CF) is a well-known coding strategy proposed for relay channels. Few works which were done about the generalization of the CF strategy to the relay networks, are based on irregular encoding/successive decoding. In this paper, a new generalization of the CF strategy to the relay networks based on regular encoding/backward decoding is presented. In general, backward decoding has been shown to yield higher rates in comparison with successive decoding. Here we will investigate the performance of backward decoding in our problem and show that our achievable rate includes the previously proposed rates
Multi-server coded caching
, Article IEEE Transactions on Information Theory ; Volume 62, Issue 12 , 2016 , Pages 7253-7271 ; 00189448 (ISSN) ; Motahari, S. A ; Khalaj, B. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, we consider multiple cache-enabled clients connected to multiple servers through an intermediate network. We design several topology-aware coding strategies for such networks. Based on the topology richness of the intermediate network, and types of coding operations at internal nodes, we define three classes of networks, namely, dedicated, flexible, and linear networks. For each class, we propose an achievable coding scheme, analyze its coding delay, and also compare it with an information theoretic lower bound. For flexible networks, we show that our scheme is order-optimal in terms of coding delay and, interestingly, the optimal memory-delay curve is achieved in certain...
On the capacity of interference channel with causal and noncausal generalized feedback at the cognitive transmitter
, Article IEEE Transactions on Information Theory ; Volume 58, Issue 5 , 2012 , Pages 2813-2837 ; 00189448 (ISSN) ; Akhbari, B ; Aref, M. R ; Sharif University of Technology
Abstract
In this paper, taking into account the effect of link delays, we investigate the capacity region of the cognitive interference channel (C-IFC), where cognition can be obtained from either causal or noncausal generalized feedback. For this purpose, we introduce the causal C-IFC with delay (CC-IFC-WD) in which the cognitive user's transmission can depend on L future received symbols as well as the past ones. We show that the CC-IFC-WD model is equivalent to a classical causal C-IFC (CC-IFC) with link delays. Moreover, CC-IFC-WD extends both genie-aided and causal cognitive radio channels and bridges the gap between them. First, we derive an outer bound on the capacity region for the arbitrary...
Achievable rate regions for relay channel with private messages with states known at the source
, Article ; Proceedings 2010 IEEE International Conference on Information Theory and Information Security, ICITIS 2010, 17 December 2010 through 19 December 2010 , 2010 , Pages 1080-1087 ; 9781424469406 (ISBN) ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
Abstract
In this paper, we consider State-Dependent Relay Channel with Private Messages (SD-RCPM) as a generalization of the state-dependent relay channel, where the relay is both a source and a sink of data. We assume that the channel state is known only to the source and investigate two main cases: SD-RCPM with non-causal Channel State Information (CSI), and SD-RCPM with causal CSI. For non-causal case, we propose a coding scheme based on Gel'fand-Pinsker type coding at the source which is informed of CSI, and Decode-and-Forward (DF) scheme at the relay. Using Shannon's strategy and DF scheme, we also propose a coding strategy for the causal case. Based on these coding strategies, we derive new...