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Quantize-map-and-forward (QMF) is a relaying scheme that has been shown to achieve the capacity of Gaussian relay networks to within a constant gap. Under QMF the compression indices forwarded by relays are not decoded explicitly. Instead, the message is decoded jointly with the compression indices. In this work we present a practical coding and signaling framework that captures this aspect of QMF...
The following topics are dealt with : network coding; automatic identification system; delay tolerant networks; modulation and coding; system architecture; estimation and synchronization theory; multibeam communication; cooperative communication; spectrum sharing; navigation and positioning; signal processing; communication theory; S-band system; and network protocol.
During recent years Wireless Body Area Networks (WBANs) have been experienced continuous developments by researchers both in academia as well as industry due to its capabilities and various promising applications, for instance, in the areas of healthcare, sports, military, etc. One of the crucial requirements in designing a WBAN, especially, for the healthcare applications is network reliability since...
Over the last decade, VoIP has had a fast growth particularly in Small Office Home Office environments overloading the wireless accesses in the last mile. Network Coding schemes have advantageous features for throughput performance but VoIP is a delay critical service requiring fast routing algorithms. In this paper, we design, implement and measure experimental values for a network coding based VoIP...
The communication of video streams over wireless not only requires the stability of channel but also needs stringent QoS (quality-of-service) constraints, such as low packet loss and latency. Therefore, radio resource allocation for different traffic becomes one of the major challenges in designing a wireless multimedia network. In this paper, a priority-based cross-layer QoS scheme for wireless channel...
In this paper, randomized distributed space-frequency coding (R-DSFC) scheme is proposed for decentralized wireless relay networks. We consider relay-assisted ARQ to overcome the problem such as transmission failure caused by lack of the knowledge of the number of relays. We analyze the throughput, the maximum achievable diversity order, and the coding gain of the proposed scheme and show that the...
Low-Density Parity-Check (LDPC) code is a class of error-correcting codes which have limited capacity. For long code lengths, LDPC codes can even outperform Turbo codes. LDPC is regarded as one of the key technologies that realize the high-speed broadband wireless networks in the future. In this thesis, a new encoding method of LDPC is attempted to construct the parity check matrix from the point...
Coding has traditionally been used at the physical layer in communication networks to prevent and correct errors and erasures incurred in transmission of data. In the past decade, other benefits of coding have been demonstrated, in particular in environments with unpredictable dynamics and limited resources. In this paper, we are concerned with using coding to reduce delay in communications environments...
In this paper, we completely characterize the deterministic multicast capacity region of the symmetric two-pair bidirectional half duplex relay network with private messages. Towards this end, we first develop a new upper bound on the deterministic capacity region, based on the notion of a one-sided genie. We then proceed to construct novel detour schemes that achieve the upper bound by routing the...
The bandwidth in wireless networks is usually shared by a number of wireless nodes. The channel capacity depends on the number of accessing nodes, time, environmental conditions and location of nodes. Due to varying channel conditions, several issues are observed in the transmission of real time multimedia. The existing research on multimedia streaming can be classified into adaptation techniques...
Area Coverage for ground-to-air voice communication can be extended largely while radio stations are connected with ground-based wired network. This application system has three main characteristics: half-duplex conversation, twice voice encoding and voice over IP transferring. Under this scenario, we present an objective calculation model, which is based on E-model, to evaluate the end-to-end voice...
The concept of STNC is very general. Fundamentally, it involves combining information from different sources at a relay node, which gives rise to the concept of network coding, and transmitting the combined signals in dedicated time slots from various locations in a network, which makes the space-time concept. Various traditional combining techniques can be used, including CDMA-like and OFDMA-like...
We investigate cooperative strategies for relay-aided multi-source multi-destination wireless networks with backhaul support. Each source multicasts information to all destinations using a shared relay. We study cooperative strategies based on different network coding (NC) schemes, namely, finite field NC (FNC), linear NC (LNC), and lattice coding. To further exploit the backhaul connection, we also...
The exact Markov modeling analysis of erasure networks with finite buffers is an extremely hard problem due to the large number of states in the system. In such networks, packets are lost due to either link erasures or blocking by the full buffers. In this paper, we propose a novel method that iteratively estimates the performance parameters of the network and more importantly reduces the computational...
In this paper we consider communication from a source to a destination over a wireless network with the help of a set of authenticated relays. We focus on a special “diamond” network, where there is no direct link between the source and the destination; however the relay nodes help to establish such a communication. There is a single adversarial node which injects signals to disrupt this communication...
In this paper we develop a discrete and distributed optimization framework that maximizes the overall spectral efficiency of heterogeneous networks while ensuring a minimum fairness among users. We split the problem into two subproblems: the first one is handled by the users and consists in a transmission by each user of a minimum rate requirement to the base stations and the second is the resource...
With the development of broadband wireless networks and increasing demand of multimedia information on internet, the study of video streaming transmission has become a hot topic in nowadays. Through analysis three main points of streaming media transmission, and by combining the forthcoming H.264 Scalable Video Coding and Congestion Control algorithm based on accumulated mechanism, this paper presents...
We propose a two-step error concealment method based on an error resilient three-dimensional discrete wavelet transform (3-D DWT) video encoding scheme. The proposed scheme consists of an error-resilient encoder duplicating the lowest sub-band bit-streams for dispersive grouped frames and an error concealment decoder. The error concealment method of this decoder is decomposed of two steps, the first...
Consider a (1 × 1, ½)K symmetric wireless interference network where K single-antenna user-pairs want to achieve ½ degrees of freedom each. It has been proved that it is almost surely infeasible to achieve interference alignment without symbol extension. While it was proved relays can not increase the degree of freedom of wireless interference networks, we show this does not preclude the usefulness...
Interference limits performance in wireless networks, and cooperation among receivers or transmitters can help mitigate interference by forming distributed MIMO systems. Earlier work shows how limited receiver cooperation helps mitigate interference. The scenario with transmitter cooperation, however, is more difficult to tackle. In this paper we study the two-user Gaussian interference channel with...
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