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This paper addresses the problem of timing synchronization at the destination node of a non-regenerative wireless relay network which employs the IEEE 802.11a standard for data transmission. The two-hop relay network consists of an IEEE 802.11a-compliant source and destination pair, each equipped with a single antenna, aided by a relay node equipped with two antennas, which operate in half-duplex...
Relay transmission has been incorporated in the 3rd Generation Partnership Project (3GPP) for Long-Term Evolution (LTE) Enhancements (LTE-Advanced, or LTE-A). To effectively harvest the performance gain introduced by the relay transmission, wireless network coding techniques can be adopted. In this paper, using a simple three-node cooperative relay channel model, based on the decode-and-forward protocol,...
In this paper, a linearly coded (LC) relaying scheme is proposed for multiuser relay network in which a number of users communicate simultaneously with a common destination with the help of one relay node, by using orthogonal frequency division multiple access (OFDMA). The proposed linear coding at the relay node enables exploiting the frequency diversity in the relay-to-destination (R-to-D) link...
Fountain codes are rateless erasure-correcting codes. Several fountain codes have been proposed recently to minimize overhead, many of which involve modifications of the Luby transform (LT) code. These fountain codes, like the LT code, have the implicit assumption that the probability distribution is fixed throughout the encoding process. In this paper, we will use the theory of posets to show that...
In this paper, we consider the half-duplex cooperative multiple-access channel (CMAC) in block-fading channels. Each link employs orthogonal frequency division multiplexing (OFDM) which is suitable for high rate wideband transmission and the modulated symbols are drawn from a finite constellation set. We first obtain the diversity order of the CMAC, as a function of the time sharing variables of the...
We derive in this paper the bit error probability and cutoff rate of an Amplify-and-Forward (AF) relay system operating in Rayleigh fast fading. In our model, we consider the relay thermal noise to be non-negligible and derive a closed form expression to approximate the bit error probability. Our approximated closed form expression matches well with simulation result. Using Chernoff bound, we upper...
Coordinated multi-point transmission/reception (CoMP), in which base stations (BSs) cooperate during the downlink, has been identified as a tool for improving user rates and mitigating interference. The cost for existing coordination schemes with joint processing is the heavy exchange of channel state information and signal information over backhaul links. In this paper, we propose a decentralized...
Network MIMO, in which base stations cooperate and coordinate through a centralized design, is an attractive technology that promises higher spectral efficiency and lower inter-cell interference. However, such performance gain comes at the cost of extensive exchange of signal information (SI), channel state information (CSI), and coordinated precoding information over backhaul links. In this paper,...
In this paper, we consider the half-duplex relay channel. We seek to design multiple turbo codes to minimize the information outage in the block fading channel. An analysis on the diversity order of the relay channel, which depends on the time sharing variable and the rate of the code, is given for practical modulations. We also give a code structure for the multiple turbo codes to achieve the full...
In two-way relaying, two sources exchange information via a relay. In the generalized two-way relay, private information is also sent by each source to the relay, which may be used for overhead data, such as for channel state information. We consider the generalized two-way relay in a multi-carrier system over the wireless channel. Our problem is to maximize the rate that the sources exchange information,...
Cooperative system has been receiving considerable attention recently as an effective approach to improve transmission reliability in slow fading wireless channels. In this paper, we exploit cooperative diversity in multiple relay networks to improve the performance of Gaussian source transmission with layered broadcast coding. Specifically, we study the distortion performance of two amplify-and-forward...
Cognitive radio is widely expected to be the next Big Bang in wireless communications. Government spectrum regulatory committees in many countries have been taking steps to open the door to dynamic spectrum access using this technology and also laying down the rules for its implementation. International organizations have also been striving for standardizing this technology for various applications...
In this paper, we consider the half-duplex cooperative multiple-access channel (CMAC). We seek to design multiple turbo codes to minimize the information outage in the block fading channel. Since we consider an outage to occur even if the message of one of the sources fails to be decoded successfully, we employ a joint network-channel coding approach in our design. The codes are optimized using the...
Average and outage capacities for nonidentical two-user opportunistic scheduling for wireless network coding (OWNC) are derived in this paper. Nonidentical user case represents a more realistic scenario in which two users have different average signal-to-noise ratio (SNR). Our derived analytical results corroborate with the simulation results in the performance evaluation of OWNC. Insight on the performance...
In multi-cell OFDMA systems, inter-cell interference can severely degrade the system throughput, particularly for cell-edge users. To mitigate the inter-cell interference problem, interference coordination is a promising approach that effectively restricts and allocates certain resources among users in different cells to minimize the effect of inter-cell interference. However, most approaches are...
The problem of multi-user cooperation to achieve cooperative diversity for single-antenna terminals is considered. A cooperative strategy is proposed which divides multiple users into groups with each group having two users as partners. The two users alternately transmit their own information first, then simultaneously amplify and forward the partner's data in the same channel. Comparing to the conventional...
Two-way relaying is an effective approach to exchange information between two simultaneously transmitting sources in wireless fading environment. Space-time non-regenerative relaying aids to keep the relay hardware simple and cheap. Accurate estimates for the channel and carrier frequency offset (CFO) are required by the receiver to reap the benefits from relaying. In this paper, we propose a training...
Cooperative communications have received considerable attention for wireless multimedia applications as a means to improve reliability. To exploit such cooperation over slow fading channels, we propose to adaptively and efficiently transmit a layered source over a non-regenerative relay network. Specifically, we jointly determine the number of source encoder layers, the transmission rate and power...
This paper provides an analytical formulation of average capacity and outage capacity for two-user opportunistic scheduling for wireless network coding (OWNC). It is shown that our derived capacity formulas can be easily evaluated without numerical integration and match exactly with the simulation results. At high SNR, it is shown that the average capacity of OWNC is double of logarithm (base 2) of...
In a previous work by Wu et ah, it is shown that the performance of the pre-transformed space-time block coded orthogonal frequency division multiplexing (PT-STBC-OFDM) system has much superior performance compared to the normal STBC-OFDM system. In this paper, we present an analytical study on the bit error rate (BER) of the PT-STBC-OFDM system. We derive the noise distribution of PT-STBC-OFDM system...
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