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We propose a novel cooperative protocol with the joint channel and network code for the multiple-access relay channel with two sources, one relay, and one destination. In the proposed cooperation, by using a superposition technique, the relay node combines the information from both sources and forwards it to the destination, simultaneously. Although several superposition techniques have been proposed...
In mobile environment, decode quality is largely influenced by multipath fading and Doppler shift. In this paper, we reported improvement of mobile reception for high-definition television (HDTV) of integrated services digital broadcasting - terrestrial (ISDB-T) by using maximum ratio combining (MRC) diversity and using two-dimensional (2D) filter in channel estimation. From computer simulations,...
In wireless dual-hop decode-and-forward (DF) relaying networks, multiple relay stations (RS) and users construct a DF broadcast channel (DFBC). Due to unpredictable decoding failure, scheduling in the DFBC should depend on not only channel qualities but also the availability of error-free data at individual RSs. Based on the reception qualities of RSs and channel quality information (CQI), we propose...
This paper considers multi-access relay networks (MARNs) where two single-antenna users communicate to one N-antenna receiver via two hops of transmissions through one R-antenna relay. Nodes in the network are under two linear constraints. The relay linearly maps its received signal to generate its forwarding signal without decoding; the receiver has linear decoding complexity in the number of users...
Signal space diversity technique has been widely adopted in wireless communication systems to combat channel fading by exploiting time diversity, frequency diversity, spatial diversity or a combination of them. Most existing signal space diversity schemes are based on linear constellation spreading. In this paper, we propose a novel nonlinear signal space diversity technique based on maximum distance...
In this paper, we propose a systematic design of space-time block codes (STBC) which can achieve high rate and full diversity when the partial interference cancellation (PIC) group decoding is used at receivers. The proposed codes can be applied to any number of transmit antennas and admit a low decoding complexity while achieving full diversity. For M transmit antennas, in each codeword real and...
In this paper, we propose a Decode-and-Forward Network Coded (DFNC) multi-user cooperation scheme for orthogonal uplink channels in a wireless network. The network consists of m peers having independent information transmitting to a common destination. Each peer transmits its own data in the first time phase and serves as a relay in the second time phase to transmit the network coded information combining...
Femtocells promise to increase the number of users served in a given macrocell by creating indoor hotspots connected to the mobile operator network via cheap backhaul links (i.e., the Internet). However, the interference created by the femtocell transmissions may critically impair the performance of the macrocell users. This effect can be potentially alleviated via so called open-access home base...
In this paper, we present new constructions of quasi-orthogonal space-time block codes for 4 and 6 transmit antennas. The proposed codes possess the following properties: full-rate, full transmit diversity, even power distribution and low decoding complexity, which make these two codes very practical spacetime coding schemes. For the case of 4 transmit antennas, the code can be decoded pair-by-pair,...
Space time coding is a powerful technique to exploit transmitter diversity. Nevertheless, to enjoy its full potential performance, a perfect knowledge of the channel state information should be available at the receiver. Since even small channel estimation error results in severe performance lose, a long, rate consuming training sequences should be used to minimize these estimation errors. Hence,...
In this work, we propose an effective live video streaming system, which exploits path diversity over heterogeneous wireless networks. Basically, fountain code is employed to efficiently integrate multiple paths and provide the error resilience for the live video streaming of high quality. In the proposed system, the path selection algorithm is designed to maximize the target video encoding rate while...
A new cooperative protocol is proposed in the context of wireless mesh networks. The protocol implements on-demand cooperation, i.e. cooperation between a source terminal and a destination terminal is activated only when needed. In that case, only the best relay among a set of available terminals is re-transmitting the source message to the destination terminal. This typical approach is improved using...
A new cooperative access protocol is presented in the context of IEEE 802.11-based fixed ad hoc networks. The protocol achieves optimal diversity-multiplexing tradeoff thanks to two known functionalities: on-demand cooperation and selection of the best relay. The on-demand approach allows maximization of the spatial multiplexing gain. The selection of the best relay allows maximization of the spatial...
Receive beamfoming techniques play an important role in MIMO communications systems as means to mitigate interference and enhance the link quality. Multipoint receive beamforming methods are expected to provide additional gains in systems employing advanced coordinated multipoint processing. Due to its importance, receive beamforming has been studied extensively in the literature. The optimal detection...
This paper proposes an improved scheme for cooperative transmit diversity, which applies the Euclidean superposition of modulated signals. Assuming two sources cooperate in transmitting information to a single destination, each source divides its transmit power between locally generated information and relayed information that originated at the other source. This leads to an encoding scheme in which...
Concurrent cooperative transmission (CCT) is a cooperative transmission (CT) technique where multiple radios transmit diversity versions of the same message at the same time. Through array gain and diversity gain, CCT achieves a signal-to-noise (SNR) advantage, which can be used for better link reliability and transmission range extension. CCT range extension can enable broadcasting with fewer hops,...
Wireless MIMO relay networks have caught a lot of attention because of the potential to enhance performance by exploiting the joint cooperative and spatial diversity. In this paper, we develop high-rate and low-complexity designs for multi-antenna MIMO relay networks by adopting zero-forcing linear equalizers at both relay and destination and designing a simple power scaling at relay. Furthermore,...
This paper studies a network coding scheme that exploits a cooperative diversity and adaptation to variant link states for reliable networks. We propose a scheme, adaptive rate network coding (ARNC), to change the number of transmission in relay nodes according to channel states over fading channels by matching network graphs with rateless code graphs, raptor codes. In ARNC scheme, a relay transmits...
This paper proposes a video streaming mechanism with packet recovery which extends the Enhanced Adaptive Forward Error Correction (EAFEC) scheme by involving Multiple Description Coding (MDC) with path diversity. The proposed mechanism transmits multiple video sub-streams along multiple disjoint paths, then recovers the sub-streams using EAFEC separately, and at last merges and reconstructs the whole...
In this paper, we study the opportunistic cooperative data transmissions based on selective single neighboring cluster head (NCH) relay in clustered wireless sensor networks (WSNs). We propose an opportunistic cooperative data transmission scheme by NCHs and analyze the symbol error rate performance of decode-and-forward (DF) cooperative protocol over Rayleigh fading channels. In our scheme, the source...
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