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In this paper, we propose a new QAPM scheme for improving power efficiency. A proposed QAPM scheme is build on QAM. And BER performance of QAPM is better than existing PSSK because BER performance of QAM is better than PSK. In this paper, we find the BER performance closed form of QAPM modulation. Also, we compare to PSSK and QAPM with regard to BER performance and throughput in AWGN channel.
A wide variety of network applications require the use of reliable multicast protocols to disseminate data from one source to a potentially large number of receivers simultaneously. We focus on multicast in single channel multi-access wireless networks and consider Automatic Repeat reQuest (ARQ) based error control algorithms. We propose a simple NACK based method, called overlapped NACKs, that exploits...
It has long been recognised that a wireless communication system can be more efficient if link-layer parameters such as modulation order are adapted to the channel conditions. The most common optimising criterion is spectral efficiency (bps/Hertz) subject to very low bit-error constraint. But this criterion is not appropriate for practical communication networks fitted with strong data-packet error...
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...
This paper presents performance analysis and cross-layer design approaches for hybrid ARQ (HARQ) protocol in wireless networks which employ adaptive modulation and coding (AMC) at the physical layer and are subject to time-correlated fading channels. Utilizing a Markov channel model which accounts for the temporal correlation in successive parity transmissions by the adaptive rate HARQ protocol, we...
Adaptive modulation has been widely adopted in broadband wireless communication systems to improve spectrum efficiency. On the other hand, user cooperative diversity has been investigated to improve system coverage and efficiency. How to take the advantage of adaptive modulation for user cooperative transmissions to maximize network throughput under the constraint of the bit error rate (BER) requirement...
In this paper, we investigate efficient scheduling algorithms in OFDMA multihop relaying networks. The scheduling scheme is modeled as a multiple objective programming problem to maximize the overall capacity and the number of satisfied users under the minimum rate constraint per user. An improved priority (IPRI) algorithm is exploited with novel opportunistic function, which relies on capacity gain,...
This paper analyzes the throughput performance of cooperative diversity wireless networks using adaptive modulation over Rayleigh fading channels. Cooperative diversity is achieved by utilizing neighbouring terminals as relays. These relays can generate copies of the same signal, which can provide spatial diversity gain and signal-to-noise ratio (SNR). The main drawback of cooperative diversity is...
Cooperative communications can exploit distributed spatial diversity gain to improve link performance. When the message is coded at a low rate, source and relay can send different parts of a codeword to destination. This is referred to as the coded cooperation. In this paper, we propose two novel coded cooperation schemes for three-node relay networks, i.e., adaptive coded cooperation and ARQ-based...
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