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A reduced complexity LDPC decoding method for regular LDPC code is extended to irregular LDPC codes; we present in this paper a full description of this method and its benefits for various row weight and length code word. The Split-Row method makes column processing parallelism easier to exploit and significantly simplifies row processors. Simulation results over an additive white Gaussian channel...
Companding schemes are widely employed to reduce the peak-to-average-power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. This paper considers the classes of linear and nonlinear companding schemes and derives a sufficient condition under which the bit error rate (BER) performance of one is superior to that of the other. The high PAPR of the OFDM signal drives the transmitter's...
In this article, a new method to design the flexible-length S-random interleaver is proposed for storage optimization in a turbo coding system. In this method, the high-spread property s-random interleaver is constructed by selecting appropriate position and element that can improve spread property of interleaver in each iteration in which length of interleaver is increased. Using this method, interleavers...
An uncoded IDMA system with chip accumulation for partial users is proposed. The rate-1 accumulators are employed for partial users. Simulation gives an optimal number Ks of partial users for K-user uncoded IDMA system with the lowest BER. Simulation results show that the performance of the proposed system is improved, compared with the conventional IDMA system, especially for few users and in high...
This paper introduces a new class of rate less forward error correction codes named semi-random Kite (SR-Kite) codes, which can be described by a sparse semi-random parity-check matrix in systematic form. SR-Kite codes have not only rate less property, but also low error floors. We present a simulation-based greedy optimization algorithm to design the degree distribution of SR-Kite codes for independent...
This paper considers a secondary user (SU) sharing the spectrum licensed to a primary user (PU) if limited interference caused to the latter can be guaranteed. In particular, besides the interference power constraint at the PU to protect the PU, the transmit power of the SU is also considered. Under such a setup, we consider the average bit error rate (BER) as the performance metric for the SU, and...
The cooperative communication makes wireless transmission reliable utilizing special diversity, where the relay selection is one of important issues. In this paper, we propose a relay selection scheme exploiting SNR and success probability of the link between nodes in network, especially focus in the link between the source and the relay. Proposed scheme is compared with previous schemes by the simulation...
In this paper, we propose and simulate an efficient interference cancellation scheme with optimally ordered successive interference cancellation (SIC) algorithm for UWB/ MIMO systems. As a spreading code, zero correlation duration (ZCD) code with robust multiple access interference (MAI) capability is employed. The performance is evaluated in terms of bit error rate (BER). From simulation results,...
In this paper we derive conditions under which Spatio-temporal power allocation provides exponential diversity when the quality of channel state information at the transmitter (CSIT) and receiver (CSIR) degrades. We show that exponential diversity is obtained provided two conditions are satisfied; 1)the feedback rate increases linearly with the signal-to-noise ratio (SNR) and 2) the channel estimate...
Closed-loop space-time block codes (STBCs) for multiple transmit antennas, using phase feedback, have recently been proposed. These codes, with perfect phase feedback, achieve full diversity. However, a large number of feedback bits are required, which is not practical. In this paper, we analyze a quantized two-phase feedback scheme for eight transmit antennas and one receive antenna system with full...
This paper describes a new BER measurement method obtaining the BER by estimating the number of error bits in discarded frames using the rate of discarded frames. The BER is obtained precisely by the method.
Cooperative diversity has been recently proposed as a technique to form virtual antenna arrays in systems with single-antenna nodes. The Amplify-and-Forward (AF) relaying strategy is one of the most popular cooperative diversity schemes due to its low complexity. Selection AF (SAF) relaying, single or multiple relay selection, has recently been proven to achieve the same diversity order as and lower...
In multiple-relay cooperative wireless networks, opportunistic relaying is a promising scheme, where the most challenging problem is to choose the best relay efficiently. The traditional opportunistic relay selection scheme is based on the channel conditions of source-relay (S-R) and relay-destination (R-D) links. In comparison with conventional narrowband networks, an appealing merit of impulse radio...
Transmitted reference pulse cluster (TRPC) was recently proposed for low data rate ultra-wideband (UWB) communications due to its robust performance, higher data rate, enhanced reliability and lower implementation complexity compared to the conventional transmitted reference technique. In this paper, we study bi-directional cooperative relay strategies for TRPC UWB networks to extend the coverage...
In Single carrier system with frequency domain equalization (SC-FDE) equalization is playing a crucial role for the system performance. A simple equalization scheme is proposed for precoding SC-FDE. This scheme doesn't need complex computation and is easy to implement. Simulations are used to demonstrate the performance of the scheme.
A semi-blind equalization method is proposed for precoding single carrier system with frequency domain equalization(SC-FDE). The method is modified according to Bussgang algorithm and the implementation is easy because it does not need complex computation. Simulations are used to demonstrate the proposed method.
In this paper, we analyze the bit error rate (BER) performance of a single relay selection with network coding (S-RS-NC) scheme in two-way relay channels. In this scheme, two source nodes first broadcast their information to the relays sequentially. A single relay which optimizes the system performance is selected. The selected relay decodes the received signals from two sources, performs network...
A physical layer simulator for the WiMAX technology is presented in this paper. The simulator encompasses the main blocks that build the physical layer from IEEE 802.16e. It allows to understand some of the physical layer mechanisms and techniques employed in WiMAX and to simulate various transmission scenarios. BER results are presented for some distributed permutation schemes, with different digital...
In order to support development of third generation partnership project long term evolution (3GPP LTE) packet scheduling algorithms, research has been conducted into several radio propagation effects. The radio channels of interest are the downlink (eNodeB to user equipment) of LTE mobile networks. Through network simulator modification and repeated testing the effects of error and delay in reporting...
The quantum key reconciliation is an essential step of Quantum Key Distribution (QKD) systems for correcting error in the raw keys which happens after the transmission over a quantum channel, where two legitimate parties make their correlated bits identical by exchanging messages over the public channel. This paper presents an alternative method for error correction of quantum key reconciliation by...
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