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We consider the problem of joint decoding and data-fusion in data gathering sensor networks modeled by the Chief Executive Officer (CEO) problem. Correlation between sensorspsila data is known at the fusion center and is employed to update extrinsic information received from soft-in soft-out (SISO) decoders. It is shown in the literature that this scheme has a lower bit error rate compared with the...
This paper investigates the adjacent channel interference (ACI) resistance of a multi-Gbps single carrier wireless personal area network (WPAN) operating in the 60 GHz millimeter-wave band. The significance of performance degradation due to ACI is investigated corresponding to varying factors such as types of modulation and radio frequency (RF) hardware impairments. The level of modulation scheme...
In a three-node wireless relay network, two nodes, BS1 and BS2, exchange information through a relay node, RL. Suppose time division duplex is used, physical network coding (PNC) uses two time slots for the information exchange instead of four time slots needed by the conventional method. In the first time slot, both BS1 and BS2 transmit simultaneously to RL. The relay node, RL does a PNC mapping...
The diversity advantage of MIMO systems has recently been exploited in collaborative schemes. This allows the nodes without access to multiple transmitting antenna elements to transmit information more efficiently. In a previous work, the authors proposed the collaborative scheme using a variable time fraction. In this paper, this scheme is further studied and an upper bound on the performance of...
This paper focuses on the applicability of bit-interleaved space-time coded modulation with iterative decoding (BI-STCM-ID) to wireless local area networks (WLAN). A new intuitive space-time diversity scheme, which ensures a low error rate for small signal-to-noise ratios (SNR) and good asymptotic performance, is provided. The presented technique can ensure compatibility with todaypsilas WLAN specifications...
In this contribution, we investigate the effect of imperfect channel estimation on the bit error rate (BER) performance of uncoded quadrature amplitude modulation (QAM) with maximal-ratio combining (MRC) multichannel reception. The propagation channels from the transmitter to each of the Nr receive antennas are assumed to be affected by (possibly correlated) flat block fading with an arbitrary fading...
Lattice reduction aided (LRA) detection with the LLL algorithm has been investigated to achieve the MIMO channel capacity with low computational complexity. This paper proposes an improved LRA-MMSE detection using the forward and the backward reduction LLL algorithms for the 8times8 MIMO to obtain more reliable estimates of the transmitted signals. The proposed method achieved much better BERs than...
The stack-based iterative precoding (SBIP) is an efficient algorithm that achieves a tradeoff between bit error rate (BER) performance and computational complexity in multi-user MIMO downlink systems. In this paper, we propose an adaptive SBIP algorithm with variable candidate set and statistically derived threshold for pruning. By analyzing the upper bound of accumulated metric, the range of candidate...
Due to small sideband power leakage, filter bank multicarrier techniques are considered as interesting alternatives to traditional OFDMs for spectrum pooling cognitive radio. In this paper, we propose an oversampled filter bank multicarrier system for cognitive radio. The increased spacing between adjacent subcarriers in the oversampled filter bank multicarrier system largely reduce the intercarrier...
Statistical properties of the four IEEE ultra-wide bandwidth channel models are derived. In particular, the correlations and probability density functions for the gains and powers of different multipath components are calculated. It is shown that most multipath components are correlated, and that most multipath components donpsilat follow a lognormal distribution. These results are useful in evaluating...
High speed wireless LAN prototype of 324 Mbit/sec has been developed. Six channel binding of 802.11 a signal on frequency domain was employed for increasing PHY data rate. Frame aggregation was employed to improve MAC-SAP throughput. Individual adaptive data rate setting on each channel, so called adaptive dynamic channel assign was implemented in order to achieve maximum MAC-SAP throughput at any...
High-definition video streaming and peripheral device communication on wireless access are promising applications of multi-gigabit 60-GHz wireless personal area networks (WPANs). For such different requirements, a frame design methodology is required which is different from that applied for the conventional wireless local area network (WLANs) and WPANs. This paper proposes a novel frame design methodology...
A generic cooperative BICM system is described and an analytical model capturing relay error through a binary symmetric channel (BSC) is presented. The analytical model is called Post-BSC model as the BSC channel is placed after encoder of the relay node. Tight BER upper bound is derived for the presented model and close match between simulation and analysis for the presented model is observed. However...
Wavelet Packet Modulation (WPM) is a novel multicarrier modulation (MCM) technique and a promising alternative to the well established OFDM. However a few key research questions remain to be addressed before WPM can become practically viable. One of them is their sensitivity and vulnerability to time synchronization errors. This is particularly interesting because WPM symbols overlap in the time domain...
Noisy radio frequency (RF) circuits tend to degrade the system performance, especially in high frequency communication systems. The performance analysis of such systems is normally based on Monte Carlo simulations which are rather time consuming and provide little insight for system performance bottle necks. In this paper, an exact closed form expression for the bit error rate (BER) of M-ary pulse...
Consider the problem of base-station and sub-carrier assignment on the downlink of a two-cell OFDMA system with adaptive modulation. The aim is to maximize a common data rate that can be offered to each user with a guaranteed maximum rate-outage probability. A target bit-error rate is also guaranteed with a maximum outage probability. The channel model takes into account the propagation path-loss...
Recently, we reported a low-complexity likelihood ascent search (LAS) detection algorithm for large MIMO systems with several tens of antennas that can achieve high spectral efficiencies of the order of tens to hundreds of bps/Hz. Through simulations, we showed that this algorithm achieves increasingly near SISO AWGN performance for increasing number of antennas in i.i.d. Rayleigh fading. However,...
Suboptimal detection schemes, such as list MIMO detection, often face the challenge of having to ldquoguessrdquo at the decision reliability for some of the detected bits. A simple yet effective way of doing this is to set the maximum magnitudes of the associated log-likelihood-ratios (LLRs) to a certain predefined value: LLR clipping. However, the choice of the clipping level has a significant impact...
In this work an iterative time domain least squares (LS) based channel estimation method using superimposed training (ST) for an orthogonal frequency division multiplexing (OFDM) system over frequency selective fading channels is proposed. The performance of the channel estimator is analyzed in terms of the mean square estimation error (MSEE) and its impact on the uncoded bit error rate (BER) of the...
A pilot emitting amplify-and-forward relay and hop-by-hop beamforming (HBF) scheme are proposed for two-hop relaying systems. The conventional beamforming (CBF) is performed with respect to an overall channel from a source node (SN) to a destination node (DN) through a relay node (RN) while the proposed HBF performs two independent beamformings, from the SN to the RN and from the RN to the DN. For...
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