Due to their correlation properties, chaotic sequences can be used in direct sequence spread spectrum systems. In this paper the application of these sequences for design of physical layer in wireless sensor networks is presented. In order to mitigate fading the chip interleaving technique is investigated. Theoretical expressions in closed form for the bit error rate (BER) are derived and confi...

The communication system under present study utilizing 1⁄2 rated convolutional encoding and interleaving schemes over an Additive White Gaussian Noise (AWGN) and other fading (Rayleigh and Rican) channels with deployment of Alamouti scheme. The simulation study is made with the development of a computer program written in MATLAB source code. Computer simulation results on BERs demonstrate that ...

Implementation of wireless wideband transmitters using ∆Σ DACs requires very high speed modulators. Digital MASH ∆Σ modulators are good candidates for speed enhancement using interleaving because they require only adders and can be cascaded. This paper presents an analysis of the integrator critical path of two-channel interleaved ∆Σ modulators. The bottlenecks for a high-speed operation are id...

Abst rac t -The Canadian mobile satellite (MSAT) channel has been modelled as the sum of lognormal and Rayleigh components to represent foliage attenuation and multipath fading, respectively. Several authors have applied trellis coded modulation (TCM) schemes to this channel, estimating the bit error performance via computer simulation. In this paper, a general expression is presented for the p...

Time transmission interval (TTI) or outer block interleaving is an important task for the implementation of UMTS turbo coding in flat Rayleigh fading environment. An efficient TTI choice can save computational complexity. However, different multimedia scenarios are investigated using the maximum UMTS frame length, and simulation results are presented for the four possible outer block interleave...

In this report, we consider the performance of trellis coded multilevel differential phase-shift-keying (MDPSK) over Rician and Rayleigh fading channels. For operation at L-Band, this signaling technique leads to a more robust system than the coherent system with dual pilot tone calibration previously proposed for UHF. The results are obtained using a Combination of analysis and simulation. The...

Performance of diversity systems is often evaluated under the assumption of perfect interleaving and characterised in terms of long-term parameters such as the average bit-error rate, which does not capture the dynamics of fading channels. Statistical characteristics (static and dynamic) of the envelope of two correlated Rayleigh fading channels are explored using a physical model. For two popu...

The reverse link encoding steps of the IS95 cellular code-division multiple-access (CDMA) standard consist of convolutional encoding, block interleaving, and orthogonal Walsh function encoding. Deinterleaving individual symbol metrics obtained from the Walsh function matched filters followed by conventional Viterbi decoding produces suboptimal results, as unwanted intersymbol Walsh function cor...

Braided convolutional codes (BCCs) form a class of iteratively decodable convolutional codes that are constructed from component convolutional codes. In braided code division multiple access (BCDMA), these very efficient error correcting codes are combined with a multiple access method and inherent interleaving for channel diversity exploitation into one single scheme. In this paper, we describ...

We present techniques for modifying a turbo decoder to incorporate a hidden Markov source model, a Markov channel model, or both. This allows the receiver to utilize the statistical characteristics of the source and/or channel during the decoding process, and leads to significantly improved performance relative to systems in which the Markov properties are not exploited. When applied for binary...