In this paper, we provide a throughput analysis of the IEEE 802.11 protocol at data link layer in non-saturated traffic conditions taking into account impact both transmission channel and capture effects Rayleigh fading environment. The non-ideal become important terms actual observed typical network whereby is mainly unsaturated, especially an environment high interference. We extend multi-dimensional Markovian state transition model characterizing behavior MAC by including states that for...

There has been a great interest in the development of high-altitude platforms, which are low cost stratospheric aircraft carrying payloads tailored for wide range applications telecommunications and remote sensing. These platforms capable flying at altitudes ranging between 17 30 km, with potential endurance weeks to months, features that make them attractive provision future personal communication services. This paper deals theoretical derivation channel model link platform terrestrial...

A description of the algorithms to evaluate main parameters determining performance a trellis-coded modulation (TCM) scheme is presented. TCM schemes are divided into classes that have an increasing degree symmetry, so as properly match various each class. The compared in terms computational complexity and tested on set multidimensional PSK codes.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

In this paper, we provide a saturation throughput analysis of the IEEE 802.11 protocol at data link layer by including impact both transmission channel and capture effects in Rayleigh fading environment. Impacts non-ideal effects, specially an environment high interference, become important terms actual observed throughput. As far as 4-way handshaking mechanism is concerned, extend multi-dimensional Markovian state transition model characterizing behavior MAC states that account for packet...

This paper focuses on multirate IEEE 802.11 Wireless LAN employing the mandatory Distributed Coordination Function (DCF) option. Its aim is threefold. Upon starting from multi-dimensional Markovian state transition model proposed by Malone et.al. for characterizing behavior of protocol at Medium Access Control layer, it presents an extension accounting packet transmission failures due to channel errors. Second, establishes conditions under which a network constituted N stations, each station...

One of the main open problems for next generation wireless networks, is to find new OFDM-based waveform be used in 5G. The modulation scheme must primarily able achieve higher spectral efficiency than its predecessor. 3GPP's candidate a version OFDM, called Filtered Orthogonal Frequency-Division Modulation (f-OFDM), which similar OFDM but with additional filtering order reduce Out-Of-Band (OOB) emissions and obtain better spectral-localization. Another option windowed-OFDM (w-OFDM),...

In this article the provision of integrated services from high-altitude platforms (HAPs) is discussed, and a flexible communication system for HAP-based communications identified analyzed, with particular attention to delivery broadband HAPs highspeed trains. The high coding gain required by proposed scenario achieved through adaptive concatenated schemes, while smart antennas operating beamforming algorithms are employed at ground stations. simulated performance based on multi-antenna model...

This letter considers low-density parity-check (LDPC) coding of correlated binary sources and a novel iterative joint channel decoding without communication any side information. We demonstrate that depending on the extent source correlation, additional gains can be obtained. Two stages are employed. During global iterations, updated estimates correlation obtained passed to sum-product decoder performs local iterations with predefined stopping criterion and/or maximum number iterations....

This paper addresses the problem of designing interleavers for parallel concatenated convolutional codes (PCCCs) tailored to specific constituent codes. We start by establishing role interleaver in PCCC and various parameters that influence performance with a given interleaver. Subsequently, we define canonical form interleaving engine denoted as finite-state permuter (FSP) demonstrate minimal delay property this form. For any permutation, present procedure deriving FSP engine. address issue...

We present a theoretical framework for rotational invariance of trellis codes. The distinction between codes and encoders plays pivotal role. Necessary sufficient conditions are derived under general assumptions, construction is presented that obtains rotationally invariant encoder almost any code, independent the code's algebraic structure. Encoders use differential precoder considered as separate case, where system-theoretic characterization precoding used to find two alternative slightly...

In this paper, we provide a throughput analysis of the IEEE 802.11 protocol at data link layer in non- saturated traffic conditions taking into account impact both transmission channel and capture effects Rayleigh fading environment. Impacts non-ideal become important terms actual observed typical network whereby is mainly unsaturated, specially an environment high interference. We extend multi-dimensional Markovian state transition model characterizing behavior MAC by including states that...

Since the software radio concept was introduced, much progress has been made in past few years making it a reality. Many based systems have designed through development efforts of both commercial and noncommercial organizations. While term meant many things, ultimate goal realization an agile that can transmit receive signals at any carrier frequency using protocol, all which be reprogrammed virtually instantaneously. Such system places great demands on limits data converter processor...

We propose a linear model of the throughput IEEE 802.11 Distributed Coordination Function (DCF) protocol at data link layer in non-saturated traffic conditions. show that is function packet arrival rate (PAR) $λ$ with slope depending on both number contending stations and average payload length. also derive interval validity proposed by showing presence critical $λ$, above which station begins operating saturated The analysis based multi-dimensional Markovian state transition Liaw \textit{et...

The theory of geometrically uniform signal sets and codes over groups is applied to the case L/spl times/MPSK constellations. Conditions for rotational invariance group are discussed. tables partitions found in Benedetto et al. (1993) used construct good trellis nonbinary Abelian groups. present authors consider times/4PSK times/8PSK constellations transmit information rates 1 2 bit/two dimensions, respectively; generating (Z4)/sup L/ (Z8)/sup L/,for L ranging from 4. In most cases, they...

The theory of geometrically uniform trellis codes is applied to the case multidimensional PSK (phase shift keying) constellations. symmetry group an L*MPSK (M-ary PSK) constellation completely characterized. Conditions for rotational invariance partitions a signal are given. Through suitable algorithms, (M=4,8,16 and L=1,2,3,4) constellations found, which present good characteristics in terms set distances at given partition level, maximum obtainable invariance, isomorphism quotient...

This correspondence looks at the problem of joint decoding serially concatenated convolutional codes (SCCCs) used for channel coding multiple correlated sources. We assume a simple model whereby two sources transmit SCCC encoded data to single destination receiver. do not existence of, nor we use side information In particular, present novel iterative algorithm by using empirical cross-correlation measurements successive iterations provide extrinsic outer configuration. Two levels soft...

We consider several issues regarding the use of a stratospheric, solar-powered, unmanned aerial vehicle named Helios Platform (HeliPlat) as mobile communications base station. This platform is currently being designed at Politecnico di Torino within HeliNet project funded by European Commission. The major potential such cellular station that it represents cost-effective solution for coverage low-user-density, impervious, or sea regions. Moreover, can be moved on demand, making suitable to...

Cascaded-integrator-comb (CIC) filters are efficient anti-aliasing rate-conversion widely used for ΣΔ A/D converters. High-order structures, attempting to increase the noise rejection within folding bands, have drawback of inserting multiple zeros in same positions and increasing edge-band attenuation. A combination sharpened CIC is proposed paper, with goal quantisation around bands reducing pass-band drop designed decimation respect classic structures. Design criteria, leading optimised...

This paper focuses on multirate IEEE 802.11 Wireless LAN employing the mandatory Distributed Coordination Function (DCF) option. Its aim is threefold. Upon starting from multi-dimensional Markovian state transition model proposed by Malone et.al. for characterizing behavior of protocol at Medium Access Control layer, it presents an extension accounting packet transmission failures due to channel errors. Second, establishes conditions under which a network constituted N stations, each station...

This paper addresses the problem of interleaver design for serially concatenated convolutional codes (SCCCs) tailored to constituent SCCC configuration. We present a theoretical framework optimization based on cost function closely tied asymptotic bit-error rate (BER) block code C/sub s/ resulting from proper termination in code. define canonical form interleaving engine denoted as finite state permuter (FSP) and using its structural property, develop systematic iterative technique...

Abstract The evaluation of the minimum distance low‐density parity‐check (LDPC) codes remains an open problem due to rather large dimension parity check matrix H associated with any practical code. In this article, we propose effective modification error impulse (EI) technique for computation LDPC codes. EI method is successfully applied sub‐optimum decoding algorithms such as iterative MAP algorithm turbo We present novel modifications and extensions sum‐product performance may be limited...

Cracks on the surfaces inside road tunnels are among most critical problems in management of such and, if not properly addressed, can have severe consequences relation to safety and costs. Nowadays, main techniques used for analysis make use either human inspections or complex automated systems, which are, respectively, very time consuming expensive, and/or difficult implement. There is therefore great interest a low-cost data-acquisition platform coupled with Artificial Intelligence-based...