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We design a multilevel data encoder for digital communication systems. Time constraints are imposed for a lot of services provided on portable devices. Hardware solutions are preferred more than software algorithms when the processing time and the power consumption are critical. Powerful error-correction coders processing multi-bit symbols can be implemented as hardware solutions in order to reduce...
This paper is an up-to-date short overview of the QoS for Satellite IP networks. Some definitions, parameters and requirements for QoS are given. IP QoS Architectures are presented and various contributions to end-to-end QoS at each layer are included. DVB-RCS and evolution to standard DVB-S2 - RCS to support emerging Internet services via satellite is also briefly approached. Possible integration...
Data Encryption Standard (DES) was initially considered a strong symmetric encryption algorithm, resistant to all known cryptographic attacks at that time [1]. But the short key used to encrypt data is a weakness of the algorithm. Increasing the data structure size and the key length are two recommended measures that ensure the strength of the encryption algorithm. The running-time is a constraint...
In this paper we present a design concept for a new family of Improved Nyquist Filters (INFs). The filters performance, in terms of error probability, depends on the presence of symbol timing errors for the same values of the excess bandwidth, timing jitter, signal to noise ratio and number of interfering pulses. The characteristic property of the new family of inter-symbol interference (ISI) free...
In this paper, we propose and investigate a new improved Nyquist pulse with an asymptotic decay rate of t-2 produced by an improved Nyquist filter with a piece-wise rectangular frequency characteristic. Both the new pulse and the one produced by the square root filter have a closed form expression in time domain and outperform the previously reported pulses in several cases of commonly considered...
The performances of a modified binary exponential backoff algorithm intended for use in IEEE 802.11e wireless local area networks (WLANs) accommodating a great number of users and different types of traffic are investigated. After the successful finalization of a transmission this algorithm operates a decrease of the current contention window size of the involved backoff entity by multiplying it with...
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