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11	Rušení v bezdrátových sítích a jejich modelování (AWGN, Rayleigh, Rice fading channels) / Wireless transmission interference modeling (AWGN, Rayleigh, Rice fading channels) Hloušek, Tomáš January 2008 (has links) This thesis describes and models wirelesss transmission intereferences in real communication channels. A signal received on a fading channel is subjected to a multiplicative distortion and to the usual additive noise. Real channel adds to the signal noise and fadings. Gaussian noise is a result of channel awgn. Fadings is implicated by multipath propagation of signal in Rayleigh and Rician channels. Main goal of this project is to program BERsolve, which is created in tool GUIDE in Matlab. User program BERsolve makes it possible to analyse bit error rate and symbol error rate for some types of channel models, which are defined by standard COST207. BERsolve offers some other functions i.e. display time behaviour, constellation diagram and spectrum. This program provides us with an overview representation of problem by multipath interferences in communication channels.
12	Performance evaluation and protocol design of fixed-rate and rateless coded relaying networks Nikjah, Reza 06 1900 (has links) The importance of cooperative relaying communication in substituting for, or complementing, multiantenna systems is described, and a brief literature review is presented. Amplify-and-forward (AF) and decode-and-forward (DF) relaying are investigated and compared for a dual-hop relay channel. The optimal strategy, source and relay optimal power allocation, and maximum cooperative gain are determined for the relay channel. It is shown that while DF relaying is preferable to AF relaying for strong source-relay links, AF relaying leads to more gain for strong source-destination or relay-destination links. Superimposed and selection AF relaying are investigated for multirelay, dual-hop relaying. Selection AF relaying is shown to be globally strictly outage suboptimal. A necessary condition for the selection AF outage optimality, and an upper bound on the probability of this optimality are obtained. A near-optimal power allocation scheme is derived for superimposed AF relaying. The maximum instantaneous rates, outage probabilities, and average capacities of multirelay, dual-hop relaying schemes are obtained for superimposed, selection, and orthogonal DF relaying, each with parallel channel cooperation (PCC) or repetition-based cooperation (RC). It is observed that the PCC over RC gain can be as much as 4 dB for the outage probabilities and 8.5 dB for the average capacities. Increasing the number of relays deteriorates the capacity performance of orthogonal relaying, but improves the performances of the other schemes. The application of rateless codes to DF relaying networks is studied by investigating three single-relay protocols, one of which is new, and three novel, low complexity multirelay protocols for dual-hop networks. The maximum rate and minimum energy per bit and per symbol are derived for the single-relay protocols under a peak power and an average power constraint. The long-term average rate and energy per bit, and relay-to-source usage ratio (RSUR), a new performance measure, are evaluated for the single-relay and multirelay protocols. The new single-relay protocol is the most energy efficient single-relay scheme in most cases. All the multirelay protocols exhibit near-optimal rate performances, but are vastly different in the RSUR. Several future research directions for fixed-rate and rateless coded cooperative systems, and frameworks for comparing these systems, are suggested. / Communications acknowledgment signals amplify-and-forward relaying average capacity average power constraint bit error rate cooperative gain cooperative communication decode-and-forward relaying degree of freedom direct transmission distributed space-time coding dual-hop relaying energy efficiency energy per bit energy per symbol feedback communication fixed-rate coded relaying fixed-rate codes fixed-rate coding large SNR approximation maximal ratio combining maximum achievable rates maximum likelihood multiple access channels mutual information nonconcave fractional programming numerical optimization optimal power allocation orthogonal relaying outage optimality outage probability parallel channel coding peak power constraint power allocation schemes power fairness protocol design rateless coded relaying rateless codes rate efficiency rateless coding Rayleigh fading relay-to-source usage ratio relaying networks repetition coding selection relaying single-hop communication superimposed relaying symbol error rate
13	Performance evaluation and protocol design of fixed-rate and rateless coded relaying networks Nikjah, Reza Unknown Date No description available. acknowledgment signals amplify-and-forward relaying average capacity average power constraint bit error rate cooperative gain cooperative communication decode-and-forward relaying degree of freedom direct transmission distributed space-time coding dual-hop relaying energy efficiency energy per bit energy per symbol feedback communication fixed-rate coded relaying fixed-rate codes fixed-rate coding large SNR approximation maximal ratio combining maximum achievable rates maximum likelihood multiple access channels mutual information nonconcave fractional programming numerical optimization optimal power allocation orthogonal relaying outage optimality outage probability parallel channel coding peak power constraint power allocation schemes power fairness protocol design rateless coded relaying rateless codes rate efficiency rateless coding Rayleigh fading relay-to-source usage ratio relaying networks repetition coding selection relaying single-hop communication superimposed relaying symbol error rate

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