On the error probability of convolutionally encoded spread spectrumBPSK in frequency selective Rayleigh fading

An exact expression for the pairwise error probability of convolutionally encoded spread spectrum BPSK with ideal interleaving and RAKE reception over frequency selective Rayleigh fading channels is presented. This expression is used to find a tight upper bound on the bit error probability using the transfer function approac

Space-time coded QPSK for rapid fading channels

This paper presents the design of space-time codes suitable for rapid fading channels. The codes are designed using the QPSK signal constellation. The design of the proposed codes utilizes two different encoding methods. The first method uses a large time diversity trellis encoder, and the second one uses the I-Q encoding technique. Both methods are expected to produce space-time codes that perform better than the codes presented in the literature. The proposed codes were simulated over different Rayleigh fading channels. Coding gains up to 3 dB have been observed over similar codes in the literatur

A tight bound on the error probability of space-time codes forrapid fading channels

This paper presents the performance of space-time (ST) codes over rapid fading channels. A tight upper bound on the pairwise error probability (PWEP) of ST codes over rapid fading channels is derived. Also, an upper bound on the bit error probability (BEP) is evaluated using the derived PWEP. The existing and new bounds are evaluated for different QPSK ST codes and compared to the simulation results. The new bound is shown to be tighter than the existing bound by almost 2 dBs and is very tight to the simulation result

A decoding algorithm for I-Q space-time coded systems in fadingenvironments

This paper presents the decoding of the I-Q space-time (ST) codes. The decoding problem of I-Q ST codes is formulated. The use of the super-trellis to solve the decoding problem results in an increased decoding complexity. Therefore, a simplified decoding algorithm is proposed. It is based on symbol-by-symbol detection of the Q/I components in the I/Q decoders. Simulation results showed that I-Q ST codes with the new algorithm provide coding gains over ST codes having the same complexity but with a single encode

A tight bound on the error probability of space-time codes forrapid fading channels

This paper presents the performance of space-time (ST) codes over rapid fading channels. A tight upper bound on the pairwise error probability (PWEP) of ST codes over rapid fading channels is derived. Also, an upper bound on the bit error probability (BEP) is evaluated using the derived PWEP. The existing and new bounds are evaluated for different QPSK ST codes and compared to the simulation results. The new bound is shown to be tighter than the existing bound by almost 2 dBs and is very tight to the simulation result

Capacity of slotted ALOHA in generalised fading environments

The channel throughput of the slotted ALOHA protocol is evaluated for a Nakagami fading channel model. General expressions for different values of the fading figure m and receiver capture ratio are presented. Evaluations of these expressions show that the throughput increases as the fade depth increase

Channel throughput of slotted ALOHA in a Nakagami fadingenvironment

Slotted ALOHA is widely used in local wireless communications as a multiple access protocol. In addition, it is also used as a component in many reservation protocols. In this paper, the channel throughput of the slotted ALOHA protocol is evaluated for a Nakagami fading channel model. General expressions for different values of the fading figure m and receiver capture ratio are presented. Evaluations of these expressions show that the throughput increases with increasing the fade dept

A general expression for the capacity of slotted ALOHA underNakagami fading

A general expression for the channel throughput of slotted ALOHA under Nakagami fading is obtained assuming different fading statistics and unequal average power levels for the desired and the interfering packets. The expression provides a better alternative to the previously reported expressions derived under similar conditions. With this general expression the effect of the use of modulation on the system performance is then studied. It is observed that the inclusion of the deleterious effects like white noise, bit error rate and the packet length reduces the throughput over the one observed under idealized condition

Channel throughput of slotted ALOHA in a Nakagami fadingenvironment

Slotted ALOHA is widely used in local wireless communications as a multiple access protocol. In addition, it is also used as a component in many reservation protocols. In this paper, the channel throughput of the slotted ALOHA protocol is evaluated for a Nakagami fading channel model. General expressions for different values of the fading figure m and receiver capture ratio are presented. Evaluations of these expressions show that the throughput increases with increasing the fade dept

Adaptive binary coding for diversity communication systems

Coding and diversity are two powerful techniques to combat fading effects on communication channels. In this paper the available diversity channels are utilized by forward error correction coding in an adaptive fashion to improve the reliability of the system. Based on the quality of the diversity channels, the code rate over each channel is determined using discrete optimization of the overall error probability, subject to the constraint of fixed overall throughput rate. It is found that the proposed system provides noticeable gain over the classical diversity system when binary BCH codes with hard-decision decoding are used. Moreover, the proposed system offers flexibility in choosing the throughput of the system, which the diversity system lacks. The advantages of the proposed system are obtained at only slight increase in implementation complexit