This paper presents the bit-error rate (BER) performance of the RAKE receiver over a multipath Rayleigh fading channel. The closed-form BER in the downlink single-cell environment is obtained through the analysis of the imperfect channel estimation. We compute the BER as a function of energy-to-noise ratio per bit including the effect of multiple access interference and multipath interference, with channel and system parameters: number of diversity channels L = 1, 3, 6, 12; Doppler frequency shift with fD T = 0.008333, 0.0167, 0.025; residual carrier frequency offset Δ f = -600 600 Hz; averaging length of the channel estimator Np = 128-1536 chips. This analysis allows predicting the system's performance and helps to optimize the parameter setting for the channel estimation process. We show that even if the optimal system parameters are used, the BER performance results in a minimal 4dB degradation in comparison to the perfect channel estimation. Finally, the theoretical results are verified by using the Monte-Carlo computer simulations.

In this paper, we propose a generalized frequency assignment algorithm to minimize the intermodulation products caused by nonlinear amplification in satellite transponder. We also analyze the performance of proposed algorithms in terms of C/IM and execution time. Most of the published algorithms are too restrictive to be applied to the frequency planning of many realistic systems that are usually characterized by multi-level and/or multi-bandwidth. In developing the proposed "TDTI algorithm," we utilized and modified basic concepts of Okinaka's DELINS-INSDEL algorithm to extend its applicability from one-level systems to more general systems. We also propose a modified version of TDTI algorithm called "WTDI-SDELINS" to circumvent the problem of relatively long execution time.

In this paper, we compare the major issues associated with TDMA and S-CDMA (Synchronous-Code Division Multiple Access), which is considered as a new cable modem standard technology for upstream channel. We mainly deal with the following 3 topics: MAC protocol, modem structure and BER (Bit Error Rate) performance comparison between TDMA and S-CDMA. Especially, we derive BER of TDMA and S-CDMA schemes in the ε-mixture impulse noise model which appropriately reflects impulse noise characteristics of the upstream channel by using various parameters.

In this paper, we propose a teletraffic model and evaluate the performance in the terrestrial/satellite integrated mobile communication networks having hierarchical structure consisting of terrestrial microcell and satellite spot beam. In the proposed teletraffic model, both the subscriber terminal mobility in the terrestrial microcell and the satellite mobility in the LEO satellite spot beam are considered. The overflow traffic from microcell can be accommodated by the satellite spot beam and is analyzed by IPP (Interrupted Poisson Process) which is often used to analyze non-random overflow traffic. Various reservation channels for handoff calls in terrestrial microcell and satellite spot beam are considered. New calls initially directed to the satellite spot beam are also considered for reservation channels. Carried traffic, blocking, forced termination and non-completion probabilities are evaluated for the overall integrated networks.

In this letter, we propose a polarity decision carrier recovery algorithm that is useful for carrier acquisition in high order QAM. The PD (Phase Detector) output and its variance characteristic are mathematically derived and the simulation results are presented. The proposed algorithm shows enhanced acquisition performance especially for large frequency offset.

This paper presents the bit error rate (BER) upper bounds for trellis coded asymmetric 8PSK (TC-A8PSK) system using the Ka-band satellite in the rain fading environment. The probability density function (PDF) for the rain fading random variable can be theoretically derived by assuming that the rain attenuation can be approximated to a log-normal distribution and the rain fading parameters are calculated by using the rain precipitation data from the Crane global model. Furthermore, we analyze the BER upper bounds of TC-A8PSK system according to the number of states in the trellis diagram and the availability of channel state information (CSI). In the past, Divsalar and Simon has analyzed the BER upper bounds of 2-state TCM system in Rician fading channels; however, this paper is the first to analyze the BER upper bounds of TCM system in the rain fading channels. Finally, we summarize the dominant six factors which are closely related to the BER upper bounds of TC-A8PSK satellite system in the rain fading channel as follows: (1) frequency band, (2) rain intensity, (3) elevation angle, (4) bit energy to noise ratio, (5) asymmetric angle, and (6) availability of CSI.

In this paper, we propose a novel algorithm for all-digital high speed symbol synchronization to be called the MBECM (Modified-Band Edge Component Maximization). The proposed algorithm has a structure based on the spectral line method. It simplifies and modifies the existing BECM algorithm to compensate for the timing offset caused by different phase characteristics of the BPF (band pass filter) at 1/2T and -1/2T. The algorithm is also independent of the carrier recovery and requires only two samples per symbol for its operation. Until now the timing detector's characteristics of the spectral line method including the M-BECM was not analyzed, particularly effect of the timing offset at convergence point. We analyze the timing detector's characteristics of the M-BECM and derive expressions for the timing detector's mean value (often called the S-curve) as a function of the normalized symbol-clock phase, the rolloff parameterand the bandwidth of the BPF. By using these expressions, the PDbias for eliminating the timing offset at an optimal convergence point are calculated. We also analyze and evaluate performance of the proposed algorithm in various ways such as jitter, timing detector output characteristics, etc. and suggest improvements. The proposed M-BECM is compared to the popular Gardner algorithm for high speed modem applications. The proposed algorithm has simpler structure than the Gardner algorithm and simulation results reveal that the proposed algorithm has better overall performance than the Gardner algorithm in narrow band.