We evaluate the system-level performance and potential capacity gain of MBSFN (Multicast/Broadcast Single Frequency Network) operation in wideband CDMA (WCDMA) and compare it to conventional multimedia broadcast/multicast service (MBMS) provision with macro-diversity combining. MBSFN operation has recently been specified in the 3rd Generation Partnership Project (3GPP) as an enhancement to MBMS. It aims to mitigate the cell-edge problem of multicast/broadcast applications, which are typically dimensioned for a predefined coverage. In WCDMA as considered here, MBSFN operation refers to the use of a single common scrambling code and the same set of spreading codes to simultaneously broadcast bit identical MBMS data in a number of cells that form an MBMS cluster. Since intercell interference is drastically reduced by this concept, it has the potential of considerably increasing the spectral efficiency of MBMS. Nevertheless, coarse synchronization of the transmitting base stations is expected to degrade the performance of MBSFN. We study the system-level performance of MBSFN for WCDMA with imperfect synchronization of the base stations considering different equalization strategies.

In this paper we introduce selective virtual antenna permutation (S-VAP) for layered OFDM-MIMO transmission in downlink cellular environments. In the S-VAP scheme, the base station spatially permutes multiple independently encoded layers and then transmits the permuted layers over selected virtual antennas. The mobile station employs a successive interference cancellation (SIC) based receiver to maximize the spectral efficiency. The layer permutation enables a significant reduction of channel quality feedback information necessary to adjust the data rate of each layer. Transmission over selected virtual antennas instead of physical antennas enables efficient power amplifier utilization and thus brings out a quantized spatial water-filling gain.

The application of multiple directive antennas, i.e., directional diversity, may lead to significant capacity benefits in cellular mobile radio systems. A flexibly configurable statistical channel model for mobile radio systems using directional diversity is presented. The parameters of this model, which is available as a FORTRAN77 program, can be easily adjusted to various propagation areas such as, for example, rural, urban, microcellular, and picocellular environments. Therefore, the model is well suited to perform simulations, evaluations, and comparisons of mobile radio systems. Simulation results concerning a code-division multiple-access (CDMA) mobile radio system which uses multiple directive base station (BS) antennas in combination with joint detection illustrate the application of the presented channel model.

This paper analyzes the influence of the geometrical distribution of mobile users on a novel balancing method for the carrier (C) to interference (I) ratio /spl gamma/ in the downlink of a digital cellular radio system. The C/I balancing concept, which uses an array antenna in conjunction with beam forming techniques at the base stations, is an extension of the well-known centralized power control scheme for single antenna systems. Based on Monte Carlo simulations of a cellular environment, cumulative distribution functions of /spl gamma/ are determined in order to find out if performance improvements can be obtained by identifying and taking out mobile users which cause especially large contributions to the total interference.

In order to guarantee communication links of sufficient quality, channel coding is required in mobile radio systems. A novel class of binary parallel concatenated recursive systematic convolutional codes termed turbo-codes allowing a near Shannon limit performance without affecting the data rate was proposed and investigated for additive white Gaussian noise channels. Using a simple turbo-code based on a 16-state recursive systematic convolutional code, the authors demonstrate the applicability of turbo-codes to a CDMA mobile radio system using joint detection and coherent receiver antenna diversity. The considered turbo-code is tailored to the delay requirements of voice communications. Furthermore, the performance advantage of this turbo-code over a regular convolutional code is demonstrated.>

For future mobile radio systems, an appropriately chosen multiple access technique is a critical issue. Multiple access techniques presently under discussion are code division multiple access (CDMA), time division multiple access (TDMA), and hybrids of both. In the paper, a hybrid C/TDMA system using joint detection (JD-C/TDMA) with coherent receiver antenna diversity (CRAD) at the base station (BS) receiver is proposed. Some attractive features of the JD-C/TDMA system are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, inherent frequency and interferer diversity, and high system capacity due to JD. Furthermore, due to JD, a cluster size equal to 1 can be realized without needing soft handover. The single cell E/sub b//N/sub 0/ performance and the interference situation in a cellular environment of the uplink of a JD-C/TDMA mobile radio system with CRAD is investigated in detail. It is shown that the cellular spectrum efficiency is remarkably high, taking values up to 0.2 bit/s/Hz/BS in the uplink, depending on the actual transmission conditions.>