Riku Pirhonen

FRAMES multiple access mode 1-wideband TDMA with and without spreading

An evaluation of several multiple access schemes against UMTS criteria has been carried out within the European FRAMES project. Based on this comprehensive evaluation, a harmonised radio interface termed FRAMES multiple access (FMA) has been designed consisting of two operating modes: a wideband TDMA mode with and without spreading (FMA1), and a wideband CDMA mode (FMA2). This paper describes the FMA1 radio access system proposal. The FMA2 proposal is described in Ovesjo et al.

FRAMES-hybrid multiple access technology

European Research Program ACTS (Advanced Communication Technologies and Services) started at the end of 1995 to support collaborative mobile research and development. Within ACTS the project FRAMES (Future Radio Wideband Multiple Access System) has been set up with an objective to define the UMTS radio access system. The first target of FRAMES is to investigate hybrid multiple access technologies and based on thorough evaluation of several candidate schemes select the best combination as a basis for further detailed development of the UMTS radio access system. The two hybrid multiple access evaluated schemes integrate a range of multiple access techniques that will lead to an optimised selection of the multiple access method for the UMTS. The first hybrid, slotted multiple access (SMA), has basically a TDMA platform. Furthermore, it contains a CDMA component which overcomes the near far problem of conventional CDMA. Also multicarrier techniques are included. Different bit rates can be flexibly provided by assigning different numbers of time slots, of carriers and of CDMA codes to a user. The second hybrid, code and time division multiple access (CATS) has basically a CDMA platform. It also includes an option for OFDM techniques in the downlink. Furthermore, by using multiuser detection CATS eliminates some of the typical CDMA drawbacks; thus has a very good spectral efficiency, just as its SMA counterpart.

TDMA convergence for packet data services

The provisioning of packet data services with evolutionary cellular networks is a challenge for current operators. For packet data services, two widely used TDMA-based systems, GSM and TIA/EIA-136, will evolve toward a common radio interface. This article discusses the benefits of that convergence. It presents the network planning principles for the common technology, and estimates the network performance with simulations and by evaluations based on measurements from a current network. The article also discusses the benefits of the convergence for implementation of a mobile handset.

Performance evaluation of space-time coding for EDGE

In this paper, we evaluate the performance of both space-time trellis codes and block codes in EDGE system against delay diversity. We address the issues related to outer channel coding and equalization of ISI due to a multipath channel and pulse shaping at the transmitter. The results show a performance advantage for a space-time coded system in ISI-free channels. However, in realistic channels with outer channel coding, delay diversity seems to be more applicable in terms of performance and complexity.

Single slot 14.4 kbit/s service for GSM

This paper presents a method to provide 14.4 kbit/s service by a single TDMA slot in the GSM system. By modification in the puncturing scheme used in the GSM channel coding the air interface speed can be enhanced to 14.4 kbit/s. The reduction in error performance and coverage area is studied by simulations. It is shown that the channel coding performance is slightly decreased, but this does not have a major influence on the coverage.