Jörg Plechinger

Performance of multicarrier joint detection CDMA mobile communications systems

For future mobile communications, an appropriately chosen multiple access scheme is a critical issue. To support robust frequency planning, multi-operator scenarios, system coexistence and hierarchical cell structures, frequency division multiple access (FDMA) and multicarrier techniques are viable choices. Further multiple access schemes presently under discussion are code division multiple access (CDMA) and time division multiple access (TDMA). A mobile radio system concept deploying a hybrid frequency and time divided code division multiple access (F/T/CDMA) scheme with a multicarrier CDMA (MC-CDMA) component, called MC/JD-CDMA, is proposed and performance results for the uplink are presented. Attractive features of the proposed system concept are the possibility to flexibly offer voice and data services with different bit rates, soft capacity, as well as inherent frequency and interferer diversity.

On multicarrier CDMA mobile radio systems with joint detection and coherent receiver antenna diversity

The combination of code division multiple access (CDMA) and multicarrier (MC) transmission techniques, termed MC-CDMA, is considered a promising alternative to conventional DS (direct sequence)-CDMA. An MC-CDMA concept which is well-suited for mobile radio applications is described. This concept overcomes the disadvantages of previously proposed concepts. In MC-CDMA mobile radio systems, signal reception is impaired by time-varying multipath propagation. The impairments can be reduced by coherent receiver antenna diversity (CRAD). The application of CRAD in combination with joint detection (JD) techniques to the more critical uplink of MC-CDMA mobile radio systems is investigated. Four JD techniques for CRAD are presented and their performance are studied.

Performance of FRAMES non-spread mode 1 (WB-TDMA) with turbo codes

Within ACTS the project FRAMES (Future Radio Wideband Multiple Access System) has been set up with an objective to define a proposal for a UMTS radio access system. Based on an initial evaluation phase in FRAMES, a harmonized multiple access platform has been designed consisting of two modes: FMA1, a wideband TDMA and FMA2, a wideband CDMA. In this paper, link level results obtained for FMA1 without spreading are presented. In particular, the application of the novel rate compatible punctured turbo-codes (RCPTC), are compared with conventional nonsystematic convolutional coding. The emphasis lies on the packet transmission and on the circuit switched high bit rates. These simulation results can be applied to frequency division duplex (FDD) and to time division duplex (TDD) operation.

Multicarrier joint detection CDMA mobile communications

One of the main requirements of a future mobile radio system is a flexible and adaptable radio interface to provide dynamically changing bit rates and a variety of services in various radio environments. Hybrid frequency and time divided code division multiple access (F/T/CDMA) represents a viable basis for the radio interface of future mobile communications. When realizing the code division multiple access (CDMA) component by multicarrier (MC) CDMA improved frequency engineering capabilities of MC techniques are beneficially combined with the frequency and interferer diversity properties of CDMA. This paper presents a generalized view on F/T/CDMA based systems deploying MC techniques overcoming the shortcomings of competing approaches.

On Multicarrier Detection and Coherent CDMA Mobile Receiver Radio Systems with Joint Antenna Diversity

The combination of code division multiple access(CDMA) and multicarrier (MC) transmission techniques,termed MC-CDMA, is considered a promising alternative toconventional DS (direct sequence)-CDMA. For this reason, recent research activities haveconcentrated on the application of MC-CDMA to mobileradio systems. In this paper an MC-CDMA concept which iswell suited for mobile radio applications is described. The described MC-CDMA concept overcomesdisadvantages of previously proposed concepts. InMC-CDMA mobile radio systems, signal reception isimpaired by time-varying multipath propagation. Theimpairments can be reduced by applying diversitytechniques. Coherent receiver antenna diversity (CRAD)is especially attractive because only the signalprocessing at the receivers must be modified. In thiscommunication, the application of CRAD in combination withjoint detection (JD) techniques to the more criticaluplink of MC-CDMA mobile radio systems is investigated.It is explained that the deployment of JD techniques for CRAD is an effective countermeasure againstthe influence of the mobile radio channel on the systemperformance. Four JD techniques for CRAD which areapplicable to MC-CDMA are presented. Their performances are studied in bad urban, typical urban, andtypical macrocellular environments. It is shown thatMC-CDMA allows a favorable performance compared to otherCDMA concepts.

Interference in cellular joint detection code division multiple access (JD-CDMA) mobile radio systems

Cellular mobile radio systems are interference limited. In this communication we investigate the influence of adjacent channel interference (ACI) on a mobile radio system concept using joint-detection (JD)-CDMA. The simulation results presented here consider varying the number of simultaneously active users, varying cluster sizes as well as the influence of up- or downlink on the outage probability P/sub out/.

Uplink spectral capacity of an MC/JD-CDMA mobile radio system

This communication addresses the spectral capacity in Erl/MHz/cell of the uplink in a novel cellular mobile radio system concept proposed for UMTS (Universal Mobile Telecommunications System) which is based on the UTRA /spl delta/-group (CDMA/TDMA basket) presently under consideration in the ETSI standardization process. UMTS will support coexistence with existing radio systems, multioperator scenarios and hierarchical cell structures, calling for flexible frequency engineering capabilities which can be facilitated by multicarrier (MC) techniques. Hence, the considered concept uses multicarrier (MC) based spreading and, since it is an extension of the well known joint detection code division multiple access (F/T/CDMA), the concept is called MC/JD-CDMA.

Coverage of macrocellular multicarrier joint detection code division multiple access (MC/JD-CDMA)

Owing to the limited transmit powers of mobiles, the coverage of macrocellular radio systems is governed by the uplink. In this communication, the coverage of a macrocellular radio system deploying the recently proposed multicarrier joint detection code division multiple access (MC/JD-CDMA) is analyzed. We set out from the uplink minimally allowed mean received power P/sub e, min/ which is required to comply with a given quality of service (QoS) criterion. With P/sub e, min/ and a given transmit power P/sub s/, the maximally allowed path loss a/sub max/ and the maximum average cell radius /spl rho//sub 0, max/ are determined.

Uplink coverage analysis of multicarrier joint detection code division multiple access based macrocellular radio systems

A method for the analysis of the coverage of macrocellular radio systems is explained and applied to multicarrier joint detection code division multiple access (MC/JD-CDMA). Owing to the limited transmit powers of mobiles, the coverage is limited by the uplink. The method starts from the determination of the minimally allowed mean received power P/sub e,min/ in the uplink. To evaluate P/sub e,min/, the carrier-to-interference ratio C/I required to meet a particular quality of service (QoS) criterion must be quantified by simulations. With P/sub e,min/ and a given transmit power P/sub s/, the maximally allowed path loss a/sub max/ and the maximum average cell radius /spl rho//sub 0,max/ are calculated.