Abstract. This article gives a comparison of beamforming concepts. Adaptive beamforming and fixed beam switching in WCDMA-FDD-mode are compared from a system level perspective, ordinary sectorization (three 120 • sectors) serves as a basis for comparison. Pilot channels P-CPICH (Primary Common Pilot Channel) and S-CPICH (Secondary CPICH) are considered as additional interference. For adaptive beamforming channel estimation has to be based on the pilot bit sequence on DPCCH (Dedicated Physical Control Channel) which leads to degradation especially for high mobile velocities and large angular dispersions of the multipath channel.

Exploitation of the spatial dimension is a significant issue for third generation wireless networks. The main benefits expected are emission reduction and system capacity enhancements. There are several approaches to exploit the spatial dimension of the mobile channel. Concepts suggested are higher order sectorization (6 sector sites), fixed beam switching concepts (a number of fixed beams covers the area of a sector) and adaptive beamforming (user specific antenna patterns are evaluated). This paper documents the results of a system level investigation considering different antenna concepts when applying power control in UTRA FDD (UMTS Terrestrial Radio Access, Frequency Division Duplex) downlink. Furthermore, load control algorithms based on power rise evaluation and user elimination applying a stepwise removal algorithm are also taken into account. Simulations have been carried out for different data services utilizing dedicated channels. The investigations were accomplished within 3GPP-UMTS boundary conditions.

No abstract

No abstract

An expanded effort is under the way to support the evolution of UMTS (Universal Mobile Telecommunication System). Apart from delivering high data rates, future UMTS releases will also require to provide high network performance in terms of system capacity, low radiated power, and high coverage. Well promising performance-enhancing technologies are smart antennas as well as multiuser detection. Although these new radio technologies have recently been subject to intense research, main UMTS network integration aspects with their specific constraints have been neglected in many cases. Especially the interaction with UMTS radio resource control being required to meet Quality of Service (QoS) constraints has to be included to assess the applicability of these technologies for UMTS.In this paper, we study the interaction of beamforming concepts as well as multiuser detection with load and power control. We also work out UMTS specific constraints like signal-to-interference-plus-noise ratio (SINR) operating points, pilot power pollution or channel estimation, all strongly limiting network performance. Results are shown for capacity gains and power reduction for all beamforming concepts of interest as well as linear multiuser detection schemes. The results show that fix as well as user-specific beamforming significantly improves network performance gains in downlink. In uplink multiuser detection indicates fairly modest system capacity gains, while it reduces tremendously mobile station power.