System capacity from UMTS smart antenna concepts

Abstract

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.

Applicability of new radio technologies for advanced UMTS networks

“…Note that the P-CPICH consumes 10% of the maximum transmitted sector power. If Secondary Common Pilot Channels (S-CPICH) exist as used for the fixed beam approach Schacht et al (2003), they also contribute to P tot . For the uplink, the noise rise is defined as:…”

“…Several smart antennas like fixed beamforming and userspecific beamforming are of high interest for UMTS 3GPP (2002). While straight forward solutions exist for the uplink Godara (2002); Farrokhi et al (1998), the downlink direction is much more challenging for UMTS, mainly caused by unknown channel profiles at the base stations as well as powerful pilot transmission Farrokhi et al (1998); Schacht et al (2003). Both fixed and user-specific beamforming lead to a performance increase by spatially suppressing inter/intracell interference.…”

ITP&SUI-Based Channel Assignment in CAC Procedure for TDD-CDMA System

“…We assume that uplink and downlink angles of arrival of user signals are correlated, so the downlink angles can be obtained from uplink measurements based on the reciprocity. We utilize a beamforming concept that directs the antenna beams directly towards the desired users, each user is served with a different beam and experiences full antenna gain [6] - [7]. The scenario is shown in the fig.…”

System Performance of Fixed Beams with S-CPICH as a Phase Reference in WCDMA

“…PO is the total base station power allocated to signals using the same scrambling code as m. Im is the interference from the non-orthogonal signals originating from the own cell and other cells. Finally am is the DL orthogonality factor, which represents the fraction of the wide band received power of the orthogonal signals causing interference to user m. It has been shown (see [11]) that the orthogonality factor may be written as follows: (5) where {rm,i [k] : I =-L + 1, . .…”

“…Other published works investigating the system performance of fixed multi-beam systems in WCDMA can be found in [3], [4], [5], [6]. In these studies, the evaluation was conducted by means of quasi-static system simulation and in most of these studies a simplified channel model was assumed.…”