WCDMA multi-cell link-level performance

Abstract

This paper presents a multi-cell simulation approach with which the impact of selected link-level aspects on cellular system performance can be investigated. The investigations are carried out for downlink dedicated physical channels (DL-DPCH) of third-generation wideband CDMA (3G WCDMA), specified by 3GPP standardization body. The simulator incorporates a user equipment (UE) that suffers from intra-cell interference of the connected base station (BS) as well as inter-cell interference originating from explicitly, i.e. chip-exact, modeled surrounding BSs. The employed multi-cell environment, based on a radio geometzy concept, is described. Coded error performance is shown for various mobile radio channel scenarios, radio geometries and different models for the interference. The question whether inter-cell intfxference of surrounding BSs can bc modcled alternatively by additive white Gaussian noise (AWGN) is addressed. It tums out that in all c a . % the chip-exact modelling of adjacent BSs is necessary in order to obtain realistic performance results. This holds especially the more the UE moves towards the cell border and beyond. Comparisons with simulations employing the AWGN model for inter-cell interference show that those results are too optimistic at low speeds. Moreover, it is shown that a performance analysis based solely on uncoded (raw) bit error rate is not sufficient, but must be complemented by decoded bit and block error rate figures.

Performance and Analysis of CDM-FH-OFDMA for Broadband Wireless Systems

“…It is therefore likely that the total interference spectrum observed by the terminal would not be flat, and hence, it might not be accurately modelled using white noise. The impact of realistic inter-cell interference on performance has therefore been evaluated using the multi-cell simulator with a radio geometry concept, which consider relative inter-cell interference and independent fading for a limited number of chip-exact modelled terminal in a neighboring cell [10]. To become independent from absolute path gains as well as cell layouts, we use the geometry factor which is defined as…”

Inter-cell Interference Analysis on Multi-Carrier CDMA System

“…R.Weber presented the concept, geometry factor, into the WCDMA multi-cell link-level performance analysis to attain an optimal trade-off between reliability of results and simulation complexity [2]. The received powers from the interfering BSs relative to the power of the connected BSs is introduced here to be geometry factors: According to this, we can get the overall geometry factor using distance between BS and UE:…”

“…Only one user exists in the cell 1,i.e., NU=1, that means no intra-cell interference considered. From the definition of geometry factor, no interference due to the thermal noise here, that means the Poc b=0 in the equation (2).…”

“…In this paper, we introduce an approach, which is widely used in the 3G multi-cell link-level simulations [2] into our analysis on the multi-cell MC-CDMA system. It takes into account features include relative propagation path losses and independent fading for a limited number of base station (BS) in neighboring cells.…”