Interference Analysis and Coexistence Studies between E-UTRA and UTRA Systems

To ensure Evolved-Universal Terrestrial Radio Access Network (E-UTRA) or Long Term Evolution (LTE) can coexist with other mobile systems operating in the same geographical area, coexistence studies involving E-UTRA are ongoing in the 3rd Generation Partnership Project (3GPP). Related work is also on the way in China Communications Standards Association (CCSA) which may influence the allocation of frequency bands. In this paper, coexistence issues between E-UTRA and Universal Terrestrial Radio Access Network (UTRA) deployed in adjacent frequency bands are investigated. Two classical approaches are used to evaluate the performance degradation of both systems caused by inter-system interference. One is theoretical analysis and the other is system level simulation. The deterministic calculation is carried out in detail for base station (BS) to BS interference scenario, while the static Monte-Carlo simulation is adopted to analyze almost all the interference scenarios. System level evaluation methodology and assumptions are provided, and simulation results for a number of typical scenarios are discussed. The results show that E-UTRA has the ability to resist interference to some extent, but it brings severe interference to UTRA, and the interference between base stations is more severe than other scenarios. It is also found that the offset of E-UTRA system sites, different frequency bandwidths and power control schemes have various impacts on UTRA performance, so they should be carefully considered during E-UTRA deployment to ensure the coexistence with UTRA.