Igor Filipovich

Random Access Design for UMTS Air-Interface Evolution

Comprehensive long term evolution of the Universal Mobile Telecommunications System (UMTS) specifications is currently ongoing to provide significant improvement over the current release. Important goals for the evolved system include significantly improved system capacity and coverage, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. To ensure low latency, users must be able to establish a connection to the network quickly. This paper provides a preliminary design and procedure for the random access channel used to establish a connection when the mobile is not yet time-synchronized to the network in the uplink.

Performance analysis of a time division duplex broadband fixed wireless access system in the 5 GHz U-NII bands

In this paper we analyze the performance of a point-to-multipoint (PTM) time division duplex (TDD), time division multiple access (TDMA) broadband fixed wireless access (FWA) system in the 5 GHz U-NII Band. After a brief background on the 5 GHz radio and then the TDD/TDMA FWA system concept, we characterize throughput and system utilization, obtained from extensive simulations. Various traffic mixes have been modeled using a modified 3GPP2 traffic model. Additionally, analytical results for end-user performance is compared with the simulations results along with a discussion.