Event Details
W-CDMA Technologies for 3G and Beyond
Presenter: Dr. Sadayuki Abeta - Research Engineer, NTT DoCoMo Inc., Kanagawa, Japan, Visiting Researcher, Princeton University
Supervisor:
Date: Fri, March 16, 2001
Time: 15:30:00 - 16:30:00
Place: EOW 230
ABSTRACT
Abstract
Wideband DS-CDMA (W-CDMA) was adopted as a wireless access technique for the FDD single carrier mode for IMT-2000. DS-CDMA wireless access, which is based on W-CDMA, has numerous advantages over TDMA or FDMA including (i) single frequency reuse, (ii) soft hand-off (or site diversity), (iii) enhanced radio transmission through Rake combining, and (iv) direct capacity increase by use of sectored antennas. Standardization and development of a W-CDMA system are well under way with enthusiastic efforts aimed at commercial services.
In this presentation, we will briefly introduce the W-CDMA physical layer field and show the experimental results. In NTT DoCoMo, we have already begun research for 4th generation systems. The main target for the 4th generation system is to support high-speed date transmission. Internet services have been gaining popularity in fixed networks and the amount of information transferred over the Internet is increasing at an amazing rate. Broadband multimedia services will soon be in full force in fixed networks based on the next generation Internet technology.
The broadband packet wireless access must be able to offer the above broadband services to mobile users, presumably with the maximum data rate of more than 2-10 Mbps in a vehicular environment and 20-100 Mbps in indoor-to-pedestrian environments. However, this is quite a difficult challenge since radio channels become quite adverse due to a large amount of resolved multipath. In such an environment, the signal power of each resolved path becomes weaker. Thus, accurate channel estimation for coherent detection becomes difficult and severe multipath interference (MPI) may occur. We compare the link level performance of different CDMA schemes and clarify the performance of each scheme in a broadband wireless channel by taking into account the effects of path search, symbol timing recovery, and channel estimation.
FREE AND OPEN TO THE PUBLIC
For Further Information Contact:
Dr. T.A. Gulliver (721 6028)