Abstract
CDMA is the most common multiple access scheme in third generation cellular systems. The gain from CDMA system is increased considerably if the spreading codes are orthogonal. The reverse link (mobile to base stations) is a multipoint to point transmission. Hence, maintaining the orthogonality between the mobiles transmissions requires that the signals being received at the same time at the base station. This is not easy to achieve due to the changes in the propagation conditions between the different mobiles and the base station. In order to receive the signal from different mobiles at the same time, the base station has to send time alignment commands to each terminal to adjust its transmission time. These commands are known as time alignment (TA) commands. In this paper, we report on some channel measurements made in a dense urban mobile environment (London, U.K.) and concludes that synchronous transmission is also practical in these and other mobile environments with some modification to the time tracking algorithm. Then we show that SCDMA can provide up to 60% increase in the system capacity.
| Original language | English |
|---|---|
| Pages (from-to) | 817-820 |
| Number of pages | 4 |
| Journal | IEEE Vehicular Technology Conference |
| Volume | 56 |
| Issue number | 2 |
| State | Published - 2002 |
ASJC Scopus subject areas
- Computer Science Applications
- Electrical and Electronic Engineering
- Applied Mathematics