Introduction:
TDMA systems improve capacity by a factor of 3 to 6 times as compared to analog cellular radio systems. Powerful error control and speech coding enable better link performance in high interference environments.
Capacity of TDMA:
- Some TDMA systems are able to better utilize each radio channel.
- Mobile assisted handoff (MAHO) allows subscribers to monitor the neighboring base stations, and the best base station choice may be made by each subscriber.
- MAHO allows the deployment of densely packed microcells, thus giving substantial capacity gains in a system.
- TDMA also makes it possible to introduce adaptive channel allocation (ACA).
- ACA eliminates system planning since it is not required to plan frequencies for cells.
- Various proposed standards such as the GSM, U.S digital cellular (USDC), and Pacific Digital Cellular (PDC) have adopted digital TDMA for high capacity
- Table 1 compares analog FM based AMPS to other digital TDMA based cellular systems
Table 1 |