Cellular digital packet data: channel availability

Cellular digital packet data (CDPD) networks borrow idle radio channels from advanced mobile phone standard (AMPS) cellular networks to send packet data traffic. We explore the amount of unused AMPS capacity available to parasitic data networks such as CDPD. Due to trunking inefficiencies, a relatively large amount of spare AMPS airlink capacity can be found. In addition, the periods of time AMPS channels are idle are fairly long. Due to fluctuations in the number of AMPS channels in a sector busy serving AMPS calls, there will be periods of time when there is not an ample number of idle AMPS channels for CDPD. Resource contention between CDPD and AMPS will affect the amount of data that can be carried on the CDPD airlink and the performance of higher layer protocols. We present analytical results which serve as the basis for cell site capacity engineering rules for CDPD networks.