JPL's Wireless Communication Reference Website Chapter: Network Concepts and Standards Section: Data Systems, CDPD

CDPD Mobile Data Base Station (MDBS)

The MDBS is responsible for detailed control of the radio interface, such as radio channel allocation, interoperation with cellular voice channel usage and radio media access control.

A MDBS consists of several modem-transceivers each of them supports one CDPD channel pair. The user data received by the modem-transceivers are processed by the control computers before being delivered to the MDIS.

• In order to share radio resources with the cellular system, MDBSs are expected to be co-located with the voice equipments that provide cellular telephone service.
• Furthermore, MDBSs may share cellular equipments (such as antennas for transmitters and receivers) to communicate with the M-ESs.
• M-ESs can only communicate with the outside world through MDBSs. There is no direct communication path between M-ESs.
• Because of the short synchronization delay (i.e., two bit delay) between the MDBS and the M-ES, the radius of a CDPD is typically limited to less than 10 miles.

JPL's Wireless Communication Reference Website © Yi-Bing Lin (Author) and Jean-Paul M.G. Linnartz (Ed.), 1996.