Cellular digital packet data (CDPD) is a new service for wide-area data communication with wireless mobile users. CDPD system uses the existing infrastructure of the analog Advanced Mobile Phone Service (AMPS) cellular telephone network to transmit data with a channel hopping technique. The CDPD system employs Gaussian minimum shift keying (GMSK) as a modulation scheme and a Reed-Solomon code for error control to transmit high-quality data in the mobile and wireless environment. Most current CDPD receivers use errors only decoding of the Reed-Solomon code, although an improved errors and erasures decoding technique would also be possible. This thesis undertakes a performance evaluation of the CDPD system with an errors and erasures decoder for the Reed-Solomon coding. A thorough system simulation is conducted for both white Gaussian noise and flat Rayleigh fading channel environments. Results show that improved coding gains of 0.5 ~ 1 dB are possible for the additive white Gaussian noise channel and improved coding gains of 1.9 ~ 2.7 dB are possible for the fading channel. / Master of Science

The aim of this thesis is to investigate the traffic patterns in the mobile data networks. In this work, a simple Cellular Digital Packet Data (CDPD) network was modeled in order to be used in simulations. For the purpose of using in the CDPD model, a synthetic bursty traffic model was produced and using different traffic patterns some performance investigations were made in CDPD network. During the whole work, OPNET simulation tool was used. The CDPD network modeled by OPNET simulation tool was compared with a CDPD model described in the literature and the differences were shown. The new model has some new features: 1) Burst transmission of MAC blocks. 2) Exponential backoff. 3) New packet structures. 4) Frame segmentation and encapsulation into MAC layer frames. Using OPNET, a traffic having higher level of burstiness was produced and applied to the CDPD network model. Under the bursty traffic, some CDPD performance parameters were collected and according to the collected results some suggestions were given.