Pigeon: A wireless two-way messaging system

Although most attention in wireless communication has focused on cellular telephony, the growth in wireless messaging is in fact stronger and is expected to increase. In particular, a new class of wireless messaging service, called two-way paging, is emerging. Current research on wireless messaging has mostly been concerned with low-level physical layer transmission issues, e.g., modulation and access. Few efforts have addressed high-level issues such as new messaging functionalities, high layer protocols, and overall system design. Most existing wireless messaging systems are built as monolithic entities in a centralized manner. We contend that the current designs lack flexibility required to meet the demand of next generation messaging needs. Pigeon is our proposal of a two-way messaging system. The novelty of our system lies in (1) the techniques used in mitigating the wireless media and end device constraints, (2) the functionalities provided, and (3) its modular architecture. Examples of (1) include the use of asymmetric protocols and the introduction of user agents. Examples of (2) include group addressing, transaction support and flexible messages. The modularity of Pigeon is especially important when it is mapped onto a specific platform, in which case the components of Pigeon, as opposed to the system as is, may be individually adopted. A prototype of Pigeon has been implemented and is operational at Bell Laboratories. In this paper, we describe the design of Pigeon. We pay particular attention to motivate its service and system concepts. We also present, as an example, a mapping of Pigeon to cellular messaging.