Patent ID: 7843869

Claim:
A communication system including: a plurality of mobile stations; and a base station system communicating with the mobile stations and providing the mobile stations with a plurality of application services, without a network layer protocol, through communication based on an Extended Link Control Protocol (ELCP), as one application of a Dedicated Short-Range Communication (DSRC) protocol, between the mobile stations, which travel on a road, and the base station system, which is located along the road, wherein each of the mobile stations and the base station system comprises a transfer service processing entity implementing data transfer among the plurality of applications, wherein the transfer service processing entity identifies an application, with one of the mobile stations and the base station system as a sending source, from among the plurality of applications, utilizing port numbers; and a transaction management entity providing unidirectional data transmission and request-response transactions, wherein the transaction management entity identifies a unit of a transaction between a mobile station and the base station system utilizing a transaction ID uniquely identifying a corresponding port number and an identifier designated by and identifying a respective application, of the plurality of applications, wherein the transaction management entity includes undelivered data segment resending means for resending undelivered data segments of a message, data sending and receiving means for sending and receiving each message of a plurality of messages, and message segmenting and assembling means for segmenting a message generated by an application into a plurality of data segments and assembling a plurality of data segments of a message into the message, the transaction management entity of a sending station, of the mobile station and the base station system, when an identifier designated by an application is unchanged, uses the same transaction ID, divides a message into a plurality of data segments and adds to each of the data segments the transaction ID corresponding to the respective port number and one of sequential numbers for transaction identification and sends the message as the plurality of data segments with the transaction ID and sequential numbers, and the transaction management entity of a receiving station, of the mobile stations and the base station system, reassembles the message sent by combining the data segments having identical transaction IDs, in an order based on the sequential numbers, and processes a newly received data segment identically to the data segment that has been previously received when the transaction ID of the newly received data segment is identical to the transaction ID of the data segment that was previously received.