Communications systems

摘要

A cellular based intelligent transport system (intelligent transportation system ITS) comprises a cellular base station 12 and road side units RSU 14. Base station 12 transmits information including about itself and the RSUs within its coverage area, and further information is transmitted in paging messages from the RSUs. If the vehicle receives a paging from a RSU it selects that RSU for communication (data exchange) providing it is within range of the base station 12. The RSU may alternatively be selected on the basis of the vehicles location and direction of movement (velocity). Wither arrangement allows a vehicle to be passed from one RSU to another within a cell, or between RSUs in different cells. The arrangement may be a LTE (Long Term Evolution) system