A radio protocol for TCP/IP application

The LAN/WAN capability of a communication system demands flexibility of the transmission protocol. This flexibility is necessitated by the variable source data quantity that has so far not been taken into account: data packets of different lengths and unknown quantity are to be sent without delay in both directions. The new RS.ITP (R&S Internet Transport Protocol) from Rohde & Schwarz with synchronous channel access for point-to-point communication is able to do this. This multiple adaptive HF transmission protocol with quasi-duplex-compatible interface response is characterized by the following features: (a) special adaptation to the limited capacity of shortwave channels (minimum overhead and thus high throughput), (b) a adaptive timeslot matching for transmitter and partner station as a function of the corresponding source data quantity, (c) a adaptive matching of frame length and number of frames, modulation type and coding to channel quality. The theoretical throughput of a transmission protocol that can be attained under special conditions (data rate of modem, switchover and signal times) was analyzed by means of computer simulation. The adaptation of the half-duplex protocol to the source data quantity is via the assignment of quantized timeslots. This new protocol is used for example for linking HF stations to computer networks such as the Internet or X.400 via standard Internet protocols based on TCP/IP (FTP, HTTP, SMTP, …)