One-line summary: Overview of existing standards (there are so many!) for transmitting packetized data over unreliable RF links, with emphasis on MOBITEX, deployed by Ericsson and used by RAM mobile data.
|Std||Air IF||NW layer||transport||comments|
|MOBITEX (Ericsson)||ROSI (GMSK), 12.5 KHz chs, CRC/Hamming, selective ARQ||MPAK (512 bytes, 24 bit addr); proprietary||MTP/1, proprietary||MASC interface: reliable data transfer (in-order?); most widely deployed today|
|ARDIS||Single freq reuse; 4.8 Kb/s (MDC-4800) or 19.2Kb/s (RD-LAP) in 25 KHz ch||?||?||RD-LAP deployment limited. ARDIS is one of only two nationwide providers. Single freq reuse is economical (single switching gateway, many BS's) but limits capacity.|
|CDPD (Baby Bells, McCaw)||19.2 Kb/s, FEC||Drafted as proprietary; changed to IP/OSI after pressure from software industry||TCP/OSI||pkt-switching overlay for analog cel voice network. Since must operate within regulatory framework of phone companies, CDPD's must be modular, independent, interoperating networks.|
|AMPS (cel modem)||Modulate data as voice at ~9600 baud; MNP-10, ETC, V.42bis for EC||None||None||Must be able to stop/restart transmission after handoff or fade|
|Metricom||FHSS, 902-928MHz (ISM) band, routing within radio mesh||proprietary||TCP/IP, AppleTalk via Hayes AT||Up to 100 Kb/s--NOT|