Browse Prior Art Database

Packet Networking Scheme for Radio Frequencies

IP.com Disclosure Number: IPCOM000108809D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 3 page(s) / 122K

Publishing Venue

IBM

Related People

Griefer, AD: AUTHOR [+2]

Abstract

Disclosed is a scheme for using radio frequencies (RF) in such a fashion to allow efficient packet transmission of data between a single central site (Host) and a larger number of remote stations (Clients). The RF may be transmitted via direct radio propagation or, more likely, be part of a broadband network within a building, campus, or Community Antenna Television (CATV) cable system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Packet Networking Scheme for Radio Frequencies

       Disclosed is a scheme for using radio frequencies (RF) in
such a fashion to allow  efficient packet transmission of data
between a single central site (Host) and a larger number of remote
stations (Clients).  The RF may be transmitted via direct radio
propagation or, more likely, be part of a broadband network  within a
building, campus, or Community Antenna Television (CATV) cable
system.

      One embodiment is a system comprising a pair of standard
television channels, one transmitting in each direction; however,
this design could equally well work on much narrower channels or
across many TV channels.  The figure shows such a cable system 1
where two channels, "ChanF" 2 and "ChanR" 3 are used for
bidirectional data transmission. "ChanF" is divided into a number of
subchannels, "ChanF"_1 - "ChanF"_n, to be used from the host to the
clients, and "ChanR" is divided into a number of subchannels
chanR_1-chanR_n, to be used from the clients to the host. Each
subchannel  from the host, i.e., "ChanF"_1 is matched to the like
numbered subchannel from the client, i.e., chanR_1.  A full-duplex
pair of subchannels is identified by its common number, i.e., 1.

      At the host site, a multiport packet switch is configured with
a fixed-frequency RF modem 5 on each port in 1-to-1 correspondence
with subchannel pairs.  The switch treats each of these ports as part
of the same parallel trunk group such that a packet arriving on any
of the sub-channels will  be identified by its internal source
address rather than by the port on which it arrives.

      At each client site a frequency agile RF modem 6 provides
access to any pair of subchannels (and therefore the associated
switch port) under control of client computer 8.  When a client
system is idle, it commands its modem to tune to a prearranged
subchannel K to wait for instruction from the host site.  To
facilitate communication with individual clients via the common
subchannel K, each is assigned to a unique address; the intended
client for each host-originated message on subchannel K is identified
by including the client's address.

      The host system controller maintains a table 7 of available
subchannel pairs and the status of each client.  A connection is
originated...