Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
366 words
In a CATV network capable of delivering program video information to each of plural user nodes, a medium-access protocol for providing two-way video communication on vacant channels not already used for delivering program video information between a first user node attached to a first group of nodes and a second user node attached to a second group of nodes, wherein said first and second groups of nodes are connected to a head end comprising a central network controller (CNC), said protocol comprising the steps of: (a) allocating a plurality of vacant CATV channels that do not carry said program video information for dynamic assignment by said CNC to communicating user nodes, each channel being assigned a separate frequency band; (b) at said first user node, transmitting a request-to-communicate signal to said CNC via a first frequency band centered at a first frequency; (c) transmitting from said CNC to said second user node via a second frequency band centered at a second frequency a checking signal to determine if said second user node is busy; (d) if said second user node is not busy, assigning a third frequency band centered at a third carrier frequency to said first user node for transmitting information to said second user node and assigning a fourth frequency band centered at a fourth carrier frequency to said second user node, for transmitting information to said first user node; (e) tuning a transmit modulator at said first user node to said third frequency, a transmit modulator at said second node to said fourth frequency, and a receive modulator at said second user node to said third frequency; (f) transmitting a first signal modulated onto said third frequency from said first user node to said head end; (g) at said head end, adding said first signal to each of said signals transmitted by said CNC, and each other node of said first and second groups to produce a combined signal; (h) transmitting said combined signal to said first and second groups of nodes connected to said head end; and (i) demodulating said first signal from said third frequency and one or more of said signals transmitted from said CNC, at said second user node.
Claim 2
Dependent Claim
366 words
In a CATV network capable of delivering program video information to each of plural user nodes, a medium-access protocol for providing two-way video communication on vacant channels not already used for delivering program video information between a first user node attached to a first group of nodes and a second user node attached to a second group of nodes, wherein said first and second groups of nodes are connected to a head end comprising a central network controller (CNC), said protocol comprising the steps of: (a) allocating a plurality of vacant CATV channels that do not carry said program video information for dynamic assignment by said CNC to communicating user nodes, each channel being assigned a separate frequency band; (b) at said first user node, transmitting a request-to-communicate signal to said CNC via a first frequency band centered at a first frequency; (c) transmitting from said CNC to said second user node via a second frequency band centered at a second frequency a checking signal to determine if said second user node is busy; (d) if said second user node is not busy, assigning a third frequency band centered at a third carrier frequency to said first user node for transmitting information to said second user node and assigning a fourth frequency band centered at a fourth carrier frequency to said second user node, for transmitting information to said first user node; (e) tuning a transmit modulator at said first user node to said third frequency, a transmit modulator at said second node to said fourth frequency, and a receive modulator at said second user node to said third frequency; (f) transmitting a first signal modulated onto said third frequency from said first user node to said head end; (g) at said head end, adding said first signal to each of said signals transmitted by said CNC, and each other node of said first and second groups to produce a combined signal; (h) transmitting said combined signal to said first and second groups of nodes connected to said head end; and (i) demodulating said first signal from said third frequency and one or more of said signals transmitted from said CNC, at said second user node.
Claim 3
Dependent Claim
27 words
A medium-access protocol according to claim 1 wherein said CATV network has a centralized star architecture or a tree-and-branch architecture connected via a single or two cables.
Claim 4
Dependent Claim
54 words
A medium-access protocol according to claim 1 which further comprising a security checking protocol, said security checking protocol comprising the step of: roll-call polling each user node to check a status thereof; and warning a network manager if no response is received from any of said user nodes within a predetermined period of time.
Claim 5
Dependent Claim
20 words
A medium-access protocol according to claim 1 wherein said CATV network comprises a mixture of coaxial cables and optical cables.
Claim 6
Dependent Claim
15 words
A medium-access protocol according to claim 1 wherein said CATV network comprises only coaxial cables.
Claim 7
Dependent Claim
19 words
A medium-access protocol according to claim 1 wherein each of said CATV channels has a bandwidth of 6 MHZ.
Claim 8
Dependent Claim
66 words
A medium-access protocol according to claim 1, further comprising the steps of: tuning a receive modulator at said first user node to said fourth, frequency; transmitting a second signal modulated onto said fourth frequency from said second user node to said head end whereby said combined signal further comprises said second signal; and demodulating said second signal from said fourth frequency at said first user node.