Frame structure for OFDM signaling, including beacons and traffic
View Patent ↗Provided is a frame structure for filtered OFDM signaling, wherein once every frame a central controller passes redundant broadcast data for a short time (e.g. 16 symbol times) over all frequencies in use. This broadcast, called a beacon, may carry control information, frame structure information, and other data. The rest of the frame is divided into other assignments, including broadband redundantly coded channels for broadcast, ALOHA contention access, or point-to-point transmissions, and including traffic channels that may use only some of the assigned frequencies intended primarily for point-to-point access. This allows a mix of TDMA and FDMA point-to-point and broadband access. This system may be controlled by a central coordinator, which issues reservations. This system allows devices on a frequency-selective channel to communicate with scheduled operations.
1. A method for scheduling access to a medium for network devices of a multi-point to multi-point network, the method comprising:
dividing a frame of time-frequency space into time slot allocations and time frequency allocations of physical channels, wherein said time slot allocations are for a single time slot across all frequencies and said time-frequency allocations are allocated for more than one time slot across more than one frequency and wherein said time frequency allocations are allocated to traffic channels and said time slot allocations are allocated to any combination of broadcast, beacon and ALOHA contention-based channels, wherein said broadcast, beacon and contention-based channels are receivable by all said devices; and
assigning said allocations to said devices according to the type of data each said device has to transmit.
2. The method according to claim 1 and wherein said beacon channel indicates a beginning of a frame.
3. The method according to claim 1 and wherein said medium is a powerline.
4. The method according to claim 1 and wherein said assigning comprises:
assigning a traffic logical channel to one of a traffic channel and a broadcast channel;
assigning a device to device control channel to a traffic channel;
assigning a device to coordinator control channel to all types of physical channels; and
assigning a beacon logical channel to said beacon channel.
5. The method according to claim 1 and wherein said assigning comprises assigning reserved slots at least for sounding measurements.
6. A method for scheduling access to a medium for network devices of a multi-point to multi-point network over a powerline, the method comprising:
a scheduler of a central network determining that a neighbor network utilizing said powerline has been added;
said scheduler dividing a frame of time-frequency space into sub-frames for a central network and for neighboring networks of said central network; and
said scheduler allocating said sub-frame for said central network; and
said scheduler enabling a scheduler of each said neighbor network to allocate its said sub-frame,
wherein said allocating said sub-frame comprises dividing a frame of time-frequency space into time slot allocations and time frequency allocations of physical channels, wherein said time slot allocations define allocations over time across all frequencies and said time-frequency allocations define allocations across time and frequency and wherein said time frequency allocations are allocated to traffic channels and said time slot allocations are allocated to any combination of broadcast, beacon and contention-based channels, wherein said broadcast, beacon and contention-based channels are receivable by all said devices.
7. The method according to claim 6 and wherein said scheduler allocates a beacon channel to indicate a beginning of a frame or a sub-frame.
8. The method according to claim 6 and wherein said allocating said sub-frame comprises:
assigning logical channels of each network device to said physical channels, according to the type of data in each logical channel and the type of traffic each physical channel carries; and
providing said ALOHA contention-based channel for unscheduled transmissions.
9. A network device for a multi-point to multi-point network: the device comprising:
a scheduler to divide a frame of time-frequency space into time slot allocations and time frequency allocations of physical channels, wherein said time slot allocations are for a single time slot across all frequencies and said time-frequency allocations are allocated for more than one time slot across more than one frequency and wherein said time frequency allocations are allocated to traffic channels and said time slot allocations, are allocated to any combination of broadcast, beacon and ALOHA contention-based channel, wherein said broadcast, beacon and contention-based channels are receivable by all said devices; and
a channel assigner to assign said allocations to said devices according to the type of data each said device has to transmit.
10. The device according to claim 9 and wherein said beacon channel indicates a beginning of a frame.
11. The device according to claim 9 and wherein said medium is a powerline.
12. The network device according to claim 9 and wherein said channel assigner comprises:
a mapper to assign a traffic logical channel to one of a traffic channel and a broadcast channel, to assign a device to device control channel to a traffic channel, to assign a device to coordinator control channel to all types of physical channels and to assign a beacon logical channel to said beacon channel.
13. The network device according to claim 9 and wherein said channel assigner comprises a slot assigner to assign reserved slots at least for sounding measurements.
14. A network device for a multi-point to multi-point network over a powerline, the device comprising:
a scheduler of a central network determining that a neighbor network utilizing said powerline has been added, to divide a frame of time-frequency space into sub-frames for said central network and for neighboring networks of said central network and to allocate a sub-frame for said central network and the remaining said sub-frames for said neighboring networks; and
a channel assigner to assign said allocations to said devices of said central network according to the type of data each said device has to transmit,
wherein said scheduler comprises a frame divider to divide a frame of time-frequency space into time slot allocations and time frequency allocations of physical channels, wherein said time slot allocations define allocations over time across all frequencies and said time-frequency allocations define allocations across time and frequency and wherein said time frequency allocations are allocated to traffic channels and said time slot allocations are allocated to any combination of broadcast, beacon and contention-based channels, wherein said broadcast, beacon and contention-based channels are receivable by all said devices.
15. The device according to claim 14 and wherein said beacon channel indicates a beginning of a frame or a sub-frame.
16. The network device according to claim 14 and wherein said channel assigner comprises:
a mapper to assign logical channels of each network device to said physical channels, according to the type of data in each logical channel and the type of traffic each physical channel carries and to provide said contention-based channel for unscheduled transmissions.