Broadband network for coaxial cable using multi-carrier modulation
View Patent ↗A broadband local area data network uses coaxial cable wiring for interconnection of terminal devices. Orthogonal frequency division multiplexing (OFDM) with bit loading is used to overcome channel impairments and provide a path for terminal devices to transmit to and receive from other terminal devices. Probe messages are sent between devices to characterize the communication channel and determine optimum bit loading. The data network shares the cable spectrum with other services and uses frequency bands not used by other services. Adaptive power control can be used to maintain signal to noise ratio in a communication between terminal devices. Frequency coordination can be used to avoid interference between the LAN communications and other services transmitted on the cable.
1. A data network comprising:
coaxial cable wiring installed in homes;
at least two terminal devices connected to branches of the coaxial cable wiring;
wherein communication between the terminal devices comprises:
using time division multiple access (TDMA) wherein devices are assigned a slot in a framing structure that contains multiple slots;
using time division duplex (TDD) protocol to receive and transmit data between terminal devices; and
using orthogonal frequency division multiplexing (OFDM) to modulate the data;
whereby the terminal devices communicate with each other over the coaxial cable wiring.
2. The data network of claim 1 further comprising:
means for frequency coordination comprising scanning the available frequency band to determine a clear area of frequency for data network operation.
3. The data network of claim 2 wherein frequency coordination is used to detect activity originating from another data network.
4. The data network of claim 1 further comprising:
means for adaptive power control wherein an originating terminal device transmits a channel probing message for the purpose of determining received power level to a responding terminal device and the responding terminal device measures the power and communicates a reply message containing the received power level.
5. The data network of claim 2 further comprising:
means for adaptive power control wherein an originating terminal device transmits a channel probing message for the purpose of determining received power level to a responding terminal device and the responding terminal device measures the power and communicates a reply message containing the received power level.
6. The data network of claim 1 further comprising:
means for power loading wherein the power loading selects the power level of the individual carriers forming the OFDM modulated data.
7. The data network of claim 1 further comprising:
a beacon message that is broadcast on the network wherein the beacon message provides a common time reference for synchronization of each data network terminal device.
8. The data network of claim 2 further comprising:
a beacon message that is broadcast on the network wherein the beacon message provides a common time reference for synchronization of each data network terminal device.
9. The data network of claim 1 further comprising a network interface device to provide additional signal coupling paths between wiring branches of the data network.
10. The data network of claim 7 further comprising a network interface device to provide additional signal coupling paths between wiring branches of the data network.
11. The data network of claim 8 further comprising a network interface device to provide additional signal coupling paths between wiring branches of the data network.
12. A data network comprising:
at least two network devices, each network device comprising a multi-carrier modulator for modulating data, an upconverter for translating the modulated data to an RF carrier frequency, a downconverter for translating an RF signal, and a multi-carrier demodulator for demodulating the translated RF signal to produce data; and
cable wiring comprising a splitter with a common port and a plurality of tap ports, and a plurality of segments of coaxial cable connecting between the splitter tap ports and the network devices;
wherein network devices communicate with each other through the cable wiring using multi-carrier signaling and share a common frequency channel through the use of time division multiple access (TDMA) wherein network devices are assigned slots in a framing structure; and
a beacon message broadcast on the data network to provide a common time reference for synchronization of each network device.
13. The data network of claim 12 further comprising:
means for frequency coordination comprising scanning the available frequency band to determine a clear area of frequency for network operation.
14. A data network of claim 12 further comprising a network interface device to provide additional signal coupling paths between wiring branches of the cable wiring.