Method and apparatus for performing constellation scrambling in a multimedia home network
DCFirst Claim
1. A method for communications transmission using orthogonal frequency division multiple access on a network comprising:
- a) providing a plurality of transmitting network devices with a set of available subcarriers for orthogonal frequency division multiple access;
b) providing a corresponding element of a pseudorandom noise sequence for each subcarrier of the set of available subcarriers;
c) allocating a subset of the set of available subcarriers to each of the transmitting network devices;
d) a transmitting network device of the plurality of devices mapping a packet onto a plurality of used subcarriers of its allocated subset of available subcarriers, wherein the step of mapping the packet comprises mapping the packet onto a plurality of quadrature amplitude modulated symbols to be transmitted on the used subcarriers;
e) the transmitting network device performing a predetermined transformation on a quadrature amplitude modulated symbol using the element of the pseudorandom noise sequence corresponding to the used subcarrier;
f) the transmitting network device transmitting the transformed symbol to a receiving network device.
9 Assignments
Litigations
1 Petition
Accused Products
Abstract
Systems and methods are provided that allow multiple transmitting network devices to transmit under an orthogonal frequency divisional multiple access (OFDMA) mode to a receiving network device. The multiple transmitting network devices may be configured to perform constellation scrambling on the symbols they will be transmitting using a predetermined scrambling sequence. They may be further configured to synchronize their use of the sequence, for example, by advancing the sequence for each available subcarrier, such that the receiving device may view the payload as if it were sent by a single transmitter. Accordingly, these multiple transmissions may be descrambled using only one instance of a sequence generator.
12 Citations
18 Claims
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1. A method for communications transmission using orthogonal frequency division multiple access on a network comprising:
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a) providing a plurality of transmitting network devices with a set of available subcarriers for orthogonal frequency division multiple access; b) providing a corresponding element of a pseudorandom noise sequence for each subcarrier of the set of available subcarriers; c) allocating a subset of the set of available subcarriers to each of the transmitting network devices; d) a transmitting network device of the plurality of devices mapping a packet onto a plurality of used subcarriers of its allocated subset of available subcarriers, wherein the step of mapping the packet comprises mapping the packet onto a plurality of quadrature amplitude modulated symbols to be transmitted on the used subcarriers; e) the transmitting network device performing a predetermined transformation on a quadrature amplitude modulated symbol using the element of the pseudorandom noise sequence corresponding to the used subcarrier; f) the transmitting network device transmitting the transformed symbol to a receiving network device. - View Dependent Claims (2, 3, 4, 5, 6, 12)
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7. A method for communications reception using orthogonal frequency division multiple access on a network comprising:
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a) receiving a first scrambled orthogonal frequency division modulation symbol from a first transmitting network device, the first orthogonal frequency division modulation symbol comprising a first plurality of scrambled quadrature amplitude modulation symbols transmitted on a corresponding first plurality of used subcarriers assigned to the first transmitting network device; b) receiving a second scrambled orthogonal frequency division modulation symbol from a second transmitting network device, the second orthogonal frequency division modulation symbol comprising a second plurality of scrambled quadrature amplitude modulation symbols transmitted on a corresponding second plurality of used subcarriers assigned to the second transmitting network device; c) wherein the first plurality of subcarriers and the second plurality of subcarriers are subsets of a set of available subcarriers, and wherein the subcarriers of the set of available subcarriers have corresponding elements of a pseudorandom noise sequence; and d) descrambling the first and second scrambled orthogonal frequency division modulation symbols, the step of descrambling comprising descrambling a scrambled quadrature amplitude modulation symbol transmitted on a used subcarrier using the element of the pseudorandom noise sequence corresponding to the used subcarrier. - View Dependent Claims (8, 9, 10, 11)
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13. A communications network system, comprising:
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a) a network device configured to transmit a quadrature amplitude modulated symbol on a subcarrier of a set of subcarriers available for orthogonal frequency division multiple access; b) wherein the network device is configured to perform a constellation scrambling operation on the quadrature amplitude modulated symbol, the constellation scrambling operation comprising; c) initializing a sequence generator with a predetermined seed; and
,d) while proceeding through the set of available suhcarriers in a predetermined order, advancing the sequence generator for each subcarrier preceding the subcarrier, and using an element of a sequence generated by the sequence generator to scramble the quadrature amplitude modulated symbol. - View Dependent Claims (14, 15)
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16. A network device configured to transmit a quadrature amplitude modulated symbol on a subcarrier of a set of subcarriers available for orthogonal frequency division multiple access, the network device comprising a non-transitory computer readable medium having a computer executable program code embodied on the non-transitory computer readable medium, wherein the computer executable code is configured to cause the network device to perform the steps of:
a) performing a constellation scrambling operation on the quadrature amplitude modulated symbol to form a scrambled quadrature amplitude modulated symbol, the constellation scrambling operation comprising; initializing a sequence generator with a predetermined seed; and
,while proceeding through the set of available subcarriers in a predetermined order, advancing the sequence generator for each subcarrier preceding the subcarrier, and using an element of a sequence generated by the sequence generator to scramble the quadrature amplitude modulated symbol. - View Dependent Claims (17, 18)
Specification