Flexible rate split method for MIMO transmission
First Claim
1. A method comprising:
- encoding, at an encoder, a plurality of N systematic bits across time and space into an encoded packet of size M bits, wherein encoding the plurality of N systematic bits comprises interleaving the plurality of N systematic bits;
determining a quality of at least a first channel from a feedback circuit;
channel interleaving the plurality of N systematic bits and parity bits corresponding to the N systematic bits;
dividing the encoded packet into a first transmission packet defining a first size M1 bits that includes N1 of the N systematic bits and a second transmission packet defining a second size M2 bits that includes N2 of the N systematic bits, wherein at least one of M1 and N1 is based on the determined quality of the first channel; and
transmitting in parallel the first transmission packet from a first antenna at a first rate at a first power modified by a first weight value over the first channel and the second transmission packet from a second antenna at a second rate that differs from the first rate and at the first power modified by a second weight value over a second channel, wherein M, M1, M2, N, N1 and N2 are all integers, M is greater than N, M is at least equal to M1+M2, and N is at least equal to N1+N2.
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Accused Products
Abstract
A method for transmitting a packet of N input bits includes encoding all of the N bits as a single entity, such as with an interleaver of length N within a turbo coder, outputting M encoded bits, channel interleaving the M bits, splitting the M encoded bits into a parallel first and second portion, and transmitting them over separate channels to achieve spatial diversity. The size of the first and second portion is determined based on a closed feedback loop that provides some knowledge of the channel, preferably a measure of channel capacity. The feedback loop may also provide channel knowledge to a subpacket selector associated with each transmit antenna, which determines an appropriate rate for that channel and selects subpackets to fill a transmission packet for that channel. The subpacket selectors choose a subpacket of systematic bits and fill the remaining transmission packet size with subpackets of parity bits. Eigenvectors may be employed to transmit each transmission packet over more than one channel with a power disparity between the channels. A transmitter according to the present invention is also described.
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Citations
24 Claims
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1. A method comprising:
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encoding, at an encoder, a plurality of N systematic bits across time and space into an encoded packet of size M bits, wherein encoding the plurality of N systematic bits comprises interleaving the plurality of N systematic bits; determining a quality of at least a first channel from a feedback circuit; channel interleaving the plurality of N systematic bits and parity bits corresponding to the N systematic bits; dividing the encoded packet into a first transmission packet defining a first size M1 bits that includes N1 of the N systematic bits and a second transmission packet defining a second size M2 bits that includes N2 of the N systematic bits, wherein at least one of M1 and N1 is based on the determined quality of the first channel; and transmitting in parallel the first transmission packet from a first antenna at a first rate at a first power modified by a first weight value over the first channel and the second transmission packet from a second antenna at a second rate that differs from the first rate and at the first power modified by a second weight value over a second channel, wherein M, M1, M2, N, N1 and N2 are all integers, M is greater than N, M is at least equal to M1+M2, and N is at least equal to N1+N2. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device comprising:
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an encoder having an input configured to receive a plurality of N systematic bits and an output configured to output a plurality of M bits, wherein M is greater than N, wherein the encoder is configured to encode the N systematic bits over time and to interleave the N systematic bits over space; a channel feedback circuit configured to determine a channel characteristic of a first communication channel; a demultiplexer having an input configured to receive an output of the channel feedback circuit, said demultiplexer configured to output in parallel a first portion M1 of the M bits at a first output and a second portion M2 of the M bits at a second output; a channel interleaver disposed between the encoder and the demultiplexer and configured to channel interleave the N systematic bits and parity bits corresponding to the N systematic bits and provide the channel interleaved N systematic bits and parity bits to the demultiplexer; a first amplifier configured to increase a power of said first portion M1 of the M bits to a first power prior to transmission from said first antenna; a first antenna configured to transmit, at a first rate, said first portion M1 of the M bits; a second amplifier configured to increase a power of said second portion M2 of the M bits to a second power prior to transmission from said second antenna; and a second antenna configured to transmit, at a second rate that differs from the first rate, said second portion M2 of the M bits; and a first eigenvector block in series with the first output, said first eigenvector block configured to apply a first power weight factor to said first portion M1 of the M bits prior to transmission from said first antenna and configured to apply a second power weight factor to said first portion M1 of the M bits prior to transmission from said second antenna. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method comprising:
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encoding a plurality of input bits across time and space; based on a determined characteristic of at least a first channel, adaptively splitting the encoded input bits into a first subpacket defining a first subpacket size and a second subpacket defining a second subpacket size; and transmitting the first subpacket at a first rate and at a first power over the first channel and the second subpacket at a second rate that differs from the first rate and at a second power that differs from the first power over a second channel, wherein the first and second powers are determined using Lagrangian maximization with a total power constraint. - View Dependent Claims (22)
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23. An apparatus comprising:
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an encoder configured to encode a plurality of input bits over time and to interleave the input bits over space; a demultiplexer configured to adaptively split the encoded plurality of bits into a first subpacket defining a first subpacket size and a second subpacket defining a second subpacket size; a channel interleaver disposed between the encoder and the demultiplexer and configured to channel interleave the plurality of input bits and parity bits corresponding to the plurality of input bits; a first antenna configured to transmit the first subpacket at a first rate and at a first power over a first channel; and a second antenna configured to transmit the second subpacket at a second rate that differs from the first rate and at a second power that differs from the first power over a second channel, wherein the first and second powers are determined using Lagrangian maximization with a total power constraint. - View Dependent Claims (24)
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Specification