System and method for high reliability transmission with superposition modulation aided network coding
Systems and methods described herein employ wireless physical network coding (WPNC) together with superposition modulation to support a highly reliable transmission. Embodiments include a composite constellation for carrying the side information that avoids use of extra resources. In additional embodiments, the MIMO, multi-stream transmission and multi-user superposition transmission (MUST) configurations are configured to utilize superposition modulation signaling.
1. A method of transmitting at least a first data packet and a second data packet, the method comprising:
generating side information as a function of the first data packet and the second data packet, wherein the side information is generated such that the first data packet is recoverable as a function of the side information and the second data packet and wherein the second data packet is recoverable as a function of the side information and the first data packet;
separately encoding the first data packet and the side information for transmission as a first set of symbols in a composite constellation, wherein the composite constellation comprises a side-information constellation for encoding the side information superimposed on a primary constellation for encoding data packet information;
separately encoding the second data packet and the side information for transmission as a second set of symbols in the composite constellation, wherein the first set of symbols and the second set of symbols are combinable to obtain the side information; and
transmitting the first set of symbols and the second set of symbols using different transmission resources.
2. The method of claim 1 , wherein generating side information comprises performing a bitwise XOR of the first data packet and the second data packet.
3. The method of claim 1 , wherein each point in the composite constellation is represented by
s i =√{square root over (1−α)} x 1 +√{square root over (α)} x 2
where x 1 is a complex value representing a point in the primary constellation, x 2 is a complex value representing a point in the side-information constellation, and α is a power split parameter with 0≤α≤1.
4. The method of claim 3 , wherein α≤0.10.
5. The method of claim 3 , wherein α≤0.05.
6. The method of claim 1 , wherein the side-information constellation has a greater number of constellation points than the primary constellation, and wherein the side information is encoded at a lower symbol rate than the first and second data packets.
7. The method of claim 1 , wherein transmitting the first set of symbols and the second set of symbols using different transmission resources comprises transmitting the first set of symbols and the second set of symbols at different times.
8. The method of claim 1 , wherein transmitting the first set of symbols and the second set of symbols using different transmission resources comprises transmitting the first set of symbols and the second set of symbols using different frequencies.
9. The method of claim 1 , further comprising, at a user equipment entity:
receiving the first set of symbols and the second set of symbols; and
aligning and combining the first and second sets of symbols to obtain the side information.
10. The method of claim 1 , wherein the side-information constellation is rotated by an amount determined by a quadrant of the composite constellation point.
11. The method of claim 1 , further comprising, at a user equipment entity:
receiving the first set of symbols and the second set of symbols;
aligning and combining the first set of symbols and the second set of symbols to obtain the side information;
decoding the second set of symbols to obtain the second data packet;
recovering the first data packet from the second data packet and the side information.
12. The method of claim 10 , wherein recovering the first data packet is performed in response to an error in decoding the first set of symbols to obtain the first data packet.
13. The method of claim 10 , wherein recovering the first data packet comprises performing a bitwise XOR of the second data packet and the side information.
14. A method comprising:
receiving a first set of symbols and a second set of symbols, each of the first and second sets of symbols comprising symbols in a composite constellation, wherein the composite constellation comprises a side-information constellation for encoding the side information superimposed on a primary constellation for encoding data packet information, wherein the side information is generated such that the first data packet is recoverable as a function of the side information and the second data packet and wherein the second data packet is recoverable as a function of the side information and the first data packet;
aligning and combining the first set of symbols and the second set of symbols to obtain the side information;
decoding the second set of symbols to obtain a second data packet; and
in response to an error in decoding the first set of symbols to obtain a first data packet, recovering the first data packet from the second data packet and the side information.
15. The method of claim 14 , wherein recovering the first data packet comprises performing a bitwise XOR of the second data packet and the side information.
16. The method of claim 14 , wherein aligning and combining the first set of symbols and the second set of symbols to obtain the side information comprises:
rotating each of the symbols in the first and second set by an amount determined by a quadrant of the respective symbol;
combining the rotated first symbol and the corresponding rotated second symbol; and
decoding the combined rotated symbol.
17. A system for transmitting at least a first data packet and a second data packet, the system comprising:
logic for generating side information as a function of the first data packet and the second data packet, wherein the side information is generated such that the first data packet is recoverable as a function of the side information and the second data packet and wherein the second data packet is recoverable as a function of the side information and the first data packet;
an encoder operative to encode the first data packet and the side information as a first set of symbols in a composite constellation, wherein the composite constellation comprises a side-information constellation for encoding the side information superimposed on a primary constellation for encoding data packet information;
the encoder further being operative to encode the second data packet and the side information as a second set of symbols in the composite constellation, wherein the first set of symbols and the second set of symbols are combinable to obtain the side information; and
a transmitter operative to transmit the first set of symbols and the second set of symbols using different transmission resources.
18. The system of claim 17 wherein the logic for generating side information comprises XOR logic.
19. The system of claim 17 , wherein each point in the composite constellation is represented by
s i =√{square root over (1−α)} x 1 +√{square root over (α)} x 2
where x 1 is a complex value representing a point in the primary constellation, x 2 is a complex value representing a point in the side-information constellation, and α is a power split parameter with 0≤α≤1.