Signal power reduction systems and methods
A method of reducing transmission power for an encoded data stream includes the steps of receiving an incoming data stream having equal probability for a plurality of incoming data bits, assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits, and transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols.
1. A method of reducing transmission power for an encoded data stream comprising the steps of:
receiving an incoming data stream having a first average transmit power for a plurality of incoming data bits;
assigning a symbol scheme to the received data bits of the incoming data stream according to probabilities of occurrence of individual ones of the received data bits; and
transmitting an outgoing data stream according to the assigned symbol scheme having a second average transmit power, different than the first average transmit power, for a plurality of outgoing symbols,
wherein each outgoing symbol of the plurality of outgoing symbols has N possible states, and
wherein a probability of occurrence for a first portion of the plurality of outgoing symbols is greater than 1/N, and a probability of occurrence for a second portion of the plurality of outgoing symbols is less than 1/N.
2. The method of claim 1 further comprising, in the step of assigning, determining the probabilities of occurrence of a sequence of the individual ones of the received data bits.
3. The method of claim 2 , wherein in the step of assigning, higher power symbols are determined to be less probable than lower power symbols.
4. The method of claim 1 , wherein:
the step of receiving comprises receiving the incoming data stream at a first bandwidth; and
the step of transmitting comprises transmitting the outgoing data stream at a second bandwidth greater than the first bandwidth.
5. The method of claim 1 , wherein the assigned symbol scheme is a lesser state scheme relative to a symbol scheme having equal probability states.
6. The method of claim 5 , wherein the assigned symbol scheme is a 3-state scheme.
7. The method of claim 5 , wherein the assigned symbol scheme represents a one-dimensional constellation diagram, and the symbol scheme having equal probability states represents a two-dimensional constellation diagram.
8. The method of claim 1 , wherein the assigned symbol scheme is an ASK symbol scheme.
9. The method of claim 1 , wherein a ratio of the second average transmit power to the first average transmit power is 3:5 or lower.
10. The method of claim 9 , wherein the ratio of the second average transmit power to the first average transmit power is 1:2 or lower.
11. The method of claim 1 , wherein the step of receiving comprises receiving the incoming data stream encoded using an encoding scheme including at least one of quadrature amplitude modulation (QAM), quadrature phase shift keying (QPSK), amplitude shift keying (ASK), and binary amplitude shift keying (BASK).
12. The method of claim 1 , wherein the first portion of the plurality of outgoing symbols are transmitted at lower power than the second portion of the plurality of outgoing symbols.
13. The method of claim 1 , wherein the assigned symbol scheme implements a non-uniform number of bits per symbol.
14. The method of claim 13 , wherein the incoming data stream includes an incoming symbol scheme implementing a uniform number of bits per symbol.
15. The method of claim 1 , wherein the assigned symbol scheme implements a non-integer number of bits per symbol.
16. The method of claim 15 , wherein the non-integer number of bits per symbol is 1.5.
17. The method of claim 15 , wherein the non-integer number of bits per symbol is 1.811.
18. A symbol transmission system for encoding a data stream comprising: a memory; and
a processor communicatively coupled with the memory, said processor programmed to execute instructions to:
receive an incoming data stream of binary data bits;
determine a probability of occurrence of the binary data bits;
assign a symbol scheme to the incoming data stream based on the determined probability, wherein the assigned symbol scheme includes a first plurality of symbols having a lower probability than the determined probability and a second plurality of symbols having a greater probability than the determined probability; and
transmit an outgoing data stream according to the assigned symbol scheme.
19. The system of claim 18 , wherein the memory includes at least one lookup table.
20. The system of claim 18 , wherein the assigned symbol scheme includes a non-integer entropy value for a number of bits assigned to one or more symbols.