Orthogonal frequency-division multiplexing (OFDM) communication slot structures and methods
View Patent ↗Improved orthogonal frequency-division multiplexing (OFDM) communication slot structures and method are described. One example method includes converting a first portion of a set of bits to a first orthogonal frequency-division multiplexing symbol to be transmitted during a first portion of a time-division multiple access time slot, and converting a second portion of the set of bits to a second orthogonal frequency-division multiplexing symbol to be transmitted during a second portion of the time-division multiple access time slot. Other embodiments are shown and described.
1. A method comprising:
converting a first portion of a set of bits that are to be encoded to a first orthogonal frequency-division multiplexing symbol to be transmitted during a first portion of a time-division multiple access time slot; and
converting a second portion of the set of bits that are to be encoded to a second orthogonal frequency-division multiplexing symbol to be transmitted during a second portion of the time-division multiple access time slot, wherein converting the first portion of the set of bits to the first orthogonal frequency-division multiplexing symbol comprises mapping the first portion of the set of bits to one or more symbols represented by one or more modulated sub-carriers, wherein the one or more sub-carriers are modulated according to different modulation schemes.
2. The method of claim 1 , wherein the time-division multiple access time slot is disjoint in time from at least one other time-division multiple access time slot carrying portions of the bits that are to be encoded.
3. The method of claim 1 , wherein a modulation scheme of a first order is used in modulating one or more sub-carriers near an edge of a transmission band and a modulation scheme of a second order higher than the first order is used to modulate one or more sub-carriers near a middle of the transmission band.
4. The method of claim 1 , wherein one or more training symbols are modulated onto one or more sub-carriers.
5. The method of claim 4 , wherein at least one training symbol is modulated onto a low frequency sub-carrier of one of the first orthogonal frequency-division multiplexing symbol or the second orthogonal frequency-division multiplexing symbol.
6. The method of claim 5 , wherein at least one training symbol is modulated onto a high frequency sub-carrier of one of the first orthogonal frequency-division multiplexing symbol or the second orthogonal frequency-division multiplexing symbol.
7. The method of claim 4 , wherein at least one training symbol is modulated onto a low frequency sub-carrier of the first orthogonal frequency-division multiplexing symbol and at least one training symbols is modulated onto a high frequency sub-carrier of the second orthogonal frequency-division multiplexing symbol.
8. The method of claim 1 , wherein converting the first portion of the set of bits to the first orthogonal frequency-division multiplexing symbol comprises mapping the first portion of the set of bits to a radix 2 number of symbols.
9. The method of claim 8 , wherein converting the second portion of the set of bits to the second orthogonal frequency-division multiplexing symbol comprises mapping the second portion of the set of bits to a radix 2 number of symbols.
10. The method of claim 8 , wherein the bits comprise information bits and training bits.
11. The method of claim 1 , wherein the first orthogonal frequency-division multiplexing symbol includes a first number of training symbols and wherein the second orthogonal frequency-division multiplexing symbol includes a second number of training symbols different from the first number of training symbols.
12. A method comprising:
converting a portion of a set of bits that are to be encoded to an orthogonal frequency-division multiplexing symbol to be transmitted during at least one time-division multiple access time slot, wherein the converting comprises mapping the portion of the set of bits to one or more symbols represented by one or more modulated sub-carriers, and wherein a modulation scheme of a first order is used to modulate sub-carriers near an edge of a transmission band and a modulation scheme of a second order higher than the first order is used to modulate sub-carriers near a middle of the transmission band.
13. The method of claim 12 , wherein one or more training symbols are modulated onto one or more sub-carriers.
14. The method of claim 13 , wherein at least one training symbol is modulated onto a low frequency sub-carrier of the orthogonal frequency-division multiplexing symbol.
15. The method of claim 13 , wherein at least one training symbol is modulated onto a high frequency sub-carrier of the orthogonal frequency-division multiplexing symbol.
16. The method of claim 12 , wherein converting the portion of the set of bits to the orthogonal frequency-division multiplexing symbol comprises mapping the portion of the set of bits to a radix 2 number of symbols.
17. The method of claim 12 , wherein the bits comprise information bits and training bits.
18. An apparatus, comprising:
a processor; and
a memory comprising machine readable instructions which, when executed, cause the processor to:
convert a first portion of a set of bits that are to be encoded to a first orthogonal frequency-division multiplexing symbol to be transmitted during a first portion of a time-division multiple access time slot; and
convert a second portion of the set of bits that are to be encoded to a second orthogonal frequency-division multiplexing symbol to be transmitted during a second portion of the time-division multiple access time slot, wherein converting the first portion of the set of bits to the first orthogonal frequency-division multiplexing symbol comprises mapping the first portion of the set of bits to one or more symbols represented by one or more modulated sub-carriers, wherein the one or more sub-carriers are modulated according to different modulation schemes.
19. The apparatus of claim 18 , wherein the instructions cause the processor to use a modulation scheme of a first order in modulating one or more sub-carriers near an edge of a transmission band and use a modulation scheme of a second order higher than the first order to modulate one or more sub-carriers near a middle of the transmission band.
20. The apparatus of claim 19 , wherein the amplitude of sub-carriers are attenuated to comply with spectral emission requirements.
21. The apparatus of claim 20 , wherein the spectral emission requirements are the requirements related to transmitting an EGPRS burst.
22. The apparatus of claim 18 , wherein the apparatus is a mobile station.
23. The apparatus of claim 18 , wherein the apparatus is a mobile communication network element.
24. An apparatus, comprising:
a processor; and
a memory comprising machine readable instructions which, when executed, cause the processor to:
convert a portion of a set of bits that are to be encoded to an orthogonal frequency-division multiplexing symbol to be transmitted during at least one time-division multiple access time slot, wherein the converting comprises mapping the portion of the set of bits to one or more symbols represented by one or more modulated sub-carriers, and wherein a modulation scheme of a first order is used to modulate sub-carriers near an edge of a transmission band and a modulation scheme of a second order higher than the first order is used to modulate sub-carriers near a middle of the transmission band.
25. The apparatus of claim 24 , wherein the apparatus is a mobile station.
26. The apparatus of claim 25 , wherein the apparatus is a mobile communication network element.
27. The method of claim 2 , wherein the bits that are to be encoded are one codeword.
28. The method of claim 3 , wherein the amplitude of sub-carriers are attenuated to comply with spectral emission requirements.
29. The method of claim 28 , wherein the spectral emission requirements are the requirements related to transmitting an EGPRS burst.