Method for frequency division duplex communications

• US 7,983,217 B2
• Filed: 08/15/2008
• Issued: 07/19/2011
• Est. Priority Date: 02/06/1997
• Status: Expired due to Fees

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Inventors: Zhang, Hongliang, Alamouti, Siavash, Hoole, Elliott, Jesse, Mary, Poon, Patrick, Veintimilla, Gregory J., Michelson, David G., Hirano, Michael, Casas, Eduardo F.
• Primary Examiner(s): Milord; Marceau
• Application Number:
  US12/192,705
• Publication Number:
  US 20080298339A1
• Time in Patent Office: 1,068 Days
• Field of Search: 370/330, 370/203, 370/281, 370/206, 370/329, 370/336, 370/337, 370/321, 370/343, 370/344, 375/267, 375/299, 375/347
• US Class Current: 370/330
• CPC Class Codes: H04B 7/0837 using pre-detection combining H04B7/0868 takes precedence
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04J 3/0652 Synchronisation among time division multiple access [TDMA] nodes, e.g. time triggered protocol [TTP] bus network with centralized control in which slots are of a TDMA packet structure H04L12/4035
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1484 operating bytewise
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource

Abstract

The high quality PCS communications are enabled in environments where adjacent PCS service bands operate with out-of-band harmonics that would otherwise interfere with the system'"'"'s operation. The highly bandwidth-efficient communications method combines a form of time division duplex (TDD), frequency division duplex (FDD), time division multiple access (TDMA), orthogonal frequency division multiplexing (OFDM), spatial diversity, and polarization diversity in various unique combinations. The method provides excellent fade resistance. The method enables changing a user'"'"'s available bandwidth on demand by assigning additional TDMA slots during the user'"'"'s session.

Claims

1. An apparatus comprising:

a remote unit configured to transmit a signal including a first data signal, the first data signal being allocated to only a first set of a plurality of sets of non-overlapping orthogonal frequency division multiplexed (OFDM) discrete frequency tones in a first frequency band of a plurality of non-overlapping frequency bands of a channel coupled to the remote unit, and in a first set of time intervals, fewer than all time intervals, of a plurality of time intervals of a time division multiple access (TDMA) frame of the channel,

wherein the remote unit comprises;

an encoder configured to encode the first data signal;

a tone mapping block configured to map the encoded first data signal to the first set of non-overlapping OFDM discrete frequency tones in a frequency domain signal;

an inverse discrete Fourier transform block configured to transform the frequency domain signal into a digital time domain signal;

a digital-to-analog converter configured to convert the digital time domain signal into an analog baseband signal;

a radio frequency (RF) transmitter configured to convert the analog baseband signal into an RF signal; and

an antenna configured to transmit the RF signal.

2. An apparatus comprising:

a remote unit configured to transmit a signal including a first data signal, the first data signal being allocated to only a first set of a plurality of sets of non-overlapping orthogonal frequency division multiplexed (OFDM) discrete frequency tones in a first frequency band of a plurality of non-overlapping frequency bands of a channel coupled to the remote unit, and in a first set of time intervals, fewer than all time intervals, of a plurality of time intervals of a time division multiple access (TDMA) frame of the channel,

wherein the remote unit is configured to recover a second data signal from a received signal, the second data signal being recovered from only a second set of the plurality of sets of non-overlapping OFDM discrete frequency tones in only a second frequency band of the plurality of non-overlapping frequency bands and in a second set of time intervals, fewer than all time intervals, of the plurality of time intervals of the TDMA frame.

3. The apparatus, as recited in claim 2,

wherein the first and second frequency bands are different, the first and second sets of time intervals are different, and the first and second sets of non-overlapping OFDM discrete frequency tones are different.

4. The apparatus, as recited in claim 2, wherein the remote unit comprises:

an antenna;

a radio frequency receiver configured to convert the received signal from an RF signal to a baseband signal;

an analog-to-digital converter configured to digitally sample the baseband signal to generate a digital version of the baseband signal;

a discrete Fourier transform block configured to transform the digital version of the baseband signal from a time domain signal into a frequency domain signal;

a tone select block configured to select the second set of tones from the plurality of sets of non-overlapping OFDM discrete frequency tones in the frequency domain signal; and

a decoder configured to recover the second data signal from a signal at least partially based on the second set of tones.

5. The apparatus, as recited in claim 2, wherein the remote unit comprises:

an encoder configured to encode the first data signal;

a tone mapping block configured to map the encoded first data signal to the first set of non-overlapping OFDM discrete frequency tones in a frequency domain signal;

an inverse discrete Fourier transform block configured to transform the frequency domain signal into a digital time domain signal;

a digital-to-analog converter configured to convert the digital time domain signal into an analog baseband signal;

a radio frequency (RF) transmitter configured to convert the analog baseband signal into an RF signal; and

an antenna configured to transmit the RF signal.

6. An apparatus comprising:

a base station configured to recover at least a first data signal from only a first set of a plurality of sets of non-overlapping orthogonal frequency division multiplexed (OFDM) discrete frequency tones in a first frequency band of a plurality of non-overlapping frequency bands of a channel coupled to the base station and in a first set of time intervals, fewer than all time intervals, of a plurality of time intervals of a time division multiple access (TDMA) frame of the channel coupled to the base station,

wherein the base station is configured to recover at least a second data signal from only a second set of the plurality of sets of non-overlapping OFDM discrete frequency tones in only the second frequency band of the plurality of non-overlapping frequency bands, and in a second set of time intervals, fewer than all time intervals, of the plurality of time intervals of the TDMA frame.

7. The apparatus, as recited in claim 6, wherein the first and second sets of non-overlapping OFDM discrete frequency tones are different, the first and second frequency bands are the same frequency band, and the first and second sets of time intervals are the same time intervals.

8. The apparatus, as recited in claim 6, wherein the first and second sets of non-overlapping OFDM discrete frequency tones are the same, the first and second frequency bands are the same, and the first and second sets of time intervals are distinct, non-overlapping time intervals.

9. The apparatus, as recited in claim 6,

wherein the first and second sets of non-overlapping OFDM discrete frequency tones are the same discrete frequency tones, the first and second frequency bands are the same frequency band, and the first and second sets of time intervals are the same time intervals,

wherein the first and second signals are received from a first remote station in a first geographic location and a second remote station in a second geographic location distinct from the first geographic location, respectively, and

wherein the base station is configured to spatially despread the first and second data signals and configured to recover first and second data from the first and second data signals, respectively.

10. The apparatus, as recited in claim 6,

wherein the first and second sets of non-overlapping OFDM discrete frequency tones are the same discrete frequency tones, the first and second frequency bands are the same frequency band, and the first and second sets of time intervals are the same time intervals,

wherein the first signal is polarized in a first direction and the second signal is polarized in a second direction orthogonal to the first direction, and

wherein the first and second signals are received from a first remote station in a first geographic location and a second remote station in a second geographic location distinct from the first geographic location, respectively.

11. An apparatus comprising:

a base station configured to recover at least a first data signal from only a first set of a plurality of sets of non-overlapping orthogonal frequency division multiplexed (OFDM) discrete frequency tones in a first frequency band of a plurality of non-overlapping frequency bands of a channel coupled to the base station and in a first set of time intervals, fewer than all time intervals, of a plurality of time intervals of a time division multiple access (TDMA) frame of the channel coupled to the base station,

wherein the base station comprises;

at least one antenna configured to receive a radio frequency (RF) signal;

at least one RF receiver configured to convert the RF signal into a baseband signal; and

an analog-to-digital converter configured to digitally sample the baseband signal and generate a digital baseband signal;

a discrete Fourier transform block configured to transform the digital baseband signal from a time domain signal into a frequency domain signal;

a tone select block configured to select the first set of tones from a plurality of sets of tones in the frequency domain signal; and

a decoder configured to recover the first data signal from a signal at least partially based on the first set of tones.

12. The apparatus, as recited in claim 11, wherein the base station comprises:

at least a second antenna; and

a despreader configured to weight the first set of tones and add the weighted first set of tones to at least one other weighted set of tones recovered from a signal received by the second antenna.

13. An apparatus comprising:

a base station configured to recover at least a first data signal from only a first set of a plurality of sets of non-overlapping orthogonal frequency division multiplexed (OFDM) discrete frequency tones in a first frequency band of a plurality of non-overlapping frequency bands of a channel coupled to the base station and in a first set of time intervals, fewer than all time intervals, of a plurality of time intervals of a time division multiple access (TDMA) frame of the channel coupled to the base station,

wherein the base station is configured to transmit a first transmit signal including a second data signal, the second data signal being allocated to only a second set of the plurality of sets of non-overlapping OFDM discrete frequency tones in a second frequency band of the plurality of non-overlapping frequency bands, and in a second set of time intervals, fewer than all time intervals, of the plurality of time intervals of the TDMA frame.

14. The apparatus, as recited in claim 13,

wherein the first and second sets of time intervals are different, the first and second frequency bands are different, and the first and second sets of discrete frequency tones are different.

15. The apparatus, as recited in claim 13,

wherein the base station is configured to transmit a second transmit signal including a third data signal, the third data signal being allocated to only a third set of the plurality of sets of non-overlapping OFDM discrete frequency tones in a third frequency band of the plurality of non-overlapping frequency bands, and in a third set of time intervals, fewer than all time intervals, of the plurality of time intervals of the TDMA frame.

16. The apparatus, as recited in claim 15,

wherein the second and third sets of time intervals are different, the second and third frequency bands are the same, and the second and third sets of discrete frequency tones are the same.

17. The apparatus, as recited in claim 15,

wherein the second and third sets of time intervals are the same, the second and third frequency bands are the same, and the second and third sets of discrete frequency tones are different.

18. The apparatus, as recited in claim 15,

wherein the second and third sets of time intervals are different, the second and third frequency bands are the same, and the second and third sets of discrete frequency tones are different.

19. The apparatus, as recited in claim 15, wherein the base station comprises:

an encoder configured to encode the second data signal;

a tone mapping block configured to map the encoded second data signal to the second set of tones in a frequency domain signal; and

an inverse discrete Fourier transform block configured to transform the frequency domain signal into a digital time domain signal;

a digital-to-analog converter configured to convert the digital time domain signal into an analog baseband signal; and

a radio frequency (RF) transmitter configured to convert the analog baseband signal into an RF signal.

20. The apparatus, as recited in claim 19, wherein the base station comprises:

a spreader configured to apply spatial spreading weights to a version of the data signal to generate weighted versions of the data signal;

a plurality of antennas configured to transmit corresponding RF versions of the weighted versions of the data signal.

21. An apparatus comprising:

means for transmitting a signal including a first data signal, the first data signal being allocated to only a first set of a plurality of sets of non-overlapping orthogonal frequency division multiplexed (OFDM) discrete frequency tones in a first frequency band of a plurality of non-overlapping frequency bands of a channel coupled to the means for transmitting, and in a first set of time intervals, fewer than all time intervals, of a plurality of time intervals of a time division multiple access (TDMA) frame of the channel; and

means to recover a second data signal from a received signal, the second data signal being recovered from only a second set of the plurality of sets of non-overlapping OFDM discrete frequency tones of the second frequency band in only a second frequency band of the plurality of non-overlapping frequency bands and in a second set of time intervals, fewer than all time intervals, of the plurality of time intervals of the TDMA frame.