Spreading and Precoding in OFDM

• US 20160254889A1
• Filed: 05/09/2016
• Published: 09/01/2016
• Est. Priority Date: 05/14/2002
• Status: Active Grant

• Current Assignee: Genghiscomm Holdings, LLC
• Original Assignee: Genghiscomm Holdings, LLC
• Inventors: Shattil, Steve
• Granted Patent: US 9,628,231 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04J 11/0093 Neighbour cell search
• CPC Class Codes: H04J 13/0003 Code application, i.e. aspects relating to how codes are applied to form multiplexed channels
• CPC Class Codes: H04J 13/004 Orthogonal
• CPC Class Codes: H04J 13/12 Generation of orthogonal codes
• CPC Class Codes: H04L 12/2854 Wide area networks, e.g. public data networks
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 41/0226 Mapping or translating multiple network management protocols
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0021 : in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA
• CPC Class Codes: H04L 5/0023 : Time-frequency-space
• CPC Class Codes: H04L 5/0035 : Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0037 : Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0073 : Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 52/42 : in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 72/046 : the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/21 : in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 84/18 : Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/02 : Terminal devices

Abstract

An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.

Claims

1. A transmitter configured to reside in a User Equipment (UE), comprising

a discrete Fourier transform (DFT) spreader configured to spread a block of original data symbols with a DFT-based spreading matrix to produce a plurality of spread data symbols;

a subcarrier mapper responsive to channel-dependent scheduling that assigns a set of uplink orthogonal frequency division multiplex (OFDM) subcarriers to the UE based on favorable channel conditions between the UE and at least one wireless wide area network (WWAN) access terminal, the subcarrier mapper configured to map each non-zero spread data symbol to one of the set of uplink OFDM subcarriers; and

an inverse-DFT configured to modulate the plurality of spread data symbols onto the set of uplink OFDM subcarriers to generate a spread-OFDM signal for transmission into the WWAN;

wherein at least one of the DFT spreader and the subcarrier mapper configures the spread data symbols to provide the spread-OFDM signal with a low PAPR.

2. The transmitter recited in claim 1, wherein the low PAPR equals a PAPR corresponding to a single-carrier signal.

3. The transmitter recited in claim 1, wherein the uplink OFDM subcarriers comprise at least one of contiguous subcarriers and non-contiguous subcarriers.

4. The transmitter recited in claim 1, wherein the DFT spreader is configured to perform a fast transform algorithm.

5. The transmitter recited in claim 1, wherein the DFT spreader is configured to provide the spread-OFDM signal with an orthogonal code space.

6. The transmitter recited in claim 1, wherein the DFT spreader comprises a precoder configured to provide at least one of pre-coding, pre-equalization, and pulse shaping to the spread-OFDM signal.

7. A transmitter comprising a processor;

and a memory coupled to the processor, the memory including instructions stored therein and executable by the processor to;

spread a block of original data symbols with a discrete Fourier transform (DFT)-based spreading matrix to produce a plurality of spread data symbols;

responsive to channel-dependent scheduling that assigns a set of uplink orthogonal frequency division multiplex (OFDM) subcarriers to the UE based on favorable channel conditions between the transmitter and at least one wireless wide area network (WWAN) access terminal, map each non-zero spread data symbol to one of the set of uplink OFDM subcarriers; and

modulate the plurality of spread data symbols onto the set of uplink OFDM subcarriers to generate a spread-OFDM signal for transmission into the WWAN;

wherein at least one of the DFT-based spreading matrix and the plurality of spread data symbols is configured to provide the spread-OFDM signal with a low PAPR.

8. The transmitter recited in claim 7, wherein the low PAPR equals a PAPR corresponding to a single-carrier signal.

9. The transmitter recited in claim 7, wherein the uplink OFDM subcarriers comprise at least one of contiguous subcarriers and non-contiguous subcarriers.

10. The transmitter recited in claim 7, wherein the block of original data symbols is spread using a fast transform algorithm.

11. The transmitter recited in claim 7, wherein the DFT-based spreading matrix is configured to provide the spread-OFDM signal with an orthogonal code space.

12. The transmitter recited in claim 7, wherein the DFT-based spreading matrix is configured to provide for at least one of pre-coding, pre-equalization, and pulse shaping to the spread-OFDM signal.

13. A transmitter configured to reside in a User Equipment (UE), comprising

a discrete Fourier transform (DFT) spreader configured to spread a block of original data symbols with a DFT-based spreading matrix to produce a plurality of spread data symbols;

a subcarrier mapper responsive to scheduling that assigns a set of uplink orthogonal frequency division multiplex (OFDM) subcarriers to the UE, the subcarrier mapper configured to map each non-zero spread data symbol to one of the set of uplink OFDM subcarriers; and

an inverse-DFT configured to modulate the plurality of spread data symbols onto the set of uplink OFDM subcarriers to generate a spread-OFDM signal for transmission into a wireless wide area network (WWAN);

wherein at least one of the DFT spreader and the subcarrier mapper configures the spread data symbols to provide the spread-OFDM signal with a low PAPR.

14. The transmitter recited in claim 13, wherein the DFT spreader is configured to operate as at least one of the inverse-DFT and a DFT demodulator used for demodulating received OFDM signals.

15. The transmitter recited in claim 13, wherein the low PAPR equals a PAPR corresponding to a single-carrier signal.

16. The transmitter recited in claim 13, wherein the uplink OFDM subcarriers comprise at least one of contiguous subcarriers and non-contiguous subcarriers.

17. The transmitter recited in claim 13, wherein the DFT spreader is configured to perform a fast transform algorithm.

18. The transmitter recited in claim 13, wherein the DFT spreader is configured to provide the spread-OFDM signal with an orthogonal code space.

19. The transmitter recited in claim 13, wherein the DFT spreader comprises a precoder configured to provide at least one of pre-coding, pre-equalization, and pulse shaping to the spread-OFDM signal.

20. A transmitter comprising a processor;

and a memory coupled to the processor, the memory including instructions stored therein and executable by the processor to;

spread a block of original data symbols with a discrete Fourier transform (DFT)-based spreading matrix to produce a plurality of spread data symbols;

responsive to channel-dependent scheduling that assigns a set of uplink orthogonal frequency division multiplex (OFDM) subcarriers to the UE, map each non-zero spread data symbol to one of the set of uplink OFDM subcarriers; and

modulate the plurality of spread data symbols onto the set of uplink OFDM subcarriers to generate a spread-OFDM signal for transmission into a wireless wide area network (WWAN);

wherein at least one of the DFT-based spreading matrix and the plurality of spread data symbols is configured to provide the spread-OFDM signal with a low PAPR.

21. The transmitter recited in claim 20, wherein the instructions executable by the processor to spread the original data symbols is configured to at least one of modulate the plurality of spread data symbols onto the set of uplink OFDM subcarriers and demodulate a received OFDM signal.

22. The transmitter recited in claim 20, wherein the low PAPR equals a PAPR corresponding to a single-carrier signal.

23. The transmitter recited in claim 20, wherein the uplink OFDM subcarriers comprise at least one of contiguous subcarriers and non-contiguous subcarriers.

24. The transmitter recited in claim 20, wherein the plurality of spread data symbols is generated using a fast transform algorithm.

25. The transmitter recited in claim 20, wherein the DFT-based spreading matrix is configured to provide the spread-OFDM signal with an orthogonal code space.

26. The transmitter recited in claim 20, wherein the DFT-based spreading matrix is configured to provide at least one of pre-coding, pre-equalization, and pulse shaping to the spread-OFDM signal.