NLOS wireless backhaul downlink communication

Patent metadata

Field	Value
Publication number	US-10880875-B2
Application number	US-201916408590-A
Country	US
Kind code	B2
Filing date	May 10, 2019
Priority date	Jun 5, 2013
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A method for communicating over a wireless backhaul channel comprising generating a radio frame comprising a plurality of time slots, wherein each time slot comprises a plurality of symbols in time and a plurality of sub-carriers in a system bandwidth, broadcasting a broadcast channel signal comprising a transmission schedule to a plurality of remote units in a number of consecutive sub-carriers centered about a direct current (DC) sub-carrier in at least one of the time slots in the radio frame regardless of the system bandwidth, and transmitting a downlink (DL) control channel signal and a DL data channel signal to a first of the remote units, wherein the DL data channel signal is transmitted by employing a single carrier block transmission scheme comprising a Discrete Fourier Transform (DFT) spreading for frequency diversity.

First claim

What is claimed is:

1. A method comprising:
generating a radio frame comprising time slots, wherein each time slot comprises sub-carriers in a system bandwidth, wherein the radio frame comprises time slots for an uplink (UL) direction and time slots for a downlink (DL) direction, wherein the DL direction comprises a DL time period;
broadcasting a broadcast channel signal to first and second remote units in consecutive sub-carriers centered about a direct current (DC) sub-carrier in at least one of the time slots in the radio frame, wherein the broadcast channel signal comprises a transmission schedule comprising slot assignments that indicate a link direction and a transmission opportunity for the first remote unit and the broadcast channel signal is broadcast in the DL time period; and
transmitting a DL control channel signal and a DL data channel signal to the first remote unit over a wireless backhaul channel, wherein the DL control channel signal comprises DL control information, wherein the broadcast channel signal, the DL control channel signal, and the DL data channel signal are transmitted using a time-frequency multiplexing scheme, and wherein the DL data channel signal is transmitted using a single carrier block transmission scheme comprising a discrete Fourier transform (DFT) spreading.

2. The method of claim 1 , wherein each time slot comprises a fixed time duration, and wherein the transmission schedule comprises a scheduling period about a half radio frame time duration or a full radio frame time duration.

3. The method of claim 2 , wherein the fixed time duration comprises about 0.5 milliseconds (ms) to provide low transmission latency, and wherein the radio frame comprises about twenty time slots.

4. The method of claim 1 further comprising transmitting a pilot sequence (PS) in a symbol time spanning all the sub-carriers in the system bandwidth, wherein the PS comprises a pre-determined sequence comprising signal properties that provide channel estimation capabilities in the system bandwidth.

5. The method of claim 4 , wherein the PS is transmitted at a beginning of each time slot assigned for the DL direction to provide low receive processing latency at the remote units.

6. The method of claim 4 , wherein the PS is transmitted at about a middle of each time slot assigned for the DL direction to provide channel estimation with low timing drift in a time-varying channel.

7. The method of claim 1 , wherein a third or thirteenth time slot in the time slots for the DL direction further comprises a guard time period to provide a link direction switching opportunity and an UL time period to provide an UL random access opportunity.

8. The method of claim 1 , wherein the DL time period comprises about four symbols, wherein the guard time period comprises about one symbol, and wherein the UL time period comprises about two symbols.

9. The method of claim 1 further comprising transmitting a synchronization sequence (SS) in a same set of sub-carriers as the broadcast channel signal in the DL time period of a third or thirteenth time slot in the time slots for the DL direction by time multiplexing with the broadcast channel signal, wherein the SS comprises a pre-determined sequence comprising signal properties that provide signal detection capabilities for identifying the radio frame.

10. The method of claim 9 , wherein the SS sequence is transmitted in about one symbol time, and wherein the broadcast channel signal is transmitted in about two symbol time.

11. The method of claim 1 , wherein the broadcast channel signal and the DL control channel signal are transmitted by employing the single carrier block transmission scheme.

12. The method of claim 1 , wherein the DL control channel signal is transmitted in a first set of the sub-carriers located near a higher frequency edge of the system bandwidth and a second set of the sub-carriers located near a lower frequency edge of the system bandwidth.

13. The method of claim 1 , wherein the slot assignments comprise a slot assignment for the first remote unit for UL transmission, wherein the DL control channel signal further comprises UL control information for the UL transmission, and wherein the method further comprises:
combining at least some of the DL control information and at least some of the UL control information to generate a control frame; and
computing a Cyclic Redundancy Check (CRC) for the control frame.

14. The method of claim 1 further comprising:
receiving a UL data channel signal comprising a UL data frame from the first remote unit;
generating a hybrid automatic repeat request (HARQ) feedback signal according to a reception status of the UL data frame;
mapping the HARQ feedback signal to a first set of the sub-carriers located near a higher frequency edge of the system bandwidth; and
repeating the mapping of the HARQ feedback signal to a second set of the sub-carriers located near a lower frequency edge of the system bandwidth.

15. The method of claim 1 , wherein either a third or thirteenth time slot in the time slots for the DL direction comprises the DL time period.

16. An apparatus comprising:
a transceiver; and
a processing unit coupled to the transceiver, the processing unit is configured to:
generate a radio frame including time slots for an uplink (UL) direction and time slots for a downlink (DL) direction, wherein each time slot comprises a plurality of sub-carriers in a system bandwidth and wherein at least one time slot for the DL direction comprises a DL time period;
broadcast a broadcast channel signal to first and second remote units over a wireless backhaul channel in consecutive sub-carriers centered about a direct current (DC) sub-carrier in at least one of the time slots in the radio frame, wherein the broadcast channel signal comprises a transmission schedule comprising slot assignments that indicate a link direction and a transmission opportunity for a first remote unit and the broadcast channel signal is broadcast in the DL time period; and
transmit a DL control channel signal and a DL data channel signal to the first remote unit over a wireless backhaul channel, wherein the DL control channel signal comprises DL control information, wherein the broadcast channel signal, the DL control channel signal, and the DL data channel signal are transmitted using a time-frequency multiplexing scheme, and wherein the DL data channel signal is transmitted using a single carrier block transmission scheme comprising a discrete Fourier transform (DFT) spreading.

17. The apparatus of claim 16 , wherein each time slot comprises a fixed time duration, and wherein the transmission schedule comprises a scheduling period about a half radio frame time duration or a full radio frame time duration.

18. The apparatus of claim 17 , wherein the fixed time duration comprises about 0.5 milliseconds (ms) to provide low transmission latency, and wherein the radio frame comprises about twenty time slots.

19. The apparatus of claim 18 , wherein a third or thirteenth time slot in the time slots for the DL direction further comprising a guard time period to provide a link direction switching opportunity, and an UL time period to provide an UL random access opportunity, and wherein the broadcast channel signal is broadcasted in the DL time period of the third or thirteenth time slot in the time slots for the DL direction.

20. The apparatus of claim 18 , wherein the processing unit is further configured to transmit a synchronization sequence (SS) in a same

Assignees

• Texas Instruments Inc

Inventors

• Roh June Chui
• Bertrand Pierre
• Hosur Srinath
• Pothukuchi Vijay
• Mansour Mohamed Farouk

Classifications

• H04W72/21 Primary

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H03M13/1515 Primary

  Reed-Solomon codes · CPC title

• H03M13/2966

  Turbo codes concatenated with another code, e.g. an outer block code · CPC title

• H03M13/635

  Error control coding in combination with rate matching · CPC title

• H04L1/0057

  Block codes (H04L1/0061, H04L1/0064 take precedence) · CPC title