Pre-communication for relay base stations in wireless communication

• US 9,154,352 B2
• Filed: 04/20/2010
• Issued: 10/06/2015
• Est. Priority Date: 04/21/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Palanki, Ravi, Gorokhov, Alexei Yurievitch, Khandekar, Aamod Dinkar
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): KAO, WEI PO ERIC
• Application Number:
  US12/763,788
• Publication Number:
  US 20100265874A1
• Time in Patent Office: 1,995 Days
• Field of Search: 370276-296, 370310-350
• US Class Current: 1/1
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04L 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

Providing for wireless communication involving supplemental wireless nodes is described herein. By way of example, prior signaling is employed between a macro base station and a set of associated supplemental nodes to support pending wireless communication with a user terminal. In some aspects, the prior signaling can include control or data traffic transmitted to or received from the user terminal. In addition, the supplemental nodes can synchronize transmission or reception of the control or data traffic transmissions with similar transmission or reception of the macro base station. In some aspects, the supplemental nodes can also replicate pilot signal transmissions on OFDM symbols employed by the macro base station for pilot signals, to give consistent downlink channel for both traffic and pilot signals. Accordingly, the user terminal observes consistent pilot transmissions over various time slots, as well as concurrent traffic transmissions that can generally be decoded with a common reference signal.

Claims

1. A method for employing a half duplex supplemental wireless node (HD-SWN) in wireless communication, comprising:

transmitting a relay pilot signal to a user equipment (UE) on a first set of orthogonal frequency division multiplex (OFDM) symbols in a subframe;

receiving from a base station a wireless signal on a second set of OFDM symbols within the subframe, at least one OFDM symbol of the second set of OFDM symbols being interposed between at least two OFDM symbols of the first set of OFDM symbols that are non-contiguous in time;

obtaining a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from the UE served by the HD-SWN, the CQI or the PMI comprising a measurement of a controlling pilot signal transmitted by the base station and observed at the UE;

forwarding the CQI or the PMI to the base station to facilitate estimating a modulation and coding scheme (MCS) for transmitting the relay pilot signal;

receiving the MCS from the base station;

transmitting the relay pilot signal in accordance with the MCS; and

receiving a second CQI or a second PMI comprising a measurement of a concurrent transmission of the controlling pilot and the relay pilot signal as observed at the UE.

2. The method of claim 1, in which the relay pilot signal is a common reference signal (CRS).

3. The method of claim 1,

in which:

the first set of OFDM symbols are also used by a base station for transmitting a controlling pilot signal; and

the base station is remotely located from the HD-SWN.

4. The method of claim 3, further comprising allocating a subset of the second set of OFDM symbols to receiving transmissions from the base station.

5. The method of claim 3, further comprising allocating a second subset of the second set of OFDM symbols to receiving transmissions from the UE that is wirelessly coupled with the HD-SWN.

6. The method of claim 1, further comprising:

receiving an updated MCS from the base station that is configured for the concurrent transmission of the controlling pilot signal and the relay pilot signal; and

transmitting the relay pilot signal in a subsequent subframe in accordance with the updated MCS.

7. The method of claim 1, further comprising transmitting the relay pilot signal on a first antenna or first antenna-group that is different from a second antenna or second antenna-group used for transmitting the controlling pilot signal.

8. The method of claim 1, further comprising transmitting the relay pilot signal on a first virtual antenna port that is different from a second virtual antenna port of the controlling pilot signal.

9. The method of claim 1, in which the subframe is a long term evolution (LTE) subframe.

10. An apparatus for wireless communication, comprising:

a half duplex wireless transceiver configured to transmit and receive signals on separate orthogonal frequency division multiplex (OFDM) symbols of a subframe;

a memory for storing instructions configured to control the half duplex wireless transceiver to switch between transmitting and receiving on contiguous OFDM symbols; and

a data processor that executes modules configured to implement the instructions, the modules comprising;

an acquisition module configured to identify a set of OFDM symbols used by a base station for transmitting a base station pilot signal; and

a configuration module configured to control the half duplex wireless transceiver to;

transmit a relay pilot signal to a user equipment (UE) on a first OFDM symbol of the subframe,

receive a wireless signal on a second OFDM symbol of the subframe, and

re-transmit the relay pilot signal to the UE on a third OFDM symbol of the subframe, the second OFDM symbol being interposed in time between the first OFDM symbol and the third OFDM symbol.

11. The apparatus of claim 10, in which the base station pilot signal is transmitted on each OFDM symbol of the set of OFDM symbols.

12. The apparatus of claim 10, in which the relay pilot signal and the base station pilot signal are common reference signals (CRSs).

13. The apparatus of claim 10, further comprising a feedback module configured to obtain a channel report including a measurement of a base station pilot signal observed at a UE served by the apparatus.

14. The apparatus of claim 13, in which the feedback module forwards the channel report to the base station for estimation of a modulation and coding scheme suited for the UE to decode a relay pilot transmitted by the half duplex wireless transceiver.

15. The apparatus of claim 10, further comprising a mediation module configured to identify a subset of OFDM symbols within the subframe that are unavailable for transmission or reception as a result of hardware time switching constraints of the half duplex wireless transceiver.

16. The apparatus of claim 15, in which the mediation module is further configured to adjust transmission times of the relay pilot signal such that the subset of OFDM symbols does not coincide with the first OFDM symbol or the third OFDM symbol.

17. The apparatus of claim 16, in which the mediation module is further configured to modify reception times of the half duplex wireless transceiver such that the subset of OFDM symbols does not coincide with the second OFDM symbol.

18. The apparatus of claim 10, in which the set of OFDM symbols comprises OFDM symbols 0, 4, 7 and 10 of the subframe if the base station transmits with a single or dual-antenna arrangement.

19. The apparatus of claim 10, in which the set of OFDM symbols comprises OFDM symbols 0, 1, 4, 7, 8 and 10 of the subframe if the base station transmits with a quad-antenna arrangement.

20. The apparatus of claim 10, in which the apparatus comprises one or more of:

a transparent repeater;

a transparent wireless relay;

a transparent pico cell;

a remote radio head;

a smart repeater;

an incremental redundancy relay, or a combination thereof.

21. An apparatus for wireless communication, comprising:

means for transmitting a relay pilot signal to a user equipment (UE) on a first set of orthogonal frequency division multiplex (OFDM) symbols in a subframe;

means for receiving from a base station a wireless signal on a second set of OFDM symbols within the subframe, at least one OFDM symbol of the second set of OFDM symbols being interposed between at least two OFDM symbols of the first set of OFDM symbols that are non-contiguous in time;

means for obtaining a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from the UE served by the HD-SWN, the CQI or the PMI comprising a measurement of a controlling pilot signal transmitted by the base station and observed at the UE;

means for forwarding the CQI or the PMI to the base station to facilitate estimating a modulation and coding scheme (a MCS) for transmitting the relay pilot signal;

means for receiving the MCS from the base station;

means for transmitting the relay pilot signal in accordance with the MCS; and

means for receiving a second CQI or a second PMI comprising a measurement of a concurrent transmission of the controlling pilot and the relay pilot signal as observed at the UE.

22. An apparatus for wireless communication, the apparatus comprising:

a memory; and

at least one processor coupled to the memory, the at least one processor configured;

to transmit a relay pilot signal to a user equipment (UE) on a first set of orthogonal frequency division multiplex (OFDM) symbols in a subframe;

to receive from a base station a wireless signal on a second set of OFDM symbols within the subframe, at least one OFDM symbol of the second set of OFDM symbols being interposed between at least two OFDM symbols of the first set of OFDM symbols that are non-contiguous in time;

to obtain a channel quality indicator (a CQI) or a precoding matrix indicator (a PMI) from the UE served by the HD-SWN, the CQI or the PMI comprising a measurement of a controlling pilot signal transmitted by the base station and observed at the UE;

to forward the CQI or the PMI to the base station to facilitate estimating a modulation and coding scheme (a MCS) for transmitting the relay pilot signal;

to receive the MCS from the base station;

to transmit the relay pilot signal in accordance with the MCS; and

to receive a second CQI or a second PMI comprising a measurement of a concurrent transmission of the controlling pilot and the relay pilot signal as observed at the UE.

23. A computer program product, comprising:

a non-transitory computer-readable medium, comprising;

code to transmit a relay pilot signal to a user equipment (UE) on a first set of orthogonal frequency division multiplex (OFDM) symbols in a subframe;

code to receive from a base station a wireless signal on a second set of OFDM symbols within the subframe, at least one OFDM symbol of the second set of OFDM symbols being interposed between at least two OFDM symbols of the first set of OFDM symbols that are non-contiguous in time;

to obtain a channel quality indicator (a CQI) or a precoding matrix indicator (a PMI) from the UE served by the HD-SWN, the CQI or the PMI comprising a measurement of a controlling pilot signal transmitted by the base station and observed at the UE;

to forward the CQI or the PMI to the base station to facilitate estimating a modulation and coding scheme (a MCS) for transmitting the relay pilot signal;

to receive the MCS from the base station;

to transmit the relay pilot signal in accordance with the MCS; and

to receive a second CQI or a second PMI comprising a measurement of a concurrent transmission of the controlling pilot and the relay pilot signal as observed at the UE.

24. A method for wireless communication at a base station comprising:

receiving a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from a remote wireless node, in which the CQI or the PMI comprises a measurement of a control pilot signal observed at a UE;

estimating a modulation and coding scheme (MCS) based, at least in part, on the received CQI or PMI;

transmitting control or data signaling information scheduled for a downlink (DL) transmission by the base station to the remote wireless node associated with the base station; and

transmitting the DL transmission to the user equipment (UE) from the base station on a single DL carrier, the DL transmission being concurrent with a transmission of the control or data signaling information to the UE by the remote wireless node, and the DL transmission from the base station to the UE being on a same set of orthogonal frequency division multiplex (OFDM) symbols as the transmission of the control or data signaling information from the remote wireless node to the UE, the control or data signaling information comprising the estimated MCS.

25. The method of claim 24, wherein transmitting the control or the data signaling information further comprises transmitting the control or the data signaling information via a wired or wireless backhaul network.

26. The method of claim 24, further comprising transmitting a common reference signal (CRS) to a set of UEs, the set of UEs using the CRS for decoding the DL transmission and the control or data signaling information.

27. The method of claim 26, further comprising identifying at least one of the set of UEs that observes a preferred DL signal from either the remote wireless node or the base station.

28. The method of claim 27, further comprising scheduling a second set of control or data signaling information for transmission to the at least one of the set of UEs exclusively via the remote wireless node or the base station.

29. The method of claim 27, further comprising identifying the preferred DL signal by receiving respective DL signal measurements of the base station and the remote wireless node from the at least one of the set of UEs, and comparing the respective DL signal measurements to a preference threshold based on signal strength, signal quality or signal path loss.

30. The method of claim 24, further comprising:

measuring an uplink (UL) signal from the UE;

receiving a commensurate measurement of the UL signal from the remote wireless node;

identifying a preferred wireless node for the UE by comparing a measurement of the UL signal at the network base station and the commensurate measurement to a threshold value; and

scheduling a second set of control or data signaling information for the UE exclusively to or from the preferred wireless node.

31. The method of claim 24, in which transmitting control or data signaling information for the DL transmission further comprises acknowledgement (ACK) or negative ACK (NACK) information, channel quality indicator (CQI) information, a request message, downlink data traffic, uplink data traffic, or a combination thereof.

32. The method of claim 24, further comprising:

referencing a distribution policy that allocates a portion of the control or signaling information or a subset of assigned resources involving a set of UEs to the remote wireless node; and

identifying the portion of the control or signaling information or the subset of assigned resources;

in which transmitting control or data signaling information for the DL transmission to the remote wireless node comprises;

only transmitting the portion of the control or signaling information, or

specifying the subset of assigned resources that are allocated to the remote wireless node by the distribution policy.

33. The method of claim 32, wherein the distribution policy allocates the portion of the control or signaling information or the subset of assigned resources to the remote wireless node based at least in part on UE scheduling, UL signal strength measurements, or DL signal strength measurements, or a combination thereof.

34. The method of claim 24, further comprising transmitting to the remote wireless node a set of modulation symbols for decoding the control or signaling information, the remote wireless node using the set of modulation symbols as a reference signal to demodulate at least a portion of the control or signaling information prior to transmitting the control or signaling information concurrent with the DL transmission.

35. An apparatus configured for wireless communication, comprising:

a communication interface configured to communicate with a base station and for wireless communication with a user equipment (UE);

a memory configured to store instructions for coordinating wireless communications of the apparatus and the base station; and

a data processor configured to execute the instructions, the instructions comprising;

instructions to obtain at least a subset of traffic involving the UE and a signal time period for reception of the subset of traffic from the base station or transmission of the subset of traffic to the UE;

instructions to transmit to the UE or receive from the UE the subset of traffic on a single carrier frequency, the transmission being concurrent with a transmission to the UE by the base station and the reception being concurrent with a reception of the traffic from the UE by the base station, and the transmission from the base station to the UE being on a same set of orthogonal frequency division multiplex (OFDM) symbols as the transmission from the communication module to the UE;

instructions to obtain a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from the UE served by the apparatus, the CQI or the PMI comprising a measurement of a controlling pilot signal transmitted by a base station and observed at the UE;

instructions to forward the CQI or the PMI to the base station to facilitate estimating a modulation and coding scheme (a MCS) for transmitting the relay pilot signal;

instructions to receive the MCS from the base station;

instructions to transmit the relay pilot signal in accordance with the MCS; and

instructions to receive a second CQI or a second PMI comprising a measurement of a concurrent transmission of the controlling pilot and the relay pilot signal as observed at the UE.

36. The apparatus of claim 35, in which the communication with the base station is via a wired backhaul link.

37. The apparatus of claim 35, in which the communication with the base station is via a wireless backhaul link.

38. The apparatus of claim 35, further comprising a coding module configured to generate a common reference signal (a CRS) for demodulating at least the subset of traffic.

39. The apparatus of claim 38, wherein the communication module is further configured to transmit the CRS to the UE.

40. The apparatus of claim 39, in which the communication module transmits the CRS on a set of OFDM symbols used by the base station for transmitting the CRS, the CRS being transmitted on the set of OFDM symbols to facilitate joint transmission of the CRS and at least the subset of traffic by the base station and the apparatus.

41. The apparatus of claim 38, in which the coding module is further configured to receive from the base station a set of modulation symbols that can be used for demodulating at least the subset of traffic by the apparatus, the set of modulation symbols comprising pre-determined time-frequency symbols and pre-determined values thereof that can be used as a proxy for the CRS.

42. The apparatus of claim 35, in which the cooperation

module is further configured to obtain a full set of traffic involving the UE from the base station, and

further comprising a priority module configured:

to reference an incremental redundancy policy governing the apparatus;

to identify and distinguish the subset of traffic from a remainder of the full set of traffic based on the incremental redundancy policy; and

to provide the communication module with a subset of traffic for concurrent transmission or reception in conjunction with the base station at the signal time period.

43. The apparatus of claim 35, further comprising a priority module configured:

to use UL or DL signal measurements involving the UE to infer whether the UE is within a preferred range of either the apparatus or the base station, and

to allocate at least a portion of subsequent traffic exclusively to either the apparatus or the base station until an inferred range of the UE is no longer within the preferred range.

44. The apparatus of claim 43, in which:

the inferred range is derived from a threshold signal characteristic based at least in part on the UL or DL signal measurements, and

the threshold signal characteristic comprises a threshold signal quality, a threshold signal strength, or a threshold signal path loss characteristic, or a combination thereof.

45. The apparatus of claim 35, wherein the apparatus comprises one or more of:

a relay node;

a pico cell;

a repeater node;

a smart repeater node;

a remote radio head;

a transparent node, or

a combination thereof.

46. An apparatus configured for wireless communication, comprising:

means for receiving a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from a remote wireless node, in which the CQI or the PMI comprises a measurement of a control pilot signal observed at a UE;

means for estimating a modulation and coding scheme (MCS) based, at least in part, on the received CQI or PMI;

means for transmitting control or data signaling information scheduled for a downlink (DL) transmission by a network base station to a remote wireless node over a backhaul network; and

means for transmitting the DL transmission to the UE from the base station on a single DL carrier, the DL transmission being concurrent with a transmission of the control or data signaling information to the UE by the remote wireless node, and the DL transmission from the base station to the UE being on a same set of orthogonal frequency division multiplex (OFDM) symbols as the transmission of the control or data signaling information from the remote wireless node to the UE, the control or data signaling information comprising the estimated MCS.

47. An apparatus for wireless communication, the apparatus comprising:

a memory; and

at least one processor configured;

to receive a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from a remote wireless node, in which the CQI or the PMI comprising a measurement of a control pilot signal observed at a UE;

to estimate a modulation and coding scheme (MCS) based, at least in part, on the received CQI and PMI;

to transmit control or data signaling information scheduled for a downlink (DL) transmission by a network base station to a remote wireless node over a backhaul network; and

to transmit the DL transmission to the UE from the base station on a single DL carrier, the DL transmission being concurrent with a transmission of the control or data signaling information to the UE by the remote wireless node, and the DL transmission from the base station to the UE being on a same set of orthogonal frequency division multiplex (OFDM) symbols as the transmission of the control or data signaling information from the remote wireless node to the UE, the control or data signaling information comprising the estimated MCS.

48. A computer program product, comprising:

a non-transitory computer-readable medium, comprising;

code to receive a channel quality indicator (CQI) or a precoding matrix indicator (PMI) from a remote wireless node, in which the CQI or the PMI comprising a measurement of a control pilot signal observed at a UE;

code to estimate a modulation and coding scheme (MCS) based, at least in part, on the received CQI and PMI;

code to transmit control or data signaling information scheduled for a downlink (DL) transmission by a network base station to a remote wireless node over a backhaul network; and

code to transmit the DL transmission to a user equipment (UE) at the network base station on a single DL carrier, the DL transmission being concurrent with a transmission of the control or data signaling information to the UE by the remote wireless node, and the DL transmission from the base station to the UE being on a same set of orthogonal frequency division multiplex (OFDM) symbols as the transmission of the control or data signaling information from the remote wireless node to the UE, the control or data signaling information comprising the estimated MCS.