Methods and apparatus for sounding channel operation in millimeter wave communication systems

1. For use by a base station (BS) in a wireless network, a method comprising:

configuring a first sounding channel to be an uplink sounding slot comprising at least one orthogonal frequency-division multiplexing (OFDM) symbol in an uplink sub-frame in order to carry one or more uplink sounding reference symbols (UL-SRSs) corresponding to at least one transmit beam of a first set of transmit beams in a first sounding channel set of sub-bands, the first sounding channel set of sub-bands comprising one or more sub-bands that cover a first data bandwidth;

transmitting, to a mobile station (MS), a first UL sounding configuration message that sets a sounding sub-band bitmap value to a maximum specifiable value and indicates UL-SRS placement in the first sounding channel set of sub-bands;

receiving, through the first sounding channel set of sub-bands from the MS, the one or more UL-SRSs corresponding to at least the one transmit beam of the first set of transmit beams for channel estimation over the first data bandwidth;

configuring a second sounding channel to be a second uplink sounding slot comprising at least the one OFDM symbol in a second uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least the one transmit beam of a second set of transmit beams in a second sounding channel set of sub-bands, the second sounding channel set of sub-bands comprising at least a subset of the first sounding channel set of sub-bands, the second set of transmit beams comprising at least a subset of the first set of transmit beams used in the first sounding channel;

transmitting, to the MS, a second UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in the second sounding channel set of sub-bands; and

receiving, through the second sounding channel set of sub-bands from the MS, the one or more UL-SRSs corresponding to at least the one transmit beam of the second set of transmit beams for channel estimation over a second data bandwidth, wherein the second data bandwidth is at least a subset of the first data bandwidth.

2. The method of claim 1 , wherein:

the first UL sounding configuration message comprises a sounding channel index value; and

the sounding channel index value provides an indication to the MS of the sounding sub-band bitmap value and the UL-SRS configuration in the first sounding channel set of sub-bands.

3. The method of claim 1 , the method further comprising:

configuring a third sounding channel to be a third uplink sounding slot comprising at least the one OFDM symbol in a third uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of the third set of transmit beams in a third sounding channel set of sub-bands, the third sounding channel set of sub-bands comprising at least the subset of the first sounding channel set of sub-bands or at least a subset of the second sounding channel set of sub-bands, the third set of transmit beams comprising at least a subset of the first set of transmit beams or the second set of transmit beams;

transmitting, to the MS, a third UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in the third sounding channel set of sub-bands; and

receiving, through the third sounding channel set of sub-bands from the MS, the one or more UL-SRSs corresponding to at least the one transmit beam of the third set of transmit beams for channel estimation over a third data bandwidth, wherein the third data band width is at least a subset of one of the first data bandwidth or the second data bandwidth.

4. The method of claim 1 , wherein a random access channel (RACH) is used by the BS to identify received beams for receiving sound reference symbols on the configured sounding channel.

5. A base station (BS) for use in a wireless network, the BS comprising:

at least one processing device configured to:

configure a first sounding channel to be an uplink sounding slot comprising at least one orthogonal frequency-division multiplexing (OFDM) symbol in an uplink sub-frame in order to carry one or more uplink sounding reference symbols (UL-SRSs) corresponding to at least one transmit beam of a first set of transmit beams in a first sounding channel set of sub-bands, the first sounding channel set of sub-bands comprising one or more sub-bands that cover a first data bandwidth;

initiate transmission, to a mobile station (MS), of a first UL sounding configuration message configured to set a sounding sub-band bitmap value to a maximum specifiable value and indicate UL-SRS placement in the first sounding channel set of sub-bands;

receive, through the first sounding channel set of sub-bands from the MS, the one or more UL-SRSs corresponding to at least the one transmit beam of the first set of transmit beams for channel estimation over the first data bandwidth;

configure a second sounding channel to be a second uplink sounding slot comprising at least the one OFDM symbol in a second uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a second set of transmit beams in a second sounding channel set of sub-bands, the second sounding channel set of sub-bands comprising at least a subset of the first sounding channel set of sub-bands, the second set of transmit beams comprising at least a subset of the first set of transmit beams used in the first sounding channel;

initiate transmission, to the MS, of a second UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in the second sounding channel set of sub-bands; and

receive, through the second sounding channel set of sub-bands from the MS, the one or more UL-SRSs corresponding to at least the one transmit beam of the second set of transmit beams for channel estimation over a second data bandwidth, wherein the second data bandwidth is at least a subset of the first data bandwidth.

6. The BS of claim 5 , wherein:

the first UL sounding configuration message comprises a sounding channel index value; and

the sounding channel index value provides an indication to the MS of the sounding sub-band bitmap value and the UL-SRS configuration in the first sounding channel set of sub-bands.

7. The BS of claim 5 , wherein the at least one processing device is further configured to:

configure a third sounding channel to be a third uplink sounding slot comprising at least the one OFDM symbol in a third uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a third set of transmit beams in a third sounding channel set of sub-bands, the third sounding channel set of sub-bands comprising at least the subset of the first sounding channel set of sub-bands or at least a subset of the second sounding channel set of sub-bands, the third set of transmit beams comprising at least a subset of the first set of transmit beams or the second set of transmit beams;

transmit, to the MS, a third UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in the third sounding channel set of sub-bands; and

receive, through the third sounding channel set of sub-bands from the MS, the one or more UL-SRSs corresponding to at least the one transmit of the third set of transmit beams for channel estimation over a third data bandwidth, wherein the third data band width is at least a subset of one of the first data bandwidth or the second data bandwidth.

8. The BS of claim 5 , wherein a random access channel (RACH) is used by the BS to identify received beams for receiving sound reference symbols on the configured sounding channel.

9. For use by a mobile station (MS) in a wireless network, a method comprising:

receiving, from a base station (BS), a first uplink (UL) sounding configuration message that sets a sounding sub-band bitmap value to a maximum specifiable value and indicates uplink sounding reference symbol (UL-SRS) placement in a first sounding channel set of sub-bands associated with a first sounding channel, the first sounding channel set of sub-bands comprising one or more sub-bands that cover a first data bandwidth, the first sounding channel configured to be an uplink sounding slot comprising at least one orthogonal frequency-division multiplexing (OFDM) symbol in an uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a first set of transmit beams in the first sounding channel set of sub-bands;

transmitting, through the first sounding channel set of sub-bands to the BS, the one or more UL-SRSs corresponding to at least the one transmit beam in the first set of transmit beams for channel estimation over the first data bandwidth;

receiving, from the BS, a second UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in a second sounding channel set of sub-bands associated with a second sounding channel, the second sounding channel set of sub-bands comprising at least the first sounding channel set of sub-bands, the second sounding channel configured to be a second uplink sounding slot comprising at least the one OFDM symbol in a second uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a second set of transmit beams, the second set of transmit beam comprising at least a subset of the first set of transmit beams used in the first sounding channel; and

transmitting, through the second sounding channel set of sub-bands to the BS, the one or more UL-SRSs corresponding to at least the one transmit beam of the second set of transmit beams for channel estimation over a second data bandwidth, wherein the second data bandwidth is at least a subset of the first data bandwidth.

10. The method of claim 9 , further comprising:

receiving a sounding channel index value, the sounding channel index value providing an indication of the sounding sub-band bitmap value and the UL-SRS configuration in the first sounding channel set of sub-bands.

11. The method of claim 9 , further comprising:

receiving, from the BS, a third UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in a third sounding channel set of sub-bands associated with a third sounding channel, the third sounding channel set of sub-bands comprising at least one of the first sounding channel set of sub-bands or the second sounding channel set of sub-bands, the third sounding channel configured to be a third uplink sounding slot comprising at least the one OFDM symbol in a third uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a third set of transmit beams, the third set of transmit beams comprises at least a subset of the first set of transmit beams or the second set of transmit beams; and

transmitting, through the third sounding channel set of sub-bands to the BS, the one or more UL-SRSs corresponding to at least the one transmit beam of the third set of transmit beams for channel estimation over a third data bandwidth, wherein the third data bandwidth is at least one of the subset of the first data bandwidth or a subset of the second data bandwidth.

12. The method of claim 9 , wherein at least the first set of transmit beams for at least the first sounding channel is identified by a random access channel (RACH).

13. A mobile station (MS) for use in a wireless network, the MS comprising:

at least one processing device configured to:

receive, from a base station (BS), a first uplink (UL) sounding configuration message that sets a sounding sub-band bitmap value to a maximum specifiable value and indicates uplink sounding reference symbol (UL-SRS) placement in a first sounding channel set of sub-bands associated with a first sounding channel, the first sounding channel set of sub-bands comprising one or more sub-bands that cover a first data bandwidth, the first sounding channel configured to be an uplink sounding slot comprising at least one orthogonal frequency-division multiplexing (OFDM) symbol in an uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a first set of transmit beams in the first sounding channel set of sub-bands;

initiate transmission, through the first sounding channel set of sub-bands to the BS, of the one or more UL-SRSs corresponding to at least the one transmit beam of the first set of transmit beams for channel estimation over the first data bandwidth;

receive, from the BS, a second UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in a second sounding channel set of sub-bands associated with a second sounding channel, the second sounding channel set of sub-bands comprising at least the first sounding channel set of sub-bands, the second sounding channel configured to be a second uplink sounding slot comprising at least the one OFDM symbol in a second uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a second set of transmit beams, wherein the second set of transmits beams comprises at least a subset of the first set of transmit beams used in the first sounding channel; and

transmit, through the second sounding channel set of sub-bands to the BS, the one or more UL-SRSs corresponding to at least the one transmit beam of the second set of transmit beams for channel estimation over a second data bandwidth, wherein the second data bandwidth is at least a subset of the first data bandwidth.

14. The MS of claim 13 , wherein the at least one processing device is further configured to receive a sounding channel index value, the sounding channel index value providing an indication of the sounding sub-band bitmap value and the UL-SRS configuration in the first sounding channel set of sub-bands.

15. The MS of claim 13 , wherein the at least one processing device is further configured to:

receive, from the BS, a third UL sounding configuration message that sets a second sounding sub-band bitmap value to a value no greater than the maximum specifiable value and indicates UL-SRS placement in a third sounding channel set of sub-bands associated with a third sounding channel, the third sounding channel set of sub-bands comprising at least one of the first sounding channel set of sub-bands or the second sounding channel set of sub-bands, the third sounding channel configured to be a third uplink sounding slot comprising at least the one OFDM symbol in a third uplink sub-frame in order to carry one or more UL-SRSs corresponding to at least one transmit beam of a third set of transmit beams, the third set of transmit beams comprising at least a subset of the first set of transmit beams or the second set of transmit beams; and

transmit, through the third sounding channel set of sub-bands to the BS, the one or more UL-SRSs corresponding to at least the one transmit beam of the third set of transmit beams for channel estimation over a third data bandwidth, wherein the third data bandwidth is at least a subset of the first data bandwidth or the second data bandwidth.

16. The MS of claim 13 , wherein at least the first set of transmit beams for at least the first sounding channel is identified by a random access channel (RACH).