Search space monitoring
There are provided mechanisms for monitoring search spaces. A first method performed by a wireless device comprises receiving an OFDM symbol in a downlink slot. At least part of the OFDM symbol is included in a device-specific search space and in a common search space. The first method comprises monitoring the device-specific search space for at least one device-specific reference signal (RS) and monitoring the common search space for at least one non-device-specific RS. In a second method, a radio access network node transmits an OFDM symbol included in a device-specific search space and in a common search space. The device-specific search space contains a device-specific RS, or the non-device specific search space contains a non-device-specific RS, or both of these apply.
1. A method for monitoring search spaces, the method being performed by a wireless device, the method comprising:
receiving an orthogonal frequency-division multiplexing (OFDM) symbol in a downlink slot, wherein a first part of the OFDM symbol is included in a device-specific search space and a second part of the OFDM symbol in a common search space;
monitoring the first part of the OFDM symbol for at least one device-specific reference signal; and
monitoring the second part of the OFDM symbol for at least one non-device-specific reference signal.
2. The method of claim 1 , further comprising:
detecting a device-specific physical downlink control channel (PDCCH) message in the first part of the OFDM symbol; and
identifying, from the device-specific PDCCH message, resource blocks for a device-specific data region.
3. The method of claim 1 , further comprising:
detecting a non-device-specific physical downlink control channel (PDCCH) message in the second part of the OFDM symbol;
identifying, from the non-device-specific PDCCH message, resource blocks for a non-device-specific data region.
4. The method of claim 1 , wherein at least part of the device-specific search space is comprised in the first OFDM symbol.
5. The method of claim 1 , wherein at least part of the common search space is comprised in the first OFDM symbol.
6. The method of claim 1 , wherein each of the device-specific search space and the common search space is contained in a respective frequency subband.
7. The method of claim 1 , wherein the OFDM symbol is an initial OFDM symbol in the downlink slot.
8. The method of claim 1 , wherein the first part of the OFDM symbol comprises resources reserved for a device-specific demodulation reference signal (DMRS), and wherein the second part of the OFDM symbol comprises resources reserved for a non-device-specific DMRS.
9. The method of claim 1 , wherein the non-device-specific demodulation reference signal (DMRS) depends on cell parameters, and wherein the device-specific DMRS depends on at least one parameter of the wireless device.
10. The method of claim 1 , wherein the first part of the OFDM symbol and the second part of the OFDM symbol at least partially overlap.
11. The method of claim 1 , wherein the first part of the OFDM symbol and the second part of the OFDM symbol are mutually disjoint.
12. The method of claim 1 , further comprising:
obtaining information regarding frequency location within the OFDM symbol of the first part of the OFDM symbol and the second part of the OFDM symbol.
13. A wireless device for monitoring search spaces, the wireless device comprising:
processing circuitry;
a communication interface operatively connected to the processing circuitry; and
a storage medium operatively connected to the processing circuitry and storing instructions that, when executed by the processing circuitry, cause the wireless device to:
receive an orthogonal frequency-division multiplexing (OFDM) symbol in a downlink slot using the communication interface, wherein a first part of the OFDM symbol is included in a device-specific search space and a second part of the OFDM symbol in a common search space;
monitor the first part of the OFDM symbol for at least one device-specific reference signal; and
monitor the second part of the OFDM symbol for at least one non-device-specific reference signal.
14. A non-transitory computer-readable medium comprising, stored thereupon, a computer program for monitoring search spaces, the computer program comprising computer code configured so that, when the computer code is run on processing circuitry of a wireless device, the computer code causes the wireless device to:
receive an orthogonal frequency-division multiplexing (OFDM) symbol in a downlink slot, wherein a first part of the OFDM symbol is included in a device-specific search space and a second part of the OFDM symbol in a common search space;
monitor the first part of the OFDM symbol using the at least one device-specific reference signal; and
monitor the second part of the OFDM symbol using the at least one non-device-specific reference signal.
15. A method for enabling monitoring of search spaces, the method being performed by a radio access network node, the method comprising:
transmitting an orthogonal frequency-division multiplexing (OFDM) symbol in a downlink slot, wherein a first part of the OFDM symbol is included in a device-specific search space and a second part of the OFDM symbol in a common search space,
wherein the first part of the OFDM symbol comprises a device-specific reference signal, and/or the second part of the OFDM symbol comprises a non-device-specific reference signal.
16. The method of claim 15 , wherein the device-specific reference signal enables a specific wireless device or a specific group of wireless devices to monitor control messages.
17. The method of claim 15 , wherein the non-device-specific reference signal enables non-specific wireless devices in a coverage area of the radio access network node to monitor control messages.
18. The method of claim 15 , further comprising:
providing information regarding frequency location within the OFDM symbol of the first part of the OFDM symbol and the second part of the OFDM symbol to a wireless device.
19. The method of claim 15 , wherein the non-device-specific reference signal depends on cell parameters, and wherein the device-specific reference signal depends on at least one parameter of the wireless device.
20. A radio access network node for enabling monitoring of search spaces, the radio access network node comprising:
processing circuitry;
a communication interface operatively connected to the processing circuitry; and
a storage medium operatively connected to the processing circuitry and storing instructions that, when executed by the processing circuitry, cause the radio access network node to:
transmit an orthogonal frequency-division multiplexing (OFDM) symbol in a downlink slot using the communications interface, wherein a first part of the OFDM symbol is included in a device-specific search space and a second part of the OFDM symbol in a common search space;
wherein the first part of the OFDM symbol comprises a device-specific reference signal, and/or the second part of the OFDM symbol comprises a non-device-specific reference signal.
21. A non-transitory computer-readable medium comprising, stored thereupon, a computer program for enabling monitoring of search spaces, the computer program comprising computer code configured so that, when the computer code is run on processing circuitry of a radio access network node, the computer code causes the radio access network node to:
transmit an orthogonal frequency-division multiplexing (OFDM) symbol in a downlink slot, wherein a first part of the OFDM symbol is included in a device-specific search space and a second part of the OFDM symbol in a common search space;
wherein the first part of the OFDM symbol comprises a device-specific reference signal, and/or the second part of the OFDM symbol comprises a non-device-specific reference signal.