Signaling method to enable controlled TX deferring in mixed license and unlicensed spectrum in carrier aggregation in future LTE-A networks
View Patent ↗The present invention discloses a signaling method, an apparatus and a computer program for controlled transmission signal deferring utilizing both licensed and unlicensed frequency bands for carrier aggregation. In the method, a connection is established between a User Equipment and a base station. For example, based on a sensed interference level, a transmission deferring indication is generated regarding a secondary component carrier locating on an unlicensed band, in case the secondary component carrier is occupied. This indication may be generated and sent either by the base station or by the User Equipment. Finally, the secondary component carrier is deactivated for data transmission, for deferring data transmission for a certain time period. After the deferring time has passed, the data transmission can be re-performed on the same secondary component carrier, or through switching to another secondary component carrier in unlicensed spectrum.
1. A method, comprising:
establishing a connection between a User Equipment (UE) and a base station (eNB) utilizing licensed and unlicensed frequency bands;
generating a transmission deferring indication regarding an allocated first component carrier located on an unlicensed band, when interference is detected on the first component carrier; and
deactivating data transmission on the first component carrier for a predetermined number of subframes without terminating the allocation of the first component carrier according to the transmission deferring indication for deferring the data transmission on the first component carrier.
2. The method according to claim 1 , further comprising:
transmitting deferred data on the first component carrier or a different component carrier after a deferring time has passed.
3. The method according to claim 1 , wherein the transmission deferring indication is triggered by detected interference exceeding a predetermined threshold on the first component carrier.
4. The method according to claim 1 , wherein the transmission deferring indication is User Equipment specific or component carrier specific.
5. The method according to claim 2 , wherein the deferred data is transmitted on the first component carrier when the interference is reduced on the first component carrier during the deferring time.
6. The method according to claim 1 , wherein the transmission deferring indication is sent by the base station (eNB) via a Physical Downlink Control Channel (PDCCH).
7. The method according to claim 1 , further comprising:
starting a timer for a Hybrid Automatic Repeat Request (HARQ) process for uplink data transmission after receiving the transmission deferring indication, and when the base station (eNB) does not schedule a data transmission for the deferred data before the timer expires:
flushing a HARQ buffer; and
indicating data transmission as failed.
8. The method according to claim 1 , wherein the User Equipment (UE) decides whether the first component carrier locating on an unlicensed band is occupied, by sensing available resources on an uplink transmission.
9. The method according to claim 8 , wherein the transmission deferring indication is sent via a physical uplink shared channel (PUSCH) of a primary component carrier (PCC) using a licensed frequency band, and where the first component carrier is a secondary component carrier (SCC).
10. The method according to claim 3 , further comprising:
lowering a modulation and coding scheme (MCS) because of the detected interference in the User Equipment (UE); and
including a lowered MCS information in a transmission deferring indication sent to the base station (eNB).
11. The method according to claim 2 , further comprising:
scheduling deferred data transmission onto another carrier via new Downlink Control Information (DCI) format using a PDCCH.
12. The method according to claim 1 , wherein the User Equipment (UE) indicates via a Physical Uplink Control Channel (PUCCH) whether the User Equipment (UE) is transmitting on the licensed frequency band.
13. The method according to claim 1 , further comprising:
marking a component carrier as heavily occupied when recurrent transmission deferring indications have been generated; and
scheduling a non-heavily occupied component carrier for the data transmission.
14. The method according to claim 1 , further comprising:
gathering information regarding the unlicensed frequency bands, comprising used and available resources on the bands, in the base station (eNB).
15. An apparatus, which is one of a User Equipment or a base station eNB), comprising:
circuitry configured to:
establish a connection between the User Equipment (UE) and the base station (eNB) utilizing licensed and unlicensed frequency bands;
generate and send either in downlink or uplink direction a transmission deferring indication regarding a first component carrier locating on an unlicensed band, when interference is detected on the first component carrier; and
deactivate data transmission on the first component carrier for a predetermined number of subframes without terminating the allocation of the first component carrier, according to the transmission deferring indication for deferring the data transmission on the first component carrier.
16. The apparatus according to claim 15 , wherein the circuitry is configured to send the transmission deferring indication on a primary component carrier (PCC) on the licensed frequency band while the first component carrier is a secondary component carrier (SCC).
17. The apparatus according to claim 15 , wherein the transmission deferring indication covers the uplink data transmission by the User Equipment (UE).
18. The apparatus according to claim 15 , wherein the transmission deferring indication covers all resources on the unlicensed spectrum or resources on the first component carrier only.
19. The apparatus according to claim 15 , wherein the circuitry is configured to transmit the deferred data either on a second component carrier or on the first component carrier, depending on the occupying condition of resources on the first component carrier.
20. The apparatus according to claim 15 , wherein the apparatus is the base station (eNB), and further, the circuitry is configured to send the transmission deferring indication via a Physical Downlink Control Channel (PDCCH).
21. The apparatus according to claim 15 , wherein the apparatus is the User Equipment (UE), and further, the circuitry is configured to send the transmission deferring indication via a physical uplink shared channel (PUSCH) of a primary component carrier using a licensed frequency band.
22. A non-transitory computer readable medium storing a computer program comprising code adapted to perform the following steps, when executed on a data-processing system, comprising:
establishing a connection between a User Equipment (UE) and a base station (eNB) utilizing licensed and unlicensed frequency bands;
generating a transmission deferring indication regarding an allocated first component carrier located on an unlicensed band, when interference is detected on the first component carrier; and
deactivating data transmission on the first component carrier for a predetermined number of subframes without terminating the allocation of the first component carrier according to the transmission deferring indication for deferring the data transmission on the first component carrier.