UE specific search space and a common search space in a wide coverage enhancement

1. A user equipment (UE), comprising:

an interface configured to receive configuration information of a UE specific Search Space (UESS) and a Common Search Space (CSS) for enhanced Physical Downlink Control Channel (ePDCCH) from a radio-frequency (RF) circuitry,

wherein the UESS and the CSS comprise four ePDCCH sets, the four ePDCCH sets being defined based upon aggregation levels (ALs), repetition levels (RLs), and numbers of blind decodings (#BDs),

wherein each ePDCCH set from among the four ePDCCH sets comprises 8 Resource Blocks (RBs), and

wherein the four ePDCCH sets are configured by an access node (AN) and comprise:

Two candidate Search Spaces (SSs) for an AL equal to 64,

Four candidate SSs for an AL equal to 32,

Four candidate SSs for an AL equal to 16,

Remaining candidate SSs are equally divided for smaller AL,

The ALs include 4 different levels or 5 different levels, and

For the AL equal to 64, two ePDCCH sets from among the four ePDCCH sets are associated by default, and within the two ePDCCH sets, the ePDCCH is generated based on the AL equal to 32 in one ePDCCH set from among the two ePDCCH sets, and repeated for another ePDCCH set from among the two ePDCCH sets; and

a processor configured to monitor the UESS and the CSS for an ePDCCH transmission in accordance one or more ePDCCH sets from among the four ePDCCH sets;

wherein at least one of the interface or the processor is further configured to support a wideband coverage enhancement (WCE), and

wherein the configuration information comprises information for configuration of one or more of:

a candidate SS,

an RB for the UESS and the CSS,

a search space reduction, or

a transmission of Downlink Control Information (DCI).

2. The UE of claim 1 , wherein the UESS and the CSS are indicated by a parameter startSymbol,

wherein the parameter startSymbol is indicated by a Control Format Indicator (CFI) or a pdsch-Start parameter, or is configured by the AN through one of a System Information Block 1 (SIB1), a Master Information Block (MIB) or a Radio Resource Control (RRC) message, and

wherein the parameter startSymbol is applicable to the CSS and its associated Physical Downlink Control Channel (PDSCH) or the UESS and its associated PDSCH.

3. The UE of claim 1 , wherein the UESS and the CSS are indicated by a parameter setConfigToReleaseList and a parameter setConfigToAddModList, and

wherein the UESS and the CSS are pre-defined if two ePDCCH sets are configured for the UESS and the CSS, or the UESS and the CSS are configured by the AN through one of a System Information Block 1 (SIB1), a Master Information Block (MIB) or a Radio Resource Control (RRC) message.

4. The UE of claim 1 , wherein the UESS and the CSS are indicated by a parameter EPDCCH-SetConfigld, which takes a value from among 0, 1, 2, or 3, while two ePDCCH sets configured for the UESS and the CSS are associated together.

5. The UE of claim 4 , wherein the parameter EPDCCH-SetConfigld comprises:

setConfigId which is pre-defined and implicitly associated with a configuration sequence;

transmissionType which is configured as a legacy system or confined to one set;

numberPRBPairs which is pre-defined for each set or configured by the AN through a System Information Block 1 (SIB1), a Master Information Block (MIB) or a Radio Resource Control (RRC) message; or

resourceBlockAssignment which is defined as a legacy resource allocation pre-defined in a unit of N contiguous distributed/localized Virtual Resource Blocks (VRBs), wherein N is 4 or 8; or hard coded, or pre-defined, and is blindly detected together with the candidate SS.

6. The UE of claim 1 , wherein the UESS and the CSS comprise two ePDCCH sets and a number of the candidate search spaces is equal to or less than that for legacy CSS PDCCHs,

for the AL equal to 64, the number of the candidate search spaces is generated based on the AL equal to 32 within one ePDCCH set and repeats in another ePDCCH set; and

for the ALless than 64, the number of the candidate search spaces is generated based on AL/2 within one ePDCCH set and repeats in another ePDCCH set or is alternatively generated based on AL within one ePDCCH set.

7. The UE of claim 1 , wherein a maximum AL for a localized ePDCCH is enhanced to 32.

8. The UE of claim 1 , wherein the UESS and the CSS comprise two ePDCCH sets, each containing 8 RBs, and the two ePDCCH sets are configured by the AN and comprise:

Maximum AL is 64 for the UE including one candidate SS for the AL equal to 64, two candidate SSs for the AL equal to 32, two/four candidate SSs for the AL equal to 16;

Maximum AL is 32 for the UE including two candidate SSs for the AL equal to 32, two/four candidate SSs for the AL equal to 16, two/four candidate SSs for an AL equal to 8;

Remaining candidates are equally divided for smaller AL; or

The ALs include 4 different levels or 5 different levels.

9. The UE of claim 1 , wherein the candidate SS reuses two distributed ePDCCH sets,

wherein one candidate SS having an AL of 64 is added, and

wherein one candidate SS having a smaller AL is decreased by one.

10. The UE of claim 1 , wherein the candidate SS focuses on an AL with 6 level ALs, and

wherein the 6 level ALs range from an AL equal to 2 to an AL equal to 64.

11. The UE of claim 1 , wherein an enhanced Control Channel Element (eCCE) is numbered within one set from among the four ePDCCH sets, and a further eCCE (FeCCE) set from among the four ePDCCH sets is obtained by concatenating across multiple eCCEs.

12. The UE of claim 1 , wherein a legacy PDCCHpdcch-candidateReductions parameter is reused in the UESS and the CSS, or alternatively a pdcch-candidateReductionAL6 parameter is introduced to the UESS and the CSS.

13. The UE of claim 1 , wherein the transmission of DCI supports a legacy DCI for wide coverage enhancement (WCE) UE scheduling; and

wherein Format 1x is utilized for the WCE UE scheduling with the Format 1x comprising:

Format 1 for a single input multiple output (SIMO) PDSCH scheduling with non-contiguous Resource Allocation (RA);

Format 1A for a SIMO PDSCH scheduling with contiguous Resource Allocation (RA),

Format 1B for a close-loop single rank transmission with the contiguous RA; or

Format 1D for a compact scheduling of one PDSCH codeword with precoding and power offset information.

14. The UE of claim 1 , wherein an enhanced Control Channel Element (eCCE) is numbered within one ePDCCH set from among the four ePDCCH sets, and a further eCCE (FeCCE) is obtained by concatenating across multiple eCCEs.

15. A method for operating a user equipment (UE), the method comprising:

receiving configuration information of a UE specific Search Space (UESS) and a Common Search Space (CSS) for enhanced Physical Downlink Control Channel (ePDCCH) from a radio-frequency (RF) circuitry, wherein the UESS and the CSS comprise four ePDCCH sets, the four ePDCCH sets being defined based upon aggregation levels (ALs), repetition levels (RLs), and numbers of blind decodings (#BDs),

wherein each ePDCCH set from among the four ePDCCH sets comprises 8 Resource Blocks (RBs), and

wherein the four ePDCCH sets are configured by an access node (AN) and comprise:

Two candidate Search Spaces (SSs) for an AL equal to 64,

Four candidate SSs for an AL equal to 32,

Four candidate SSs for an AL equal to 16,

Remaining candidate SSs are equally divided for smaller AL,

The ALs include 4 different levels or 5 different levels, and

For the AL equal to 64, two ePDCCH sets from among the four ePDCCH sets are associated by default, and within the two ePDCCH sets, the ePDCCH is generated based on the AL equal to 32 in one ePDCCH set from among the two ePDCCH sets, and repeated for another ePDCCH set from among the two ePDCCH sets; and

monitoring the UESS and the CSS for an ePDCCH transmission in accordance with one or more ePDCCH sets from among the four ePDCCH sets, and

wherein the configuration information comprises information for configuration of one or more of:

a candidate SS,

an RB for the UESS and the CSS,

a search space reduction, or

a transmission of Downlink Control Information (DCI).

16. The method of claim 15 , wherein an enhanced Control Channel Element (eCCE) is numbered within one ePDCCH set from among the four ePDCCH sets, and a further eCCE (FeCCE) is obtained by concatenating across multiple eCCEs.

17. One or more non-transitory computer-readable media comprising instructions to, upon execution of the instructions by one or more processors of a user equipment (UE), cause the UE to:

receive configuration information of a UE specific Search Space (UESS) and a Common Search Space (CSS) for enhanced Physical Downlink Control Channel (ePDCCH) from a radio-frequency (RF) circuitry, wherein the UESS and the CSS comprise four ePDCCH sets, the four ePDCCH sets being defined based upon aggregation levels (ALs), repetition levels (RLs), and numbers of blind decodings (#BDs),

wherein each ePDCCH set from among the four ePDCCH sets comprises 8 Resource Blocks (RBs), and

wherein the four ePDCCH sets are configured by an access node (AN) and comprise:

Two candidate Search Spaces (SSs) for an AL equal to 64,

Four candidate SSs for an AL equal to 32,

Four candidate SSs for an AL equal to 16,

Remaining candidate SSs are equally divided for smaller AL,

The ALs include 4 different levels or 5 different levels, and

For the AL equal to 64, two ePDCCH sets from among the four ePDCCH sets are associated by default, and within the two ePDCCH sets, the ePDCCH is generated based on the AL equal to 32 in one ePDCCH set from among the two ePDCCH sets, and repeated for another ePDCCH set from among the two ePDCCH sets; and

monitor the UESS and the CSS for an ePDCCH transmission in accordance with one or more ePDCCH sets from among the four ePDCCH sets, and

wherein the configuration information comprises information for configuration of one or more of:

a candidate SS,

an RB for the UESS and the CSS,

a search space reduction, or

a transmission of Downlink Control Information (DCI).

18. The or more non-transitory computer-readable media of claim 17 , wherein an enhanced Control Channel Element (eCCE) is numbered within one ePDCCH set from among the four ePDCCH sets, and a further eCCE (FeCCE) is obtained by concatenating across multiple eCCEs.