Enhanced node B, UE and method for selecting cell discovery signals in LTE networks
View Patent ↗Embodiments allow selection of a Discovery signal (DS) used to identify an eNB to a UE receiving the DS. The DS allows the UE to ascertain the existence and/or cell identifier of the eNB. DS comprise a plurality of other signals such as a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), a Cell Specific Reference Signal (CRS) and/or a Channel State Information Reference Signal (CSI-RS). A DS occasion comprises a number of subframes where the selected signals that comprise the DS are transmitted. The signals selected for the DS, their characteristics and properties allow a UE to decode the cell identifier. The DS occasion occurs with a designated periodicity.
1. An apparatus for a user equipment (LIE), the apparatus comprising:
processing circuitry; and memory, the processing circuitry configured to:
decode a message that includes a value indicating a periodicity of discovery signal (DS) occasions;
decode a DS transmitted within the DS occasions, the DS comprising:
a cell-specific reference signal (CRS) in a downlink subframe;
a primary synchronization signal (PSS); and
exactly one secondary synchronization signal (SSS),
wherein the processing circuitry is further configured to determine an identity of an enhanced Node B (eNB) based on the DS, wherein for frame structure type 1, the PSS is received in a first subframe of the DS occasion and for frame structure type 2, the PSS is received in a second subframe of the DS occasion.
2. The apparatus of claim 1 , wherein the periodicity is one of 40 milliseconds, 80 milliseconds, and 160 milliseconds.
3. The apparatus of claim 1 , wherein the DS occasion comprises a period having a duration of:
one to five consecutive subframes for frame structure type 1, and
two to five consecutive subframes for frame structure type 2.
4. The apparatus of claim 3 , wherein the DS comprises a non-zero-power Channel State Information Reference Signal (CSI-RS) received in zero or more subframes in the period.
5. The apparatus of claim 1 wherein the PSS and SSS are received within a same subframe of a sequence of subframes and wherein the PSS is received before the SSS within the subframe.
6. The apparatus of claim 1 wherein a location of time domain and/or frequency domain for PSS, SSS and/or CRS is based upon either a cell identifier or virtual cell identifier.
7. A computer readable storage medium comprising instructions that, when executed by, hardware processing circuitry of a user equipment (UE) configured the hardware processing circuitry to at least:
decode a message that includes a value indicating a periodicity of one of 40 milliseconds, 80 milliseconds, and 160 milliseconds for discovery signal (DS) occasions;
decode a DS received within the DS occasion, the DS comprising:
a cell-specific reference signal (CRS);
a primary synchronization signal (PSS); and
exactly one secondary synchronization signal (SSS), wherein for frame structure type 1, the PSS is received in a first subframe of the DS occasion and for frame structure type 2, the PSS is received in a second subframe of the DS occasion.
8. The computer readable storage medium of claim 7 , wherein instructions further configure the hardware processing circuitry to connect to a small cell based on the DS.
9. The computer readable storage medium of claim 7 , wherein the DS occasion comprises a period having a duration of:
one to five consecutive subframes for frame structure type 1, and
two to five consecutive subframes for frame structure type 2.
10. The computer readable storage medium of claim 9 , wherein the DS comprises the CRS on antenna port 0 in a downlink subframe and in a subframe containing a Downlink Pilot Time Slot (DwPTS) of the DS occasion; and
wherein the DS further comprises a non-zero-power Channel State Information Reference Signal (CSI-RS) transmitted in zero or more subframes in the period.
11. The computer readable storage medium of claim 7 , wherein the PSS and SSS are received within a same subframe of a sequence of subframes and wherein the PSS is received before the SSS within the subframe.
12. The computer readable storage medium of claim 7 , wherein a location of time domain and/or frequency domain for PSS, SSS and/or CRS is based upon either a cell identifier or virtual cell identifier.
13. An apparatus for an evolved NodeB (eNB), the apparatus comprising:
transceiver circuitry configured to:
transmit a signal that includes a value indicating a periodicity of discovery signal (DS) occasions; and
transmit, within the DS occasion:
a cell-specific reference signal (CRS);
a primary synchronization signal (PSS); and
exactly one secondary synchronization signal (SSS), wherein for frame structure oft type 1, the PSS is transmitted in a first subframe of the DS occasion and for frame structure type 2 the PSS is transmitted in a second subframe of the DS occasion.
14. The apparatus of claim 13 , wherein the periodicity is one of 40 milliseconds, 80 milliseconds, and 160 milliseconds.
15. The apparatus of claim 13 , wherein the DS occasion comprises a period having a duration of:
one to five consecutive subframes for frame structure type 1, and
two to five consecutive subframes for frame structure type 2.
16. The apparatus of claim 15 , wherein the DS comprises the CRS on antenna port 0 in a downlink subframe and in a subframe containing a Downlink Pilot Time Slot (DwPTS) of the DS occasion; and
wherein the DS further comprises a non-zero-power Channel State Information Reference Signal CSI-RS) transmitted in zero or more subframes in the period.
17. The apparatus of claim 13 wherein the PSS and SSS are received within a same subframe of a sequence of subframes and wherein the PSS is received before the SSS within the subframe.