Narrowband internet of things devices and method of operation thereof
Devices and methods of enhancing narrowband communications are generally described. NPSS and NSSS are modulated to include an additional bit that indicates a duplexing scheme, a raster frequency offset (zero or non-zero), an operating mode (in-band or standalone/guard-band) or frame timing used by the eNB. The NPSS modulation uses conjugate ZC sequences multiplied by a cover code for each OFDM symbol. The NMIB may provide additional information related to the operating mode or offset. NSSS cyclic shifts may be used to indicate the offset or TDD/FDD use, as may relative locations of the NPSS and NSSS. The NSSS may use symbol-level modulation and time domain cyclic shifts to indicate the frame timing.
1. An apparatus of a narrowband user equipment (UE), the apparatus comprising:
a memory; and
processing circuitry in communication with the memory and arranged to:
decode narrowband synchronization and control signals from an evolved NodeB (eNB), the narrowband control signals modulated for communication with the narrowband UE through use of at least one modulation, the narrowband synchronization and control signals received within a bandwidth spanned by a single physical resource block and comprising a narrowband Primary Synchronization Signal (NPSS), a narrowband Secondary Synchronization Signal (NSSS) and a narrowband Master Information Block (NMIB) on a narrowband physical broadcast channel (NPBCH), the at least one modulation comprising a NPSS modulation that indicates a single bit of frame configuration information, the NPSS modulation comprising use of conjugate Zadoff Chu (ZC) sequences multiplied by a cover code for each orthogonal frequency division multiplexed (OFDM) symbol in a narrowband subframe;
determine, from the at least one modulation, configuration information of the eNB;
differentiate a raster frequency offset between a zero and non-zero kHz raster frequency offset through determination of the single bit of frame configuration information, and
determine, through the raster frequency offset, which of different sets of operating modes is deployed by the eNB, the sets of operating modes comprising a first set comprising a standalone operation mode and a second set comprising an in-band operation mode and a guard-band operation mode; and
establish initial communication with the eNB based on the configuration information determined from the at least one modulation.
2. The apparatus of claim 1 , wherein:
the NSSS comprises a ZC sequence mapped to multiple OFDM symbols to form NSSS sequence elements for the OFDM symbols, and
the at least one modulation comprises an OFDM symbol-level modulation of the NSSS sequence elements.
3. The apparatus of claim 2 , wherein:
the frame configuration information comprises frame timing information, the frame timing information encoded in time domain cyclic shifts of the ZC sequence and the OFDM symbol-level modulation.
4. The apparatus of claim 3 , wherein:
the OFDM symbol-level modulation is a length-11 binary sequence based on length-16 binary Golay sequences.
5. The apparatus of claim 3 , wherein:
the OFDM symbol-level modulation bears a one-to-one mapping to a 20 ms timing boundary indicated using different time-domain cyclic shifts of the ZC sequence.
6. The apparatus of claim 1 , wherein the processing circuitry is configured to:
in response to the single bit of frame configuration information indicating the non-zero kHz raster frequency offset, determine from the NMIB which of the in-band and guard-band operation mode is deployed by the eNB.
7. The apparatus of claim 6 , wherein:
the NMIB indicates that the raster frequency offset has a value selected from among ±2.5 kHz and ±7.5 kHz.
8. The apparatus of claim 6 , wherein the processing circuitry comprises baseband circuitry configured to:
determine the raster frequency offset from a time-domain or frequency-domain cyclic shift of the NSSS.
9. The apparatus of claim 1 , wherein the processing circuitry is configured to:
differentiate between which of other sets of operating modes is deployed by the eNB through determination of the single bit of frame configuration information, the other sets of operating modes comprising a third set comprising the in-band operation mode and a fourth set comprising the standalone operation mode and the guard-band operation mode.
10. The apparatus of claim 9 , wherein the processing circuitry is configured to:
when the single bit of frame configuration information indicates the fourth set of operation modes, determine from the NMIB which of the standalone and guard-band operation mode is deployed by the eNB.
11. The apparatus of claim 1 , wherein the processing circuitry is configured to:
determine between which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) is used by the eNB as indicated by the single bit of frame configuration information.
12. The apparatus of claim 1 , wherein the processing circuitry is configured to:
perform correlations on the conjugate ZC sequences multiplied by the cover codes, the cover codes selected such that a cross-correlation between an NPSS based on an original set of ZC sequences and an NPSS based on a set of the conjugate ZC sequences is at least 10 dB lower than a peak of an auto-correlation profile for either NPSS.
13. The apparatus of claim 1 , wherein the processing circuitry is configured to:
determine which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) is used by the eNB through one of a time or frequency cyclic shift of the NSSS.
14. The apparatus of claim 1 , wherein the processing circuitry is configured to:
determine which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) is used by the eNB through relative locations of the NPSS and NSSS.
15. The apparatus of claim 1 , further comprising:
an antenna configured to provide communications between the UE and the eNB.
16. An apparatus of an evolved NodeB (eNB) comprising:
processing circuitry arranged to:
generate a narrowband Primary Synchronization Signal (NPSS) and a narrowband Secondary Synchronization Signal (NSSS), at least one of the NPSS or NSSS modulated using a modulation that indicates one of a duplexing scheme, a raster frequency offset, an operating mode or frame timing used by the eNB; and
encode the NPSS and NSSS for transmission to a narrowband user equipment (UE) on a narrowband channel of one physical resource block (PRB), the NSSS comprising a Zadoff Chu (ZC) sequence mapped to multiple orthogonal frequency division multiplexed (OFDM) symbols to form NSSS sequence elements for the OFDM symbols, and the modulation comprising an OFDM symbol-level modulation of the NSSS sequence elements in which frame timing information is encoded through use of time domain cyclic shifts of the ZC sequence and the OFDM symbol-level modulation, the OFDM symbol-level modulation is a length-11 binary sequence based on length-16 binary Golay sequences, and the OFDM symbol-level modulation bears a one-to-one mapping to a 20 ms timing boundary indicated using different time-domain cyclic shifts of the ZC sequence; and
a memory configured to store the modulation.
17. The apparatus of claim 16 , wherein:
the modulation comprises a NPSS modulation that indicates a single bit, the NPSS modulation comprising use of conjugate ZC sequences multiplied by a cover code for each OFDM symbol in a narrowband subframe, and
the single bit indicates one of:
which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD),
which operation mode of:
an in-band operation mode, or
a standalone or guard-band operation mode, or
whether a zero or non-zero raster frequency offset,
is used by the eNB.
18. The apparatus of claim 17 , wherein the processing circuitry is configured to:
generate a narrowband Master Information Block (NMIB), and
when the single bit indicates that the operation mode is the standalone or guard-band operation mode, indicate in the NMIB which of the standalone and guard-band operation mode is deployed, and
when the single bit indicates the non-zero raster frequency offset is used, indicate in the NMIB which of the in-band or guard-band operation mode is deployed, the standalone operation mode being indicated when the single bit indicates the zero raster frequency offset is used.
19. The apparatus of claim 16 , wherein the processing circuitry is configured to:
encode in a time-domain or frequency-domain cyclic shift of the NSSS one of:
the raster frequency offset, or
which of Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD) is used.
20. The apparatus of claim 16 , wherein the processing circuitry is configured to:
encode which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) is used through relative locations of the NPSS and NSSS.
21. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a user equipment (UE), the one or more processors to configure the UE to:
receive from an evolved NodeB (eNB) a narrowband Primary Synchronization Signal (NPSS) and a narrowband Secondary Synchronization Signal (NSSS), at least one of:
the NPSS being modulated using a first modulation that indicates via a first single bit one of a duplexing scheme, a raster frequency offset, or an operating mode used by the eNB, or
the NSSS being modulated using a second modulation that indicates via a second single bit frame timing used by the eNB;
determine eNB information of the NPSS and NSSS, including information indicated by at least one of the first or second bit; and
initiate communications with the eNB based on the information of the NPSS and the NSSS, the NSSS comprising a Zadoff Chu (ZC) sequence mapped to multiple orthogonal frequency division multiplexed (OFDM) symbols to form NSSS sequence elements for the OFDM symbols, and the second modulation comprising an OFDM symbol-level modulation of the NSSS sequence elements in which frame timing information is encoded through use of time domain cyclic shifts of the ZC sequence and the OFDM symbol-level modulation, the OFDM symbol-level modulation bearing a one-to-one mapping to a 20 ms timing boundary indicated using different time-domain cyclic shifts of the ZC sequence.
22. The medium of claim 21 , wherein:
the NPSS modulation comprises use of conjugate ZC sequences multiplied by a cover code for each OFDM symbol in a narrowband subframe, and
the first single bit indicates one of:
which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD),
which operation mode of:
an in-band operation mode, or
a standalone or guard-band operation mode, or
whether a zero or non-zero raster frequency offset,
is used by the eNB.
23. The medium of claim 22 , wherein the instructions further configure the UE to:
receive a narrowband Master Information Block (NMIB), and
when the first single bit indicates that the operation mode is the standalone or guard-band operation mode, indicate in the NMIB which of the standalone and guard-band operation mode is deployed by the eNB, and
when the first single bit indicates the non-zero raster frequency offset is used, indicate in the NMIB which of the in-band or guard-band operation mode is deployed, the standalone operation mode being indicated when the single bit indicates the zero raster frequency offset is used by the eNB.
24. The medium of claim 21 , wherein the one or more processors are configured to at least one of:
determine from a time-domain or frequency-domain cyclic shift of the NS SS one of:
the raster frequency offset, or
which of Frequency Division Duplexing (FDD) or Time Division Duplexing (TDD) is used by the eNB, or
determine from relative locations of the NPSS and NSSS which of Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) is used by the eNB.