NB-IoT synchronization signals with offset information

1. One or more non-transitory computer-readable media having instructions that, when executed, cause an evolved NodeB (eNB) to perform operations to transmit synchronization signals for time and frequency synchronization between the eNB and one or more user equipments (UEs) for narrowband Internet of Things (NB-IoT) comprising:

concatenating a plurality of short Zadoff-Chu (ZC) sequences each having a different root index, the ZC sequences being ordered to indicate an offset for use by a UE;

generating an NB-IoT Primary Synchronization Signal (NB-PSS) using the concatenation of short ZC sequences; and

transmitting the resulting NB-PSS by the eNB in a periodic manner to the UE, wherein, the offset is identified by the order of the ZC sequences in the concatenation of short ZC sequences each having a different root index.

2. The media of claim 1 , wherein transmitting comprises transmitting a single NB-PSS over multiple subframes in an NB-frame.

3. The media of claim 1 , wherein generating comprises generating in the frequency domain and the NB-PSS is spread across multiple symbols in time.

4. The media of claim 1 , wherein the concatenation of short ZC sequences is a prime number of ZC sequences.

5. The media of claim 1 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence.

6. The media of claim 5 , wherein the last symbol of the sequence of symbols is a repeat of the previous symbol if the number of multiple symbols used to map the NB-PSS is odd.

7. The media of claim 1 , wherein the offset is a frequency offset that comprises a local oscillator offset and a channel raster offset.

8. The media of claim 1 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence wherein the ordering of the ZC sequence conveys information about the channel raster offset.

9. The media of claim 1 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence wherein the ordering of the ZC sequence is reversed with respect to the complex conjugate of the ZC sequence to indicate one of two different channel raster offsets.

10. Baseband circuitry of an evolved NodeB (eNB) to perform operations to generate synchronization signals for time and frequency synchronization between the eNB and user equipments (UEs) for narrowband Internet of Things (NB-IoT), the baseband circuitry configured to:

concatenate a plurality of short Zadoff-Chu (ZC) sequences each having a different root index, the ZC sequences being ordered to indicate an offset for use by a UE;

generate an NB-IoT Primary Synchronization Signal (NB-PSS) using the concatenation of short ZC sequences; and

multiplex the resulting NB-PSS by the eNB in a periodic manner to the UE, wherein, the offset is identified by the order of the ZC sequences in the concatenation of short ZC sequences each having a different root index.

11. The baseband circuitry of claim 10 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence and wherein the ordering of the ZC sequence conveys information about the channel raster offset.

12. The baseband circuitry of claim 10 , wherein the offset is a frequency offset that comprises a local oscillator offset and a channel raster offset.

13. An evolved NodeB having the baseband circuitry of claim 10 .

14. A method for a base station to perform operations to transmit synchronization signals for time and frequency synchronization between the base station and one or more user equipments (UEs) for narrowband Internet of Things (NB-IoT), comprising:

concatenating a plurality of short Zadoff-Chu (ZC) sequences each having a different root index, the ZC sequences being ordered to indicate an offset for use by a UE;

generating an NB-IoT Primary Synchronization Signal (NB-PSS) using the concatenation of short ZC sequences; and

transmitting the resulting NB-PSS by the eNB in a periodic manner to the UE, wherein, the offset is identified by the order of the ZC sequences in the concatenation of short ZC sequences each having a different root index.

15. The method of claim 14 , wherein transmitting comprises transmitting a single NB-PSS over multiple subframes in an NB-frame.

16. The method of claim 14 , wherein generating comprises generating in the frequency domain and the NB-PSS is spread across multiple symbols in time.

17. The method of claim 14 , wherein the concatenation of short ZC sequences is a prime number of ZC sequences.

18. The method of claim 14 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence.

19. The method of claim 18 , wherein the last symbol of the sequence of symbols is a repeat of the previous symbol if the number of multiple symbols used to map the NB-PSS is odd.

20. The method of claim 14 , wherein the offset is a frequency offset that comprises a local oscillator offset and a channel raster offset.

21. The method of claim 14 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence wherein the ordering of the ZC sequence conveys information about the channel raster offset.

22. The method of claim 14 , wherein the NB-PSS is formed of symbol pairs and each symbol pair has a ZC sequence and a complex conjugate of the same ZC sequence wherein the ordering of the ZC sequence is reversed with respect to the complex conjugate of the ZC sequence to indicate one of two different channel raster offsets.