WO2018073683A1

WO2018073683A1 - Synchronization of narrowband and wideband user equipment

Info

Publication number: WO2018073683A1
Application number: PCT/IB2017/056194
Authority: WO
Inventors: Sami-Jukka Hakola; Kari Pekka Pajukoski; Mihai Enescu; Mikko Tapio KOKKONEN; Jorma Johannes Kaikkonen; Esa Tapani Tiirola
Original assignee: Nokia Technologies Oy; Nokia USA Inc
Current assignee: Nokia Technologies Oy; Nokia USA Inc
Priority date: 2016-10-10
Filing date: 2017-10-06
Publication date: 2018-04-26
Anticipated expiration: 2019-04-10

Abstract

Various communication systems may benefit from improved signal synchronization. For example, communication systems may benefit from a common synchronization signal (310) for 5G New Radio systems. A method may include determining by a network entity a wideband synchronization signal (410). The method may also include generating a common synchronization signal (310) comprising the wideband synchronization signal (410) and a narrowband synchronization signal (420). A portion of the wideband synchronization signal (410) corresponds to the narrowband synchronization signal (420). In addition, the method may include transmitting the common synchronization signal from the network entity (720) to a user equipment (710).

Description

TITLE:

SYNCHRONIZATION OF NARROWBAND AND WIDEBAND USER EQUIPMENT

BACKGROUND:

Field:

[0001] Various communication systems may benefit from improved signal synchronization. For example, New Radio systems may benefit from a common synchronization signal for user equipment.

Description of the Related Art:

[0002] Third generation partnership project (3GPP) 5^th generation (5G) or new radio (NR) technology is a new generation of radio systems and network architecture that can deliver extreme broadband and ultra-robust, low latency connectivity. As part of the development of NR technology, components that are able to use any spectrum band are being identified and developed. Such components may be used to achieve a single technical framework addressing all usage scenarios. The spectrum band, for example, may be any band up to hundred gigahertz (GHz) or so.

[0003] Different types of user equipment (UE) are generally limited to decoding signals and channels on a limited frequency band. With the development of NR systems, however, UEs and other entities within the system may be asked to decode signals received in a variety of different spectrum bands. For example, upon entering the NR system, synchronization between a UE and a network entity within the NR system may occur. Synchronization is facilitated by a synchronization signal sent from the network to the UE. In an NR system, the synchronization signal may be sent on a wide ranging spectrum band.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0004] For proper understanding of the invention, reference should be made to the accompanying drawings, wherein:

[0005] Figure 1 illustrates a synchronization table according to certain embodiments.

[0006] Figure 2 illustrates a flow diagram according to certain embodiments.

[0007] Figure 3 illustrates a synchronization signal according to certain embodiments.

[0008] Figure 4 illustrates a synchronization signal according to certain embodiments.

[0009] Figure 5 illustrates a synchronization signal according to certain embodiments.

[0010] Figure 6 illustrates a flow diagram according to certain embodiments. [0011] Figure 7 illustrates a system according to certain embodiments. DETAILED DESCRIPTION:

[0012] Certain embodiments may provide for a common NR synchronization signal that can be utilized by both wideband UEs and narrowband UEs. Wideband UEs may be those UEs who receive signals at a frequency band that is higher than the frequency band at which narrowband UEs receive signals. For example, a signal bandwidth for a wideband UE may be 5 megahertz (MHz) or 200 MHz, while the bandwidth for a narrowband UE may be 1 MHz. In certain embodiments, a wideband UE may be an enhanced mobile broadband (eMBB) UE or a massive machine type communication (mMTC) UE. A narrowband UE, for example, may be a narrowband internet of things (NB-IoT) UE or an enhanced machine type communication (eMTC) UE.

[0013] The NR system may support multiplexing multiple numerologies within an NR carrier using frequency division multiplexing (FDM) or time division multiplexing (TDM). Multiplexing multiple numerologies, for example, may include multiple carrier or signal characteristic being defined within the same signal, such as symbol duration, sub-carrier spacing, and the number of symbols per subframe. Figure 1 illustrates a synchronization table according to certain embodiments. In particular, Figure 1 illustrates a table 110 listing physical layer parameters or numerologies for a first carrier or signal frequency 120 below 6 GHz and a second carrier or signal frequency 130 between 6 and 40 GHz.

[0014] In certain embodiments, table 1 may illustrate different physical layer parameters for a synchronization signal bandwidth. For example, first signal frequency 120 may have a subcarrier spacing (SCS) of 15 kHz, which may utilize a 1 MHz bandwidth. On the other hand, a subcarrier spacing of 60 kHz in first signal frequency 120 may utilize a 4 MHz bandwidth. Second signal frequency 130 also includes a subcarrier spacing of 60 kHz which utilizes 4 MHz bandwidth. The synchronization signal bandwidth may be calculated so that the inverse of the bandwidth is one fourth of the cyclic prefix (CP). The CP may be either a normal CP (NCP) or an extended CP (ECP). Other numerology illustrated in table 110 include a default SCS, minimum system bandwidth (BW), channel raster, synchronization raster, and/or residual carrier-frequency offset (CFO) after synchronization.

[0015] As described in 3GPP TSG RANI #86 Rl- 168494, a frequency domain raster that is more sparse than the standard channel raster may be used for synchronization transmissions in eMBB or ultra-reliable and low-latency communications (URLLC) UEs. Using a sparser frequency domain raster may reduce the amount of frequency domain hypothesis that the UE may need to perform in searching for a synchronization signal. Under 3GPP Rl-168494, however, the synchronization raster for NB-IoT and eMTC UEs will be the same as the standard channel raster. 3GPP Rl-168494, and the entire content recited therein, is hereby incorporated by reference.

[0016] Certain embodiments may provide for a common synchronization signal that may be used by both narrowband UEs and wideband UEs. Narrowband UEs may use a narrower reception bandwidth than wideband UEs. A common synchronization signal may include both a wideband synchronization signal and a narrowband synchronization signal, allowing all or some UEs in the system to receive and decode the common synchronization signal. In some embodiment, a synchronization signal domain raster may be different for wideband UEs and narrowband UEs. A common synchronization signal may therefore be used to synchronize both narrowband and wideband UEs.

[0017] Figure 2 illustrates a flow diagram according to certain embodiments. In particular, Figure 2 illustrates an embodiment of a network entity, such as a 5G Node B (5G NB). In step 210, a wideband synchronization signal may be determined or defined by a network entity. In certain embodiments, a wideband synchronization signal may be either a long sequence or a concatenated sequence from multiple narrowband synchronization signals. The network entity may then generate a common synchronization signal, as shown in step 220. The common synchronization signal may comprise both a wideband synchronization signal and a narrowband synchronization signal. In other words, both a wideband UE and a narrowband UE may be able to receive and decode the signal. In some embodiment, the common synchronization signal may be the wideband synchronization signal with the narrowband synchronization signal added therein.

[0018] In certain embodiments, the common synchronization signal may have the same frequency band as the wideband synchronization signal. A portion of the wideband synchronization signal included in the common synchronization signal, however, may correspond to a narrowband synchronization signal. The corresponding portion may be determined by the size of the portion. In some embodiments, the size of the portion of the wideband synchronization signal may be equal to the size of the narrowband synchronization signal. The portion size, in some embodiments, may be defined based on the range of frequencies the portion occupies. In step 230, the generated common synchronization signal may be transmitted from the network entity to the user equipment.

[0019] Figure 3 illustrates a synchronization signal according to certain embodiments. In particular, Figure 3 illustrates a common synchronization signal 310 in which a narrowband synchronization signal can overlay any part of the frequency band of the wideband synchronization signal. Common synchronization signal 310 may have the same frequency band as a wideband synchronization signal. As shown in Figure 3, four separate narrowband synchronization signals 310, 330, 340, and 350 may be determined from the common synchronization signal. The narrowband synchronization signal may be determined or generated by a network entity applying an orthogonal cover code on common synchronization signal 310.

[0020] An orthogonal cover code, for example, may be a sequence, such as a Walsh-Hadamard linear code, that is used to orthogonalize signals that are transmitted on the same radio resource in a code domain. In certain embodiments, a network entity within a cell may apply an orthogonal cover code on the wideband synchronization signal, included in the common synchronization signal, to form a single narrow band synchronization within the cell. Such embodiment may assume that the web synchronization signal is cell specific.

[0021] In some embodiments, the number of narrowband synchronization signals for which to search in common synchronization signal 310 may be limited by adjusting the channel raster of common synchronization signal 310, or of the wideband synchronization signal included therein. In such embodiments, a narrowband UE using at least one of the narrowband synchronization signals may receive an indication about a relaxed channel raster.

[0022] In certain embodiments, the synchronization raster for the narrowband synchronization signal may be different than the raster of the wideband synchronization signal. As can be seen in Figure 3, the raster of the narrowband synchronization signal may be smaller than the raster of the wideband synchronization signal. In some embodiments, the synchronization raster for the wideband synchronization signal may be an integer multiple of the narrowband synchronization raster and/or the subcarrier spacing. For example, Figures 3 and 5 illustrate an embodiment in which the raster for the wideband synchronization signal is three times that of the narrowband synchronization signal. Such an embodiment can help to facilitate frequency bin alignment between the narrowband and the wideband synchronization signals.

[0023] In other embodiments, the synchronization raster for the narrowband synchronization signal and the wideband synchronization signal may be equal. Figure 4 illustrates a synchronization signal according to certain embodiments, in which the narrowband synchronization signal can be allocated in a center of the wideband synchronization signal. In particular, Figure 4 illustrates an embodiment in which the synchronization raster of the narrowband synchronization signal and the wideband synchronization signal are equal. The narrowband synchronization signal and the wideband synchronization signal may have different channel rasters when transmitted separately. When transmitted as part of a common synchronization signal, however, the narrowband synchronization signal 420 and the wideband synchronization signal 410 have the same channel raster. This embodiment can help to reduce the number of narrowband UE synchronization signal candidates within the common synchronization signal.

[0024] In the embodiment shown in Figure 4, the narrowband synchronization raster over the whole band may be assumed. The transmission of the narrowband synchronization, however, is only constrained when transmitted as part of the common synchronization signal.

[0025] In certain embodiments, the synchronization raster for narrowband synchronization signal may allow for building a common synchronization signal and/or a wideband synchronization signal included in the common signal from concatenated sequences of the narrowband synchronization signal. The narrowband raster may not allow for partial overlap between the narrowband signal and the wideband signal to take place. For example, the wideband synchronization signal raster included in the common synchronization signal may be an integer multiple of the narrowband channel raster. This embodiment allows for the use of a denser raster in the common synchronization signal than the narrowband synchronization signal.

[0026] Figure 5 illustrates a synchronization signal according to certain embodiments. In particular, Figure 5 illustrates an embodiment in which the synchronization raster of the wideband synchronization signal and the narrowband synchronization signal, included within the common synchronization signal, are integer multiples of one another. For example, the raster of wideband synchronization signal 510 may be three times larger than the raster of narrowband synchronization signal 520. The raster of the wideband signal being a multiple of the narrowband signal allows for the building of a common synchronization signal from concatenated sequences, which can avoid overlap between the wideband signal and the narrowband signal. As shown in the embodiments of Figure 5, the narrowband synchronization signal may be in at least one of four positions within the wideband synchronization signal. For example, the narrowband synchronization signal may be in the end of the wideband signal.

[0027] Figure 6 illustrates a flow diagram according to certain embodiments. In particular, Figure 6 may illustrate an embodiment of the user equipment entering a cell in a NR system, moving to a new cell within an NR system, or exiting an idle or a powered off state. In step 610, the user equipment may receive from a network entity a common synchronization signal. The common synchronization signal may include a wideband synchronization signal and a narrowband synchronization signal. A portion of the wideband synchronization signal within the common synchronization signal may correspond to a narrowband synchronization signal. The corresponding portion may be determined by the size of the portion. In some embodiments, the size of the portion of the wideband synchronization signal may be equal to the size of the narrowband synchronization signal. The portion size, in some embodiments, may be defined based on the range of frequencies the portion occupies.

[0028] Upon receiving the common synchronization signal, the UE may use the the narrowband synchronization signal, which may be generated by applying an orthogonal cover code upon a narrow portion of the wideband synchronization signal, as shown in step 620. In step 630, the UE may use the common synchronization signal to synchronize the user equipment with the network entity. The synchronization may occur when the UE enters a new cell in the NR system or when exiting an idle state or a powered off state.

[0029] In certain embodiments, wideband UEs may initially search for one or more narrowband synchronization signal for initial time and/or frequency synchronization. The wideband UE may then carry out certain procedures, for example, initial access, using this initial synchronization, but may in later stage or after getting initial synchronization receive more accurate time period and/or frequency synchronization. The UE may receive more accurate time and/or frequency synchronization by detecting the wideband synchronization signal included in the common synchronization signal that may be at least partly constructed from one or more narrowband synchronization signals in a frequency domain.

[0030] Figure 7 illustrates a system according to certain embodiments. It should be understood that each signal or block in Figures 1, 2, 3, 4, 5, and 6 may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry. In one embodiment, a system may include several devices, such as, for example, network entity 720 or UE 710. The system may include more than one UE 710 and more one network entity 720, although only one access node shown for the purposes of illustration. The network entity may be a network node, access node, a base station, a 5G NB, server, host, or any of the other access or network node discussed herein.

[0031] Each of these devices may include at least one processor or control unit or module, respectively indicated as 711 and 721. At least one memory may be provided in each device, and indicated as 712 and 722, respectively. The memory may include computer program instructions or computer code contained therein. One or more transceiver 713 and 723 may be provided, and each device may also include an antenna, respectively illustrated as 714 and 724. Although only one antenna each is shown, many antennas and multiple antenna elements may be provided to each of the devices. Higher category UEs generally include multiple antenna panels. Other configurations of these devices, for example, may be provided. For example, network entity 720 and UE 710 may be additionally configured for wired communication, in addition to wireless communication, and in such a case antennas 714 and 724 may illustrate any form of communication hardware, without being limited to merely an antenna.

[0032] Transceivers 713 and 723 may each, independently, be a transmitter, a receiver, or both a transmitter and a receiver, or a unit or device that may be configured both for transmission and reception. In other embodiments, the UEs or the network node may have at least one separate receiver or transmitter. The transmitter and/or receiver (as far as radio parts are concerned) may also be implemented as a remote radio head which is not located in the device itself, but in a mast, for example. The operations and functionalities may be performed in different entities, such as nodes, hosts or servers, in a flexible manner. In other words, division of labor may vary case by case. One possible use is to make a network node deliver local content. One or more functionalities may also be implemented as virtual application(s) in software that can run on a server. A beamformer may be a type of transceiver.

[0033] A user device or user equipment 710 may be a narrowband UE, a wideband UE, an eMBB UE, eMTC UE, mMTC UE, NB-IoT UE, a mobile station (MS) such as a mobile phone or smart phone or multimedia device, a computer, such as a tablet, provided with wireless communication capabilities, personal data or digital assistant (PDA) provided with wireless communication capabilities, portable media player, digital camera, pocket video camera, navigation unit provided with wireless communication capabilities or any combinations thereof.

[0034] In some embodiments, an apparatus, such as a network entity, may include means for carrying out embodiments described above in relation to Figures 1, 2, 3, 4, 5, and 6. In certain embodiments, at least one memory including computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform any of the processes described herein.

[0035] According to certain embodiments, an apparatus 710 may include at least one memory 712 including computer program code, and at least one processor 711. The at least one memory 712 and the computer program code are configured, with the at least one processor 711, to cause the apparatus 710 at least to receive from a network entity at a user equipment a common synchronization signal comprising a wideband synchronization signal and a narrowband synchronization signal. A portion of the wideband synchronization signal corresponds to a narrowband synchronization signal. The at least one memory 712 and the computer program code may be configured, with the at least one processor 711, to also cause the apparatus 710 at least to use the common synchronization signal to synchronize the user equipment with the network entity.

[0036] According to certain embodiments, an apparatus 720 may include at least one memory 722 including computer program code, and at least one processor 721. The at least one memory 722 and the computer program code are configured, with the at least one processor 721, to cause the apparatus 720 at least to determine by a network entity a wideband synchronization signal. The at least one memory 722 and the computer program code may be configured, with the at least one processor 721, to also cause the apparatus 720 at least to generate a common synchronization signal comprising the wideband synchronization signal and a narrowband synchronization signal. A portion of the wideband synchronization signal corresponds to the narrowband synchronization signal. In addition, the at least one memory 722 and the computer program code may be configured, with the at least one processor 721, to cause the apparatus 720 at least to transmit the common synchronization signal from the network entity to a user equipment.

[0037] Processors 711 and 721 may be embodied by any computational or data processing device, such as a central processing unit (CPU), digital signal processor (DSP), application specific integrated circuit (ASIC), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), digitally enhanced circuits, or comparable device or a combination thereof. The processors may be implemented as a single controller, or a plurality of controllers or processors.

[0038] For firmware or software, the implementation may include modules or unit of at least one chip set (for example, procedures, functions, and so on). Memories 712 and 722 may independently be any suitable storage device, such as a non-transitory computer-readable medium. A hard disk drive (HDD), random access memory (RAM), flash memory, or other suitable memory may be used. The memories may be combined on a single integrated circuit as the processor, or may be separate therefrom. Furthermore, the computer program instructions may be stored in the memory and which may be processed by the processors can be any suitable form of computer program code, for example, a compiled or interpreted computer program written in any suitable programming language. The memory or data storage entity is typically internal but may also be external or a combination thereof, such as in the case when additional memory capacity is obtained from a service provider. The memory may be fixed or removable.

[0039] The memory and the computer program instructions may be configured, with the processor for the particular device, to cause a hardware apparatus such as network entity 720 or UE 710, to perform any of the processes described above (see, for example, Figures 1, 2, 3, 4, 5, and 6). Therefore, in certain embodiments, a non-transitory computer-readable medium may be encoded with computer instructions or one or more computer program (such as added or updated software routine, applet or macro) that, when executed in hardware, may perform a process such as one of the processes described herein. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, CM, Java, etc., or a low-level programming language, such as a machine language, or assembler. Alternatively, certain embodiments may be performed entirely in hardware.

[0040] Furthermore, although Figure 7 illustrates a system including a network entity 720 and UE 710, certain embodiments may be applicable to other configurations, and configurations involving additional elements, as illustrated and discussed herein. For example, multiple user equipment devices and multiple network entities may be present, or other nodes providing similar functionality, such as nodes that combine the functionality of a user equipment and an network entity, such as a relay node. The UE 710 may likewise be provided with a variety of configurations for communication other than communication network entity 720. For example, the UE 710 may be configured for device-to-device, machine to machine, or vehicle-to-vehicle communication.

[0041] Certain embodiments provide an embodiment in which wideband UEs and narrowband UEs may decode a common synchronization signal. In some embodiments, the synchronization signal frequency domain raster may be different for wideband and narrowband UEs, in order to limit the number of synchronization signals to be searched.

[0042] A common synchronization signal can help to reduce the amount of resources used by the network and the UE, by avoiding having to send separate synchronization signals for narrowband and wideband UEs. Adjusting the synchronization signal raster can also help to further reduce the amount of resources used by the UE. The above embodiments therefore provide significant improvements to the functioning of a network and/or to the functioning of the network entities or UEs.

[0043] The features, structures, or characteristics of certain embodiments described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, the usage of the phrases "certain embodiments," "some embodiments," "other embodiments," or other similar language, throughout this specification refers to the fact that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. Thus, appearance of the phrases "in certain embodiments," "in some embodiments," "in other embodiments," or other similar language, throughout this specification does not necessarily refer to the same group of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0044] One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. While many of the above embodiments refer to a NR system, the above embodiments may be used in any other systems, such as third generation (3G), 5G, Long Term Evolution (LTE), and/or LTE Advanced (LTE-A) systems.

[0045] Partial Glossary

[0046] 3GPP third generation partnership project

[0047] 5G 5^th generation

[0048] NR new radio

[0049] UE user equipment

[0050] eMBB enhanced mobile broadband

[0051] mMTC massive machine type communication

[0052] NB-IoT narrowband internet of things

[0053] eMTC enhanced machine type communication

[0054] FDM frequency division multiplexing

[0055] TDM time division multiplexing

[0056] SCS subcarrier spacing

[0057] CP cyclic prefix

[0058] NPC normal cyclic prefix

[0059] ECP extended cyclic prefix

[0060] CFO carrier-frequency offset

[0061] URLLC ultra-reliable and low-latency communications

[0062] According to a first embodiment, a method may include determining by a network entity a wideband synchronization signal. The method may also include generating a common synchronization signal comprising the wideband synchronization signal and a narrowband synchronization signal. A portion of the wideband synchronization signal corresponds to the narrowband synchronization signal. In addition, the method includes transmitting the common synchronization signal from the network entity to a user equipment.

[0063] In a variant, the network entity may broadcast the common synchronization signal from the network entity to a user equipment.

[0064] In another variant, using an orthogonal cover code to determine the narrowband synchronization signal from the wideband synchronization signal.

[0065] In yet another variant, the portion of the wideband synchronization signal may correspond to a size of the narrowband synchronization signal.

[0066] In yet another variant, a channel raster of the narrowband synchronization signal may be equal to a channel raster of the wideband synchronization signal.

[0067] In some variants, a channel raster of the narrowband synchronization signal may be different than a channel raster of the wideband synchronization signal.

[0068] In a further variant, a channel raster of the wideband synchronization signal may be an integer multiple of the narrowband synchronization signal.

[0069] In a variant, the common synchronization signal may include a concatenated sequence of the wideband synchronization signal and the narrowband synchronization signal.

[0070] In another variant, the common synchronization signal is a new radio synchronization signal.

[0071] According to a second embodiment, a method may include receiving from a network entity at a user equipment a common synchronization signal comprising a wideband synchronization signal and a narrowband synchronization signal. A portion of the wideband synchronization signal corresponds to a narrowband synchronization signal. The method may also include using the common synchronization signal to synchronize the user equipment with the network entity.

[0072] In a variant, the user equipment may initially search for the narrowband synchronization signal for at least one of an initial time period or an initial frequency synchronization. The user equipment may then later search for the narrowband synchronization signal included in the common synchronization signal for a more accurate at least one of time period or frequency synchronization.

[0073] In a variant, the common synchronization signal or the wideband synchronization signal includes one or more narrowband synchronization signals.

[0074] In another variant, the common synchronization signal may be received by the user equipment upon entering a cell.

[0075] In an additional variant, the narrowband synchronization signal may be determined from the portion of the wideband synchronization signal by using an orthogonal cover code.

[0076] In some variants, the portion of the wideband synchronization signal may correspond to a size of the narrowband synchronization signal.

[0077] In a further variant, a channel raster of the narrowband synchronization signal may be equal to a channel raster of the wideband synchronization signal.

[0078] In a variant, a channel raster of the narrowband synchronization signal may be different than a channel raster of the wideband synchronization signal.

[0079] In another variant, a channel raster of the wideband synchronization signal may be an integer multiple of the narrowband synchronization signal.

[0080] In yet another variant, the common synchronization signal comprises a concatenated sequence of the wideband synchronization signal and the narrowband synchronization signal.

[0081] In another variant, the user equipment may be at least one of an enhanced broadband user equipment, a massive machine type communication user equipment, a narrowband internet of things user equipment, or an enhanced machine type communication user equipment.

[0082] According to a third and a fourth embodiment, an apparatus can include at least one processor and at least one memory and computer program code. The at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform the method according to the first and second embodiments respectively, and any of their variants.

[0083] According a fifth and a sixth embodiment, an apparatus can include means for performing the method according to the first and second embodiments respectively, and any of their variant.

[0084] According to a seventh and an eighth embodiment, a computer program product may encode instructions for performing a process including the method according to the first and second embodiments respectively, and any of their variants.

[0085] According to a ninth and a tenth embodiment, a non-transitory computer-readable medium may encode instructions that, when executed in hardware, perform a process including the method according to the first and second embodiments respectively, and any of their variants.

[0086] According to an eleventh embodiment, a system may include the third embodiment and the fourth embodiment.

Claims

WE CLAIM:

1. A method, comprising:

receiving, at a user equipment, a common synchronization signal; and

using the common synchronization signal to synchronize with a network entity, wherein the common synchronization comprises a wideband synchronization signal and a narrowband synchronization signal.

2. A method according to claim 1, wherein a portion of the wideband synchronization signal corresponds to the narrowband synchronization signal.

3. A method according to claim 1 or 2 further comprising:

searching for the narrowband synchronization signal for at least one of an initial time period or an initial frequency synchronization.

4. A method according to claim 1 or 3 further comprising:

searching for the narrowband synchronization signal included in the common synchronization signal for at least one of another time period or another frequency synchronization.

5. A method according to any one of claims 1 through 4, wherein the common synchronization signal or the wideband synchronization signal comprises one or more narrowband synchronization signals.

6. A method according to any one of claims 1 through 5, wherein the common synchronization signal is received by the user equipment upon the user equipment entering a cell.

7. A method according to any one of claims 2 through 6, further comprising applying an orthogonal cover code to the portion of the wideband synchronization signal to form the narrowband synchronization signal.

8. A method according to any one of claims 2 through 7, wherein the portion of the wideband synchronization signal corresponds to a size of the narrowband synchronization signal.

9. A method according to any one of claims 1 through 8, wherein a channel raster of the narrowband synchronization signal is equal to a channel raster of the wideband synchronization signal.

10. A method according to any one of claims 1 through 8, wherein a channel raster of the narrowband synchronization signal is different than a channel raster of the wideband synchronization signal.

11. A method according to claim 10, wherein the channel raster of the wideband synchronization signal is integer multiple of the channel raster of the narrowband synchronization signal.

12. A method according to any one of claims 1 through 11 , wherein the common synchronization signal comprises a concatenated sequence of the wideband synchronization signal and the narrowband synchronization signal.

13. A method according to any one of claims 1 through 12, wherein the user equipment is at least one of an enhanced broadband user equipment, a massive machine type communication user equipment, a narrowband internet of things user equipment, or an enhanced machine type communication user equipment.

14. A method, comprising:

determining, by a network entity, a wideband synchronization signal;

generating a common synchronization signal; and,

transmitting the common synchronization signal from the network entity to a user equipment, wherein

the common synchronization signal comprises the wideband synchronization signal and a narrowband synchronization signal.

15. A method according to claim 14, wherein a portion of the wideband synchronization signal corresponds to the narrowband synchronization signal.

16. A method according to claim 14 or 15 further comprising broadcasting the common synchronization signal from the network entity to the user equipment.

17. A method according to any one of claims 14 to 16, further comprising: using an orthogonal cover code to determine the narrowband synchronization signal from the wideband synchronization signal.

18. A method according to any one of claims 15 to 17, wherein the portion of the wideband synchronization signal corresponds to a size of the narrowband synchronization signal.

19. A method according to any one of claims 14 to 18, wherein a channel raster of the narrowband synchronization signal is equal to a channel raster of the wideband synchronization signal.

20. A method according to any one of claims 14 to 18, wherein a channel raster of the narrowband synchronization signal is different than a channel raster of the wideband synchronization signal.

21. A method according to claim 20, wherein the channel raster of the wideband synchronization signal is an integer multiple of the channel raster of the narrowband synchronization signal.

22. A method according to any one of claims 14 to 21, wherein the common synchronization signal comprises a concatenated sequence of the wideband synchronization signal and the narrowband synchronization signal.

23. A method according to any one of claims 14 to 22, wherein the common synchronization signal comprises a new radio synchronization signal.

24. An apparatus comprising: at least one processor and at least one memory and computer program code;

the at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform the method according to any one of claims 1 to 13.

25. An apparatus, comprising: at least one processor and at least one memory and computer program code;

the at least one memory and the computer program code can be configured to, with the at least one processor, cause the apparatus at least to perform the method according to any one of claims 14 to 23.

26. An apparatus, comprising means for performing the method according to any one of claims 1 to 13.

27. An apparatus comprising means for performing the method according to any one of claims 14 to 23.