Synchronization of user equipments of different radio access technologies coexisting in same channel

Abstract

Systems, methods, apparatuses, and computer program products are provided for synchronization of user equipments providing different radio access technologies, such as long term evolution and new radio sidelinks, coexisting in the same channel. For example, a first user equipment may receive a first radio transmission from a second user equipment. The first user equipment may determine a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment based on the received first radio transmission. The first user equipment may send a second radio transmission indicating the determined misalignment to the third user equipment.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 336,143, filed on April 28, 2022. The contents of this previously filed application are incorporated herein by reference in their entirety. Technical Field

[0003] Some example embodiments may generally relate to communications including mobile or wireless telecommunication systems such as long term evolution (LTE) or fifth generation (5G) radio access technology or new radio (NR) access technology or other communication systems. For example, certain example embodiments may generally relate to systems and / or methods for providing synchronization of user equipment of different radio access technologies such as long term evolution and new radio sidelinks coexisting in the same channel. Background Art

[0004] Examples of mobile or wireless telecommunication systems may include Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), Advanced LTE (LTE-A), MulteFire, LTE-A Pro, and / or fifth generation (5G) radio access technology or new radio (NR) access technology. 5G wireless systems refer to next generation (NG) radio systems and network architectures. 5G systems are primarily built on 5G New Radio (NR), but 5G (or NG) networks may also be built on E-UTRA radio. It is estimated that NR provides bit rates of about 10-20 Gbit / s or higher, and may support at least service categories such as enhanced mobile broadband (eMBB) and ultra-reliable low latency communications (URLLC) and massive machine type communications (mMTC). NR is expected to provide extreme broadband and ultra-robust low latency connections and large-scale networks to support the Internet of Things (IoT). As IoT and machine-to-machine (M2M) communications become more popular, the demand for networks that meet the requirements of lower power, low data rates, and long battery life will grow. Next Generation Radio Access Network (NG-RAN) refers to the RAN for 5G, which can provide both NR and LTE (and Advanced LTE) radio access. Note that in 5G, a node that can provide radio access functions to user equipment (i.e., similar to a Node B (NB) in UTRAN or an evolved NB (eNB) in LTE) can be referred to as a Next Generation NB (gNB) when built on an NR radio and a Next Generation eNB (NG-eNB) when built on an E-UTRA radio. Summary of the invention

[0005] Embodiments may relate to an apparatus. The apparatus may include at least one processor and at least one memory including computer program code. The at least one memory and the computer program code may be configured to, together with the at least one processor, cause the apparatus to at least: receive, at a first user equipment, a first radio transmission from a second user equipment. The at least one memory and the computer program code may also be configured to, together with the at least one processor, cause the apparatus to at least: determine, based on the received first radio transmission, a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment. The at least one memory and the computer program code may further be configured to, together with the at least one processor, cause the apparatus to at least: send, to a third user equipment, a second radio transmission indicating the determined misalignment.

[0006] Embodiments may be directed to a method. The method may include: at a first user equipment, receiving a first radio transmission from a second user equipment. The method may also include: based on the received first radio transmission, determining a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment. The method may further include: sending a second radio transmission indicating the determined misalignment to a third user equipment.

[0007] Embodiments may be directed to an apparatus. The apparatus may include means for receiving, at a first user equipment, a first radio transmission from a second user equipment. The apparatus may also include means for determining, based on the received first radio transmission, a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment. The apparatus may further include means for sending, to a third user equipment, a second radio transmission indicating the determined misalignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a proper understanding of the example embodiments, reference should be made to the accompanying drawings, in which:

[0009] Figure 1A A frequency division multiplexing coexistence method is shown;

[0010] Figure 1B Shows the time division multiplexing coexistence method;

[0011] Figure 1C Shows the coexistence method of frequency division multiplexing and time division multiplexing;

[0012] Figure 1D Showing a method where there is a superimposed new radio (with dedicated frequencies for the new radio) on long term evolution;

[0013] Figure 1EShowing a method where there is new radio present in long term evolution (without dedicated frequencies for new radio);

[0014] Figure 2A 3. LTE secondary link resource allocation mode 3 is shown;

[0015] Figure 2B 4. LTE secondary link resource allocation mode 4 is shown;

[0016] Figure 3 1. The long term evolution vehicle-to-everything subframe slot format for the physical secondary link shared channel and the physical secondary link control channel is shown;

[0017] Figure 4 LTE vehicle-to-everything channelization with adjacent and non-adjacent physical sidelink control channels and physical sidelink shared channels is shown;

[0018] Figure 5A Shows the structure of the LTE sidelink synchronization signal / physical sidelink broadcast channel block;

[0019] Figure 5B shows the structure of the new radio sidelink synchronization block;

[0020] Fig. 6A A table showing various synchronization source priority levels in the LTE secondary link for the case where an evolved Node B is configured as the preferred synchronization source;

[0021] Figure 6B A table showing various synchronization source priority levels in the LTE secondary link for the case where a global navigation satellite system is configured as the preferred synchronization source;

[0022] Fig. 7A New radio secondary link resource allocation mode 1 is shown;

[0023] Figure 7B New radio sub-link resource allocation mode 2 is shown;

[0024] Fig. 8A A secondary link time slot format showing a time slot with a physical secondary link control channel / physical secondary link shared channel;

[0025] Figure 8B A secondary link time slot format showing a time slot having a physical secondary link control channel / physical secondary link shared channel and a physical secondary link feedback channel;

[0026] Fig.9A A table showing various synchronization source priority levels in the NR secondary link for the case where the Next Generation Node B is configured as the preferred synchronization source;

[0027] Fig. 9BA table showing various synchronization source priority levels in the NR secondary link for the case where a global navigation satellite system is configured as the preferred synchronization source;

[0028] Fig.10 illustrating methods according to certain embodiments; and

[0029] Fig.11 An example block diagram of a system according to an embodiment is shown. DETAILED DESCRIPTION

[0030] It will be readily appreciated that the components of certain example embodiments as generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of some example embodiments of systems, methods, apparatuses, and computer program products for providing synchronization of user equipment of different radio access technologies (such as long term evolution and new radio sidelinks) coexisting in the same channel is not intended to limit the scope of certain embodiments but rather represents selected example embodiments.

[0031] The features, structures or characteristics of the example embodiments described in this specification may be combined in any suitable manner in one or more example embodiments. For example, the use of the phrases "certain embodiments," "some embodiments," or other similar language in this specification means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment. Therefore, the appearance of the phrases "certain embodiments," "in some embodiments," "in other embodiments," or other similar language in this specification does not all refer to the same set of embodiments, and the described features, structures, or characteristics may be combined in any suitable manner in one or more example embodiments.

[0032] Certain embodiments may have various aspects and features. These aspects and features may be applied alone or in any desired combination with each other. Other features, processes, and elements / components may also be applied in combination with some or all aspects and features disclosed herein.

[0033] Additionally, if desired, the different functions or processes discussed below may be performed in different orders and / or simultaneously with each other. In addition, if desired, one or more of the described functions or processes may be optional or may be combined. Therefore, the following description should be considered as an explanation of the principles and teachings of certain example embodiments, rather than as a limitation thereof.

[0034] New Radio (NR) sidelink evolution can extend the applicability of NR sidelink to commercial use cases and can also consider vehicle-to-everything (V2X) deployment scenarios, where both Long Term Evolution (LTE) V2X and NR V2X devices can coexist in the same frequency channel. In order to enable two different types of devices to coexist when using a common carrier frequency, a mechanism can be used to effectively utilize the resource allocation of the two technologies without negatively impacting the operation of each technology. Certain embodiments relate to this aspect, namely, coexistence of LTE V2X and NR V2X.

[0035] European regulators have designated the bands 5855-5875MHz and 5875-5925MHz - referred to as the 5.9GHz band - for use by intelligent transportation systems (ITS) on the road. The industry is planning the deployment of coexisting LTE-V2X and NR-V2X (C-V2X) technologies for direct communication via the PC5 interface in the 5.9GHz band. Within the 5.9GHz band, various sub-bands may be designated for non-safety road ITS (5855MHz to 5875MHz), safety-related ITS (5855MHz to 5915MHz), and safety-related railway ITS (5925MHz to 5935MHz). Non-safety road ITS sub-bands may be shared with non-specific short-range devices (SRDs), and safety-related ITS sub-bands may be partially prioritized for road ITS (5875MHz to 5915MHz) and partially prioritized for railway ITS (5915MHz to 5925MHz).

[0036] In general, such prioritization may mean that no harmful interference will be caused to priority applications. In addition, until an appropriate spectrum sharing solution is defined by ETSI, road ITS and rail ITS may still be restricted to their respective prioritized frequency ranges. Once the European Telecommunications Standards Institute (ETSI) has developed a spectrum sharing solution for protecting rail ITS, vehicle-to-vehicle (V2V) communications for road ITS at 5915-5925 MHz may be permitted only. In the absence of such a sharing solution for protecting rail ITS, national authorities may permit infrastructure-to-vehicle (I2V) communications for road ITS at 5915-5925 MHz, but coordination with rail ITS is required. In addition, the use of spectrum in the frequency range 5855-5875 MHz may be on a non-interference / non-protected basis and may include use by non-safety road ITS and non-specific short-range devices.

[0037] In the deployment band configuration proposed in Europe for C-V2X at 5.9 GHz, LTE-V2X may be restricted to the 5905-5915 MHz and 5915-5925 MHz sub-bands. The remaining spectrum in the 5.9 GHz band may be used for NR-V2X.

[0038] NR SL can use an in-device coexistence framework, including both time division multiplexing (TDM) and frequency division multiplexing (FDM). For TDM-based coexistence operations, synchronization / subframe boundary alignment may be required between LTE and NR SL. For long-term time scale TDM operation, LTE SL and NR SL resource pools can be configured to be non-overlapping in the time domain. For short-term time scale TDM operation, for TX / TX and TX / RX overlap, if both radio access technologies (RATs) know the packet priority of LTE and NR sidelink transmission / reception before the transmission time limited by processing time, packets with higher relative priority can be sent / received. Equal priority TX / TX or TX / RX can be implemented depending on the user equipment (UE), as can the RX / RX situation. The priority of the physical sidelink feedback channel (PSFCH) can be the same as the corresponding physical sidelink shared channel (PSSCH). The priorities of the LTE physical sidelink broadcast channel (PSBCH) and the NR sidelink synchronization signal block (S-SSB) can be configured or pre-configured. If multiple NR SL transmissions / receptions overlap with a single LTE SL TX / RX, the highest priority NR SL TX / RX may determine the priority of the NR SL.

[0039] For FDM-based coexistence, there can be a static frequency allocation between NR and LTE SL. If the frequency separation between LTE and NR is large enough, then synchronization may not be required between NR and LTE, but in co-channel coexistence operation, the frequency separation may not be large enough. Static power allocation may be applied, which may mean that the full UE TX power is used only when LTE and NR SL are transmitting at the same time.

[0040] Figures 1A to 1E Various time and frequency coexistence methods are shown. Figure 1A shows the FDM coexistence method, Figure 1B shows the TDM coexistence method, Figure 1C A hybrid FDM and TDM coexistence approach is shown. Figure 1D shows a method in which there is an overlaid new radio (with a dedicated frequency for the new radio) on the long term evolution, while Figure 1E A method is shown in which there is a new radio present in the long term evolution (without a dedicated frequency for the new radio). Figure 1Dshows the coexistence of LTE-V2X and NR-V2X in the same resources, where NR-V2X has additional dedicated resources. Figure 1E Coexistence of LTE-V2X and NR-V2X in the same resources is shown, where NR-V2X accesses the resources opportunistically.

[0041] From the perspective of resource use, Figure 1D and Figure 1E The example of dynamic spectrum sharing shown in FIG. 4 can be more flexible than static sharing and enable higher efficiency. However, these schemes can be more complex due to auxiliary mechanisms that enable them to coexist with other systems. In contrast, Figure 1A , Figure 1B and Figure 1C The static spectrum sharing option shown in may be simpler. Figure 1E This may be the only available option in practice, as LTE-V2X devices may be configured to occupy the entire bandwidth, and NR-V2X devices may need to be able to adapt to this in order to be able to access the ITS band. However, it may be desirable to allow NR V2X UEs to use all available resources, so that there are no dedicated resources for LTE or NR, but the same resources are available for both, which may be referred to as full overlap.

[0042] This complete overlap may not be achievable via enhancements from the perspective of LTE-V2X, but may be achievable via enhancements from the perspective of NR-V2X devices. Therefore, a dynamic spectrum sharing scheme may provide a method for LTE-V2X and NR-V2X coexistence.

[0043] Additionally, as newer vehicles enter the market, it may be beneficial to support advanced V2X use cases that require NR-V2X to operate. Since Collaborative Awareness Messages (CAM) or Basic Safety Messages (BSM) may be sent using LTE-V2X and / or NR-V2X, an increasing number of vehicles may use NR-V2X and less LTE-V2X. Therefore, by enabling LTE-V2X and NR-V2X to coexist in the same resources, this may enable soft reallocation of LTE-V2X resources. In contrast, if static TDM or FDM deployments were considered for LTE-V2X and NR-V2X instead, this could mean that resources associated with LTE-V2X would likely remain allocated for decades, without NR-V2X being able to use these resources. Of course, in order for this to make sense, NR-V2X would also likely have to be allowed to be used for safety-related ITS.

[0044] In deployment scenarios where NR-V2X devices can use the same resources (e.g. Figure 1D), the NR-V2X parameter set may need to be contained as perfectly as possible in the LTE-V2X parameter set. NR-V2X can be deployed in frequency range 1 (FR1) with a subcarrier spacing of 30kHz, while the subcarrier spacing of LTE-V2X can be 15kHz. Therefore, in the time domain, two NR-V2X time slots can be contained in one LTE-V2X subframe, while in the frequency domain, the bandwidth of the NR-V2X physical resource block (PRB) can be twice that of the LTE-V2X PRB. Both LTE-V2X and NR-V2X SL resources can be organized into resource pools, which can be organized into time slots in NR-V2X or subframes in LTE-V2X in the time domain. In the frequency domain, these resources can be organized into subchannels including multiple PRBs.

[0045] The configurable number of PRBs for LTE-V2X and NR-V2X can be as follows: 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 25, 30, 48, 50, 72, 75, 96 and 100 for LTE-V2X; and 10, 12, 15, 20, 25, 50, 75 and 100 for NR-V2X.

[0046] Assuming that there is complete overlap between the LTE-V2X resource pool and one (or more) NR-V2X resource pools, the following paired configurations may be provided: for an LTE-V2X 20 subchannel configuration, there may be an NR-V2X 10 subchannel configuration with complete overlap; for an LTE-V2X 30 subchannel configuration, there may be an NR-V2X 15 subchannel configuration with complete overlap; for an LTE-V2X 48 subchannel configuration, there may be an NR-V2X 12 subchannel configuration with complete overlap; for an LTE-V2X 50 subchannel configuration, there may be an NR-V2X 25 subchannel configuration with complete overlap; for an LTE-V2X 75 subchannel configuration, there may be an NR-V2X 25 subchannel configuration with complete overlap; and for an LTE-V2X 20 subchannel configuration, there may be an NR-V2X 50 or 25 subchannel configuration with complete overlap.

[0047] This is just an example, but in practice, any number of LTE-V2X and NR-V2X resource pools may be implemented, as there will be multiple LTE-V2X resource pools. LTE-V2X and NR-V2X PRBs may be aligned in both time and frequency to enable such a variety of resource pools.

[0048] During the 3rd Generation Partnership Project (3GPP) Release 14 (Rel-14) and Release 15 (Rel-15), LTE-V2X has been designed to facilitate vehicles to communicate with other nearby vehicles via direct / SL communications. Communication between these vehicles can be carried out using Mode 3 or Mode 4 in LTE-V2X, which Figure 2A and Figure 2B More specifically, Figure 2A shows the long-term evolution secondary link resource allocation mode 3, and Figure 2B LTE secondary link resource allocation mode 4 is shown.

[0049] like Figure 2A As shown in , when in Mode 3, the secondary link radio resources may be scheduled by the base station or evolved Node B (eNB). Therefore, this approach may be available when the vehicle is under cellular coverage. Figure 2B As shown in , when in mode 4, vehicles can autonomously select their sidelink radio resources regardless of whether they are under cellular coverage. When the vehicle is under cellular coverage, the network can decide how to configure the LTE-V2X channel and can notify the vehicle through LTE-V2X configurable parameters. The message may include the carrier frequency of the LTE-V2X channel, the LTE-V2X resource pool, the synchronization reference, the channelization scheme, the number of subchannels per subframe, and the number of RBs per subchannel, etc. When the vehicles are not under cellular coverage, they can replace the LTE-V2X configurable parameters with a preconfigured set of parameters. The LTE-V2X resource pool can indicate the subframes of the channel used for LTE-V2X. Other services (including cellular communications) can use the remaining subframes.

[0050] Autonomous resource selection in Mode 4 can be performed using Release 14 sensing and resource exclusion procedures, where a vehicle reserves selected subchannels for multiple periodically repeating packet transmissions. This in turn can be sensed by other vehicles, thereby influencing the resource selection / exclusion decisions of other vehicles.

[0051] Figure 3 The Long Term Evolution Vehicle-to-Everything subframe slot format for the physical sidelink shared channel and the physical sidelink control channel is shown. LTE-V2X can use single carrier frequency division multiple access (SC-FDMA) and can support 10MHz and 20MHz channels. The channel can be divided into 180kHz resource blocks (RBs), which correspond to 12 subcarriers, 15kHz each. In the time domain, the channel can be organized into 1ms subframes.

[0052] Each subframe may have 14 OFDM symbols (with a normal cyclic prefix). Nine of these symbols may be used to send data, and four of them (such as Figure 3 As shown in , the third, sixth, ninth, and twelfth symbols) can be used to send demodulation reference signals (DMRS) for channel estimation and to combat Doppler effects at high speeds. The last symbol can be used as a guard symbol for timing adjustment and to allow vehicles to switch between transmission and reception between subframes. Each of these subframes can be Figure 3 See the example illustration.

[0053] RBs can be grouped into subchannels. A subchannel may include only RBs within the same subframe. The number of RBs per subchannel may vary and may be configured or preconfigured. Subchannels are used to send data and control information. The data may be organized in a transport block (TB) carried in a physical sidelink shared channel (PSSCH). A TB may contain a complete packet, such as a CAM or BSM. A TB may occupy one or several subchannels, depending on the size of the packet, the number of RBs per subchannel, and the modulation and coding scheme (MCS) used. A TB may be sent using QPSK, 16-QAM, or 64QAM modulation and turbo coding.

[0054] Each TB may have an associated sidelink control information (SCI) message, which may be carried in a physical sidelink control channel (PSCCH). The SCI message may also be referred to as a scheduling assignment (SA). The SCI may occupy 2 RBs and may include information such as an indication of the RBs occupied by the associated TB, the MCS used for the TB, the priority of the message being sent, an indication of whether the message in the TB is the first transmission of the TB or a blind retransmission, and a resource reservation interval. Blind retransmission may refer to a scheduled retransmission or repetition of a TB, rather than a retransmission based on feedback from a receiver. The resource reservation interval may specify when the vehicle will use the reserved subchannel to send the next TB of the vehicle. The SCI may include key information for correctly receiving the TB. If the associated SCI is not received correctly, the TB may not be correctly decoded. The TB and the SCI associated with the TB may be sent in the same subframe.

[0055] Figure 4 LTE-V2X channelization with adjacent and non-adjacent PSCCH and PSSCH is shown. Figure 4As shown in , the TB in the PSSCH and the associated SCI in the PSCCH can be sent in adjacent or non-adjacent subchannels. For adjacent PSCCH and PSSCH, the SCI and TB can be sent in adjacent RBs. For each SCI and TB transmission, the SCI can occupy the first two RBs of the first subchannel used for transmission. The TB can be sent in the RB after the SCI and can occupy several subchannels, depending on the size of the SCI. If the SCI occupies several subchannels, the SCI can also occupy the first two RBs of the subsequent subchannels.

[0056] For non-adjacent PSCCH and PSSCH, RBs can be divided into pools. One pool can be dedicated to sending only SCI, and SCI can occupy two RBs. The second pool can be reserved to send only TBs and can be divided into subchannels.

[0057] To receive the PSCCH, the UE may have to monitor each defined PRB pair to determine whether the PSCCH has been transmitted therein. The power control procedures for the PSSCH and PSCCH are described by way of example in 3GPP Technical Specification (TS) 36.213 Sections 14.1.1.5 and 14.2.1.3, respectively.

[0058] For secondary link transmission mode 4, the UE may send power P for PSSCH transmission in subframe n. PSSCH ,as follows: Among them, P CMAX It can be defined by 3GPP TS 36.101, M PSSCH is the bandwidth of PSSCH resource allocation expressed in the number of resource blocks, M PSCCH =2, and PL = PL c , where PL c It may be defined by 3GPP TS 36.213 Section 5.1.1.1. O_PSSCH,4 and α PSSCH,4 The higher layer parameters p0SL-V2V and alphaSL-V2V may be provided respectively and may be associated with the corresponding PSSCH resource configuration. If the higher layer parameter maxTxpower is configured, then

[0059]

[0060] otherwise

[0061]

[0062] For secondary link transmission mode 4, the UE may send power P for PSCCH transmission in subframe n. PSCCH , which can be obtained by Given, where PCMAX It can be defined by 3GPP TS 36.213, M PSSCH M can be the bandwidth of PSSCH resource allocation expressed in the number of resource blocks. PSCCH =2, and PL = PL c , where PL c Can be defined by Article 5.1.1.1. O_PSSCH,4 and α PSSCH,4 The higher layer parameters p0SL-V2V and alphaSL-V2V may be provided respectively and may be associated with the corresponding PSSCH resource configuration. If the higher layer parameter maxTxpower is configured, then

[0063]

[0064] otherwise

[0065]

[0066] Wherein, P can be based on the priority level of PSSCH and the CBR range including the CBR measured in subframe n-4. MAX_CBR Set to the maxTxpower value.

[0067] Furthermore, the difference in power level between PSSCH and PSCCH can be calculated as:

[0068]

[0069] Therefore, the power spectral density (PSD) (in terms of the power content of the signal versus frequency) of the PSCCH may be improved by 3 dB compared to the corresponding PSSCH.

[0070] An LTE V2X UE can be synchronized to an evolved Node B (eNB), a Global Navigation Satellite System (GNSS), or other V2X UEs with the help of a Secondary Link Synchronization Signal (SLSS). If the highest priority synchronization signal cannot be found, the UE can select a lower priority synchronization source based on a predefined priority order. An LTE V2X UE forwards the synchronization it is using to other UEs using SLSS / PSBCH. Figure 5A The structure of the sidelink synchronization signal / physical sidelink broadcast channel block is shown.

[0071] exist Fig. 6A and Figure 6B The table of provides the priority of synchronization sources when the UE does not detect an eNB that can be used as a synchronization reference and two resources (R1 and R2) are reserved for SLSS / PSBCH. More specifically, Fig. 6AA table showing various priority levels for the case where an evolved Node B is configured as a preferred synchronization source, and Figure 6B A table of various priority levels is shown for the case where a global navigation satellite system is configured as a preferred synchronization source. The SLSS identification may be sent with the primary secondary link synchronization signal (PSSS) / secondary secondary link synchronization signal (SSSS), and in-coverage information may be sent in the PSBCH. The PSBCH may also include information about the channel bandwidth, time division duplex (TDD) configuration, and direct frame number (DFN) in the channel.

[0072] Fig. 7A shows a new radio sub-link resource allocation mode 1, while Figure 7B New radio side link resource allocation mode 2 is shown. During 3GPP Release 16 (Rel-16), NR SL has been designed to facilitate UEs to communicate with other nearby UEs via direct / SL communication. Two resource allocation modes have been specified, and a SL transmitter (TX) UE can be configured with one of the modes to perform its NRSL transmission. These modes are denoted as NRSL Mode 1 ( Fig. 7A ) and NR SL Mode 2 ( Figure 7B In mode 1, the network (NW) may allocate or schedule the secondary link transmission resources to the SL TX UE, while the SL TX UE in mode 2 may autonomously select the SL TX UE's own SL transmission resources.

[0073] In mode 1, where the next generation Node B (gNB) may be responsible for SL resource allocation, the configuration and operation may be similar to that on the Uu interface, such as Fig. 7A The Medium Access Control (MAC) level details of this procedure are given by way of example in Section 5.8.3 of 3GPP TS 38.321.

[0074] In mode 2, the SL UE can autonomously select resources with the help of a sensing process. More specifically, a SL TX UE in NR SL mode 2 can first perform a sensing process on the configured SL transmission resource pool in order to obtain an understanding of the reserved resources by other nearby SLTX UEs. Based on the understanding obtained from the sensing, the SL TX UE can select resources from the available SL resources. In order for the SL UE to perform sensing and obtain the information required to receive the SL transmission, the SL UE may need to decode the SCI. For example, in Release 16, the SCI associated with data transmission includes a first-level SCI and a second-level SCI, and their contents are standardized in 3GPP TS 38.212.

[0075] The SCI may follow a 2-level SCI structure, for example, to support size differences between SCIs for various NR-V2X SL service types such as broadcast, multicast, and unicast. The first level SCI (SCI format 1-A) may be carried by the PSCCH and may contain information to enable sensing operations and / or to determine resource allocations for the PSSCH and information for decoding the second level SCI. The second level SCI (SCI formats 2-A and 2-B) carried by the PSSCH and multiplexed with the SL-SCH may include the following items: source and destination identification, information for identifying and decoding associated SL-SCH TBs, control of hybrid automatic repeat request (HARQ) feedback in unicast / multicast, and / or triggers for channel state information (CSI) feedback in unicast.

[0076] The configuration of resources in the secondary link resource pool may define the minimum information required for the RX UE to be able to decode the transmission. This minimum information may include the number of subchannels, the number of PRBs per subchannel, the number of symbols in the PSCCH, which time slots have PSFCH, and other configuration aspects, which are omitted here for simplicity.

[0077] For each individual transmission, the actual sidelink transmission, payload details may be provided in the PSCCH as the first level SCI. The payload details may include: time and frequency resources, demodulation reference signal (DMRS) configuration of the PSSCH, modulation and coding scheme (MCS), and PSFCH, etc.

[0078] exist Fig. 8A and Figure 8B An example of a SL slot structure is shown in FIG, which illustrates a slot with PSCCH / PSSCH and a slot with PSCCH / PSSCH in which the last symbol is used for PSFCH. More specifically, Fig. 8A The secondary link time slot format with a time slot of a physical secondary link control channel / physical secondary link shared channel is shown, and Figure 8B A secondary link time slot format is shown with time slots for a physical secondary link control channel / physical secondary link shared channel and a physical secondary link feedback channel.

[0079] The configuration of the PSCCH (e.g., DMRS, MCS, and number of symbols used) can be part of the resource pool configuration. In addition, an indication of which time slots have PSFCH symbols can also be part of the resource pool configuration. However, the configuration of the PSSCH (e.g., number of symbols used, DMRS pattern, and MCS) can be provided by the first-level SCI, which can be the payload sent within the PSCCH, and it can follow the configuration shown in Table 8.4.1.1.2-1 of 3GPP TS 38.211. The second SL symbol (which can contain the first PSCCH or PSCCH / PSSCH symbol) can be replicated in the first SL symbol used for automatic gain control (AGC) purposes.

[0080] More specifically, see Table 8.4.1.1.2-1 of 3GPP TS 38.211 for PSSCH DMRS configuration based on the number of symbols used and the duration of PSCCH. In NR V2X, a TX UE may transmit PSSCH and PSCCH with the same power spectral density (e.g., with the same power on a PRB) in all symbols with PSCCH, PSSCH, or PSCCH / PSSCH.

[0081] The NR secondary link synchronization block may include primary and secondary synchronization signals and broadcast channels, as in LTE. Figure 5B The structure of the new radio sidelink synchronization block is shown. Compared to LTE, the DMRS of the PSBCH is transmitted in PSBCH symbols in some resource elements.

[0082] The number of SLSSIDs sent in the S-PSS / S-SSS can be increased from 336 in LTE to 672 in NR. The starting point of the defined priority of synchronization sources is LTE, therefore, Fig.9A and Fig. 9B The table shown in is similar to LTE prioritization. More specifically, Fig.9A A table showing various priority levels for the case where a gNB or an eNB is configured as the preferred synchronization source, and Fig. 9B A table showing various priority levels for the case where a global navigation satellite system is configured as the preferred synchronization source.

[0083] To support V2X deployment scenarios where both LTE-V2X and NR-V2X devices coexist in the same frequency channel, the time slot and subframe boundaries of LTE and NR devices can benefit from alignment. The first symbol of the NR SL time slot and LTE SL subframe can be used to set the AGC level of the receiving UE. If the transmission of the LTE SL UE starts after the NR SL UE has set its own AGC, the reception of the remaining NR symbols may fail because the LTE SL transmission may overload the NR SL UE receiver. Vice versa: if the NR transmission starts after the AGC of the LTE SL UE is set, the NR SL UE transmission may overload the LTE SL receiver.

[0084] In V2X carrier / frequency channels intended for use by both LTE and NR SL devices, the UE may be configured to prioritize the same synchronization source, and the highest priority synchronization source may be GNSS, Global Positioning Satellite (GPS), etc. For ease of reference, any such satellite reference source is shown by GNSS. GNSS cannot be received everywhere, for example, in tunnels and in underground parking lots. In such GNSS out-of-coverage areas, the UE may need to switch to a lower priority synchronization source, which may be a base station or another SL UE that is sending a synchronization signal.

[0085] According to the current specifications, an LTE SL UE can synchronize to eNB and SLSS from another LTE SL UE and GNSS, but the LTE SL UE cannot synchronize to gNB or SLSS from an NR SL UE. On the other hand, in addition to GNSS, if the radio access node has a corresponding Uu interface module, the NR SL UE can also synchronize to eNB or gNB, and to SLSS from another NR SL UE. In these specifications, an NR SL UE cannot synchronize to SLSS from an LTE SL UE. Therefore, if the connection to the primary synchronization source is lost, it is very likely that the NR and LTE SL UEs will not be able to find a common synchronization source.

[0086] Certain embodiments address the problem of synchronizing NR and LTE subframe boundaries when no common synchronization source exists for NR and LTE SL devices.

[0087] from Fig. 6A , Figure 6B , Fig.9A and Fig. 9B As can be seen in the synchronization prioritization table of , common synchronization sources for LTE and NR V2X UEs can include GNSS and eNB. If all UEs in the channel are synchronized to these references, either directly or indirectly via another SL UE, the UE behavior currently defined in the specification may be sufficient.

[0088] The NR UE can detect whether the transmission in the SL channel is from an LTE SLUE based on the frequency domain characteristics of the received signal. In some embodiments, the ability to detect LTE transmissions can be utilized and developed.

[0089] An LTE SL UE may already be deployed in a frequency channel intended for co-existence operation, and the behavior of such a UE may be considered unchangeable from the perspective of the associated user equipment in which certain embodiments may be implemented. For example, an NR SL UE may be configured to detect and adapt to LTE SL subframe boundaries. Certain embodiments may be implemented in an NR SL UE deployed in the same V2X carrier / frequency channel in which an LTE SL UE already exists.

[0090] In certain embodiments, the NR SL UE may be able to detect the subframe boundaries of the LTE SL transmission and may also detect the DFN used by LTE. This may be based on the following. The NR SL UE may have LTE SLSS reception capability and may also have the ability to decode the LTE PSBCH so that the NR SL UE can synchronize to the LTE SL transmission.

[0091] Additionally, the NR SL UE may not have LTE SLSS reception capability, but the NR SL UE can identify LTE SL transmissions based on the time and frequency characteristics of the LTE SL transmissions. In LTE V2X, the PSCCH corresponding to the 24 subcarriers of the 15kHz SCS can be transmitted in the same subframe with a PSD 3dB higher than the PSSCH, as described above. When the NR SL UE discovers a transmission with these frequency characteristics, the NR SL UE can find the starting and ending points of the LTE SL transmission and infer the subframe boundaries of the LTE SL transmission. The last symbol of the LTE V2X transmission can be reserved for a guard period and thus no content may be sent, as described above. The guard period can make it easier to detect the starting and ending points even if multiple consecutive subframes are used for transmission.

[0092] After detecting LTE SL timing synchronization, the NR SL UE can forward the timing synchronization information of the LTE SL UE to other NR SL UEs in the carrier / frequency channel. If the NR UE finds that the difference in synchronization between LTE and the NR SL UE is less than a predefined value (such as the cyclic prefix length), the NR SL UE can omit the forwarding of the timing synchronization. NR S-SSB / PSBCH can be used to forward timing synchronization, especially when it can be detected that the LTE timing has a higher priority than the current NR timing or is the same as the current NR timing.

[0093] If the LTE timing has a lower priority than the current NR timing, a message indicating the offset between the NR and LTE timing may be used and the NR UE may continue to use the current timing of the NR UE.

[0094] An NR SL UE (receiving an NR S-SSB / PSBCH indicating the timing synchronization used by the LTE device) may switch to using the synchronization source based on the predefined priority of the synchronization source in the carrier / frequency channel. Alternatively, if a timing offset message is received, the NR UE may be able to infer which NR SL transmissions or resource pools will conflict with LTE.

[0095] In addition, there may be NR SL UEs in the carrier / frequency channel that may also transmit LTE SLSS. These NR SL UEs may indicate to the LTE SL UEs a synchronization source of higher priority than the source they are currently using. For example, if the NR SL UE is synchronized to a NR SL UE that is using GNSS as a synchronization reference, the NR SL UE may forward its own timing synchronization information using both LTE SLSS and NR SLSS transmissions.

[0096] These processes and operations can be implemented in various ways. The following discussion is a non-limiting example. Regarding timing synchronization based on LTE SLSS reception, there may be an operating mode in which the NR UE is also able to decode the LTE PSBCH so that the NR UE knows the LTE SL DFN and subframe number. The NR UE may even know the resource pools configured or pre-configured for LTE. In this case, the NR UE may know the time instances when the LTE resource pools are not configured and may use these times for NR SL transmissions. Another mode is that the NR SL UE may detect subframe boundaries based solely on LTE SLSS transmissions, and in this case, LTE PSBCH decoding may not be performed.

[0097] In contrast to SLSS detection, subframe boundary detection can be based on the time and frequency characteristics (including PSD characteristics) of the LTE SL signal, as described above. SC-FDMA can be used to transmit the LTE PSCCH and PSSCH so that the PSCCH and PSSCH can be precoded separately. This means that in the time domain, the transmitted signal can include both transmitted quadrature phase shift keying (QPSK) symbols (such as PSCCH) and QPSK / quadrature amplitude modulation (QAM) symbols (such as PSSCH). Compared to normal orthogonal frequency division multiplexing (OFDM), the determination of the start and end points of the LTE SL subframe can be easier because the amplitude variation of the LTE SL signal can be smaller than that of the OFDM signal. The accuracy of subframe boundary timing can be improved by analyzing multiple LTE SL transmissions across multiple subchannels and subframes and then averaging the results.

[0098] In some embodiments, the NR UE may calculate the spread of subframe boundaries and may exclude from the average any LTE UE transmissions whose associated subframe boundary offset is above a threshold, for example, based on maximum propagation delay or relative difference to other LTE UEs. Other ways of detecting outliers are also permitted. In this way, the NR UE can ensure that the NR UE is detecting subframe boundaries that are representative of the majority of LTE UEs, without being biased due to LTE UEs having poor synchronization or other peculiar behavior.

[0099] The DMRS for the LTE PSCCH can also be used to detect the timing of the LTE SL, or to improve the accuracy of the method based on finding the start and end points of the LTE SL transmission. The DMRS sequence for the LTE PSCCH is specified in the standard. Within the standard definition, the only random aspect in the sequence is the cyclic shift value. The transmitting UE can select one of four possible cyclic shift (CS) values ​​for the PSCCH DMRS. The NR UE can associate the received PSCCH with four different CS versions and select the location of the strongest correlation peak, which is also closest to the timing obtained using the start point / end point method. Since the length of the sequence is only 24 elements spaced 15kHz apart, the initial accuracy of the timing may not be good, but the correlations with multiple DMRS sequences can be averaged to obtain more accurate timing information.

[0100] Some SL-SSIDs sent with NR S-PSS / S-SSS may be defined to indicate that the source of the timing is an LTE UE. For example, it may be defined that in a channel used for both LTE and NR SL transmissions, NR SLSS-ID[1,167] indicates that the timing source is from an LTE UE synchronized to an eNB, and SLSS-ID[168,335] indicates that the timing source is an NR UE synchronized to an eNB / gNB. SLSS-IDs for multi-hop may be generated in a specified manner by adding a value of 336 to the one hop value. In addition, one SLSS-ID value may be reserved for GNSS timing obtained from an LTE UE, and another value may be reserved if the GNSS of the LTE UE is forwarded over multiple hops of the LTE UE.

[0101] If the synchronization obtained from the LTE UE has the same or higher priority than the synchronization obtained from the NR UE, the LTE based synchronization should be selected. If the synchronization from the LTE SL UE has a lower priority, the procedure described below can be used.

[0102] As described above, if the LTE synchronization source has a lower priority than the NR UE's synchronization source, it may be better for the NR UE not to switch to using LTE timing. For example, if the NR UE has GNSS coverage, but nearby LTE SL UEs use their internal clocks for synchronization, it may be better to assume that the LTE UEs can also find GNSS after they have moved to a better position for some time. At the same time, the NR UE can detect the LTE synchronization signal and indicate the timing offset between LTE and NR to other nearby NR UEs. In turn, the NR UE can use time slots that completely overlap with the LTE subframes, which can be assumed that NR uses, for example, 0.5ms or shorter time slots for transmission and the LTE subframes are 1ms. In order not to overload the LTE SL UE's receiver, if the NR UE plans to transmit using FDM between LTE and NR in the time slots overlapping with LTE, the NR UE can send some dummy data in the symbols where the LTE UEs are setting their AGC levels.

[0103] The detection of LTE synchronization priority may involve the NR UE being aware of the configuration regarding the priority of the LTE synchronization source. If the NR UE has LTE downlink (DL) reception capability, the NR UE may obtain such information from the eNB, or the NR UE may be pre-configured in the same manner as an LTE SL UE, in which case the NR UE may also obtain such information.

[0104] Fig.10An example flow diagram of a method for providing synchronization of user equipment of different radio access technologies (such as Long Term Evolution and New Radio Side Link) coexisting in the same channel is shown in accordance with certain embodiments.

[0105] Fig.10 Methods according to some embodiments are shown. Fig.10 The method may be performed by a first user equipment, which may be an NR SL UE. The method may include: at 1010, at the first user equipment, receiving a first radio transmission from a second user equipment. The second user equipment may be different from the first user equipment and may be, for example, an LTE SLUE.

[0106] The first radio transmission may be a synchronization signal (SLSS) of the second UE.The first radio transmission may include a PSSCH and a PSCCH of the second UE.

[0107] The method may also include, at 1020, determining a misalignment between a first radio transmission timing of the first UE and a second radio transmission timing of the second UE based on the received first radio transmission.

[0108] Determining the misalignment at 1020 may include, at 1022, determining a start time (t0) and / or end time (t1) of a first radio access technology (RAT) subframe (such as an LTE SL subframe) based on the first radio transmission, and comparing the determined t0 / t1 with a start time of a second RAT slot / subframe (such as an NR SL slot / subframe). Determining the misalignment at 1020 may also or alternatively include, at 1024, detecting a power spectral density (PSD) characteristic of the first radio transmission, deriving a value of at least one of a start time or an end time of a sidelink subframe of the first radio access technology, and comparing the value with a start time of a subframe or slot of the second radio access technology. In this case, the first radio transmission may include an LTE PSSCH and an LTE PSCCH. Determining the misalignment at 1020 may also or alternatively include, at 1026, detecting a SLSS of the first radio transmission.

[0109] Thus, there may be three methods for determining the misalignment or timing difference between LTE and NR SL, or any other timing for the first and second radio transmissions, respectively. The first method shown at 1026 and discussed above may involve the NR UE having LTE SLSS reception capability so that the NR UE can find subframe boundaries in the same manner as the LTE SL UE. The second method shown at 1024 and discussed above may involve the NR UE detecting that the received signal has the PSD characteristics of LTE SL and discovering when the received signal starts and stops. The third method shown at 1028 may involve the NR UE discovering / detecting the LTE PSCCH demodulation reference signal, and based on the DMRS, the NR UE determines the subframe start and end of the LTE SL transmission, as described above. These methods may be alternative or complementary methods.

[0110] At 1030, the method may include sending a second radio transmission to a third UE, which may be an NR SL UE or an LTE SL UE. The transmission to the third UE may indicate the determined misalignment. The first UE, the second UE, and the third UE may operate in the same SL channel or on the same secondary link carrier.

[0111] In some embodiments, the second radio transmission may be a synchronization signal of the first UE, such as a SLSS. In some embodiments, the second radio transmission may include a message sent from the first UE to the third UE.

[0112] Sending the second radio transmission at 1030 may be dependent on a priority associated with the received first radio transmission.The second radio transmission may include a time offset indicative of the determined misalignment.

[0113] Notice, Fig.10 An example embodiment of a method or process is provided. However, certain embodiments are not limited to this example, and other examples are possible as discussed elsewhere herein.

[0114] Fig.11 An example of a system including an apparatus 10 according to an embodiment is shown. In an embodiment, the apparatus 10 may be a node, a host, or a server in a communication network or serving such a network. For example, the apparatus 10 may be a network node, a satellite, a base station, a Node B, an evolved Node B (eNB), a 5G Node B or access point associated with a radio access network (such as an LTE network, 5G or NR), a TRP, a HAPS, an integrated access and backhaul (IAB) node, and / or a WLAN access point. In some example embodiments, the apparatus 10 may be, for example, a gNB or other similar radio node.

[0115] It should be understood that in some example embodiments, the device 10 may include an edge cloud server as a distributed computing system, wherein the server and the radio node may be independent devices that communicate with each other via a radio path or via a wired connection, or they may be located in the same entity that communicates via a wired connection. For example, in certain example embodiments in which the device 10 represents a gNB, it may be configured in a central unit (CU) and distributed unit (DU) architecture that divides the gNB functionality. In such an architecture, the CU may be a logical node that includes gNB functionality (such as user data transmission, mobility control, radio access network sharing, positioning, and / or session management, etc.). The CU may control the operation of the DU over a medium-range interface (referred to as the F1 interface), and the DU may have one or more radio units (RUs) connected to the DU via a fronthaul interface. The DU may be a logical node that includes a subset of the gNB functionality, depending on the functional splitting option. It should be noted that a person of ordinary skill in the art will understand that the device 10 may include Fig.11 Components or features not shown.

[0116] like Fig.11 As shown in the example of , the device 10 may include a processor 12 for processing information and executing instructions or operations. The processor 12 may be any type of general or special purpose processor. In fact, as an example, the processor 12 may include one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), and a processor based on a multi-core processor architecture, or any other processing component. Although Fig.11 A single processor 12 is shown in FIG. 1 , but multiple processors may be used according to other embodiments. For example, it should be understood that in some embodiments, the device 10 may include two or more processors that may form a multiprocessor system that may support multiprocessing (e.g., in which case, the processor 12 may represent a multiprocessor). In some embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0117] Processor 12 may perform functions associated with the operation of device 10, which may include, for example, precoding of antenna gain / phase parameters, encoding and decoding of individual bits that make up a communication message, formatting of information, and overall control of device 10, including processes related to communications or management of communication resources.

[0118] The device 10 may further include or be coupled to a memory 14 (internal or external), which may be coupled to the processor 12 for storing information and instructions that can be executed by the processor 12. The memory 14 may be one or more memories and may be of any type suitable for the local application environment, and may be implemented using any suitable volatile or non-volatile data storage technology (such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and / or removable memory). For example, the memory 14 may include any combination of random access memory (RAM), read-only memory (ROM), static storage devices such as magnetic disks or optical disks, hard disk drives (HDDs), or any other type of non-transitory machine or computer readable media or other suitable storage components. The instructions stored in the memory 14 may include program instructions or computer program code, which, when executed by the processor 12, enables the device 10 to perform tasks as described herein.

[0119] In an embodiment, the device 10 may further include or be coupled to a (internal or external) drive or port configured to accept and read an external computer-readable storage medium, such as an optical disk, a USB drive, a flash drive, or any other storage medium. For example, the external computer-readable storage medium may store a computer program or software for execution by the processor 12 and / or the device 10.

[0120] In some embodiments, the device 10 may also include or be coupled to one or more antennas 15 for sending signals and / or data to the device 10 and receiving signals and / or data from the device 10. The device 10 may further include or be coupled to a transceiver 18, which is configured to send and receive information. The transceiver 18 may include, for example, a plurality of radio interfaces that may be coupled to the antenna 15, or may include any other suitable transceiver components. The radio interface may correspond to a variety of radio access technologies, including one or more of the following: Global System for Mobile Communications (GSM), Narrowband Internet of Things (NB-IoT), LTE, 5G, WLAN, Bluetooth (BT), Bluetooth Low Energy (BT-LE), Near Field Communication (NFC), Radio Frequency Identification (RFID), Ultra Wideband (UWB), MulteFire, etc. The radio interface may include components such as filters, converters (e.g., digital-to-analog converters, etc.), mappers, Fast Fourier Transform (FFT) modules, etc., to generate symbols for transmission via one or more downlinks, and receive symbols (e.g., via uplinks).

[0121] Thus, the transceiver 18 may be configured to modulate information onto a carrier waveform for transmission by the antenna 15, and to demodulate information received via the antenna 15 for further processing by other elements of the apparatus 10. In other embodiments, the transceiver 18 may be capable of directly transmitting and receiving signals or data. Additionally or alternatively, in some embodiments, the apparatus 10 may include input and / or output devices (I / O devices), or input / output components.

[0122] In an embodiment, the memory 14 may store software modules that provide functionality when executed by the processor 12. These modules may include, for example, an operating system that provides operating system functionality for the device 10. The memory may also store one or more functional modules, such as applications or programs, to provide additional functionality to the device 10. The components of the device 10 may be implemented in hardware, or as any suitable combination of hardware and software.

[0123] According to some embodiments, the processor 12 and the memory 14 may be included in a processing circuit / component or a control circuit / component, or may constitute a part of a processing circuit / component or a control circuit / component. In addition, in some embodiments, the transceiver 18 may be included in a transceiver circuit / component, or may constitute a part of a transceiver circuit / component.

[0124] As used herein, the term "circuit" may refer to any portion of a hardware circuit implementation (e.g., analog and / or digital circuits), a combination of hardware circuits and software, a combination of analog and / or digital hardware circuits and software / firmware, a hardware processor (including a digital signal processor) with software that works together to enable a device (e.g., device 10) to perform various functions, and / or a hardware circuit and / or processor, or portion thereof, that uses software to operate but the software may not be present when the operation does not require the software. As a further example, as used herein, the term "circuit" may also cover an implementation of a hardware circuit or processor (or multiple processors), or a portion of a hardware circuit or processor and its accompanying software and / or firmware. The term "circuit" may also cover, for example, a baseband integrated circuit in a server, a cellular network node or device, or other computing or network device.

[0125] As described above, in some embodiments, the device 10 may be a network element or RAN node (such as a base station, access point, Node B, eNB, gNB, TRP, HAPS, IAB node, relay node, WLAN access point, satellite, etc.) or may be a part thereof. In an example embodiment, the device 10 may be a gNB or other radio node, or may be a CU and / or DU of a gNB. According to some embodiments, the device 10 may be controlled by the memory 14 and the processor 12 to perform functions associated with any of the embodiments described herein. For example, in some embodiments, the device 10 may be configured to perform any flowchart or signaling diagram described herein (such as Figures 1A to 10 In some embodiments, as discussed herein, the apparatus 10 may be configured to perform processes related to synchronization of user equipment of different radio access technologies (such as long term evolution and new radio side links) coexisting in the same channel.

[0126] Fig.11 An example of an apparatus 20 according to an embodiment is further shown. In an embodiment, the apparatus 20 may be a node or element in or associated with a communication network, such as a UE, a communication node, a mobile device (ME), a mobile station, a mobile device, a fixed device, an IoT device, or other device. As described herein, a UE may be alternatively referred to as, for example, a mobile station, a mobile device, a mobile unit, a mobile device, a user device, a subscriber station, a wireless terminal, a tablet, a smart phone, an IoT device, a sensor or a NB IoT device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, a medical device and its application (e.g., remote surgery), an industrial device and its application (e.g., a robot and / or other wireless devices operating in the context of an industrial and / or automated processing chain), a consumer electronic device, a device operating on a commercial and / or industrial wireless network, etc. As an example, the apparatus 20 may be implemented in, for example, a wireless handheld device, a wireless plug-in accessory, etc.

[0127] In some example embodiments, the apparatus 20 may include one or more processors, one or more computer-readable storage media (e.g., memory, storage device, etc.), one or more radio access components (e.g., modem, transceiver, etc.), and / or a user interface. In some embodiments, the apparatus 20 may be configured to operate using one or more radio access technologies, such as GSM, LTE, LTE-A, NR, 5G, WLAN, WiFi, NB-IoT, Bluetooth, NFC, MulteFire, and / or any other radio access technology. It should be noted that one of ordinary skill in the art will appreciate that the apparatus 20 may include Fig.11Components or features not shown.

[0128] like Fig.11 As shown in the example of , the device 20 may include a processor 22 for processing information and executing instructions or operations. The processor 22 may be any type of general or special purpose processor. In fact, as an example, the processor 22 may include one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), and a processor based on a multi-core processor architecture. Although Fig.11 A single processor 22 is shown, but multiple processors may be used according to other embodiments. For example, it should be understood that in some embodiments, the device 20 may include two or more processors that may form a multiprocessor system that may support multiprocessing (e.g., in which case, the processor 22 may represent a multiprocessor). In some embodiments, the multiprocessor system may be tightly coupled or loosely coupled (e.g., to form a computer cluster).

[0129] Processor 22 may perform functions associated with the operation of device 20, including, as some examples, precoding of antenna gain / phase parameters, encoding and decoding of individual bits that make up a communication message, formatting of information, and overall control of device 20, including processes associated with management of communication resources.

[0130] The device 20 may further include or be coupled to a memory 24 (internal or external), which may be coupled to the processor 22 for storing information and instructions that can be executed by the processor 22. The memory 24 may be one or more memories and may be of any type suitable for the local application environment, and may be implemented using any suitable volatile or non-volatile data storage technology (such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and / or removable memory). For example, the memory 24 may include any combination of random access memory (RAM), read-only memory (ROM), static storage devices such as magnetic disks or optical disks, hard disk drives (HDDs), or any other type of non-transitory machine or computer readable media. The instructions stored in the memory 24 may include program instructions or computer program codes that, when executed by the processor 22, enable the device 20 to perform tasks as described herein.

[0131] In an embodiment, the device 20 may further include or be coupled to a (internal or external) drive or port configured to accept and read an external computer-readable storage medium, such as an optical disk, a USB drive, a flash drive, or any other storage medium. For example, the external computer-readable storage medium may store a computer program or software for execution by the processor 22 and / or the device 20.

[0132] In some embodiments, the device 20 may also include or be coupled to one or more antennas 25 for receiving downlink signals from the device 20 and transmitting via an uplink. The device 20 may further include or be coupled to a transceiver 28 configured to send and receive information. The transceiver 28 may include a radio interface (e.g., a modem) coupled to the antenna 25. The radio interface may correspond to a variety of radio access technologies, including one or more of the following: GSM, LTE, LTE-A, 5G, NR, WLAN, NB-IoT, Bluetooth, BT-LE, NFC, RFID, UWB, etc. The radio interface may include components such as filters, converters (e.g., digital-to-analog converters, etc.), symbol demappers, signal shaping components, inverse fast Fourier transform (IFFT) modules, etc., to process symbols carried by a downlink or uplink, such as OFDMA symbols.

[0133] Thus, the transceiver 28 may be configured to modulate information onto a carrier waveform for transmission by the antenna 25, and to demodulate information received via the antenna 25 for further processing by other elements of the device 20. In other embodiments, the transceiver 28 may be capable of directly transmitting and receiving signals or data. Additionally or alternatively, in some embodiments, the device 20 may include input and / or output devices (I / O devices). In certain embodiments, the device 20 may further include a user interface, such as a graphical user interface or a touch screen.

[0134] In an embodiment, the memory 24 may store software modules that provide functionality when executed by the processor 22. These modules may include, for example, an operating system that provides operating system functionality for the device 20. The memory may also store one or more functional modules, such as applications or programs, to provide additional functionality for the device 20. The components of the device 10 may be implemented in hardware, or as any suitable combination of hardware and software. According to an example embodiment, the device 20 may optionally be configured to communicate with the device 10 via a wireless or wired communication link 70 according to any radio access technology (such as NR).

[0135] According to some embodiments, the processor 22 and the memory 24 may be included in a processing circuit or a control circuit, or may constitute a part of a processing circuit or a control circuit. In addition, in some embodiments, the transceiver 28 may be included in a transceiver circuit, or may constitute a part of a transceiver circuit.

[0136] As described above, according to some embodiments, the apparatus 20 may be, for example, a UE, a SL UE, a relay UE, a mobile device, a mobile station, a ME, an IoT device, and / or a NB-IoT device, etc. According to some embodiments, the apparatus 20 may be controlled by the memory 24 and the processor 22 to perform functions associated with any of the embodiments described herein, such as Figures 1A to 10 as shown in or concerning Figures 1A to 10 One or more operations described herein, or any other method described herein. For example, in one embodiment, the apparatus 20 may be controlled to perform processes related to providing synchronization of user equipment of different radio access technologies (such as long term evolution and new radio sidelink) coexisting in the same channel, as described in detail elsewhere herein.

[0137] In some embodiments, an apparatus (e.g., apparatus 10 and / or apparatus 20) may include components for performing the methods, processes, or any variants discussed herein. Examples of components may include one or more processors, memories, controllers, transmitters, receivers, and / or computer program codes for causing any operations discussed herein to be performed.

[0138] In view of the above, certain example embodiments provide several technical improvements, enhancements and / or advantages over prior art processes and constitute improvements in at least the field of wireless network control and / or management technology. Certain embodiments may have various benefits and / or advantages. For example, certain embodiments may provide improvements and enhancements to the manner in which synchronization may occur between UEs of different RATs (such as LTE UEs and NRSL UEs). In addition, certain embodiments may permit a UE to obtain timing information from a radio of another RAT without being able to decode bits provided by the other radio. Thus, for example, certain embodiments may utilize radio frequency (RF) characteristics (such as PSD in a received signal) to obtain timing information even in the absence of a common timing source.

[0139] In some example embodiments, the functionality of any method, process, signaling diagram, algorithm, or flow chart described herein may be implemented by software and / or computer program code or code portions stored in a memory or other computer-readable or tangible medium, and may be executed by a processor.

[0140] In some example embodiments, a device may include or be associated with at least one software application, module, unit or entity, which is configured as an arithmetic operation, or as a program or program portion (including added or updated software routines), which can be executed by at least one operating processor or controller. Programs, also known as program products or computer programs, include software routines, applets and macros, which can be stored in any device-readable data storage medium and can include program instructions for performing specific tasks. A computer program product may include one or more computer executable components, which are configured to perform some example embodiments when the program is running. One or more computer executable components may be at least one software code or code portion. Modifications and configurations required to implement the functions of the example embodiments may be performed as routines, which may be implemented as added or updated software routines. In one example, the software routines may be loaded into the device.

[0141] As an example, software or computer program code or code portions may be in source code form, object code form, or some intermediate form, and may be stored in some carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers may include, for example, recording media, computer memory, read-only memory, optoelectronic and / or electrical carrier signals, telecommunication signals, and / or software distribution packages. Depending on the processing power required, the computer program may be executed in a single electronic digital computer or may be distributed among multiple computers. The computer readable medium or computer readable storage medium may be a non-transitory medium.

[0142] In other example embodiments, the functions of the example embodiments may be performed by hardware or circuitry included in a device, such as by using an application specific integrated circuit (ASIC), a programmable gate array (PGA), a field programmable gate array (FPGA), or any other combination of hardware and software. In yet another example embodiment, the functions of the example embodiments may be implemented as signals, such as non-tangible components, which may be carried by electromagnetic signals downloaded from the Internet or other networks.

[0143] According to an example embodiment, an apparatus such as a node, a device or a corresponding component may be configured as a circuit, a computer or a microprocessor, such as a single-chip computer unit, or as a chipset, which may include at least a memory for providing storage capacity for arithmetic operations and / or an operation processor for performing arithmetic operations.

[0144] The example embodiments described herein may apply to both singular and plural implementations, regardless of whether singular or plural language is used in conjunction with describing certain embodiments. For example, an embodiment describing the operation of a single network node may also apply to example embodiments including multiple instances of the network node, and vice versa.

[0145] Those skilled in the art will readily appreciate that the example embodiments described above may be practiced with processes in a different order and / or with hardware units that are different from the disclosed configurations. Therefore, although some embodiments have been described based on these example embodiments, it will be apparent to those skilled in the art that certain modifications, variations, and alternative configurations will be apparent while still within the spirit and scope of the example embodiments.

[0146] Partial glossary:

[0147] AGC Automatic Gain Control

[0148] BSM Basic Safety Message

[0149] CA Carrier Aggregation

[0150] CAM Collaborative Awareness Message

[0151] DC Dual Connection

[0152] DFN Direct Frame Number

[0153] DMRS demodulation reference signal

[0154] HARQ Hybrid Automatic Repeat Request

[0155] MCS modulation and coding scheme

[0156] OFDM Orthogonal Frequency Division Multiplexing

[0157] PRB Physical Resource Block

[0158] PSBCH Physical Sidelink Broadcast Channel

[0159] PSCCH Physical Secondary Link Control Channel

[0160] PSD power spectral density

[0161] PSFCH Physical Secondary Link Feedback Channel

[0162] PSSCH Physical Secondary Link Shared Channel

[0163] QPSK Quadrature Phase Shift Keying

[0164] QAM Quadrature Amplitude Modulation

[0165] RP Resource Pool

[0166] RX Receiver

[0167] SCI Sublink Control Information

[0168] SA Scheduling Allocation

[0169] SCS Subcarrier Spacing

[0170] SL Secondary Link

[0171] SLSS Secondary Link Synchronization Signal

[0172] TB Transfer Block

[0173] TX Transmitter

[0174] U2N UE to Network Relay

[0175] V2X Vehicle to Everything

Claims

1. A device comprising: at least one processor; as well as at least one memory including computer program code, The at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to at least: At a first user equipment, receiving a first radio transmission from a second user equipment; determining, based on the received first radio transmission, a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment; and A second radio transmission indicating the determined misalignment is sent to a third user equipment.

2. The device according to claim 1, wherein: The first user equipment, the second user equipment and the third user equipment are configured to operate in the same secondary link channel or on the same secondary link carrier.

3. The device according to claim 1, wherein: The first radio transmission comprises a synchronization signal for the second user equipment.

4. The device according to claim 1, wherein: The first radio transmission includes a physical side link shared channel, a physical side link control channel, or both the physical side link shared channel and the physical side link control channel of the second user equipment.

5. The device according to claim 1, wherein: Determining the misalignment includes determining a value of at least one of a start time or an end time of a sidelink subframe of a first radio access technology based on the first radio transmission, and comparing the value to a start time of a subframe or time slot of a second radio access technology.

6. The device according to claim 1, wherein: Determining the misalignment includes: detecting a power spectral density characteristic of the first radio transmission, deriving a value of at least one of a start time or an end time of a side link subframe of the first radio access technology, and comparing the value with a start time of a subframe or time slot of a second radio access technology.

7. The device according to claim 1, wherein: The second radio transmission comprises a synchronization signal for the first user equipment.

8. The device according to claim 1, wherein: The second radio transmission comprises a message sent from the first user equipment to the third user equipment.

9. The device according to claim 1, wherein: Sending the second radio transmission is dependent on a priority level associated with the first radio transmission.

10. The device according to claim 1, wherein: The second radio transmission includes a timing offset indicative of the misalignment.

11. A method comprising: At a first user equipment, receiving a first radio transmission from a second user equipment; determining, based on the received first radio transmission, a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment; as well as A second radio transmission indicating the determined misalignment is sent to a third user equipment.

12. The method according to claim 11, wherein: The first user equipment, the second user equipment and the third user equipment operate in the same secondary link channel or on the same secondary link carrier.

13. The method according to claim 11, wherein: The first radio transmission comprises a synchronization signal for the second user equipment.

14. The method according to claim 11, wherein: The first radio transmission includes a physical side link shared channel, a physical side link control channel, or both the physical side link shared channel and the physical side link control channel of the second user equipment.

15. The method according to claim 11, wherein: Determining the misalignment includes determining a value of at least one of a start time or an end time of a sidelink subframe of a first radio access technology based on the first radio transmission, and comparing the value to a start time of a subframe or time slot of a second radio access technology.

16. The method according to claim 11, wherein: Determining the misalignment includes: detecting a power spectral density characteristic of the first radio transmission, deriving a value of at least one of a start time or an end time of a side link subframe of the first radio access technology, and comparing the value with a start time of a subframe or time slot of a second radio access technology.

17. The method according to claim 11, wherein: The second radio transmission comprises a synchronization signal for the first user equipment.

18. The method according to claim 11, wherein: The second radio transmission comprises a message sent from the first user equipment to the third user equipment.

19. The method according to claim 11, wherein: Sending the second radio transmission is dependent on a priority level associated with the first radio transmission.

20. The method according to claim 11, wherein: The second radio transmission includes a timing offset indicative of the misalignment.

21. An apparatus comprising: means for receiving, at a first user equipment, a first radio transmission from a second user equipment; means for determining, based on the received first radio transmission, a misalignment between a first radio transmission timing of the first user equipment and a second radio transmission timing of the second user equipment; as well as Means for sending a second radio transmission indicating the determined misalignment to a third user equipment.

22. The device according to claim 21, wherein The first user equipment, the second user equipment and the third user equipment are configured to operate in the same secondary link channel or on the same secondary link carrier.

23. The device according to claim 21, wherein The first radio transmission comprises a synchronization signal for the second user equipment.

24. The device according to claim 21, wherein The first radio transmission includes a physical side link shared channel, a physical side link control channel, or both the physical side link shared channel and the physical side link control channel of the second user equipment.

25. The device according to claim 21, wherein Determining the misalignment includes determining a value of at least one of a start time or an end time of a sidelink subframe of a first radio access technology based on the first radio transmission, and comparing the value to a start time of a subframe or time slot of a second radio access technology.

26. The device according to claim 21, wherein Determining the misalignment includes: detecting a power spectral density characteristic of the first radio transmission, deriving a value of at least one of a start time or an end time of a side link subframe of the first radio access technology, and comparing the value with a start time of a subframe or time slot of a second radio access technology.

27. The device according to claim 21, wherein The second radio transmission comprises a synchronization signal for the first user equipment.

28. The device according to claim 21, wherein The second radio transmission comprises a message sent from the first user equipment to the third user equipment.

29. The device according to claim 21, wherein Sending the second radio transmission is dependent on a priority level associated with the first radio transmission.

30. The device according to claim 21, wherein The second radio transmission includes a timing offset indicative of the misalignment.

31. A computer program product encoded with instructions for performing the method according to any one of claims 11-20.

32. A non-transitory computer readable medium encoded with instructions that, when executed in hardware, perform the method according to any one of claims 11-20.

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