WO2018042373A2

WO2018042373A2 - Methods for signaling or receiving cell identity, network identity, and time hopping patterns

Info

Publication number: WO2018042373A2
Application number: PCT/IB2017/055252
Authority: WO
Inventors: Yi-Pin Eric Wang; Cagatay Capar; Jung-Fu Cheng; Havish Koorapaty; Xingqin LIN; Amitav Mukherjee
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2016-09-01
Filing date: 2017-08-31
Publication date: 2018-03-08
Also published as: WO2018042373A3; AR109491A1

Abstract

Systems and methods for signaling or receiving cell identity, network identity, and/or Time Hopping (TH) patterns are disclosed. In some embodiments, a method of operating a wireless device in a wireless communication network includes obtaining a signal transmitted from a network node and determining a physical cell Identity (ID) of the network node based on the signal. The method also includes determining a TH pattern of the network node based on the determined physical cell ID of the network node. In this manner, the wireless device can efficiently determine the TH pattern used and may be able to determine if the wireless device should connect to the network node.

Description

METHODS FOR SIGNALING OR RECEIVING CELL IDENTITY, NETWORK IDENTITY, AND TIME HOPPING PATTERNS

Related Applications

[0001] This application claims the benefit of provisional patent application serial number 62/382,556, filed September 1 , 2016, the disclosure of which is hereby incorporated herein by reference in its entirety.

Technical Field

[0002] The present disclosure relates to a method for signaling or receiving cell identity, network identity, and/or time hopping patterns as well as

determining time hopping patterns.

Background

[0003] The Internet of Things (loT) is a vision for the future world where everything that can benefit from a connection will be connected. Cellular technologies are being developed or evolved to play an indispensable role in the loT world, particularly Machine Type Communication (MTC). MTC is characterized by lower demands on data rates than, for example, mobile broadband, but with higher requirements on, e.g., low cost device design, better coverage, and ability to operate for years on batteries without charging or replacing the batteries. To meet the loT design objectives, Third Generation Partnership Project (3GPP) has standardized Narrowband loT (NB-loT) in Release (Rel) 13 that has a system bandwidth of 180 kilohertz (kHz) and targets improved coverage, long battery life, low complexity communication design, and network capacity that is sufficient for supporting a massive number of devices.

[0004] To further increase the market impact of NB-loT, extending its deployment mode to unlicensed band operation is being considered. For example, in the United States of America (US), the 915 megahertz (MHz) and 2.4 gigahertz (GHz) Industrial, Scientific, and Medical (ISM) bands may be considered, and in Europe (EU) the 868 MHz Short Range Device (SRD) band may be considered. However, an unlicensed band has specific regulations to ensure different systems can co-exist in the band with good performance and fairness. This requires certain modifications to Rel-13 NB-loT for it to comply with the regulations. In the EU 868 MHz SRD band, a transmitter using a higher power level is subject to a duty factor limitation. For example, a transmitter with 27 decibel-milliwatt (dBm) Equivalent Isotropically Radiated Power (EIRP) is subject to a 10% duty factor limitation. Such a transmitter is ON for no more than 10% of the time and OFF for at least 90% of the time. Summary

[0005] Systems and methods for signaling or receiving cell identity, network identity, and/or Time Hopping (TH) patterns are disclosed. In some

embodiments, a method of operating a wireless device in a wireless

communication network includes obtaining a signal transmitted from a network node and determining a physical cell Identity (ID) of the network node based on the signal. The method also includes determining a TH pattern of the network node based on the determined physical cell ID of the network node. In this manner, the wireless device can efficiently determine the TH pattern used and may be able to determine if the wireless device should connect to the network node.

[0006] In some embodiments, determining the TH pattern based on the physical cell ID includes determining the TH pattern based on each physical cell ID corresponding to a unique TH pattern. In some embodiments, there are 504 possible physical cell IDs and 504 corresponding TH patterns.

[0007] In some embodiments, determining the TH pattern based on the physical cell ID includes determining the TH pattern which can be shared between different physical cell IDs. In some embodiments, determining the TH pattern based on the physical cell ID includes determining m%K = k where m is the physical cell ID, K is a number of unique TH patterns, and k is the TH pattern associated with the physical cell ID. [0008] In some embodiments, the method also includes determining a network ID of the network node based on the signal obtained from the network node and, in response to determining that the network ID is part of a network able to be accessed by the wireless device, determining the TH pattern based on the physical cell ID and the network ID.

[0009] In some embodiments, the method also includes, in response to determining that the network ID is not part of a network able to be accessed by the wireless device, refraining from receiving a System Information Block (SIB) from the network node.

[0010] In some embodiments, determining the TH pattern based on the physical cell ID includes determining the TH pattern based on the physical cell ID and a predefined network ID for the wireless device; and the method also includes, in response to determining that the determined TH pattern matches the TH pattern of the network node, determining that the network node is part of a network able to be accessed by the wireless device.

[0011] In some embodiments, the method also includes, in response to determining that the determined TH pattern does not match the TH pattern of the network node, refraining from receiving a SIB from the network node.

[0012] In some embodiments, obtaining the signal transmitted from a network node includes obtaining a Master Information Block (MIB) that includes the network ID of the network node.

[0013] In some embodiments, obtaining the signal transmitted from the network node includes obtaining a Narrowband Secondary Synchronization Signal (NSSS) used in an unlicensed spectrum. In some embodiments, obtaining the signal transmitted from the network node includes obtaining the signal in the 868 megahertz (MHz) Short Range Device (SRD) band.

[0014] In some embodiments, a wireless device includes at least one processor and memory. The memory contains instructions whereby the wireless device is operative to obtain a signal transmitted from a network node in a wireless communication network; determine a physical cell ID of the network node based on the signal obtained from the network node; and determine a TH pattern of the network node based on the determined physical cell ID of the network node.

[0015] In some embodiments, methods of signaling or receiving cell identity, network identity, and TH patterns for Narrowband Internet of Things (NB-loT) operation in an unlicensed band are disclosed. In some embodiments, the same signaling capability of Release (Rel) 13 NB-loT NSSS, which supports 504 Physical Cell Identities (PCIDs), is used. In some embodiments, each PCID is mapped to one unique TH pattern. In some embodiments, the TH pattern is also determined by the PCID; however, the same hopping patterns may be shared by one or more PCIDs. In some embodiments, the TH pattern is determined by both PCID and Network Identifier (NetID). In some

embodiments, the TH pattern is not determined by the NetID, but the NetID is carried in the MIB instead of the legacy SIB. According to some embodiments, this allows the User Equipment device (UE) to identify whether the acquired cell belongs to its subscribed network at an earlier stage than in legacy Long Term Evolution (LTE). This is especially important for unlicensed operation as multiple networks may share the same band. Combinations of one or more embodiments described above may also be considered.

[0016] Depending on the combination of embodiments, additional advantages may include: PCID based TH patterns randomize inter-cell interference and avoid persistent interference; NetID based TH patterns randomize inter-network interference and avoid persistent interference; a UE can acquire hopping patterns during an early phase of the initial acquisition process, e.g. by reading the MIB instead of the lengthy SIB, which helps the UE save power and time by aborting a connection attempt to an unsubscribed network sooner; and proposed solutions reuse Rel-13 NB-loT NSSS waveforms while addressing the important considerations of unlicensed band operation.

[0017] Systems and methods to implement TH for meeting duty factor requirements are also disclosed. In some embodiments, the ON periods of each transmitter are randomized to avoid persistent interference between transmitters. In some embodiments, such a design can be thought of as a TH design in the sense that the ON periods "hop" between cycles. In some embodiments, TH is used in frequency bands that have duty factor limitation. In this way, persistent interference can be avoided when two transmitters sharing the unlicensed band are both active.

[0018] In some embodiments, a method of operating a network node in a wireless communication network includes determining a TH pattern to use with transmissions and transmitting only once during an ON-OFF cycle comprising a number of dwell slots, where the dwell slot of the transmission is based on the TH pattern of the network node. In some embodiments, transmitting only once during the ON-OFF cycle includes transmitting during the same dwell slot in multiple ON-OFF cycles.

[0019] In some embodiments, transmitting only once during the ON-OFF cycle includes scheduling downlink transmissions for one or more wireless devices during the ON dwell slots corresponding to the TH pattern of the network node. The method also includes scheduling uplink transmissions for one or more wireless devices during the OFF dwell slots corresponding to the TH pattern of the network node.

[0020] In some embodiments, a System Frame Number (SFN) increases during the dwell slots corresponding to the TH pattern, but the SFN stops increasing during the dwell slots not corresponding to the TH pattern of the network node. In some embodiments, the SFN increases during the dwell slots corresponding to the TH pattern and during the dwell slots not corresponding to the TH pattern. In some embodiments, transmitting includes transmitting in an unlicensed spectrum. In some embodiments, transmitting includes transmitting in the 868 MHz SRD band.

Brief Description of the Drawings

[0021] The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure and the accompanying claims. [0022] Figure 1 illustrates a cellular communications network according to some embodiments of the present disclosure;

[0023] Figures 2A and 2B illustrate Time Hopping (TH) configurations according to some embodiments of the present disclosure;

[0024] Figure 3 illustrates a process for determining parameters of a cell according to some embodiments of the present disclosure;

[0025] Figures 4 through 8 illustrate processes for determining parameters of a cell according to some embodiments of the present disclosure;

[0026] Figure 9 illustrates a process for determining parameters of a cell according to some embodiments of the present disclosure;

[0027] Figures 10 and 1 1 illustrate TH configurations according to some embodiments of the present disclosure;

[0028] Figures 12 and 13 illustrate ways to number system frames according to some embodiments of the present disclosure;

[0029] Figure 14 is a diagram of a network node according to some embodiments of the present disclosure;

[0030] Figure 15 is a schematic block diagram of a network node according to some embodiments of the present disclosure;

[0031] Figure 16 is a diagram of a wireless device according to some embodiments of the present disclosure;

[0032] Figure 17 is a diagram of a network node including modules according to some embodiments of the present disclosure; and

[0033] Figure 18 is a diagram of a wireless device including modules according to some embodiments of the present disclosure.

Detailed Description

[0034] The embodiments set forth below represent information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure.

[0035] Any two or more embodiments described in this document may be combined in any way with each other. Furthermore, even though the examples herein are given in the Internet of Things (loT) context, the embodiments described herein are not limited to loT and can also apply in a more general case when a network node or User Equipment device (UE) may need to signal or receive cell identity, network identity, and/or Time Hopping (TH) patterns.

[0036] In some embodiments, a non-limiting term "UE" is used. The UE herein can be any type of wireless device capable of communicating with a network node or another UE over radio signals. The UE may also be a radio communication device, a target device, a Device-to-Device (D2D) UE, a machine type UE, a UE capable of Machine-to-Machine communication (M2M), a sensor equipped with a UE, an iPad, a tablet, a mobile terminal, a smart phone, a smart watch, a wearable, Laptop Embedded Equipment (LEE), Laptop Mounted Equipment (LME), a Universal Serial Bus (USB) dongle, Customer Premises Equipment (CPE), etc.

[0037] Also, in some embodiments, generic terminology "network node" is used. It can be any kind of network node which may be comprised of a radio network node such as a base station, a radio base station, a base transceiver station, a base station controller, a network controller, an enhanced or evolved Node B (eNB), a Node B, a Multimedia Broadcast/Multicast Service (MBMS) Coordination Entity (MCE), a relay node, an access point, a radio access point, a Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., a Mobility Management Entity (MME), a Self-Organizing Network (SON) node, a coordinating node, etc.), or even an external node (e.g., a third party node, a node external to the current network), etc.

[0038] The term "radio node" used herein may be used to denote a UE or a radio network node.

[0039] The embodiments are applicable to single carrier as well as to multicarrier or Carrier Aggregation (CA) operation of the UE in which the UE is able to receive and/or transmit data to more than one serving cells. The term CA is also called (e.g., interchangeably called) "multi-carrier system," "multi-cell operation," "multi-carrier operation," "multi-carrier transmission," and/or reception. In CA, one of the Component Carriers (CCs) is the Primary

Component Carrier (PCC) or simply primary carrier or even anchor carrier. The remaining CCs are called Secondary Component Carriers (SCCs) or simply secondary carriers or even supplementary carriers. The serving cell is interchangeably called a Primary Cell (PCell) or Primary Serving Cell (PSC). Similarly the secondary serving cell is interchangeably called a Secondary Cell (SCell) or Secondary Serving Cell (SSC).

[0040] The term "signaling" used herein may comprise any of: high-layer signaling (e.g., via Radio Resource Control (RRC)), lower-layer signaling (e.g., via a physical control channel or a broadcast channel), or a combination thereof. The signaling may be implicit or explicit. The signaling may further be unicast, multicast, or broadcast. The signaling may also be directly to another node or via a third node.

[0041] The term "signal transmission" used herein may refer to a certain type of periodic signal that is transmitted by the network node in downlink or by the UE in the uplink. The signal transmission may comprise a physical signal or a physical channel or both. The physical signal does not carry higher layer information whereas the physical channel carries higher layer information.

These signals are used by the network node and/or by the UE for performing one or more operations.

[0042] Figure 1 illustrates a cellular communications network 10 in which embodiments of the present disclosure can be implemented. In some

embodiments, the cellular communications network 10 includes a Radio Access Network (RAN) (e.g., an Evolved Universal Mobile Telecommunications System (UMTS) RAN (E-UTRAN) for Long Term Evolution (LTE)) including at least one base station 12 (sometimes referred to herein as a "network node 12") providing a cell of the cellular communications network 10. The network node 12 provides radio access to a UE 14 located within the respective cell. The network node 12 may be communicatively coupled via a base station to a base station interface (e.g., an X2 interface in LTE), to another base station, or to another network node. Further, in some embodiments, the network node 12 is connected to a core network (e.g., an Evolved Packet Core (EPC) in LTE) via corresponding interfaces (e.g., S1 interfaces in LTE). The core network includes various core network nodes such as, e.g., MMEs, Serving Gateways (S-GWs), and Packet Data Network (PDN) Gateways (P-GWs), as will be appreciated by one of ordinary skill in the art.

[0043] Narrowband loT (NB-loT) is a radio access technology introduced in Third Generation Partnership Project (3GPP) Release (Rel) 13 targeting specifically the loT and Machine Type Communication (MTC) use cases. It has a system bandwidth of 180 kilohertz (kHz) and achieves improved coverage, long battery life, and network capacity that is sufficient for supporting a massive number of devices. It further allows low complexity communication design and facilitates low UE module cost.

[0044] Currently, extending NB-loT deployment to unlicensed band operation is being considered. For example, in the United States of America (US), the 915 megahertz (MHz) and 2.4 gigahertz (GHz) Industrial, Scientific, and Medical (ISM) bands may be considered. The 915 MHz ISM band in the US spans over 902-926 MHz, and the 2.4 GHz ISM band starts from 2.4 GHz and goes up to 2.4835 GHz. However, an unlicensed band has specific regulations to ensure different systems can co-exist in the band with good performance and fairness. This requires certain modifications of the Rel-13 NB-loT for it to comply with the regulations. In the European (EU) 868 MHz Short Range Device (SRD) band, a transmitter using a higher power level is subject to a duty factor limitation. For example, a transmitter with 27 decibel-milliwatt (dBm) Equivalent Isotropically Radiated Power (EIRP) is subject to a 10% duty factor limitation. Such a transmitter is ON for no more than 10% of the time and OFF for at least 90% of the time. Considering the prevalent interference situation in an unlicensed band, it is advantageous to randomize the ON periods of each transmitter to avoid persistent interference between transmitters. Such a design can be thought of as a TH design in the sense that the ON periods "hop" between cycles. An example of one ON-OFF cycle consisting of ten dwell slots is shown in Figure 2A.

Examples of two network nodes 12 using different hopping patterns are shown in Figure 2B. As shown, a transmitter transmits during one and only one of the dwell slots during one ON-OFF cycle. The dwell slot chosen in an ON-OFF cycle is based on a pseudo-random pattern, referred to as the TH pattern.

[0045] In the discussion below, N is the number of dwell slots. Figure 2A shows an example where N = 10, with dwell slots labeled with indices 1, 2, "·,10.

[0046] A TH pattern is an ordering of dwell slot indices. A TH pattern may be designed to be repetitive, i.e., the ordering of dwell slot indices repeats itself after a certain number of ON-OFF cycles ("hops"). Suppose Q is a pseudo-random hopping pattern with a periodicity of T ON-OFF cycles. In that case, Q can be written as

Q = (t^, ... , ^), ^ 6 {1. ... .. N}

where each ON dwell slot is represented by an integer from 1 to N. Integer n means that the transmitter uses the nth dwell slot within an ON-OFF cycle. For example, for N = 10, T = 10, (3, 8, 5, 1, 7, 9, 2, 6, 10, 4) represents one possible TH pattern, where, in the first ON-OFF cycle, the transmitter transmits only during dwell slot #3; in the second ON-OFF cycle, the transmitter transmits only during dwell slot #8, and so on. After T ON-OFF cycles are over, the hopping pattern is repeated. For the preceding example, in the eleventh ON-OFF cycle, the transmitter returns to the beginning of the TH pattern and transmits only during dwell slot #3, and so on. In general, T is a design choice, and does not necessarily equal N. In one non-limiting example, T is chosen as an integer multiple of N. When TH is adopted, the hopping pattern used in a cell should be signaled to the UE 14 so that the UE 14 and the network node 12 are perfectly synchronized regarding which hopping channel is used at any given time. Some embodiments included herein reuse the Rel-13 NB-loT Narrowband Secondary Synchronization Signal (NSSS) waveforms. To differentiate from Rel-13 NB-loT, this disclosure adds a suffix "U" when describing the version of NB-loT that is intended for unlicensed band operation. For example, NB-loT-U represents such a system, and PCID-U is the Physical Cell Identity (PCID) of a NB-loT-U cell.

[0047] Figure 3 illustrates a process for determining parameters of a cell according to some embodiments of the present disclosure. The network node 12 broadcasts a signal which is obtained by the UE 14 (step 100). The UE 14 determines a physical cell Identity (ID) of the network node 12 based on the signal obtained from the network node 12 (step 102). The UE 14 then

determines a TH pattern of the network node 12 based on the determined physical cell ID of the network node 12. Some examples of these steps are discussed below.

[0048] Figure 4 illustrates processes for determining parameters of a cell according to some embodiments of the present disclosure. In NB-loT, NSSS is used to signal the cell ID and the 80 millisecond (ms) framing information. 504 PCIDs can be supported, each mapped to specific NSSS waveforms. In some embodiments, illustrated in Figure 4, NSSS-U adopts the same waveforms as NSSS and also supports 504 PCID-Us. The network node 12 broadcasts a NSSS-U containing the PCID-U of the cell (step 200). By detecting the NSSS-U, the UE 14 learns the PCID-U of the cell (step 202). In these embodiments, there are 504 TH patterns and each PCID-U is mapped to a unique TH pattern. Thus, after the UE 14 learns the PCID-U from NSSS, the UE 14 knows the TH pattern (step 204).

[0049] Figure 5 illustrates processes for determining parameters of a cell according to some embodiments of the present disclosure. In some

embodiments, illustrated in Figure 5, NSSS-U adopts the same waveforms as NSSS and also supports 504 PCID-Us. The network node 12 broadcasts a

NSSS-U containing the PCID-U of the cell (step 300). By detecting the NSSS-U, the UE 14 learns the PCID-U of the cell (step 302). In this embodiment, there are K hopping patterns, K < 504, and one hopping pattern is shared by multiple PCID-Us. For example, hopping pattern k, 0≤ k≤ K - l \s used by PCID-U m, 0≤ m≤ 503, if the remainder of m divided by K is equal to k, i.e. m%K = k. As in the previous embodiments, once the UE 14 knows PCID-U, the UE 14 figures out the TH pattern (step 304).

[0050] Figure 6 illustrates processes for determining parameters of a cell according to some embodiments of the present disclosure. In some

embodiments, the TH pattern is determined by both PCID-U and a Network Identifier (NetlD-U). The NetID is similar to the Public Land Mobile Network (PLMN) ID used in other wireless communications networks. It is used to identify the mobile operator providing services in the cell. Unlike the licensed band operation, NB-loT-U may be deployed by multiple operators in the same region using the same portion of the unlicensed spectrum. In an NB-loT network, a UE 14 in an extreme coverage-limited condition may take up to a few minutes to acquire the complete system information. In this case, it is important that the UE 14 identifies whether a cell belongs to its own operator early on during the initial acquisition process.

[0051] Figure 6 illustrates processes for determining parameters of a cell according to some embodiments of the present disclosure. For example, the 504 PCIDs signaled in NSSS can be mapped to 504 different combinations of NetlD- U and PCID-U. Assume M₁ NetlD-U can be supported and each supports M₂ = 504/Mi PCID-U. The NetlD-U, η¾, and PCID-U, m₂, can be determined based on the ID number, ID, 0, 1 , or 503, carried in NSSS,

ID

mⁱ = w

m₂ = ID%M₂

[0052] The above formulas illustrate just one example. Any one-to-one mapping from PCID-U to (m₁, m₂) is valid.

[0053] As shown in Figure 6, the network node 12 broadcasts a NSSS-U containing the identity number of the cell (step 400). The UE 14 determines both the NetlD-U and the PCID-U of the cell (step 402). In this case, the UE 14 learns whether the NSSS is transmitted from a network able to be accessed by the UE 14, e.g., a cell in its operator's network, through detecting the NetlD-U carried in the NSSS. In some embodiments, if the NetlD-U does not match its operator's identity, the UE 14 shall continue searching for a synchronization signal until a NSSS that carries a NetlD-U matching its operator's identity is found.

[0054] The hopping pattern is determined jointly by NetlD-U, m₁, and PCID-U, m₂ (step 404). In some embodiments, there could be 504 hopping patterns, each corresponding to one combination of NetlD-U, m₁, and PCID-U, m₂.

[0055] Figure 7 illustrates another process for determining parameters of a cell according to some embodiments of the present disclosure. As an example, this embodiment supports up to 504 PCID-U, and up to 504 NetlD-U. In this embodiment, illustrated in Figure 7, the network node 12 broadcasts a NSSS-U containing the PCID-U of the cell (step 500). In some embodiments, the NSSS carries the information about PCID-U, m₂, reusing the same Rel-13 NSSS waveforms. The hopping pattern is determined based on

q = (m₁ + m₂) modulo 504, where m₁ is the NetlD-U. In this case, the UE 14 learns PCID-U, m₂ , from NSSS, and uses its operator's NetlD-U, m₁, which is known a priori, and, for example, stored in the Subscriber ID Module or

Subscriber Identification Module (SIM), implemented either in software or hardware (step 502), to figure out the value of hopping pattern q (step 504). If the NSSS is transmitted by another operator with a different NetlD-U, e.g. m₂ the hopping pattern q = (m₁ + m₂) modulo 504 determined by the UE 14 would be different from the hopping pattern, q' = (m₁ + m₂ ) modulo 504, used in the cell that transmits the received NSSS signal. In this case, the UE 14 will not be synchronized with the hopping pattern used in the cell, and will not be able to read the Master Information Block (MIB) successfully. In some embodiments, this allows the UE 14 to abort further reading the system information in this cell and continue to search for a cell that belongs to its subscribed network.

[0056] These formulas are merely one example and the current disclosure is not limited thereto. Given m_±, any one-to-one mapping from m₂ to hopping pattern is valid.

[0057] Any embodiments discussed herein can be adapted to work with a number of hopping patterns that are fewer than 504. For example, if the number of hopping patterns is less than 504, the mapping presented above can be used to map the ID, 0, 503, signaled in NSSS to the hopping pattern. The PCID-U and NetlD-U are determined based on the ID value carried in NSSS, e.g., by the method presented above. This creates a mapping between the combination of (PCID-U, NetlD-U) and the hopping pattern.

[0058] Similarly, the modulo sum of (m₁ + m₂) modulo 504 can be used to determine a hopping pattern q based on:

q = ((m₁ + m₂) modulo 504) modulo K, where K is the number of hopping patterns.

[0059] In some embodiments, the hopping pattern is only determined by PCID-U, not by NetlD-U. In a legacy LTE system, the PLMN ID is carried in SIB #1 , known as SIB1 . The initial system acquisition procedure requires the UE 14 to read MIB first to learn the scheduling information of SIB1. Thus, it takes additional time for the UE 14 to acquire the PLMN ID after acquiring the MIB. In this embodiment, illustrated in Figure 8, in an NB-loT-U system, the information about NetlD-U is included as a part of MIB (step 600). This allows the UE 14 to identify whether the acquired cell belongs to its subscribed network (step 602) without potentially going through a lengthy reception of SIB1 if the UE 14 is in an extremely coverage limited condition (step 604), for example. In other words, if the UE 14 is not subscribed to the network, the UE 14 refrains from further receiving the SIB1.

[0060] Combinations of one or more embodiments described above may also be considered.

[0061] As mentioned above, when two transmitters use the same ON period, a receiver will experience interference from the undesired transmitter. The two transmitters may be from different networks and thus their radiated powers may not be coordinated. As a result, the interference could cause significant performance degradation.

[0062] Considering the prevalent interference situation in an unlicensed band, it is advantageous to randomize the ON periods of each transmitter to avoid persistent interference between transmitters or even completely avoid

interference between two transmissions if they use orthogonal hopping patterns and are time synchronized. In some embodiments, uplink and downlink partition and system frame numbering methods are provided. In this way, persistent interference can be avoided when two transmitters sharing the unlicensed band are both active.

[0063] In some embodiments, one ON-OFF cycle can be divided into a number of dwell slots, and a transmitter transmits during one and only one dwell slot as is shown in Figures 2A and 2B. The location of the ON dwell slot may be changed in different ON-OFF cycles.

[0064] Examples of two network nodes 12 using different hopping patterns are shown in Figure 2B. As shown, a transmitter transmits during one and only one of the dwell slots during one ON-OFF cycle. In some embodiments, the dwell slot chosen in an ON-OFF cycle is based on a TH pattern. These TH patterns can be completely orthogonal patterns, or non-orthogonal patterns with low cross correlations, or a mix of orthogonal patterns and non-orthogonal patterns with low cross correlations.

[0065] Figure 9 illustrates a process for determining parameters of a cell according to some embodiments of the present disclosure. First, a network node 12 determines a TH pattern of the network node 12 to use with transmissions (step 700). The network node 12 then transmits only once during an ON-OFF cycle comprising a number of dwell slots, where the dwell slot of the transmission is based on the TH pattern of the network node (step 702). In some

embodiments, the ON dwell slot may be the same for more than one consecutive ON-OFF cycles. An example is shown in Figure 10. The transmitter uses dwell slot #2 during the first two ON-OFF cycles, and changes to dwell slot #8 during the next two ON-OFF cycles. The time period during which the ON dwell slot remains the same can be referred to as a hop. Thus, in this embodiment a hop consists of multiple ON-OFF cycles.

[0066] As discussed above, a transmitter mentioned in the previous embodiments may be a network node 12 (such as an eNB). In this embodiment, the network node 12 uses the ON dwell slots for downlink transmissions and schedules the uplink transmissions during the OFF dwell slots. An example is shown in Figure 1 1 . Note however that a UE 14 is also subject to a duty factor limitation, and thus it shall not exceed the duty factor limitation even if it is scheduled to do so. A UE 14 can implement a gated transmission to turn off its transmission during its scheduled transmission interval if it has reached its duty factor limitation.

[0067] In some embodiments, the system frame numbering in a network with TH may benefit from being changed. In some embodiments, the system frame numbering is only applied to the ON dwell slots. For example, in NB-loT the System Frame Number (SFN) increases by 1 every 10 ms. According to some embodiments, SFN increases during the ON dwell slot, but stops increasing during the OFF dwell slots. An example is shown in Figure 12. As shown, the SFN starts from 0 and ends at K - 1 during the ON dwell slot in the first ON-OFF cycle. The SFN starts increasing again only after the OFF dwell slots are over and when the next ON dwell slot arrives. In the second ON dwell slot, the SFN goes from K to 2K - 1. Since the downlink OFF dwell slots do not have SFN association, these time periods may be used for uplink transmissions. When the SFN timing is changed, one issue is how to describe the uplink time. According to some embodiments, the uplink time can be specified by an offset relative to a SFN.

[0068] In some embodiments, the SFN increases during both ON and OFF dwell slots. An example is shown in Figure 13, where SFN starts from 0 to K-1 during the first dwell slot. Then SFN goes from ^"to 2K-1 during the second dwell slot. During the third slot, SFN goes from 2K\o 3K-1, and so on. This does not require any additional changes since all subframes have a

corresponding SFN.

[0069] Figure 14 is a schematic block diagram of the network node 12 according to some embodiments of the present disclosure. As illustrated, the network node 12 includes a control system 20 that includes one or more processors 22 (e.g., Central Processing Units (CPUs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), and/or the like), memory 24, and a network interface 26. In addition, the network node 12 includes one or more radio units 28 that each includes one or more

transmitters 30 and one or more receivers 32 coupled to one or more antennas 34. In some embodiments, the radio unit(s) 28 is external to the control system 20 and connected to the control system 20 via, e.g., a wired connection (e.g., an optical cable). However, in some other embodiments, the radio unit(s) 28 and potentially the antenna(s) 34 are integrated together with the control system 20. The one or more processors 22 operate to provide one or more functions of a network node 12 as described herein. In some embodiments, the function(s) are implemented in software that is stored, e.g., in the memory 24 and executed by the one or more processors 22.

[0070] Figure 15 is a schematic block diagram that illustrates a virtualized embodiment of the network node 12 according to some embodiments of the present disclosure. This discussion is equally applicable to other types of network nodes. Further, other types of network nodes may have similar virtualized architectures.

[0071] As used herein, a "virtualized" network node 12 is an implementation of the network node 12 in which at least a portion of the functionality of the network node 12 is implemented as a virtual component(s) (e.g., via a virtual machine(s) executing on a physical processing node(s) in a network(s)). As illustrated, in this example, the network node 12 includes the control system 20 (optional) that includes the one or more processors 22 (e.g., CPUs, ASICs, FPGAs, and/or the like), the memory 24, and the network interface 26 and the one or more radio units 28 that each includes the one or more transmitters 30 and the one or more receivers 32 coupled to the one or more antennas 34, as described above. The control system 20 is connected to the radio unit(s) 28 via, for example, an optical cable or the like. The control system 20 is connected to one or more processing nodes 36 coupled to or included as part of a network(s) 38 via the network interface 26. Each processing node 36 includes one or more processors 40 (e.g., CPUs, ASICs, FPGAs, and/or the like), memory 42, and a network interface 44. [0072] In this example, functions 46 of the network node 12 described herein are implemented at the one or more processing nodes 36 or distributed across the control system 20 and the one or more processing nodes 36 in any desired manner. In some particular embodiments, some or all of the functions 46 of the network node 12 described herein are implemented as virtual components executed by one or more virtual machines implemented in a virtual

environment(s) hosted by the processing node(s) 36. As will be appreciated by one of ordinary skill in the art, additional signaling or communication between the processing node(s) 36 and the control system 20 is used in order to carry out at least some of the desired functions 46. Notably, in some embodiments, the control system 20 may not be included, in which case the radio unit(s) 28 communicate directly with the processing node(s) 36 via an appropriate network interface(s).

[0073] In some embodiments, a computer program including instructions which, when executed by at least one processor, causes the at least one processor to carry out the functionality of a network node 12 or a node (e.g., a processing node 36) implementing one or more of the functions 46 of the network node 12 in a virtual environment according to any of the embodiments described herein is provided. In some embodiments, a carrier comprising the

aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as memory).

[0074] Figure 16 is a diagram of a UE 14 according to some embodiments of the present disclosure. As illustrated, the UE 14 includes at least one processor 48 and memory 50. The UE 14 also includes a transceiver 52 with one or more transmitters 54, one or more receivers 56, and one or more antennas 58. In some embodiments, UE 14, or the functionality of the wireless device 14 described with respect to any one of the embodiments described herein, is implemented in software that is stored in, e.g., the memory 50 and executed by the processor 48. The transceiver 52 uses the one or more antennas 58 to transmit and receive signals and may include one or more components that connect the UE 14 to other systems.

[0075] In some embodiments, a computer program including instructions which, when executed by at least one processor 48, causes the at least one processor 48 to carry out the functionality of the UE 14 according to any one of the embodiments described herein is provided. In some embodiments, a carrier containing the aforementioned computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer readable storage medium (e.g., a non-transitory computer readable medium such as the memory 50).

[0076] Figure 17 is a diagram of a network node 12 including modules according to some embodiments of the present disclosure. A configuration determining module 60 and a transmission module 62 are each implemented in software that, when executed by a processor of the network node 12, causes the network node 12 to operate according to one of the embodiments described herein.

[0077] Figure 18 is a diagram of a wireless device or UE 14 including modules according to some embodiments of the present disclosure. A reception module 64 and a parameter determining module 66 are each implemented in software that, when executed by a processor of the UE 14, causes the UE 14 to operate according to one of the embodiments described herein.

[0078] The following acronyms are used throughout this disclosure.

• 3GPP Third Generation Partnership Project

• ASIC Application Specific Integrated Circuit

• CA Carrier Aggregation

• CC Component Carrier

• CPE Customer Premises Equipment

• CPU Central Processing Unit

• D2D Device-to-Device

• dBm Decibel-Milliwatt

• EIRP Equivalent Isotropically Radiated Power • eNB Enhanced or Evolved Node B

• EPC Evolved Packet Core

• EU Europe

• E-UTRAN Evolved UMTS Radio Access Network

• FPGA Field Programmable Gate Array

• GHz Gigahertz

• ID Identifier

• loT Internet of Things

• ISM Industrial, Scientific, and Medical

• kHz Kilohertz

• LEE Laptop Embedded Equipment

• LME Laptop Mounted Equipment

• LTE Long Term Evolution

• M2M Machine-to-Machine

• MBMS Multimedia Broadcast/Multicast Service

• MCE MBMS Coordination Entity

• MHz Megahertz

• MIB Master Information Block

• MME Mobility Management Entity

• ms Millisecond

• MTC Machine Type Communication

• NB-loT Narrowband Internet of Things

• NetID Network Identifier

• NSSS Narrowband Secondary Synchronization Signal

• PCC Primary Component Carrier

• PCell Primary Cell

• PCID Physical Cell Identity

• PDN Packet Data Network

• P-GW Packet Data Network Gateway

• PLMN Public Land Mobile Network • PSC Primary Serving Cell

• RAN Radio Access Network

• Rel Release

• RRC Radio Resource Control

· RRH Remote Radio Head

• RRU Remote Radio Unit

• SCC Secondary Component Carrier

• SCell Secondary Cell

• SFN System Frame Number

· S-GW Serving Gateway

• SIB System Information Block

• SIM Subscriber Identity Module/Subscriber Identification

Module

• SON Self-Organizing Network

· SRD Short Range Device

• SSC Secondary Serving Cell

• TH Time Hopping

• UE User Equipment

• UMTS Universal Mobile Telecommunications System · US United States of America

• USB Universal Serial Bus

[0079] Those skilled in the art will recognize improvements and modifications to the embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

Claims

Claims What is claimed is:

1 . A method of operating a wireless device (14) in a wireless communication network (10), comprising:

obtaining a signal transmitted from a network node (12) in the wireless communication network (10);

determining a physical cell Identity, ID, of the network node (12) based on the signal obtained from the network node (12); and

determining a time hopping, TH, pattern of the network node (12) based on the determined physical cell ID of the network node (12).

2. The method of claim 1 wherein determining the TH pattern based on the physical cell ID comprises determining the TH pattern based on each physical cell ID corresponding to a unique TH pattern.

3. The method of any of claims 1 through 2 wherein there are 504 possible physical cell IDs and 504 corresponding TH patterns.

4. The method of claim 1 wherein determining the TH pattern based on the physical cell ID comprises determining the TH pattern which can be shared between different physical cell IDs.

5. The method of claim 4 wherein determining the TH pattern based on the physical cell ID comprises determining m%K = k where mis the physical cell ID, K^'\s a number of unique TH patterns, and Zeis the TH pattern based on the physical cell ID.

6. The method of claim 1 further comprising:

determining a network Identity, ID, of the network node (12) based on the signal obtained from the network node (12); and in response to determining that the network ID is part of a network able to be accessed by the wireless device (14), determining the TH pattern based on the physical cell ID and the network ID.

7. The method of claim 6 further comprising:

in response to determining that the network ID is not part of a network able to be accessed by the wireless device (14), refraining from receiving a System Information Block, SIB, from the network node (12).

8. The method of claim 1 wherein determining the TH pattern based on the physical cell ID comprises determining the TH pattern based on the physical cell ID and a predefined network ID for the wireless device (14); and further comprising:

in response to determining that the determined TH pattern matches the TH pattern of the network node (12), determining that the network node (12) is part of a network able to be accessed by the wireless device (14).

9. The method of claim 8 further comprising:

in response to determining that the determined TH pattern does not match the TH pattern of the network node (12), refraining from receiving a System Information Block, SIB, from the network node (12).

10. The method of any of claims 1 through 5 wherein obtaining the signal transmitted from the network node (12) comprises obtaining a Master Information Block, MIB, that comprises a network ID of the network node (12).

1 1 . The method of any of claims 1 through 10 wherein obtaining the signal transmitted from the network node (12) comprises obtaining a Narrowband Secondary Synchronization Signal, NSSS, used in an unlicensed spectrum.

12. The method of any of claims 1 through 1 1 wherein obtaining the signal transmitted from the network node (12) comprises obtaining the signal in the 868 MHz Short Range Device, SRD, band.

13. A wireless device (14) comprising:

at least one processor (48); and

memory (50) containing instructions whereby the wireless device (14) is operative to:

obtain a signal transmitted from a network node (12) in a wireless communication network (10);

determine a physical cell Identity, ID, of the network node (12) based on the signal obtained from the network node (12); and

determine a time hopping, TH, pattern of the network node (12) based on the determined physical cell ID of the network node (12).

14. The wireless device (14) of claim 13 wherein being operative to determine the TH pattern based on the physical cell ID comprises being operative to determine the TH pattern based on each physical cell ID corresponding to a unique TH pattern.

15. The wireless device (14) of any of claims 13 through 14 wherein there are 504 possible physical cell IDs and 504 corresponding TH patterns.

16. The wireless device (14) of claim 13 wherein being operative to determine the TH pattern based on the physical cell ID comprises being operative to determine the TH pattern which can be shared between different physical cell IDs.

17. The wireless device (14) of claim 16 wherein being operative to determine the TH pattern based on the physical cell ID comprises being operative to determine m%K = k where mis the physical cell ID, K\s a number of unique TH patterns, and k is the TH pattern based on the physical cell ID.

18. The wireless device (14) of claim 13 further operative to:

determine a network ID of the network node (12) based on the signal obtained from the network node (12); and

in response to determining that the network ID is part of a network able to be accessed by the wireless device (14), determine the TH pattern based on the physical cell ID and the network ID.

19. The wireless device (14) of claim 18 further operative to:

in response to determining that the network ID is not part of a network able to be accessed by the wireless device (14), refrain from receiving a System Information Block, SIB, from the network node (12).

20. The wireless device (14) of claim 13 wherein being operative to determine the TH pattern based on the physical cell ID comprises being operative to determine the TH pattern based on the physical cell ID and a predefined network ID for the wireless device (14); and the wireless device (14) is further operative to:

in response to determining that the determined TH pattern matches the TH pattern of the network node (12), determine that the network node (1 2) is part of a network able to be accessed by the wireless device (14).

21 . The wireless device (14) of claim 20 further operative to:

in response to determining that the determined TH pattern does not match the TH pattern of the network node (12), refrain from receiving a System

Information Block, SIB, from the network node (12).

22. The wireless device (14) of any of claims 13 through 17 wherein being operative to obtain the signal transmitted from the network node (12) comprises being operative to obtain a Master Information Block, MIB, that comprises a network ID of the network node (12).

23. The wireless device (14) of any of claims 13 through 22 wherein being operative to obtain the signal transmitted from the network node (12) comprises being operative to obtain a Narrowband Secondary Synchronization Signal, NSSS, used in an unlicensed spectrum.

24. The wireless device (14) of any of claims 13 through 23 wherein being operative to obtain the signal transmitted from the network node (12) comprises being operative to obtain the signal in the 868 MHz Short Range Device, SRD, band.

25. A wireless device (14) adapted to:

determine a time hopping, TH, pattern of the network node (12) based on the determined physical cell ID of the network node (12)

26. The wireless device (14) of claim 25 adapted to perform the method of any of claims 2-12.

27. A wireless device (14) comprising:

a reception module (64) operative to obtain a signal transmitted from a network node (12) in a wireless communication network (10); and

a parameter determining module (66) operative to determine a physical cell Identity, ID, of the network node (12) based on the signal obtained from the network node (12); and determine a time hopping, TH, pattern of the network node (12) based on the determined physical cell ID of the network node (12).

28. A method of operating a network node (12) in a wireless communication network (10), comprising:

determining a time hopping, TH, pattern of the network node (12) to use with transmissions; and

transmitting only once during an ON-OFF cycle comprising a number of dwell slots, where the dwell slot of the transmission is based on the TH pattern of the network node (12).

29. The method of claim 28 wherein transmitting only once during the ON- OFF cycle comprises transmitting during the same dwell slot in a plurality of ON- OFF cycles.

30. The method of any of claims 28 through 29 wherein transmitting only once during the ON-OFF cycle comprises scheduling downlink transmissions for one or more wireless devices (14) during the ON dwell slots corresponding to the TH pattern of the network node (12); and

the method further comprises:

scheduling uplink transmissions for the one or more wireless devices (14) during the OFF dwell slots corresponding to the TH pattern of the network node (12).

31. The method of any of claims 28 through 30 wherein a System Frame Number, SFN, increases during the dwell slots corresponding to the TH pattern, but the SFN stops increasing during the dwell slots not corresponding to the TH pattern of the network node (12).

32. The method of any of claims 28 through 30 wherein a System Frame Number, SFN, increases during the dwell slots corresponding to the TH pattern and during the dwell slots not corresponding to the TH pattern.

33. The method of any of claims 28 through 32 wherein transmitting

comprises transmitting in an unlicensed spectrum.

34. The method of any of claims 28 through 33 wherein transmitting

comprises transmitting in the 868 MHz Short Range Device, SRD, band.

35. A network node (12) comprising:

at least one processor (22); and

memory (24) containing instructions whereby the network node (12) is operative to:

determine a time hopping, TH, pattern of the network node (12) to use with transmissions; and

transmit only once during an ON-OFF cycle comprising a number of dwell slots, where the dwell slot of the transmission is based on the TH pattern of the network node (12).

36. The network node (12) of claim 35 wherein being operable to transmit only once during the ON-OFF cycle comprises being operable to transmit during the same dwell slot in a plurality of ON-OFF cycles.

37. The network node (12) of any of claims 35 through 36 wherein being operable to transmit only once during the ON-OFF cycle comprises being operable to schedule downlink transmissions for one or more wireless devices (14) during the ON dwell slots corresponding to the TH pattern of the network node (12); and

the network node (12) is further operable to:

schedule uplink transmissions for the one or more wireless devices (14) during the OFF dwell slots corresponding to the TH pattern of the network node (12).

38. The network node (12) of any of claims 36 through 37 wherein a System Frame Number, SFN, increases during the dwell slots corresponding to the TH pattern, but the SFN stops increasing during the dwell slots not corresponding to the TH pattern of the network node (12).

39. The network node (12) of any of claims 35 through 37 wherein a System Frame Number, SFN, increases during the dwell slots corresponding to the TH pattern and during the dwell slots not corresponding to the TH pattern.

40. The network node (12) of any of claims 35 through 39 wherein being operable to transmit comprises being operable to transmit in an unlicensed spectrum.

41. The network node (12) of any of claims 35 through 40 wherein being operable to transmit comprises being operable to transmit in the 868 MHz Short Range Device, SRD, band.

42. A network node (12) adapted to:

43. The network node (12) of claim 42 adapted to perform the method of any of claims 29-34.

44. A network node (12) comprising:

a configuration determining module (60) operative to determine a time hopping, TH, pattern of the network node (12) to use with transmissions; and a transmission module (62) operative to transmit only once during an OFF cycle comprising a number of dwell slots, where the dwell slot of the transmission is based on the TH pattern of the network node (12).