WO2017119843A1

WO2017119843A1 - Utilization of resources in narrowband internet of things physical broadcast channel transmission

Info

Publication number: WO2017119843A1
Application number: PCT/SE2017/050009
Authority: WO
Inventors: Ansuman ADHIKARY; Asbjörn GRÖVLEN; Yi-Pin Eric Wang; Niklas Johansson; Yutao Sui; Xingqin LIN; Johan Bergman; Yufei Blankenship
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2016-01-08
Filing date: 2017-01-05
Publication date: 2017-07-13

Abstract

In Narrowband, NB, networks such as NB Internet of Things, IoT, transmissions of NB Physical Broadcast Channel, NPBCH from a NB base station (11) to in-band mode NB IoT UEs (31) requires the reservation of predetermined symbols and resource elements, RE, for non-interference with legacy LTE UE operation. In contrast, in stand-alone and guard-band mode deployments, transmissions to NB IoT UEs (31) may include NB IoT data in these resources. Examples include the first, e.g., three symbols of NPBCH, reserved for the LTE Physical Downlink Control Channel, PDCCH, and numerous REs reserved for LTE Cell-specific Reference Symbols, CRS. These resources may be used to transmit NB IoT data to stand-alone and guard-band mode NB IoT UEs (31), such as by repeating data from other symbols or REs. The repetition allows the stand-alone and guard-band mode NB IoT UEs (31) to perform frequency tracking or enhanced reception by energy accumulation.

Description

UTILIZATION OF RESOURCES IN NARROWBAND INTERNET OF THINGS PHYSICAL

BROADCAST CHANNEL TRANSMISSION

FIELD OF INVENTION

The present invention relates generally to wireless communication, and in particular to the full use of resources in transmitting the Physical Broadcast Channel in Narrowband Internet of Things signaling to NB loT User Equipment deployed in guard-band or stand-alone mode.

BACKGROUND

Cellular wireless communication systems are currently being developed and improved for machine type communication (MTC), which is characterized by lower demands on data rates than, e.g., mobile broadband, but with higher requirements on aspects such as low cost device design, better coverage, and years-long battery life. In Release 13, the Third Generation Partnership Project (3GPP) standardized two different approaches to MTC type

communications. Enhanced MTC (eMTC), also known as Long Term Evolution - Machine-to- machine (LTE-M), includes cost reduction measures such as lower bandwidth, lower data rates, and reduced transmit power, as compared to legacy (broadband) LTE. Narrowband Internet of Things (NB loT) more aggressively addresses the extremely low cost market with less than 200 KHz of spectrum and flexibility to deploy concurrently with legacy networks or outside of active legacy spectrum. The NB loT protocol is designed for NB loT networks to be deployed without having to change the behavior of legacy LTE UEs in the current wideband LTE radio access technology.

For NB loT, three different operating modes are defined: stand-alone, guard-band, and in-band. In stand-alone mode, the NB loT system is operated in dedicated frequency bands. For in-band operation, the NB loT network is deployed inside the frequency bands used by the current LTE system. Finally, in the guard-band mode, the NB loT network is operated in the guard band - the reserved, but unused spectrum at the edges of allocated frequency bands - used by the current LTE system. For a NB loT system deployed in-band, NB loT signaling must not interfere with the resources used by the LTE system to transmit control signaling to legacy LTE UEs; systems deployed in guard-band or stand-alone are not subject to this restriction, as there are no legacy LTE UEs operating in those bands, the signal integrity of which must be preserved.

The Master Information Block (MIB) is an information message that is periodically broadcast by a NB base station. The MIB conveys important system information that assists the UE to gain access to the system. The MIB is carried by the Narrowband Physical Broadcast Channel (NPBCH). In order to reduce the system complexity and try to maintain the

commonalities of the physical layer design of the three different operating modes, it has been proposed to use the same design of the NPBCH for all three different NB loT operating modes. However, because, as observed above, the different operating modes have different requirements of non-interference to the legacy LTE system, this proposal results in poor physical resource utilization in some of the modes.

The Background section of this document is provided to place embodiments of the present invention in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.

SUMMARY

The following presents a simplified summary of the disclosure in order to provide a basic understanding to those of skill in the art. This summary is not an extensive overview of the disclosure and is not intended to identify key/critical elements of embodiments of the invention or to delineate the scope of the invention. The sole purpose of this summary is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

According to one or more embodiments of the present invention described and claimed herein, in stand-alone and guard-band modes, where NB loT transmissions do not have a requirement of non-interference with legacy wideband LTE UE operation (as in-band NB loT transmissions do), some symbols and resources elements (RE) reserved for use by the legacy LTE system - such as the Physical Downlink Control Channel (PDCCH) or LTE Cell-specific Reference Symbols (LTE CRS) - may be used for the transmission of NB loT data, such as repetitions of data transmitted in the NPBCH or neighboring subframes. The insertion of data may be per-symbol, per-RE, or a combination.

One embodiment relates to a method of transmitting information in a Narrow Band (NB) Physical Broadcast Channel (NPBCH) from a base station to one or more NB Internet of Things (loT) User Equipment (UE) using NB loT signaling. Information is transmitted informing a NB loT UE whether it is operating in an in-band mode, wherein the NB loT UE operates within a Long Term Evolution (LTE) transmission band; a guard-band mode, wherein the NB loT UE operates in a frequency guard band of an LTE transmission band; or a stand-alone mode, wherein the NB loT UE operates in a frequency band outside of an LTE transmission band. NB loT data is transmitted to a NB loT UE operating in a guard-band or stand-alone mode, in symbol periods or resource elements (RE) which are reserved for the LTE Physical Downlink Control Channel (PDCCH) or LTE Cell-specific Reference Signals (CRS), respectively, in NB loT UEs operating in in-band mode.

Another embodiment relates to a base station operative to transmit a NPBCH to one or more NB loT UE, using NB loT signaling. The base station includes one or more antenna and a transceiver operatively connected to the antenna. The base station also includes processing circuitry operatively connected to the transceiver. The processing circuitry is operative to cause the transceiver to transmit information informing an NB loT UE whether it is operating in an in- band mode, a guard-band mode, or a stand-alone mode. The processing circuitry is further operative to cause the transceiver to transmit to a NB loT UE operating in a guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE

PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode.

Yet another embodiment relates to an apparatus operative to transmit a NPBCH to one or more NB loT UE, using NB loT signaling. The apparatus includes a first module operative to transmit information informing an NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode; and a second module operative to transmit to an NB loT UE operating in a guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode.

Still another embodiment relates to a method, performed by a NB loT UE, of receiving and utilizing information in a NPBCH from a NB base station. Information is received informing the NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode. NB loT data is received, by a NB loT UE operating in a guard-band or stand-alone mode, in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode. The NB loT data are utilized by the NB loT UE operating in a guard-band or stand-alone mode, to perform one of frequency tracking and enhanced reception by accumulating energy.

Still another embodiment relates to a NB loT UE operative to receive a NPBCH from a NB base station. The NB loT UE includes one or more antenna and a transceiver operatively connected to the antenna. The NB loT UE also includes processing circuitry operatively connected to the transceiver. The processing circuitry is operative to cause the transceiver to receive information informing the NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode. The processing circuitry is further operative to cause the transceiver to receive, by a NB loT UE operating in a guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode. The processing circuitry of a NB loT UE operating in a guard-band or stand-alone mode is further operative to utilize the NB loT data to perform one of frequency tracking and enhanced reception by accumulating energy.

Still another embodiment relates to an apparatus operative to receive a NPBCH from a NB base station. The apparatus includes a first module operative to receive information informing the NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode. The apparatus includes a second module operative to receive, by a NB loT UE operating in a guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode. The apparatus also includes a third module operative to utilize the NB loT data, by a NB loT UE operating in a guard-band or stand-alone mode, to perform one of frequency tracking and enhanced reception by accumulating energy.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

Figure 1 is an OFDM time-frequency grid depicting REs in a NPBCH (normal CP) for in- band mode NB loT UEs.

Figure 2 is an OFDM time-frequency grid depicting REs in a NPBCH (normal CP) for guard-band or stand-alone mode NB loT UEs, in which NB loT data is transmitted in symbols reserved for non-interference with the LTE PDCCH in NB loT UEs in in-band mode.

Figure 3 is an OFDM time-frequency grid depicting REs in a NPBCH (extended CP) for guard-band or stand-alone NB loT UEs, in which NB loT data is transmitted in symbols reserved for non-interference with the LTE PDCCH in NB loT UEs in in-band mode.

Figure 4 is an OFDM time-frequency grid depicting REs in a NPBCH (normal CP) for guard-band or stand-alone NB loT UEs, in which NB loT data is transmitted in REs reserved for non-interference with the LTE CRS in NB loT UEs in in-band mode. Figure 5 is an OFDM time-frequency grid depicting REs in a NPBCH (extended CP) for guard-band or stand-alone NB loT UEs, in which NB loT data is transmitted in REs reserved for non-interference with the LTE CRS in NB loT UEs in in-band mode.

Figure 6 is flow diagram of a method of transmitting information in a NPBCH from a base station to one or more NB loT UE.

Figure 7 is a block diagram of a network node configured to transmit NPBCH.

Figure 8 is a block diagram of the network node of Fig. 7 configured as a base station.

Figure 9 is a diagram of physical units in processing circuitry in the network node of Fig.

7.

Figure 10 is a diagram of software modules in memory in the network node of Fig. 7.

Figure 11 is a diagram of modules comprising a virtual function module architecture of a network node apparatus.

Figure 12 is flow diagram of a method, by a NB loT UE, of receiving and utilizing information in a NPBCH from a NB base station.

Figure 13 is a block diagram of a radio network device configured to receive NPBCH.

Figure 14 is a block diagram of the radio network device of Fig. 13 configured as a UE.

Figure 15 is a diagram of physical units in processing circuitry in the radio network device of Fig. 13.

Figure 16 is a diagram of software modules in memory in the radio network device of

Fig. 13.

Figure 17 is a diagram of modules comprising a virtual function module architecture of a radio network device.

DETAILED DESCRIPTION

For simplicity and illustrative purposes, the present invention is described by referring mainly to an exemplary embodiment thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention.

However, it will be readily apparent to one of ordinary skill in the art that the present invention may be practiced without limitation to these specific details. In this description, well known methods and structures have not been described in detail so as not to unnecessarily obscure the present invention.

Embodiments of the present invention relate to MTC type networks and radio network devices. Such networks are referred to generally herein as "narrowband" or NB. The bandwidth is "narrow" as compared to contemporaneous broadband networks (also referred to herein as "legacy" networks). For example, the NB loT network utilizes the smallest allocable bandwidth unit in LTE: a Physical Resource Block (PRB), defined as 12 subcarriers by one slot (0.5 msec). With 15 KHz subcarrier spacing, an NB loT network deployment has a bandwidth of 180 KHz. This is in contrast to legacy wideband networks, such as LTE. For example, LTE Rel. 8 supports six bandwidth options, ranging from 1.4 MHz to 20 MHz. LTE Rel. 10 introduced the ability aggregate up to five component carriers, for an aggregated bandwidth up to 100 MHz.

As discussed above, when a NB network is deployed in-band within an operating frequency band of a legacy wideband network, the NB network is constrained to not cause undue interference with the legacy network and UE operation. In particular, certain specific physical resources have been allocated, or reserved, for system signaling (also known as control plane signaling, or more informally as system overhead). One specific example of such reserved control plane signaling (LTE PDCCH), and its non-interference requirement on NB loT UE deployed in-band, is explained herein in detail; however, this specific example is not limiting.

In legacy LTE systems, the Channel Format Indicator (CFI) indicates to UEs the number of OFDM symbols that are used as legacy control region, which contains the Physical Downlink Control Channel (PDCCH), which carries Downlink Control Information (DCI). The CFI = 1 , 2, or 3. For system bandwidths ^ , the CFI directly indicates the number of OFDM symbols dedicated to the legacy control region - i.e., 1 , 2, or 3.

For system bandwidths ^ , the span of the control region, in units of OFDM symbol periods, is CFI+1 = 2, 3 or 4. For NB loT in-band deployment, it is assumed that the central six physical resource blocks (PRBs) in the LTE system are never used by NB loT.

Hence in practice, there is no in-band NB loT deployment in LTE system with bandwidths

_/V^" < 10

^{J V} RB - ^iu Accordingly, an NB loT network need not consider this case, and may assume that the legacy control region of any legacy LTE network in which it may operate in in-band mode, occupies at most three OFDM symbol periods at the beginning of a subframe.

For eMTC networks, eNB broadcasts via SIB1 bis the number of OFDM symbol periods (i.e., CFI) the eMTC UE should assume for legacy control region. To ensure efficient utilization of resources, a similar design is also provided for NB loT, so that the NB loT UE does not always assume the maximum CFI possible.

In NB loT in-band deployment, the CFI is broadcast to NB loT UEs in

SystemlnformationBlockType1-NB (abbreviated SIB1-NB). Before the broadcast CFI is received, e.g., for NB MIB or SIB1-NB reception, the maximum CFI must be assumed. For any downlink transmission to NB loT UEs, these k initial OFDM symbol periods are assumed to be used by the legacy LTE network for legacy control region, and no NB-loT data are transmitted in these symbol periods for NB-loT in-band operation. Rather, rate matching is performed so that the symbol periods are effectively bypassed.

The LTE CFI information is sent in NB loT system information SIB1-NB, if NB loT is deployed in-band. It is assumed that the operation mode (in-band, guard-band, or stand-alone) is either indicated by the synchronization signals (NB PSS and/or NB SSS) or indicated by the NB MIB. Hence, upon receiving NB MIB, the NB loT UE assumes the legacy control region as follows:

• For in-band mode deployment, for all signal and channel types that come after NB MIB, the NB loT UE shall assume the legacy control region as defined by the CFI.

• For guard-band and stand-alone mode deployments, the NB loT UE shall always

assume zero OFDM symbol periods for legacy control region, for receiving all signal and channel types that come after NB MIB.

Before receiving NB MIB (including during the process of receiving NB MIB):

· For in-band mode deployment, the NB loT UE shall assume maximum CFI for the legacy control region, i.e., CFI = 3. The first k=3 OFDM symbols are not usable, and are to be ignored by the NB loT UE.

• For guard-band and stand-alone mode deployments, it is necessary to have the same NPBCH signal as that of in-band mode deployment in the data region (i.e., the OFDM symbols in the NPBCH subframe after the first three OFDM symbol periods). The first k=3 OFDM symbol periods are extra resources which are usable by the NB loT UE. Accordingly, in guard-band and stand-alone mode deployments, the legacy control region - up to the first three OFDM symbol periods - is available for the transmission of NB loT data. As used herein, "NB loT data" refers to data intended for, and useful to, NB loT UEs. Some data normally transmitted in LTE PBCH - such as such as PDCCH, PCFICH, PHICH, LTE CRS, and CSI-RS - is neither intended for, nor useful to, NB loT UE, and is explicitly excluded from the definition of "NB loT data."

One specific example of NB loT data is a repetition of data transmitted to the NB loT UE using another transmission physical resource, either within the same NPBCH or in preceding or following subframes. Many NB loT UEs operate at low power, and at very low Signal to Noise Ratio (SNR) and/or Signal to Interference and Noise Ratio (SINR). Additionally, the oscillators used in low-cost NB loT UEs experience frequency drift with temperature and also possibly Doppler shift, resulting in frequency offset drift. See 3GPP R1-160769: TSG RAN WG1 Meeting #84, Feb. 2016. Redundant data is useful in these cases, for at least two reasons. First, the NB ΙοΤ UE may use redundant data for incremental reception. In incremental reception, the N B loT UE accumulates the energy over numerous repetitions of the same data, and may thus more easily and accurately resolve the received data. Additionally, the NB loT UE may use repeated data to perform frequency tracking, by comparing data redundantly transmitted. The frequency tracking may reduce or eliminate frequency offset, or "drift," which if uncompensated can result in inter-carrier interference (ICI), destroying OFDM sub-carrier orthogonality. Of course, NB loT data is not limited to repetitions of data otherwise transmitted, and may include additional unique data transmitted to the NB loT UE.

In some embodiments, an LTE NB loT network operating in guard-band and/or stand- alone mode utilizes the initial k=3 OFDM symbol periods to transmit data redundant to other symbols in the same NPBCH, which other symbols do not include LTE CRS.

Figure 1 depicts an in-band mode NPBCH subframe. During the initial three OFDM symbol periods, the transmission of NPBCH must not interfere with the transmission of legacy LTE PDCCH. The NPBCH similarly accommodates numerous LTE CRS in known RE positions throughout the subframe, by rate matching and hence not transmitting data in these REs. For guard-band and/or stand-alone mode deployments, none of the physical transmission resources reserved for non-interference with LTE PDCCH or LTE CRS transmissions in in-band mode deployments, needs to be reserved, and the initial k=3 OFDM symbols may be used to transmit other data.

Note that in the discussion herein, for stand-alone and guard-band modes of NB loT deployment, it is assumed that during NPBCH transmission and reception, there are in general k (k being an integer >=1 , such as 3) OFDM symbol periods at the beginning of the subframe which are vacant, unless filled using one of the methods described herein. It is noted, however, that other number of OFDM symbol periods (e.g., k=2), which are vacant, can also be utilized by NB loT U Es using methods described herein. Accordingly, k=3 is a representative example, and is not limiting.

Figure 2 depicts one embodiment, in which, for a standard Cyclic Prefix (CP) NPBCH subframe, OFDM symbols 3, 5, and 6 are repeated in OFDM symbol periods 0, 1 , and 2. Again, none of symbols 3, 5, or 6 reserve REs for non-interference with LTE CRS in in-band mode. This embodiment also exhibits the benefit of duplicated transmission close in time, which assists frequency tracking.

Other repetition patterns (not shown in drawing figures) for standard CP, which avoid replicating data from symbols including LTE CRS, include:

• NPBCH in OFDM symbols 5, 6, and 9 are repeated in OFDM symbol periods 0, 1 , and 2. • NPBCH in OFDM symbols 3, 9, and 10 are repeated in OFDM symbol periods 0, 1 , and 2.

• NPBCH in OFDM symbols 9, 10, and 12 are repeated in OFDM symbol periods 0, 1 , and 2.

· NPBCH in OFDM symbols 10, 12, and 13 are repeated in OFDM symbol periods 0, 1 , and 2.

Figure 3 depicts an embodiment applicable to an extended CP NPBCH subframe. In this embodiment, OFDM symbols 4, 5, and 8 are repeated in OFDM symbol periods 0, 1 , and 2. Note that none of symbols 4, 5, or 8 reserve REs for non-interference with LTE CRS in in-band mode. This embodiment exhibits the benefit of duplicated transmission close in time, which assists frequency tracking.

Other repetition patterns (not shown in drawing figures) for extended CP, which avoid replicating data from symbols including LTE CRS, include:

• NPBCH in OFDM symbols 8, 10, and 1 1 are repeated in OFDM symbol periods 0, 1 , and 2.

• NPBCH in OFDM symbols 4, 8, and 10 are repeated in OFDM symbol periods 0, 1 , and 2.

• NPBCH in OFDM symbols 5, 8, and 11 are repeated in OFDM symbol periods 0, 1 , and 2.

In other embodiments, the reserved OFDM symbol periods 0-2 may be used to repeat symbols with reserved LTE CRS REs. In this case, the LTE CRS may be replaced with NB loT data. Repeating symbols which include NB loT CRS is useful, since these are known symbols that the NB loT UE can use to enhance reception.

Examples of repetition patterns for normal CP, which replicate data from symbols including LTE CRS, include:

• NPBCH in OFDM symbols 3, 4, and 5 are repeated in OFDM symbol periods 0, 1 , and 2.

• NPBCH in OFDM symbols 7, 8, and 9 are repeated in OFDM symbol periods 0, 1 , and 2.

That is, first 3 OFDM symbols of the second slot are repeated in first 3 OFDM symbol periods of the first slot in the same subframe.

Examples of repetition patterns for extended CP, which replicate data from symbols including LTE CRS, include:

• NPBCH in OFDM symbols 3, 4, and 5 are repeated in OFDM symbol periods 0, 1 , and 2. • NPBCH in OFDM symbols 6, 7, and 8 are repeated in OFDM symbol periods 0, 1 , and 2. That is, first 3 OFDM symbols of the second slot are repeated in first 3 OFDM symbol periods of the first slot in the same subframe.

In other embodiments, the REs in the initial k=3 OFDM symbol periods can be configured as a part of the NB PDCCH, either for the common search space (CSS) or UE- specific search space (USS). In one embodiment, the design of NB PDCCH in NB loT systems is similar to the LTE ePDCCH or M-PDCCH in eMTC. Therefore, any nine REs can be grouped together.

In the guard-band and stand-alone operating modes, it is not necessary to reserve the LTE CRS in the first three OFDM symbols, as is required in in-band mode to avoid interference with LTE UEs. Therefore, up to 36 OFDM REs are available for the transmission of NB loT data. These can be grouped into 4 groups (such a group is called eREG in ePDCCH or REG in PDCCH). These four groups can be used to extend the search space of NB PDCCH. In the cases NB loT CRS are needed, the NB loT CRS positions can be punctured, which is similar to the case in ePDCCH.

In other embodiments, in the guard-band and stand-alone operating modes, the unused initial k=3 OFDM symbol periods may be configured as a part of the NB Physical Downlink Shared Channel (PDSCH). These k OFDM symbols may be scheduled as part of the NB PDSCH subframes either before or after the NPBCH subframe.

In another embodiment, in the guard-band and stand-alone operating modes, the available initial k OFDM symbol periods may repeat the last j OFDM symbols of the immediately preceding subframe, which are not configured to be NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS). In another embodiment, the available initial k OFDM symbol periods may repeat the first m OFDM symbols of the immediately following subframe, which are not configured to be NB PSS or SSS. In these embodiments, k, j, and m are all positive integers.

In other embodiments, in the guard-band and stand-alone operating modes, REs other than those in the initial k OFDM symbol periods may be utilized to improve performance and efficiency. Referring back to Figure 1 , in an in-band mode NPBCH subframe, sixteen LTE CRS are accommodated in REs in a known pattern throughout the subframe. In guard-band and stand-alone operating modes, where no legacy LTE UEs operate, the LTE CRS need not be reserved for non-interference, and these REs may be used to transmit NB loT data.

One way to utilize the REs corresponding to LTE CRS is to repeat adjacent NPBCH modulation symbols. In Figure 4 (illustrating standard CP) and Figure 5 (extended CP), one example of a repetition pattern is illustrated, where each RE marked with capital letter (in a RE corresponding to a LTE CRS) is a repetition of data in the RE marked with the corresponding lower-case letter. That is, each RE reserved for non-interference with LTE CRS in in-band mode, is filled with the modulation symbol immediately below (modulo 12). Other repetition patterns are possible; for example, each CRS RE may be filled with the modulation symbol immediately above (modulo 12).

Note that Figures 4 and 5 depict the legacy control region - the initial k OFDM symbol periods of the NPBCH subframe. This indicates that the embodiments described with reference to Figures 4 and 5 - placing NB loT data in individual LTE CRS REs - are independent from embodiments described with respect to Figures 2 and 3 - replacing the entire OFDM symbols in symbol positions 0-2 with other symbols. Although these approaches are independent, they are not exclusive. Applying two or more of the embodiments - that is, replacing the initial k OFDM symbol positions with copies of other symbols in the NPBCH, and additionally filling the individual, scattered LTE CRS REs with NB loT data - will maximize the amount of NB loT data sent to guard-band and stand-alone mode NB loT UEs, minimize overhead and wasted air interface resources, and hence maximize system efficiency.

Figure 6 depicts a method 100, performed by a NB base station, of transmitting information in a NPBCH to one or more NB loT UEs. The base station transmits information informing a NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode (block 102). In in-band mode, the NB loT UE operates within a LTE transmission band; in guard-band mode, the NB loT UE operates in a frequency guard band of a LTE transmission band; in stand-alone mode, the NB loT UE operates in a frequency band outside of an LTE transmission band. The base station transmits to a NB loT UE operating in either a guard-band or a stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode (block 104).

Figure 7 depicts a network node 10 operative in a NB wireless communication network such as NB loT. The network node 10 includes communication circuits 12 operative to exchange data with other network nodes; processing circuitry 14; memory 16; and radio circuits, such as a transceiver 18, one or more antennas 20, and the like, to effect wireless

communication across an air interface to one or more radio network devices. As those of skill in the art are aware, the antenna(s) 20 may be physically located separately from the network node 10, such as mounted on a tower, building, or the like. Although the memory 16 is depicted as being separate from the processing circuitry 14, those of skill in the art understand that the processing circuitry 14 includes internal memory, such as a cache memory or register files. Those of skill in the art additionally understand that virtualization techniques allow some functions nominally executed by the processing circuitry 14 to actually be executed by other hardware, perhaps remotely located (e.g., in the so-called "cloud").

According to embodiments of the present invention, the memory 16 is operative to store, and the processing circuitry 14 is operative to execute, software 22 which when executed is operative to cause the network node 10 to transmit information informing a NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode, and to transmit to a N B loT UE in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode, as described and claimed herein. In particular, the software 22, when executed on the processing circuitry 14, is operative to perform the method 100 described and claimed herein. This allows the network node 10 to transmit utilize physical transmission resources which must be reserved, by NB loT UEs operating in in-band mode, for non-interference with legacy LTE UE operation. Accordingly, the transmissions to guard-band and stand-alone mode NB loT U Es may more efficiently utilize the physical transmission resources.

Figure 8 depicts an embodiment in which the network node 10 of Fig. 7 is a base station 1 1 providing NB wireless communication services to one or more NB radio network devices in a geographic region (known as a cell or sector).

Figure 9 illustrates example processing circuitry 14, such as that in the network node 10 of Figure 7. The processing circuitry 14 comprises a plurality of physical units. In particular, the processing circuitry 14 comprises a NB loT U E operating mode transmitting unit 50 and a NB loT data transmitting unit 52. The NB loT UE operating mode transmitting unit 50 is configured to transmit information whether a NB loT U E is operating in in-band, guard-band, or stand-alone mode. The NB loT data transmitting unit 52 is configured to transmit to a NB loT UE operating in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode.

Figure 10 illustrates example software 22, such as that depicted in the memory 16 of the network node 10 of Figure 7. The software 22 comprises a plurality of software modules. In particular, the software 22 comprises a NB loT UE operating mode transmitting module 54 and a NB loT data transmitting module 56. The NB loT UE operating mode transmitting module 54 is configured to transmit information whether a NB loT U E is operating in in-band, guard-band, or stand-alone mode. The NB loT data transmitting module 56 is configured to transmit to a N B loT UE operating in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode.

Figure 1 1 illustrates a plurality of modules comprising a virtual function module architecture of an apparatus operative to transmit a NB NPBCH to one or more NB loT UE, using NB loT signaling. A first module 58 is configured to transmit information whether a NB loT UE is operating in in-band, guard-band, or stand-alone mode. A second module 60 is configured to transmit to a NB loT UE operating in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode.

Figure 12 depicts a method 200, performed by a NB loT UE, of receiving and utilizing information in a NPBCH from a NB base station. The NB loT UE receives information informing the NB loT UE whether it is operating in an in-band mode, a guard-band mode, or a stand-alone mode (block 202). In in-band mode, the NB loT UE operates within a LTE transmission band; in guard-band mode, the NB loT UE operates in a frequency guard band of a LTE transmission band; in stand-alone mode, the NB loT UE operates in a frequency band outside of an LTE transmission band. A NB loT UE operating in a guard-band or a stand-alone mode receives NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode (block 204). The NB loT UE operating in a guard-band or stand-alone mode utilizes the NB loT data to perform one of frequency tracking and enhanced reception by accumulating energy (block 206).

Figure 13 depicts a radio network device 30 operative in a NB wireless communication network such as NB loT. A radio network device 30 is any type device capable of

communicating with a network node 10 and/or base station 1 1 over radio signals. A radio network device 30 may therefore refer to a machine-to-machine (M2M) device, a machine-type communications (MTC) device, a Narrowband Internet of Things (NB loT) device, etc. The radio network device 30 may also be a User Equipment (UE); however it should be noted that the UE does not necessarily have a "user" in the sense of an individual person owning and/or operating the device. A radio network device 30 may also be referred to as a radio device, a radio communication device, a wireless communication device, a wireless terminal, or simply a terminal - unless the context indicates otherwise, the use of any of these terms is intended to include device-to-device UEs or devices, machine-type devices, or devices capable of machine- to-machine communication, sensors equipped with a radio network device, wireless-enabled table computers, mobile terminals, smart phones, laptop-embedded equipped (LEE), laptop- mounted equipment (LME), USB dongles, wireless customer-premises equipment (CPE), etc. In the discussion herein, the terms machine-to-machine (M2M) device, machine-type communication (MTC) device, wireless sensor, and sensor may also be used. It should be understood that these devices may be UEs, but may be configured to transmit and/or receive data without direct human interaction.

A radio network device 30 as described herein may be, or may be comprised in, a machine or device that performs monitoring or measurements, and transmits the results of such monitoring measurements to another device or a network node 10, 11. Particular examples of such machines are power meters, industrial machinery, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a wireless communication device as described herein may be comprised in a vehicle and may perform monitoring and/or reporting of the vehicle's operational status or other functions associated with the vehicle.

In some embodiments, the radio network device 30 includes a user interface 32 (display, touchscreen, keyboard or keypad, microphone, speaker, and the like); in other embodiments, such as in many M2M, MTC, or NB loT scenarios, the radio network device 30 may include only a minimal, or no, user interface 32 (as indicated by the dashed lines of block 32 in Figure 13). The radio network device 30 also includes processing circuitry 34; memory 36; and radio circuits, such a transceiver 38, one or more antennas 40, and the like, to effect wireless communication across an air interface to one or more radio network nodes 10, 1 1. As indicated by the dashed lines, the antenna(s) 40 may protrude externally from the radio network device 30, or the antenna(s) 40 may be internal.

According to embodiments of the present invention, the memory 36 is operative to store, and the processing circuitry 34 operative to execute, software 42 which when executed is operative to cause the radio network device 30 to receive information informing the radio network device 30 whether it is operating in an in-band mode, a guard-band mode, or a standalone mode; receive, by a radio network device 30 operating in a guard-band or a stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in radio network devices 30 operating in in-band mode; and utilize the NB loT data to perform one of frequency tracking and enhanced reception by accumulating energy, as described and claimed herein. In particular, the software 42, when executed on the processing circuitry 34, is operative to perform the method 200 described and claimed herein. This allows the radio network device 30, when operating in guard-band or stand-alone mode, to more fully utilize the available downlink transmission physical resources than would be the case for radio network devices 30 operating in in-band mode. Figure 14 depicts an embodiment in which the radio network device 30 is a NB loT UE 31. As noted above, a NB loT UE may differ significantly from a legacy LTE UE, in that the NB loT UE may not be associated with a "user," may lack a user interface, and may operate at lower power, over a narrow bandwidth, with lower data rate, and the like.

Figure 15 illustrates example processing circuitry 34, such as that in the radio network device 30 of Figure 13. The processing circuitry 34 comprises a plurality of physical units. In particular, the processing circuitry 34 comprises a NB loT UE operating mode receiving unit 62, a NB loT data receiving unit 64, and a frequency tracking or enhanced reception unit 66. The NB loT UE operating mode receiving unit 62 is configured to receive information whether the NB loT UE is operating in in-band, guard-band, or stand-alone mode. The NB loT data receiving unit 64 is configured to receive, by a NB loT UE operating in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT radio network devices 30 operating in in-band mode. The frequency tracking or enhanced reception unit 66 is operative, in radio network devices 30 operating in guard-band or stand-alone mode, to utilize the NB loT data to perform one of frequency tracking and enhanced reception by accumulating energy.

Figure 16 illustrates example software 42, such as that in the radio network device 30 of Figure 13. The software 42 comprises a plurality of software modules. In particular, the software 42 comprises a NB loT UE operating mode receiving module 68, a NB loT data receiving module 70, and a frequency tracking or enhanced reception module 72. The NB loT UE operating mode receiving module 68 is configured to receive information whether the NB loT UE is operating in in-band, guard-band, or stand-alone mode. The NB loT data receiving module 70 is configured to receive, by a NB loT UE operating in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT radio network devices 30 operating in in-band mode. The frequency tracking or enhanced reception module 72 is operative, in radio network devices 30 operating in guard- band or stand-alone mode, to utilize the NB loT data to perform one of frequency tracking and enhanced reception by accumulating energy.

Figure 17 illustrates a plurality of modules comprising a virtual function module architecture of an apparatus operative to receive a NB NPBCH from a NB base station, using NB loT signaling. A first module 74 is configured to receive information whether the apparatus is operating in in-band, guard-band, or stand-alone mode. A second module 76 is configured to receive, by an apparatus operating in guard-band or stand-alone mode, NB loT data in symbol periods or RE which are reserved for the LTE PDCCH or LTE CRS, respectively, in NB loT UEs operating in in-band mode. A third module 78 is configured, for an apparatus operating in guard- band or stand-alone mode, to utilize the NB loT data to perform frequency tracking or enhanced reception by accumulating energy.

In all embodiments described herein, the processing circuitry 14, 34 may comprise any sequential state machine operative to execute machine instructions stored as machine-readable computer programs in the memory, such as one or more hardware-implemented state machines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logic together with appropriate firmware; one or more stored-program, general-purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above.

In all embodiments described herein, the memory 16, 36 may comprise any non- transitory machine-readable media known in the art or that may be developed, including but not limited to magnetic media (e.g., floppy disc, hard disc drive, etc.), optical media (e.g., CD-ROM, DVD-ROM, etc.), solid state media (e.g., SRAM, DRAM, DDRAM, ROM, PROM, EPROM, Flash memory, solid state disc, etc.), or the like.

In all embodiments described herein, the radio circuits may comprise one or more transceivers 18, 38 used to communicate with one or more other transceivers 38, 18 via a Radio Access Network according to one or more communication protocols known in the art or that may be developed, such as I EEE 802.xx, CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like. In particular, the transceivers 18, 38 may conform to MTC-type radio protocols such as eMTC or NB loT. The transceiver 18, 38 implements transmitter and receiver functionality appropriate to the Radio Access Network links (e.g., frequency allocations and the like). The transmitter and receiver functions may share circuit components and/or software, or alternatively may be implemented separately.

In all embodiments described herein, the communication circuits 12 may comprise a receiver and transmitter interface used to communicate with one or more other nodes over a communication network according to one or more communication protocols known in the art or that may be developed, such as Ethernet, TCP/I P, SONET, ATM, or the like. The

communication circuits 12 implement receiver and transmitter functionality appropriate to the communication network links (e.g., optical, electrical, and the like). The transmitter and receiver functions may share circuit components and/or software, or alternatively may be implemented separately.

Embodiments of the present invention present numerous advantages over the prior art. NB loT U E operating in guard-band or stand-alone mode may more fully utilize transmission physical resources to receive NB loT data from a NB base station, as compared to NB loT UE operating in in-band mode, which must reserve symbols and RE for non-interference with legacy LTE UE operation. In the case that these resources are used to transmit repetitions of data in the same or a preceding or following subframe, the NB loT UE in guard-band or stand- alone mode may use the repeated data to perform advanced functions, such as frequency tracking or enhanced reception by accumulating energy.

The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

Claims

CLAIMS What is claimed is:

1. A method (100) of transmitting information in a Narrow Band, NB, Physical Broadcast Channel, NPBCH, from a base station (11) to one or more NB Internet of Things, loT, User Equipment, UE (31), using NB loT signaling, comprising:

transmitting (102) information informing a NB loT UE (31) whether it is operating in an in- band mode wherein the NB loT UE (31) operates within a Long Term Evolution, LTE, transmission band, a guard-band mode wherein the NB loT UE (31) operates in a frequency guard band of an LTE transmission band, or a standalone mode wherein the NB loT UE (31) operates in a frequency band outside of an LTE transmission band; and

transmitting (104) to a NB loT UE (31) operating in a guard-band or stand-alone mode, NB loT data in symbol periods or resource elements, RE, which are reserved for the LTE Physical Downlink Control Channel, PDCCH, or LTE Cell-specific Reference Signals, CRS, respectively, in NB loT UEs (31) operating in in-band mode.

2. The method (100) of claim 1 wherein transmitting (104) NB loT data in symbol periods which are reserved for the LTE PDCCH in NB loT UEs (31) operating in in-band mode, comprises transmitting NB loT data in the initial k OFDM symbol periods of the subframe, where k is an integer, k>=1.

3. The method (100) of claim 2 wherein transmitting (104) NB loT data further comprises, for both normal Cyclic Prefix (CP) and extended CP cases, transmitting data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which do not include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

4. The method (100) of claim 3 further comprising, for a normal CP subframe, transmitting (104) also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 3, 5, and 6;

OFDM symbol periods 5, 6, and 9;

OFDM symbol periods 3, 9, and 10;

OFDM symbol periods 9, 10, and 12; and

OFDM symbol periods 10, 12, and 13;

5. The method (100) of claim 3 further comprising, for an extended CP subframe, transmitting (104) also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 4, 5, and 8;

OFDM symbol periods 8, 10, and 1 1 ;

OFDM symbol periods 4, 8, and 10; and

OFDM symbol periods 5, 8, and 11.

6. The method (100) of claim 2 wherein transmitting (104) NB loT data further comprises, for both normal Cyclic Prefix (CP) and extended CP cases, transmitting data in the initial k

OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

7. The method (100) of claim 6 further comprising transmitting (104) NB loT data in REs corresponding to REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

8. The method (100) of claim 7 further comprising, for a normal CP subframe, transmitting (104) also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 7, 8, and 9;

wherein the NB loT data transmitted in OFDM symbol periods 0, 1 , and 2 includes NB loT data in REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

9. The method (100) of claim 7 further comprising, for an extended CP subframe, transmitting (104) also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 6, 7, and 8;

10. The method (100) of claim 2 wherein transmitting (104) NB loT data in the initial k OFDM symbol periods further comprises transmitting a NB Physical Downlink Control Channel, PDCCH, in the initial k OFDM symbol periods.

1 1. The method (100) of claim 10 further comprising grouping REs in the initial k OFDM symbol periods into groups of four REs, to extend a search space of NB PDCCH.

12. The method (100) of claim 2 wherein transmitting (104) NB loT data in the initial k OFDM symbol periods comprises transmitting a NB Physical Downlink Shared Channel, PDSCH, in the initial k OFDM symbol periods.

13. The method (100) of claim 12 wherein the NB PDSCH transmitted in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH before the NPBCH.

14. The method (100) of claim 12 wherein the NB PDSCH transmitted in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH after the NPBCH.

15. The method (100) of claim 2 wherein transmitting (104) NB loT data in the initial k OFDM symbol periods comprises transmitting information corresponding to the last j OFDM symbols in the immediate previous subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where j is an integer, j>=1.

16. The method (100) of claim 2 wherein transmitting (104) NB loT data in the initial k OFDM symbol periods comprises transmitting information corresponding to the first m OFDM symbols in the immediate following subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where m is an integer, m>=1.

17. The method (100) of claim 1 wherein transmitting (104) NB loT data in RE which are reserved for the LTE CRS in NB loT UEs (31) operating in in-band mode, comprises

transmitting, in the reserved LTE CRS REs, a modulation symbol that is a repetition of a modulation symbol carrying NPBCH.

18. The method (100) of claim 17 wherein the modulation symbol transmitted in a reserved LTE CRS RE is a repetition of the modulation symbol immediately below, modulo 12.

19. The method (100) of claim 17 wherein the modulation symbol transmitted in a reserved LTE CRS RE is a repetition of the modulation symbol immediately above, modulo 12.

20. A base station (11) operative to transmit a Narrow Band, NB, Physical Broadcast Channel, NPBCH, to one or more NB Internet of Things, loT, User Equipment, UE (31), using NB loT signaling, the base station (1 1) comprising:

one or more antenna (20);

a transceiver (18) operatively connected to the antenna (20); and

processing circuitry (14) operatively connected to the transceiver (18) and operative to cause the transceiver (18) to:

transmit (102) information informing a NB loT UE (31) whether it is operating in an in-band mode wherein the NB loT UE (31) operates within a Long Term Evolution, LTE, transmission band, a guard-band mode wherein the NB loT UE (31) operates in a frequency guard band of an LTE transmission band, or a stand-alone mode wherein the NB loT UE (31) operates in a frequency band outside of an LTE transmission band; and transmit (104) to an NB loT UE (31) operating in a guard-band or stand-alone mode, NB loT data in symbol periods or resource elements, RE, which are reserved for the LTE Physical Downlink Control Channel, PDCCH, or LTE Cell-specific Reference Signals, CRS, respectively, in NB loT UEs

(31) operating in in-band mode.

21. The base station (11) of claim 20 wherein the processing circuitry (14) is operative to cause the transceiver (18) to transmit NB loT data in symbol periods which are reserved for the LTE PDCCH in NB loT UEs (31) operating in in-band mode, by transmitting NB loT data in the initial k OFDM symbol periods of the subframe, where k is an integer, k>=1.

22. The base station (11) of claim 21 wherein the processing circuitry (14) is operative to cause the transceiver (18) to transmit (104) NB loT data by, for both normal Cyclic Prefix (CP) and extended CP cases, transmitting data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which do not include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

23. The base station (11) of claim 22 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104), for a normal CP subframe, also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 3, 5, and 6;

OFDM symbol periods 5, 6, and 9;

OFDM symbol periods 3, 9, and 10;

OFDM symbol periods 9, 10, and 12; and

OFDM symbol periods 10, 12, and 13;

24. The base station (11) of claim 22 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104), for an extended CP subframe, also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 4, 5, and 8; OFDM symbol periods 8, 10, and 1 1 ;

OFDM symbol periods 4, 8, and 10; and

OFDM symbol periods 5, 8, and 11.

25. The base station (11) of claim 21 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data by, for both normal Cyclic Prefix (CP) and extended CP cases, transmitting data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

26. The base station (11) of claim 25 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data in REs corresponding to REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

27. The base station (1 1) of claim 26 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104), for a normal CP subframe, also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 7, 8, and 9;

28. The base station (1 1) of claim 26 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104), for an extended CP subframe, also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 6, 7, and 8;

29. The base station (11) of claim 21 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data in the initial k OFDM symbol periods by transmitting a NB Physical Downlink Control Channel, PDCCH, in the initial k OFDM symbol periods.

30. The base station (1 1) of claim 29 wherein the processing circuitry (14) is operative to group REs in the initial k OFDM symbol periods into groups of four REs, to extend a search space of NB PDCCH.

31. The base station (1 1) of claim 21 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data in the initial k OFDM symbol periods by transmitting a NB Physical Downlink Shared Channel, PDSCH, in the initial k OFDM symbol periods.

32. The base station (1 1) of claim 31 wherein the NB PDSCH transmitted in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH before the NPBCH.

33. The base station (1 1) of claim 31 wherein the NB PDSCH transmitted in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH after the NPBCH.

34. The base station (1 1) of claim 21 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data in the initial k OFDM symbol periods by transmitting information corresponding to the last j OFDM symbols in the immediate previous subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where j is an integer, j>=1.

35. The base station (1 1) of claim 21 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data in the initial k OFDM symbol periods by transmitting information corresponding to the first m OFDM symbols in the immediate following subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where m is an integer, m>=1.

36. The base station (1 1) of claim 20 wherein the processing circuitry (14) is operative to cause the transmitter (18) to transmit (104) NB loT data in RE which are reserved for the LTE CRS in NB loT UEs (31) operating in in-band mode, by transmitting, in the reserved LTE CRS REs, a modulation symbol that is a repetition of a modulation symbol carrying NPBCH.

37. The base station (1 1) of claim 36 wherein the modulation symbol transmitted in a reserved LTE CRS RE is a repetition of the modulation symbol immediately below, modulo 12.

38. The base station (1 1) of claim 36 wherein the modulation symbol transmitted in a reserved LTE CRS RE is a repetition of the modulation symbol immediately above, modulo 12.

39. An apparatus (11) operative to transmit a Narrow Band, NB, Physical Broadcast Channel, NPBCH, to one or more NB Internet of Things, loT, User Equipment, UE (31), using NB loT signaling, the apparatus (1 1) comprising:

a first module (58) operative to transmit information informing a NB loT UE (31) whether it is operating in an in-band mode wherein the NB loT UE (31) operates within a Long Term Evolution, LTE, transmission band, a guard-band mode wherein the NB loT UE (31) operates in a frequency guard band of an LTE transmission band, or a stand-alone mode wherein the NB loT UE (31) operates in a frequency band outside of an LTE transmission band; and

a second module (60) operative to transmit to a NB loT UE (31) operating in a guard- band or stand-alone mode, NB loT data in symbol periods or resource elements, RE, which are reserved for the LTE Physical Downlink Control Channel, PDCCH, or LTE Cell-specific Reference Signals, CRS, respectively, in NB loT UEs (31) operating in in-band mode.

40. A method (200) by a Narrow Band, NB, Internet of Things, loT, User Equipment, UE (31), of receiving and utilizing information in a Physical Broadcast Channel, NPBCH, from a NB base station (1 1), comprising:

receiving (202) information informing the NB loT UE (31) whether it is operating in an in- band mode wherein the NB loT UE (31) operates within a Long Term Evolution, LTE, transmission band, a guard-band mode wherein the NB loT UE (31) operates in a frequency guard band of an LTE transmission band, or a stand- alone mode wherein the NB loT UE (31) operates in a frequency band outside of an LTE transmission band;

receiving (204), by a NB loT UE (31) operating in a guard-band or stand-alone mode,

NB loT data in symbol periods or resource elements, RE, which are reserved for the LTE Physical Downlink Control Channel, PDCCH, or LTE Cell-specific

Reference Signals, CRS, respectively, in NB loT UEs (31) operating in in-band mode; and

utilizing (206) the NB loT data, by the NB loT UE (31) operating in a guard-band or stand-alone mode, to perform one of frequency tracking and enhanced reception by accumulating energy.

41. The method (200) of claim 40 wherein receiving (204) NB loT data in symbol periods which are reserved for the LTE PDCCH in NB loT UEs (31) operating in in-band mode, comprises receiving NB loT data in the initial k OFDM symbol periods of the subframe, where k is an integer, k>=1.

42. The method (200) of claim 41 wherein receiving (204) NB loT data further comprises, for both normal Cyclic Prefix (CP) and extended CP cases, receiving data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which do not include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

43. The method (200) of claim 42 further comprising, for a normal CP subframe, receiving (204) also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 3, 5, and 6;

OFDM symbol periods 5, 6, and 9; OFDM symbol periods 3, 9, and 10;

OFDM symbol periods 9, 10, and 12; and

OFDM symbol periods 10, 12, and 13;

44. The method (200) of claim 42 further comprising, for an extended CP subframe, receiving (204) also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 4, 5, and 8;

OFDM symbol periods 8, 10, and 1 1 ;

OFDM symbol periods 4, 8, and 10; and

OFDM symbol periods 5, 8, and 11.

45. The method (200) of claim 41 wherein receiving (204) NB loT data further comprises, for both normal Cyclic Prefix (CP) and extended CP cases, receiving data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

46. The method (200) of claim 45 further comprising receiving (204) NB loT data in REs corresponding to REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

47. The method (200) of claim 46 further comprising, for a normal CP subframe, receiving (204) also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 7, 8, and 9; wherein the NB loT data transmitted in OFDM symbol periods 0, 1 , and 2 includes NB loT data in REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

48. The method (200) of claim 46 further comprising, for an extended CP subframe, receiving (204) also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 6, 7, and 8;

49. The method (200) of claim 41 wherein receiving (204) NB loT data in the initial k OFDM symbol periods further comprises receiving a NB Physical Downlink Control Channel, PDCCH, in the initial k OFDM symbol periods.

50. The method (200) of claim 49 further comprising grouping REs in the initial k OFDM symbol periods into groups of four REs, to extend a search space of NB PDCCH.

51. The method (200) of claim 41 wherein receiving (204) NB loT data in the initial k OFDM symbol periods comprises receiving a NB Physical Downlink Shared Channel, PDSCH, in the initial k OFDM symbol periods.

52. The method (200) of claim 51 wherein the NB PDSCH received in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH before the NPBCH.

53. The method (200) of claim 51 wherein the NB PDSCH received in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH after the NPBCH.

54. The method (200) of claim 41 wherein receiving (204) NB loT data in the initial k OFDM symbol periods comprises receiving information corresponding to the last j OFDM symbols in the immediate previous subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where j is an integer, j>=1.

55. The method (200) of claim 41 wherein receiving (204) NB loT data in the initial k OFDM symbol periods comprises receiving information corresponding to the first m OFDM symbols in the immediate following subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where m is an integer, m>=1.

56. The method (200) of claim 40 wherein receiving (204) NB loT data in RE which are reserved for the LTE CRS in NB loT UEs (31) operating in in-band mode, comprises receiving, in the reserved LTE CRS REs, a modulation symbol that is a repetition of a modulation symbol carrying NPBCH.

57. The method (200) of claim 56 wherein the modulation symbol received in a reserved LTE CRS RE is a repetition of the modulation symbol immediately below, modulo 12.

58. The method (200) of claim 56 wherein the modulation symbol received in a reserved LTE CRS RE is a repetition of the modulation symbol immediately above, modulo 12.

59. A Narrow Band, NB, Internet of Things, loT, User Equipment, UE, (31) operative to receive a NB Physical Broadcast Channel, NPBCH, from a NB base station (11), the NB loT UE (31) comprising:

one or more antenna (40);

a transceiver (38) operatively connected to the antenna (40); and

processing circuitry (34) operatively connected to the transceiver (38) and operative to cause the transceiver (38) to:

receive (202) information informing the NB loT UE (31) whether it is operating in an in-band mode wherein the NB loT UE (31) operates within a Long

Term Evolution, LTE, transmission band, a guard-band mode wherein the NB loT UE (31) operates in a frequency guard band of an LTE transmission band, or a stand-alone mode wherein the NB loT UE (31) operates in a frequency band outside of an LTE transmission band; and receive (204), by a NB loT UE (31) operating in a guard-band or stand-alone mode, NB loT data in symbol periods or resource elements, RE, which are reserved for the LTE Physical Downlink Control Channel, PDCCH, or LTE Cell-specific Reference Signals, CRS, respectively, in NB loT UEs (31) operating in in-band mode; and

wherein the processing circuitry (34) in a NB loT UE (31) operating in a guard-band or stand-alone mode is further operative to utilize (206) the NB loT data to perform one of frequency tracking and enhanced reception by accumulating energy.

60. The NB loT UE (31) of claim 59 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in symbol periods which are reserved for the LTE PDCCH in NB loT UEs (31) operating in in-band mode, by receiving NB loT data in the initial k OFDM symbol periods of the subframe, where k is an integer, k>=1.

61. The NB loT UE (31) of claim 60 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data by, for both normal Cyclic Prefix (CP) and extended CP cases, receiving data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which do not include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

62. The NB loT UE (31) of claim 61 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204), for a normal CP subframe, also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 3, 5, and 6;

OFDM symbol periods 5, 6, and 9;

OFDM symbol periods 3, 9, and 10;

OFDM symbol periods 9, 10, and 12; and

OFDM symbol periods 10, 12, and 13;

63. The NB loT UE (31) of claim 61 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204), for an extended CP subframe, also in OFDM symbol periods 0, 1 , and 2, data from one of:

OFDM symbol periods 4, 5, and 8;

OFDM symbol periods 8, 10, and 1 1 ;

OFDM symbol periods 4, 8, and 10; and

OFDM symbol periods 5, 8, and 11.

64. The NB loT UE (31) of claim 60 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data by, for both normal Cyclic Prefix (CP) and extended CP cases, receiving data in the initial k OFDM symbol periods that carries the same information as data transmitted in one or more other OFDM symbol periods in the same subframe, outside the initial k ODFM symbol periods, which include REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

65. The NB loT UE (31) of claim 64 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in REs corresponding to REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

66. The NB loT UE (31) of claim 65 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204), for a normal CP subframe, also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 7, 8, and 9;

67. The NB loT UE (31) of claim 65 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204), for an extended CP subframe, also in OFDM symbol periods 0, 1 , and 2, NB loT data from one of:

OFDM symbol periods 3, 4, and 5; and

OFDM symbol periods 6, 7, and 8; wherein the NB loT data transmitted in OFDM symbol periods 0, 1 , and 2 includes NB loT data in REs reserved for LTE CRS in NB loT UEs (31) operating in in-band mode.

68. The NB loT UE (31) of claim 60 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in the initial k OFDM symbol periods by receiving a NB Physical Downlink Control Channel, PDCCH, in the initial k OFDM symbol periods.

69. The NB loT UE (31) of claim 68 wherein the processing circuitry (34) is operative to group REs in the initial k OFDM symbol periods into groups of four REs, to extend a search space of NB PDCCH.

70. The NB loT UE (31) of claim 60 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in the initial k OFDM symbol periods by receiving a NB Physical Downlink Shared Channel, PDSCH, in the initial k OFDM symbol periods.

71. The NB loT UE (31) of claim 70 wherein the NB PDSCH received in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH before the NPBCH.

72. The NB loT UE (31) of claim 70 wherein the NB PDSCH received in the initial k OFDM symbol periods is scheduled as part of the NB PDSCH after the NPBCH.

73. The NB loT UE (31) of claim 60 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in the initial k OFDM symbol periods by receiving information corresponding to the last j OFDM symbols in the immediate previous subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where j is an integer, j>=1.

74. The NB loT UE (31) of claim 60 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in the initial k OFDM symbol periods by receiving information corresponding to the first m OFDM symbols in the immediate following subframe, which are not configured to NB Primary Synchronization Signal (PSS) or Secondary Synchronization Signal (SSS), in the initial k OFDM symbol periods, where m is an integer, m>=1.

75. The NB loT UE (31) of claim 59 wherein the processing circuitry (34) is operative to cause the transceiver (38) to receive (204) NB loT data in RE which are reserved for the LTE CRS in NB loT UEs (31) operating in in-band mode, by receiving, in the reserved LTE CRS REs, a modulation symbol that is a repetition of a modulation symbol carrying NPBCH.

76. The NB loT UE (31) of claim 75 wherein the modulation symbol received in a reserved LTE CRS RE is a repetition of the modulation symbol immediately below, modulo 12.

77. The NB loT UE (31) of claim 75 wherein the modulation symbol received in a reserved LTE CRS RE is a repetition of the modulation symbol immediately above, modulo 12.

78. An apparatus (31) operative to receive a Narrow Band, NB, Physical Broadcast Channel, NPBCH, from a NB base station (11), the apparatus (31) comprising:

a first module (74) operative to receive information informing a NB loT UE (31) whether it is operating in an in-band mode wherein the NB loT UE (31) operates within a Long Term Evolution, LTE, transmission band, a guard-band mode wherein the NB loT UE (31) operates in a frequency guard band of an LTE transmission band, or a stand-alone mode wherein the NB loT UE (31) operates in a frequency band outside of an LTE transmission band;

a second module (76) operative to receive by a NB loT UE (31) operating in a guard- band or stand-alone mode, NB loT data in symbol periods or resource elements, RE, which are reserved for the LTE Physical Downlink Control Channel, PDCCH, or LTE Cell-specific Reference Signals, CRS, respectively, in NB loT UEs (31) operating in in-band mode; and

a third module (78) operative to utilize the NB loT data, by a NB loT UE (31) operating in a guard-band or stand-alone mode, to perform one of frequency tracking and enhanced reception by accumulating energy.