Long term evolution-M resource reservation using bitmap

A method and network node for flexible indication of resources in LTE-M using bitmaps are disclosed. According to one aspect, a method includes indicating to the wireless device a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap operating in the time-domain, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

FIELD

The present disclosure relates to wireless communications, and in particular, to Long term Evolution-Machine type (LTE-M) resource reservation using a bitmap.

BACKGROUND

The Third Generation Partnership Project (3GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs.

Machine-type communications are widely used in many applications such as vehicle tracking, user and home security, banking, remote monitoring and smart grids. According to some reports, by 2023 there will be 3.5 billion wide-area devices connected to cellular networks. In this regard, LTE-M (also referred to as LTE-Machine Type Communications (LTE-MTC), or eMTC) networks are being rolled out at a fast pace, and it is foreseen that in the next few years, a massive number of devices will be connected to the networks, addressing a wide spectrum of LTE-M use cases. Thanks to a design that enables 10-year battery lifetime of LTE-M devices, many of these devices will remain in service years after deployment. During the lifetime of these deployed LTE-M devices, many networks will undergo LTE to NR migration. A smooth migration without causing service interruption to the deployed LTE-M devices is desirable to mobile network operators (MNO). Furthermore, a migration solution that ensures superior radio resource utilization efficiency and superior coexistence performance between LTE-M and NR is highly desirable.FIG.1is a diagram showing NR and LTE-M coexistence.

NR resources in the frequency and time domains can be configured for embedding LTE-M inside an NR carrier. In the frequency domain, LTE-M specific physical signals and channels are transmitted within so called narrow bands. A narrow band may span over six Physical Resource Blocks (PRBs) where each PRB consists of 12 subcarriers.

To ensure an efficient coexistence between NR and LTE-M, it may be desirable to avoid collision between NR and LTE-M key transmissions and protecting specific signals/channels, such as NR Control Resource Set (CORESET), synchronization signal block (SSB), LTE-M cell specific reference signal (CRS), primary synchronization signal (PSS) and secondary synchronization signal (SSS). Moreover, while avoiding collision between NR and LTE-M transmissions, resource efficiency should be considered in the coexistence scenario.

NR Resource Reservation

In NR, the concept of reserved resources was introduced to, among other benefits, facilitate forward compatibility and future radio interface extensions. These reserved resources, which are not used by NR-compatible wireless devices (WDs), can also be utilized to facilitate the coexistence of NR and LTE-M. “Not used” means that an NR physical downlink shared channel (PDSCH) transmission is not mapped to resource elements that are reserved. As these reserved resources are known to the NR WD, the WD knows which resource elements are used for PDSCH and which are not for correct de-mapping. Resource reservation in NR exists on two levels, the resource block (RB) level and the resource element (RE) level. On the RB level, a reserved resource consists of all subcarrier in an indicated resource block in the frequency domain and for all or a subset of the symbols in the time slot. On RE level, certain individual resource elements in an RB and slot are indicated as reserved.

A flexible way to configure RB level resource reservation in the frequency domain is to use a bit map (bit stream) where each bit represents a resource block (RB). In NR, bitmap 1 (RBs in the frequency domain) and bitmap 2 (symbols in the time domain) are used to reserve resources in the frequency and time domains, respectively. Hence, the resource reservation in NR is two dimensional. SeeFIG.2for an example of the use of bitmap 1 and 2, using RB level resource reservation to reserve the REs of one RB and one OFDM symbol. The darkened area inFIG.2is the reserved region.

An NR reserved resource configuration is needed to support LTE-M embedding on the same carrier being used by NR, i.e., to protect LTE-M signals from NR PDSCH transmission. To this end, a set of NR resources can be reserved for non-dynamically scheduled LTE-M transmissions. In particular, resources should be reserved for at least these LTE signals, and in particular for this use case, these LTE-M signals:PSS (Primary Synchronization Signal), and SSS (Secondary Synchronization Signal) used by LTE/LTE-M WD for cell search procedure;CRS (Cell-specific Reference signal) used by LTE/LTE-M WD for channel estimation, cell selection, and coherent demodulation;PBCH (Physical Broadcast Channel) that carries system information (i.e., master information block (MIB)) for LTE/LTE-M WD requiring to access the network; and/orSIB1-BR (SystemInformationBlockType1) contents assist the LTE-M WD when it is evaluating cell access and also defines the scheduling of other system information.
Valid/invalid LTE-M subframes: LTE-M resource reservation

In LTE-M, the principle of resource reservation also exists, where a cell-specific subframe bitmap can be broadcasted by the eNB to WDs, in order to declare valid downlink subframes for LTE-M subframes. Hence, the resource reservation is one dimensional, either a subframe is valid or invalid (i.e., reserved). In this case, the bitmap length of 10 or 40 bits are used to determine valid/invalid subframes within 1 or 4 frames (a frame is 10 subframes).

For instance, an LTE-M network can indicate to an LTE-M WD, the subframes which are used for Positioning Reference Signal (PRS) or Multimedia Broadcast Multicast Service Single Frequency Network (MBSFN) transmissions as invalid for LTE-M subframes.

When LTE-M coexists with NR as in dynamic spectrum sharing (DSS), there may be several cases where it would be beneficial if the LTE-M system avoids transmitting on resources that are desired to be used by an NR system. In some cases, it is enough to handle this by having the LTE-M and NR schedulers divide the resources on a PRB and subframe/slot/symbol level, but in some cases, it may also be useful if LTE-M and NR transmission can coexist within the same PRBs. In this regard, valid and invalid LTE-M subframes can additionally be configured to protect various essential NR signals and channels. In particular, the following NR signals/channels need to be protected:CORESET (Control Resource Set) where NR PDCCH is located;The SS/PBCH block (sometimes referred to as SSB) which consists of synchronization signals (PSS and SSS), PBCH and PBCH DM-RS;TRS (Tracking Reference Signal) which is a CSI-RS resource set configured to be used for fine synchronization and channel analysis; andCSI-RS (Channel State Information Reference Signal) to be used for CSI measurements.
Clearly, valid/invalid LTE-M subframes can be useful to avoid collision between NR and LTE-M.FIG.3shows valid/invalid LTE-M subframes.

It should again be noted that invalid LTE-M subframe configurations can be considered as subframe-level LTE-M resource reservations. Here, the focus is on the LTE-M resource reservation. Note that reserved resources in LTE-M are not used for LTE-M transmissions and can be dedicated to NR signals and channels.

In the existing subframe-level LTE-M resource reservations, LTE-M transmissions are not allowed in the entire invalid LTE-M subframe(s). This, however, degrades the coexistence performance in terms of resource utilization. Considering the time-domain structure of NR signals and channels, it can be seen that they only occupy few OFDM symbols thus if such subframe is reserved for NR transmission, the rest of the reserved LTE-M subframe will be wasted as LTE-M transmission cannot take place there.

For example, SSB spans over 4 orthogonal frequency division multiplexed (OFDM) symbols, and the CORESET can occupy one, two, or three symbols within an NR slot (i.e., one subframe in 15 kHz SCS case). Similarly, channel state information reference signals (CSI-RS) and tracking reference signal (TRS) can occupy only few symbols of a slot (typically one or two). As can be seen, subframe-level LTE-M resource reservation is not efficient from resource utilization point of view.

In this case, one promising approach is to consider a finer granularity for reserving LTE-M resources in the time domain. In particular, slot-level and/or symbol-level resource reservation can be introduced in LTE-M. Having a finer resource reservation (e.g., slot-level or symbol-level) can have two advantages: 1) it improves the resource utilization in NR and LTE-M coexistence, and 2) it provides a flexibility that can facilitate the coexistence of NR URLLC services with LTE-M.

A problem exists as to how to achieve an efficient resource reservation scheme to properly configure LTE-M reserved resources.

SUMMARY

Some embodiments advantageously provide methods and network nodes for Long Term Evolution-Machine type (LTE-M) resource reservation using a bitmap.

Some embodiments provide an efficient LTE-M resource reservation scheme to ensure coexistence between NR and LTE-M systems with minimal waste of resources. According to some embodiments, a method is based on a two-level bitmap that allows reserving time-domain resources in LTE-M to prevent LTE-M transmissions in specific resources. To efficiently reserve LTE-M resources, in some embodiments, a two-level time domain bitmap solution leverages the existing bitmap-based valid/invalid subframes. In the two-level bitmap (bitmap 1 and bitmap 2) solution, the first bitmap indicates the subframes and the second bitmap shows the reserved symbols within those subframes identified by the first bitmap. Hence, partially valid subframes are introduced, where in some subframes, some symbols are valid.

Some embodiments can be used to effectively deploy LTE-M in coexistence with NR. With the LTE-M resource reservation scheme of some embodiments, signals and channels essential to NR are protected while maintaining LTE-M performance. In fact, some embodiments of a two-level bitmap-based resource reservation method in LTE-M has one or more of the following advantages: 1) some embodiments improve the resource utilization in NR and LTE-M coexistence, i.e., minimizes the amount of wasted (unused) resource elements; and 2) some embodiments provide a flexibility that can facilitate the coexistence of NR ultra reliable low latency communication (URLLC) services with LTE-M; 3) some embodiments have low overhead and implementation complexity by leveraging existing bitmap structure used for valid/invalid LTE-M subframes; and 4) some embodiments are backward compatible.

According to one aspect, a network node configured to communicate with a wireless device (WD) is provided. The network node includes processing circuitry configured to indicate to the wireless device a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap operating in the time-domain, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the processing circuitry (68) is further configured to indicate to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the broadband radio access technology is New Radio, NR. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the granularity is one of one symbol, two symbols, seven symbols and 14 symbols. In some embodiments, the processing circuitry is further configured to define multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps. In some embodiments, a first subset of subframes indicated by the first bitmap level of a first pair of two-level bitmaps and a second subset of frames indicated by the first bitmap level of a second pair of two-level bitmaps do not overlap. In some embodiments, the processing circuitry is further configured to introduce a third two-level bitmap configurable to make resources available outside the frequency band. In some embodiments, the processing circuitry is further configured to jointly encode a bitmap indicated by the first bitmap level of the two level bitmap with a bitmap indicating that a particular subframe indicated by the first bitmap level of the two level bitmap is fully valid, partially valid or invalid.

According to another aspect, a method in a network node configured to communicate with a wireless device (WD) is provided. The method includes indicating indicate to the wireless device a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap operating in the time-domain, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the method further includes indicating to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the broadband radio access technology is New Radio, NR. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the granularity is one of one symbol, two symbols, seven symbols and 14 symbols. In some embodiments, the method further includes defining multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps. In some embodiments, a first subset of subframes indicated by the first bitmap level of a first pair of two-level bitmaps and a second subset of frames indicated by the first bitmap level of a second pair of two-level bitmaps do not overlap. In some embodiments, the method includes introducing a third two-level bitmap configurable to make resources available outside the frequency band. In some embodiments, the method includes jointly encoding a bitmap indicated by the first bitmap level of the two level bitmap with a bitmap indicating that a particular subframe indicated by the first bitmap level of the two level bitmap is fully valid, partially valid or invalid.

According to another aspect, a WD, is configured to communicate with a network node. The wireless device includes processing circuitry configured to receive an indication from the network node, the indication indicating a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the processing circuitry (68) is further configured to indicate to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the processing circuitry is further configured to define multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps. In some embodiments, a first subset of subframes indicated by the first bitmap level of a first pair of two-level bitmaps and a second subset of frames indicated by the first bitmap level of a second pair of two-level bitmaps do not overlap. In some embodiments, the processing circuitry is further configured to jointly encode a bitmap indicated by the first bitmap level of the two level bitmap with a bitmap indicating that a particular subframe indicated by the first bitmap level of the two level bitmap is fully valid, partially valid or invalid.

According to yet another aspect, a method in a WD includes receiving an indication from the network node, the indication indicating a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the method further includes indicating to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the method includes defining multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps.

DETAILED DESCRIPTION

A method and network node for flexible indication of resources in LTE-M using bitmaps are disclosed. According to one aspect, a method includes indicating a set of reserved LTE-M resources using a two-level bitmap, a first bitmap level indicating a first set of subframes and a second bitmap level indicating reserved symbols within an indicated subframe. It is noted that, although embodiments are described in which a network node establishes the reserved LTE-M resources, implementations are not limited to such. It is contemplated that other network elements, such as WDs could, in some embodiments, establish the reservation of the LTE-M resources. Thus, embodiments described with respect to a network node, could apply equally to a WD.

A network node16is configured to include a reservation unit32which is configured to indicate a set of reserved Long Term Evolution-M (LTE-M), resources using a two level bitmap, a first bitmap level indicating a first set of subframes and a second bitmap level indicating reserved symbols within an indicated subframe.

Thus, the network node16further has software74stored internally in, for example, memory72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node16via an external connection. The software74may be executable by the processing circuitry68. The processing circuitry68may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node16. Processor70corresponds to one or more processors70for performing network node16functions described herein. The memory72is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software74may include instructions that, when executed by the processor70and/or processing circuitry68, causes the processor70and/or processing circuitry68to perform the processes described herein with respect to network node16. For example, processing circuitry68of the network node16may include reservation unit32configured to indicate a set of reserved Long Term Evolution-M (LTE-M), resources using a two level bitmap, a first bitmap level indicating a first set of subframes and a second bitmap level indicating reserved symbols within an indicated subframe.

The communication system10further includes the WD22already referred to. The WD22may have hardware80that may include a radio interface82configured to set up and maintain a wireless connection64with a network node16serving a coverage area18in which the WD22is currently located. The radio interface82may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

The processing circuitry84may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD22. The processor86corresponds to one or more processors86for performing WD22functions described herein. The WD22includes memory88that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software90and/or the client application92may include instructions that, when executed by the processor86and/or processing circuitry84, causes the processor86and/or processing circuitry84to perform the processes described herein with respect to WD22.

In some embodiments, the inner workings of the network node16, WD22, and host computer24may be as shown inFIG.5and independently, the surrounding network topology may be that ofFIG.4.

In some embodiments, the host computer24includes processing circuitry42and a communication interface40that is configured to a communication interface40configured to receive user data originating from a transmission from a WD22to a network node16. In some embodiments, the WD22is configured to, and/or comprises a radio interface82and/or processing circuitry84configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the network node16, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the network node16.

AlthoughFIGS.4and5show various “units” such as reservation unit32as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG.10is a flowchart of an exemplary process in a network node16according to some embodiments disclosed herein. One or more blocks described herein may be performed by one or more elements of network node16such as by one or more of processing circuitry68(including the reservation unit32), processor70, radio interface62and/or communication interface60. Network node16such as via processing circuitry68and/or processor70and/or radio interface62and/or communication interface60is configured to indicate a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap, a first bitmap level of the two level bitmap indicating a first set of subframes, and a second bitmap level of the two level bitmap indicating one of reserved symbols and reserved slots within an indicated subframe, the indicated one of reserved symbols and reserved slots being indicated as valid (Block S134).

Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for Long term Evolution-Machine type (LTE-M) resource reservation using a bitmap.

A flexible way to indicate reserved resources in LTE-M is to use a set of bitmaps. In particular, a bitmap with a specific length can point to time-domain resources (symbols, slots, or subframes) which should not be used by LTE-M WDs22(an illustrative example is shown inFIG.11). In the current LTE-M system there are bitmaps of length 10 or 40 bits that can be used for indicating valid/invalid subframes in downlink and/or uplink within one or four frames.

In order to configure slot-level or symbol-level LTE-M resource reservation, some embodiments include a two-level bitmap (bitmap level 1 and bitmap level 2, not to be confused with the NR resource reservation parameters bitmap 1 and bitmap 2 described earlier) operating in the time domain, in which bitmap level 1 indicates a subset of subframes and bitmap level 2 shows the reserved symbols within those subframes identified by bitmap level 1.

For example, in bitmap level 1, a “0” indicates a subframe which is fully available (valid) for LTE-M, and a “1” refers to a subframe which is not fully available (or partially valid) for LTE-M (i.e., some of the symbols within this subframe are reserved). Then, bitmap level 2 can be used only for those partially valid subframes to indicate which symbols are reserved. As an example,FIG.12shows the slot-level resource reservation using two-level bitmap. In this figure, the second slot of the partially valid is reserved.

In general, the granularity of the second level resource reservation can be one OFDM symbol, two symbols, seven symbols, or 14 symbols. The one-symbol granularity may be the smallest granularity, the seven-symbol granularity may be slot-level, and 14-symbol granularity may be the existing subframe-level resource reservation.

The overhead of resource reservation may depend on the bitmap length which itself depends on the granularity. Table 1 lists the length of bitmap 1 and bitmap 2 in some embodiments showing the two-level bitmap resource reservation method described herein.

Given the resource reservation schemes described, at least the following embodiments are set forth:

In one embodiment, a two-level bitmap may be used, such as by the network node16, to indicate the set of reserved LTE-M resources.

In another embodiment, symbol-level, slot-level, or subframe-level resource reservation can be configured.

In another embodiment, in the two-level bitmap, bitmap level 1 indicates the subframes and bitmap level 2 shows the reserved symbols within those subframes identified by the first bitmap.

In another embodiment, bitmap level 1 indicates whether each subframe is fully available (valid) or partially available (partially valid) for LTE-M. In another embodiment, bitmap level 2 can determine reserved symbols within each partially valid subframe identified by bitmap level 1. In another embodiment, the granularity of resource reservation is determined based on the overhead of bitmaps.

In one embodiment, multiple pairs of two-level bitmaps are defined, where in each pair, bitmap level 1 indicates a subset of subframes and the bitmap level 2 in each pair uses a different granularity. Each pair may use a bitmap level 1 of the same or different lengths. The subset of subframes indicated by bitmap level 1 of the different pairs may only be allowed to be non-overlapping. Configuration of overlapping subframes of bitmap level 1 from different pairs is an invalid configuration.

In a related embodiment, one two-level bitmap is combined with a bitmap representing subframe-level resource reservation, such as an existing bitmap for signaling valid/invalid subframes, for example fdd-DownlinkOrTddSubframeBitmapBR. This way, it is possible to signal that a particular subframe is “fully valid”, “partially valid” and “invalid”. The same functionality can be achieved by jointly encoding the bitmaps, thereby optimizing the number of bits needed to be signaled. In one such embodiment, the length of bitmap level 1 is reduced from its original size (e.g. 10 or 40 as indicated above), to a length equal to the number of subframes indicated as valid, e.g., by an existing bitmap such as fdd-DownlinkOrTddSubframeBitmapBR.

In partially available subframes, the WD22may assume that LTE-M transmission takes place in the non-reserved resources.

In yet another embodiment, a third bitmap, bitmap level 3, operates on an RB level in the frequency domain. The third bitmap can be used to make resources available outside a certain frequency band, i.e., a band containing the SSB. Hence, when bitmap level 1 and 2 reserve resources in the time domain, i.e., in certain symbols in some subframes, this is then combined with bitmap level 3 information which has the length equal to the number of RBs. If bitmap level 1 and bitmap level 2 indicate that a symbol is reserved, then that symbol is only reserved for those RBs as indicated by bitmap level 3. If bitmap level 3 indicates that an RB is valid, then that RB is valid for all symbols in all subframes, without regard to the information in bitmap level 1 and bitmap level 2. This can be used to protect NR SSB and NR CORESET from LTE-M collisions.

According to one aspect, a network node16configured to communicate with a wireless device (WD)22is provided. The network node16includes processing circuitry68configured to indicate to the wireless device22a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap operating in the time-domain, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the processing circuitry68is further configured to indicate to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the broadband radio access technology is New Radio, NR. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the granularity is one of one symbol, two symbols, seven symbols and 14 symbols. In some embodiments, the processing circuitry68is further configured to define multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps. In some embodiments, a first subset of subframes indicated by the first bitmap level of a first pair of two-level bitmaps and a second subset of frames indicated by the first bitmap level of a second pair of two-level bitmaps do not overlap. In some embodiments, the processing circuitry68is further configured to introduce a third two-level bitmap configurable to make resources available outside the frequency band. In some embodiments, the processing circuitry is further configured to jointly encode a bitmap indicated by the first bitmap level of the two level bitmap with a bitmap indicating that a particular subframe indicated by the first bitmap level of the two level bitmap is fully valid, partially valid or invalid.

According to another aspect, a method in a network node16configured to communicate with a wireless device (WD)22is provided. The method includes indicating, via the processing circuitry68, to the wireless device a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap operating in the time-domain, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the method further includes indicating to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the broadband radio access technology is New Radio, NR. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the granularity is one of one symbol, two symbols, seven symbols and 14 symbols. In some embodiments, the method further includes defining multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps. In some embodiments, a first subset of subframes indicated by the first bitmap level of a first pair of two-level bitmaps and a second subset of frames indicated by the first bitmap level of a second pair of two-level bitmaps do not overlap. In some embodiments, the method includes introducing a third two-level bitmap configurable to make resources available outside the frequency band. In some embodiments, the method includes jointly encoding a bitmap indicated by the first bitmap level of the two level bitmap with a bitmap indicating that a particular subframe indicated by the first bitmap level of the two level bitmap is fully valid, partially valid or invalid.

According to another aspect, a WD22is configured to communicate with a network node16. The wireless device22includes processing circuitry84configured to receive an indication from the network node, the indication indicating a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the processing circuitry (68) is further configured to indicate to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the processing circuitry is further configured to define multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps. In some embodiments, a first subset of subframes indicated by the first bitmap level of a first pair of two-level bitmaps and a second subset of frames indicated by the first bitmap level of a second pair of two-level bitmaps do not overlap. In some embodiments, the processing circuitry is further configured to jointly encode a bitmap indicated by the first bitmap level of the two level bitmap with a bitmap indicating that a particular subframe indicated by the first bitmap level of the two level bitmap is fully valid, partially valid or invalid.

According to yet another aspect, a method in a WD22includes receiving an indication from the network node16, the indication indicating a set of reserved resources for machine communications in compatibility with a broadband radio access technology sharing resources in a time frame and frequency band that encompasses the set of reserved resources, the indicating using a two level bitmap, a first bitmap level of the two level bitmap indicating a first set of subframes containing reserved resources, and a second bitmap level of the two level bitmap indicating reserved symbols within an indicated subframe.

According to this aspect, in some embodiments, the indicated reserved resources are not used for Long Term Evolution Machine Communications, LTE-M, transmissions. In some embodiments, resources not indicated as reserved resources may be used by for LTE-M transmissions. In some embodiments, the first bitmap level of the two level bitmap indicates whether a subframe is available or partially available for Long Term Evolution Machine Communications, LTE-M. In some embodiments, the method further includes indicating to the wireless device a set resource blocks using a third bitmap, the third bitmap indicating for which resource blocks in frequency domain the time-domain resource reservation indicated by the two level bitmap applies. In some embodiments, a granularity of a resource reservation is based on an overhead of bitmaps. In some embodiments, the method includes defining multiple pairs of two-level bitmaps, within each pair, the first bitmap level of the two level bitmap indicating a subset of subframes and the second bitmap level of the two level bitmap indicating a granularity of resource reservation. In some embodiments, the second bitmap level of a first pair of two-level bitmaps is of indicates a resource reservation granularity that is different from a second bitmap level of a second pair of two-level bitmaps.

Some embodiments include:

Embodiment A1. A network node configured to communicate with a wireless device (WD), the network node configured to, and/or comprising a radio interface and/or comprising processing circuitry configured to:indicate a set of reserved Long Term Evolution machine type, LTE-M, resources using a two level bitmap, a first bitmap level indicating a first set of subframes and a second bitmap level indicating reserved symbols within an indicated subframe.

Embodiment A2. The network node of Embodiment A1, wherein the first bitmap level indicates whether a subframe is available or partially available for LTE-M.

Embodiment A3. The network node of Embodiment A1, wherein a granularity of a resource reservation is based on an overhead of bitmaps.

Embodiment A4. The network node of any of Embodiments A1-A3, wherein the network node and/or the radio interface and/or the processing circuitry is further configured to define multiple pairs of two-level bitmaps, within each pair, the first bitmap level indicates a subset of subframes and the second bitmap level uses a different granularity.

Embodiment A5. The network node of any of Embodiments A1-A4, wherein the network node and/or the radio interface and/or the processing circuitry is further configured to introduce a third bitmap level configurable to make resources available outside a frequency band.

Embodiment B1. A method implemented in a network node, the method comprising:indicating a set of reserved Long Term Evolution machine type, LTE-M, resources using a two level bitmap, a first bitmap level indicating a first set of subframes and a second bitmap level indicating reserved symbols within an indicated subframe.

Embodiment B2. The method of Embodiment B1, wherein the first bitmap level indicates whether a subframe is available or partially available for LTE-M.

Embodiment B3. The method of Embodiment B1, wherein a granularity of a resource reservation is based on an overhead of bitmaps.

Embodiment B4. The method of any of Embodiments B1-B3, further comprising defining multiple pairs of two-level bitmaps, within each pair, the first bitmap level indicates a subset of subframes and the second bitmap level uses a different granularity.

Embodiment B5. The method of any of Embodiments B1-B4, further comprising introducing a third bitmap level configurable to make resources available outside a frequency band.

Abbreviations that may be used in the preceding description include: