Patent Description:
Currently V2V(vehicle to vehicle)/V2X (vehicle to everything) resource pool which is used for transmitting and/or receiving sidelink signals consists of certain resources in time and frequency domains, and the resource positions in the time domain are indicated by a bitmap. If a certain bit of the bitmap indicates "<NUM>", it means that it is a V2V/V2X subframe, otherwise if a certain bit of the bitmap indicates "<NUM>", it means that it is not a V2V/V2X subframe.

Based on current agreement of 3GPP (the 3rd Generation Partnership Project), the size of the bitmap can be <NUM>, <NUM> or <NUM> bits. Which bitmap size is used in the communication could be configured or preconfigured. Based on current agreement of 3GPP, some subframes such as the subframes transmitting sidelink synchronization signal (SLSS) should be excluded for the resource pool, and the bitmap may not be repeated by integer times within the remaining subframes (after excluding SLSS subframes) within the system frame number (SFN/DFN) cycle. For example, it is assumed that there are <NUM> subframes within a SFN cycle, and a SLSS subframe is transmitted per <NUM> so there are <NUM> SLSS subframes within the SFN cycle, the number of the remaining subframes are <NUM>-<NUM>=<NUM>, which cannot be divided by the size of the bitmap such as <NUM> bits or <NUM> bits. There would be some resource collision problems in case that the remaining subframes cannot be divided by the size of the bitmap.

<FIG> shows an example of non-integer times of bitmap repetition within the SFN cycle.

In <FIG>, the subframes that are indicated with ` <NUM>' via a bitmap represent that they are within the resource pool, and the subframes that are indicated with '<NUM>' via a bitmap represent that they are not within the resource pool. The indications of the bitmap are repeated within the SFN cycle. In <FIG>, the subframes indicated by '<NUM>' according to the bitmap may be used by other user equipments or other usages like transmitting PUSCH.

As shown in <FIG>, the last bitmap repetition is crossing the DFN/SFN boundary. If a UE (User Equipment) uses this bitmap and reserves the resource as indicated with a numeral reference '<NUM>' , the reserved resource may collide with the resources of other UEs in a next DFN/SFN cycle as the bitmap is applied from start or certain offset of SFN/DFN cycle.

Based on this consideration, RAN1 of 3GPP agreed to adopt a concept of "reserved subframe", which should be excluded from the resource pool configuration within the SFN/DFN cycle. In this case, the remaining subframes after excluding the SLSS subframes and the reserved subframes could allow the bitmap repetition with integer times within the SFN/DFN cycle. Still based on the above example that there are <NUM> subframes within the SFN cycle, the number of the SLSS subframes is <NUM>, and the number of the reserved subframes is <NUM>, the number of the remaining subframes for the resource pool is <NUM>-<NUM>-<NUM>=<NUM>, which could be divided by a <NUM>-bit bitmap. In this case, the collision problem described by <FIG> can be solved.

<FIG> shows an example that a subframe is reserved within the SFN/DFN cycle presented in the R1-<NUM> (a meeting disclosure of RAN1).

As shown in <FIG>, a subframe <NUM> is a reserved subframe and should be excluded for the resource pool. In addition, subframes <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> are used to transmit the SLSS signals and should be excluded for the resource pool as well.

Ericsson, Pool design for V2V, 3GPP Draft, R1-<NUM>, relates to a structure and subframe indexing for pools for V2V communication. In particular, the V2V is defined by a repeating bitmap of length <NUM>, <NUM>, or <NUM> mapped to a period of <NUM> subframes except for at least SLSS subframes. A number of reserved subframes which cannot be used for V2X communication is introduced such that the remaining number of subframes has an integer number of <NUM>-subframe periods corresponding to the bitmap length.

LG Electronics, Summary of Wednesday V2V offline discussions, 3GPPP Draft, R1-<NUM>, relates to resource pool design for V2X communication. In particular, a V2X period consists of <NUM> consecutive subframes. Subframes used for the transmission of SLSS are excluded from V2X periods. Moreover, Nreserved subframes are excluded from V2X periods to ensure that N divides the number of available subframes (i.e. <NUM> - #N_SLSS-subframes - Nreserved).

Based on the above background art, the problem is how to set or indicate the reserved subframes within the SFN/DFN cycle. Therefore, the present disclosure is made in consideration of the above aspects.

The methods of the present disclosure could realize the advantages that the resource waste and sidelink transmission latency in the communication system are minimized.

These and/or other aspects and advantages of the present disclosure will become more clear and easier to be understood in detailed description of embodiments of the present disclosure below in conjunction with attached drawings, in which:.

In the following detailed description, reference is made to the accompanying drawings, which form a part of the present disclosure. In the drawings, similar symbols typically indicate similar components, unless the context dictates otherwise. It will be readily understood that aspects of the present disclosure can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make a part of the present disclosure.

<FIG> shows a method of setting the reserved subframes according to one embodiment of the present disclosure.

The method as shown in <FIG> is performed in a V2V(Vehicle to vehicle)/V2X (vehicle to everything) communication system. In the V2V/V2X communication system, the resource pool is used for transmitting and/or receiving sidelink signals within a system frame number (SFN/DFN) cycle. DFN is Direct Frame Number which could refer to 3GPP TS <NUM>. It is a cycle which consists of uplink subframes. In FDD, SFN cycle is basically the same as DFN cycle, but in TDD, SFN cycle will include all of downlink subframe, special subframe and uplink subframes. The proposed methods could be used for both SFN cycle and DFN cycle, but for description simplicity, SFN is mainly assumed in the following examples.

The system frame number (SFN) cycle includes predefined subframes and remaining subframes. The remaining subframes are subframes after excluding the predefined subframes within the system frame number cycle. In the present disclosure, a bitmap indicates whether or not a subframe is a V2V/V2X resource. In the present disclosure, the terms "predefined subframe" and "excluded subframe" have the same meaning in the context. The method as shown in <FIG> can be executed in either a user equipment side or a base station side.

As shown in <FIG>, the method of setting the reserved subframes for indication of a resource pool according to one embodiment of the present disclosure comprises of a step S301 and a step S302. In the step S301, a number of the reserved subframes is determined so that the bitmap is repeated by integer times within the subframes after excluding the reserved subframes and the predefined subframes within the system frame number cycle. In the step S302, a position of each of the reserved subframes is set, wherein at most two reserved subframes are set per n subframes within the system frame number cycle.

According to all embodiments of the present disclosure, the number of the reserved subframes can be determined based on the size of the bitmap and the number of the remaining subframes within the system frame number cycle. For example, the number of the reserved subframes equals to the operation of (the number of the remaining subframes) mod (the bitmap size). Specifically, the number 'Y' of the reserved subframes can be determined based on the following formula: X=(a number of the total subframes within a system frame number cycle - a number of the predefined subframes within a system frame number cycle), and Y = X mod (the bitmap size).

<FIG> shows an example of the method of setting the reserved subframes according to one embodiment of the present disclosure.

In the <FIG>, each subframe is transmitted in a time of <NUM>. In <FIG>, the blank blocks represent the excluded subframes such as SLSS subframes, and the blocks with oblique lines represent the reserved subframes.

As stated above, based on the agreement, the subframes transmitting sidelink synchronization signal (SLSS) should be excluded for the resource pool. In the following context, the subframes that should be excluded is referred to as "excluded subframes" or "predefined subframes". In the example as shown in <FIG>, it is assumed that there are <NUM> subframes within a system frame number (SFN) cycle, and each SLSS subframe is transmitted per <NUM> so there are <NUM> SLSS subframes within the SFN cycle. The number of the remaining subframes after the excluded subframes are excluded are <NUM>-<NUM>=<NUM>.

For a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM> as the calculation (<NUM> mod <NUM>) equals to <NUM>. For a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM> as the calculation (<NUM> mod <NUM>) equals to <NUM>. For a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM> as the calculation (<NUM> mod <NUM>) equals to <NUM>.

According to an embodiment of the present disclosure, the `n' subframes are determined based on subframe index that is continuous within the system frame number cycle. For example, the subframe index can be the subframe order number such as SF#<NUM>, SF#<NUM>, SF#<NUM>, SF#<NUM>,. , SF#<NUM> as shown in <FIG>, which are continuous within the system frame number cycle. In this case, the above `n subframes' include both of the remaining subfrmaes and the predefined subframes such as SLSS subframes. That is, the reserved subframes are set per `n subframes' no matter whether or not the predefined subframes are contained in the `n subframes'.

In this situation, the position of a reserved subframe may overlap with any of the predefined subframes which should be excluded for indication of the resource pool within the system frame number cycle. In this case, the reserved subframe should be set in a subframe closest to and before or after the predefined subframe within the remaining subframes.

According to an embodiment of the present disclosure, as shown in <FIG>, it can be assumed that n=<NUM>, i.e., one subframe can be reserved per <NUM> subframes (as indicated as HFN). According to another embodiment, the "<NUM> subframes" can be counted from the start of system frame number cycle (in this example, the number of subframe offset is assumed as zero). In an example that there is a subframe offset within the SFN cycle, the "<NUM> subframes" can be counted from the end of the subframe offset within system frame number cycle.

In this case, for a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM>, so the reserved subframes can be from HFN#<NUM> to HFN#<NUM>. For a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM>, so the reserved subframes can be from HFN#<NUM> to HFN#<NUM>.

According to another example, the "<NUM> subframes" are not necessary to be counted from the start of the system frame number cycle, the "<NUM> subframes" can be counted from any position of the system frame number cycle. For example, In the case of a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM>, the "<NUM> subframes" can be from HFN#<NUM> to HFN#<NUM>, or from HFN#<NUM> to HFN#<NUM>, etc. In the case of a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM>, the "<NUM> subframes" can be from HFN#<NUM> to HFN#<NUM>, or from HFN#<NUM> to HFN#<NUM>, or from HFN#<NUM> to HFN#<NUM>, etc..

For the embodiment that n=<NUM>, the benefit is that it is a simple solution from standardization point of view, and it can be used for any case considering that a maximum number of subframes after mod operation is <NUM>. Also as the position of the reserved subframe is somehow common, different resource pool configurations may be related with the same reserved subframes so that resource utilization is improved.

According to another example of the present embodiment, the n subframes can be determined based on the remaining subframes within the system frame number cycle. That means that the above `n subframes' do not include the predefined subframes. That is, the reserved subframes are set per `n subframes' in which the `n subframes' are n remaining subframes available for the resource pool that do not contain the predefined subframes.

The number 'n' equals to the operation of FLOOR (the number of the remaining subframes / the number of the reserved subframes)", where FLOOR is the operation of round down to the nearest integer. Specifically, the number 'n' can be determined based on the following formula: <MAT>.

where FLOOR is the operation of round down to the nearest integer.

According to another example of the embodiment, a reserved subframe and an excluded subframe such as the SLSS subframe can not overlap. If their positions overlap, the reserved subframe should be placed in a subframe before or after the excluded subframe that is overlapped.

<FIG> shows another example of the method of setting the reserved subframes according to one embodiment of the present disclosure.

In <FIG>, the blank blocks represent the predefined subframes such as the SLSS subframes, and the blocks with oblique lines represent the reserved subframes.

In this example, it is also assumed that there are <NUM> subframes within a SFN cycle, and <NUM> SLSS subframes are excluded for V2X resource pool in which <NUM> periodicity of a SLSS subframe is assumed so that the remaining subframes are <NUM>-<NUM>=<NUM> subframes.

In the example as shown in <FIG>, each of the reserved subframes is set at middle of two predefined subframes such as the SLSS subframes that are adjacent to each other. In this case, since each SLSS subframe is transmitted in a period of <NUM> periodicity, one or two reserved subframes are set per <NUM> subframes within the system frame number cycle.

Specifically, for a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM>. For a bitmap with a size of <NUM>, the number of the reserved subframe is <NUM>, and one reserved subframe can be set at middle of two SLSS subframes from start or other positions of the SFN cycle.

However, for a bitmap with a size of <NUM> bits, the number of the reserved subframe is <NUM>. In this case, if only one reserved subframe is set at middle of two adjacent predefined subframes such as the SLSS subframes, there are <NUM> reserved subframes left nowhere to be set. According to another example of the present disclosure, a pair of two reserved subframes will be set at middle of two predefined subframes such as the SLSS subframes. The number of "<NUM>" reserved subframes between the same two predefined subframes such as the SLSS subframes is <NUM>-<NUM> = <NUM>, and the number of '<NUM>' reserved subframes is <NUM>. The pattern setting the reserved subframes may be like {<NUM><NUM><NUM>. <NUM><NUM><NUM>. <NUM><NUM><NUM>}, or {<NUM><NUM><NUM>. <NUM><NUM><NUM>. <NUM><NUM><NUM>}, or {<NUM><NUM><NUM>. <NUM>}, {<NUM><NUM>. <NUM><NUM><NUM>}, or {<NUM><NUM><NUM>. <NUM><NUM><NUM>}, or {<NUM><NUM>. <NUM><NUM><NUM>. <NUM>, or {<NUM><NUM><NUM>. <NUM><NUM><NUM>. <NUM><NUM><NUM>}, or others. The above pattern means that the "<NUM>" reserved subframes between the same two predefined subframes such as the SLSS subframes can be placed at any position within the SFN cuycle.

The benefit of such an embodiment is that all the predefined subframes and the reserved subframes for the resource pool are distributed as much as possible and it minimizes the latency of the sidelink signal transmission.

<FIG> shows a further example of the method of setting the reserved subframes according to one embodiment of the present disclosure.

In this example, it is also assumed that there are <NUM> subframes within a SFN cycle, <NUM> SLSS subframes are excluded for V2X resource pool, and the periodicity of a SLSS subframe is assumed as <NUM>, so V2X resource pool has <NUM>-<NUM>=<NUM> subframes.

As stated above, the number 'n' is determined based on the following formula: <MAT>.

Based on the above formula, for a bitmap with a size of <NUM> bits, X = <NUM>, Y = <NUM> mod <NUM> = <NUM>, n = floor (<NUM> / <NUM>) = <NUM>. Therefore, one reserved subframe can be set per <NUM> subframes within the SFN cycle, and totally there are <NUM> reserved subframes. In this case, the bitmap with <NUM> bits could be repeated by integer times within the SFN cycle. For a bitmap with a size of <NUM> bits and a bitmap with a size of <NUM> bits, the same procedure could be carried out.

In all embodiments, in addition to the sidelink synchronization subframes (SLSS), the predefined subframes further include downlink subframes and/or special subframes in TDD, and subframes indicatd by a subframe offset with the first system frame number (SFN#<NUM>) within the system frame number cycle. That is, the predefined subframes include at least one of the downlink subframes and the special subframes in TDD, the sidelink synchronization subframes, and the subframes indicated by a subframe offset with the start of the system frame number cycle. In a special case for example for FDD, the subframe offset could be set to zero.

Specifically, in case of TDD where there are downlink (DL) subframes, special subframes and uplink (UL) subframes, the DL subframes and the special subframes as well as the SLSS subframes should be excluded for the resource pool. For example, for TDD configuration <NUM>, there are only <NUM> uplink subframes within a SFN cycle, and these <NUM> uplink subframes are potential subframes for V2X resource pool. Assuming the number of the SLSS subframes is <NUM>, the remaining subframes are <NUM>-<NUM> = <NUM> subframes for V2X resource pool. Based on the above formula, X= <NUM>, Y = (<NUM> mod <NUM>) = <NUM>, n = FLOOR (<NUM>/<NUM>) = <NUM>. It means that one reserved subframe is set per <NUM> uplink subframes.

<FIG> shows an example of the user equipment for setting reserved subframes according to one embodiment of the present disclosure.

In the user equipment as shown in <FIG>, the resource pool is used for transmitting and/or receiving sidelink signals within a system frame number cycle. The system frame number cycle includes predefined subframes and remaining subframes. The remaining subframes are subframes after excluding the predefined subframes within the system frame number cycle. A bitmap indicates whether or not a subframe is a V2V/V2X resource.

As shown in <FIG>, the user equipment <NUM> according to the embodiment of the present disclosure includes a communication unit <NUM>, a subframe reservation unit <NUM>, a microprocessor unit <NUM>, and a memory unit <NUM>. The above respective units are interconnected by use of data and/or control bus within the user equipment <NUM>.

According to an embodiment of the present disclosure, the user equipment <NUM> is configured to communicate with other user equipments or base stations by use of a resource pool.

The communication unit <NUM> is configured to transmit sidelink signals to other user equipments or base stations and/or receive sidelink signals from the other user equipments or base stations by use of V2V(vehicle to vehicle)/V2X (vehicle to everything) resource pool in the communication system. The communication unit <NUM> may further comprise other hardware such as a baseband processor and a radio frequency modulation unit for processing and/or modulating the signals to be transmitted in the communication system.

The subframe reservation unit <NUM> is configured to set reserved subframes, wherein a number of the reserved subframes is determined so that the bitmap is repeated by integer times within the subframes after excluding the reserved subframes and the predefined subframes within the system frame number cycle, and at most two reserved subframes are set per n subframes within the system frame number cycle.

The microprocessor unit <NUM> is configured to execute related programs to process various data stored in the memory unit <NUM>, and control operations of respective units in the user equipment <NUM>.

The memory unit <NUM> may further include a ROM (Read Only Memory) and a RAM (Random Access Memory) which are not shown in the Figure. The ROM is configured to store various programs required for performing various processes and controls by the microprocessor <NUM>, and the RAM is configured to store intermediate data temporarily produced in the procedure of the processes and controls by the microprocessor unit <NUM>.

According to one embodiment of the present disclosure, the user equipment <NUM> may further comprise an antenna unit. The antenna unit is configured to transmit and/or receive signals to and/or from other user equipments or base stations.

According to one embodiment of the present disclosure, the user equipment <NUM> may further comprise an interface unit. The interface unit may be but not limited to one type of USB, IEEE13954, RJ11, RJ45, etc. The interface unit is configured to connect with user's external devices, such as but not limited to a computer device, a keyboard, or a mouse, and receive control information and/or program command from the user and/or output data to the user's external devices.

Respective devices and/or units as described above do not limit the scope of the present disclosure, and the user equipment <NUM> of the present disclosure may include more or less devices and/or units.

According to all embodiments of the present disclosure, the number of the reserved subframes is determined based on the size of the bitmap and the number of the remaining subframes within the system frame number cycle.

According to all embodiments of the present disclosure, the number of the reserved subframes equals to the operation of (the number of the remaining subframes) mod (the bitmap size).

According to another embodiment of the present disclosure, each of the reserved subframes is set at middle of the adjacent predefined subframes.

According to another embodiment of the present disclosure, the n subframes are based on subframe index that is continuous within the system frame number cycle.

According to another embodiment of the present disclosure, if the position of the reserved subframe overlaps with any of the predefined subframe that should be excluded for indication of the resource pool within the system frame number cycle, the reserved subframe is set in a closest subframe before or after the predefined subframe within remaining subframes.

According to another embodiment of the present disclosure, the number 'n' is at least <NUM>.

According to another embodiment of the present disclosure, the n subframes are based on the remaining subframes within the system frame number cycle.

According to all embodiments of the present disclosure, the number n equals to the operation of FLOOR (the number of the remaining subframes / the number of the reserved subframes)", where FLOOR is the operation of round down to the nearest integer.

According to all embodiments of the present disclosure, the predefined subframes include at least one of downlink subframes and special subframes in TDD, sidelink synchronization subframes, and subframes indicated by a subframe offset with the start of system frame number within the system frame number cycle.

<FIG> shows an example of the base station for setting reserved subframes according to one embodiment of the present disclosure.

In the base station as shown in <FIG>, the resource pool is used for transmitting and/or receiving sidelink signals within a system frame number cycle. The system frame number cycle includes predefined subframes and remaining subframes. The remaining subframes are subframes after excluding the predefined subframes within the system frame number cycle. A bitmap indicates whether or not a subframe is a V2V/V2X resource.

As shown in <FIG>, the base station <NUM> according to the embodiment of the present disclosure includes a communication unit <NUM>, a subframe reservation unit <NUM>, a microprocessor unit <NUM>, and a memory unit <NUM>. The above respective units are interconnected by use of data and/or control bus within the base station <NUM>.

According to an embodiment of the present disclosure, the base station <NUM> is configured to communicate with other base stations or user equipments by use of the resource pool.

The communication unit <NUM> is configured to transmit sidelink signals to other base stations or user equipments and/or receive sidelink signals from the other base stations or user equipments by use of V2V(vehicle to vehicle)/V2X (vehicle to everything) resource pool in the communication system. The communication unit <NUM> may further comprise other hardware such as a baseband processor and a radio frequency modulation unit for processing and/or modulating the signals to be transmitted in the communication system.

The subframe reservation unit <NUM> is configured to set reserved subframes, wherein the number of the reserved subframes is determined so that the bitmap is repeated by integer times within the subframes after excluding the reserved subframes and the predefined subframes within the system frame number cycle, and at most two reserved subframes are set per n subframes within the system frame number cycle.

The microprocessor unit <NUM> is configured to execute related programs to process various data stored in the memory unit <NUM>, and control operations of respective units in the base station <NUM>.

According to one embodiment of the present disclosure, the base station <NUM> may further comprise an antenna unit. The antenna unit is configured to transmit and/or receive sidelink signals to and/or from other base stations or user equipments.

According to one embodiment of the present disclosure, the base station <NUM> may further comprise an interface unit. The interface unit may be but not limited to one type of USB, IEEE13954, RJ11, RJ45, etc. The interface unit is configured to connect with user's external devices, such as but not limited to a computer device, a keyboard, or a mouse, and receive control information and/or program command from the user and/or output data to the user's external devices.

Respective devices and/or units as described above do not limit the scope of the present disclosure, and the base station <NUM> of the present disclosure may include more or less devices and/or units.

According to all embodiments of the present disclosure, the number 'n' equals to the operation of FLOOR (the number of the remaining subframes / the number of the reserved subframes)", where FLOOR is the operation of round down to the nearest integer.

The above embodiments of the present disclosure are only exemplary description, and their specific structures and operations do not limit the scope of the present disclosure. Those skilled in the art can recombine different parts and operations of the above respective embodiments to produce new implementations which equally accord with the concept of the present disclosure.

The embodiments of the present disclosure may be implemented by hardware, software and firmware or in a combination thereof, and the way of implementation does not limit the scope of the present disclosure.

The connection relationships between the respective functional elements (units) in the embodiments of the present disclosure do not limit the scope of the present disclosure, in which one or multiple functional element(s) or unit(s) may contain in or be connected to any other functional elements.

Claim 1:
A communication method comprising:
determining a first set of subframes available for a sidelink operation; and
transmitting a sidelink signal in a subframe among the first set of subframes,
wherein the first set of subframes is comprised of subframes within <NUM> subframes except both of a second set of subframes and reserved subframes, the second set of subframes including subframes in which sidelink synchronization signal, SLSS, is configured, the reserved subframes being determined based on a length of a bitmap configured for resource pools of the sidelink operation,
characterized in that
a number of the reserved subframes within the <NUM> subframes is determined by a following formula: <MAT> (the length of the bitmap),
where X=<NUM> - (a number of the second set of subframes), and
the reserved subframes are set per n subframes to subframes except the second set of subframes within the <NUM> subframes, the n subframes not containing the second set, n being determined by a following formula: <MAT>
where FLOOR is the operation of round down to the nearest integer,
wherein, the second set of subframes includes at least one of downlink subframes and special subframes in TDD, and
wherein, each bit of the bitmap indicates whether each corresponding subframe is a subframe used for the sidelink operation.