WO2018030258A1

WO2018030258A1 - Wireless terminal

Info

Publication number: WO2018030258A1
Application number: PCT/JP2017/028198
Authority: WO
Inventors: 裕之安達; 真人藤代; 真裕美甲村; ヘンリーチャン
Original assignee: 京セラ株式会社
Priority date: 2016-08-10
Filing date: 2017-08-03
Publication date: 2018-02-15

Abstract

A wireless terminal having a first feature and to be used in a mobile communication system, the wireless terminal being equipped with a control unit for performing processing for transmitting, to a base station, location information indicating the geographical location of the wireless terminal. The location information is used in order for the base station to allocate wireless resources to the wireless terminal. The control unit performs compression processing for reducing the bit number of the location information to be transmitted, on the basis of the movement speed and/or movement distance of the wireless terminal.

Description

Wireless terminal

The present disclosure relates to a wireless terminal used in a mobile communication system.

In 3GPP (3rd Generation Partnership Project), a standardization project for mobile communication systems, direct communication between terminals (D2D: Device-to-Device) that directly communicates between wireless terminals is specified. In recent years, vehicle-to-vehicle (V2V: Vehicle-to-Vehicle) communication using an in-vehicle wireless terminal has attracted attention. In the V2V communication technology, it is assumed that the occurrence of interference is suppressed by changing radio resources used for transmission according to the position of the radio terminal.

In order to realize such a resource allocation method, the radio terminal transmits position information indicating the geographical position of the radio terminal to the base station, and the base station allocates radio resources to the radio terminal based on the position information. Can be considered. However, the resource allocation method based on position information requires detailed position information (for example, latitude and longitude information) of the wireless terminal. For this reason, there is a concern about an increase in overhead associated with position information transmission.

The wireless terminal according to the first feature is a wireless terminal for a mobile communication system. The wireless terminal includes a control unit that performs a process of transmitting position information indicating a geographical position of the wireless terminal to a base station. The location information is used by the base station to allocate radio resources to the radio terminal. The control unit performs a compression process for reducing the number of bits of the position information to be transmitted based on at least one of a moving distance and a moving speed of the wireless terminal.

The wireless terminal according to the second feature is a wireless terminal for a mobile communication system. The wireless terminal includes a control unit that performs a process of transmitting position information indicating a geographical position of the wireless terminal to a base station. The location information is used by the base station to allocate radio resources to the radio terminal. The control unit determines a transmission timing of the position information based on at least one of a moving distance and a moving speed of the wireless terminal.

The wireless terminal according to the third feature is a wireless terminal for a mobile communication system. The wireless terminal is a wireless terminal for a mobile communication system. A control unit is provided that performs processing for transmitting position information indicating a geographical position of the wireless terminal to a base station. The location information is used by the base station to allocate radio resources to the radio terminal. The control unit performs a process of switching to a specific method based on at least one of a moving distance and a moving speed of the wireless terminal. The specific method is a method in which the wireless terminal autonomously selects a radio resource based on the position information without transmitting the position information.

It is a figure which shows the structure of the LTE system which concerns on embodiment. It is a figure which shows the structure of UE (radio | wireless terminal) which concerns on embodiment. It is a figure which shows the structure of eNB (base station) which concerns on embodiment. It is a figure which shows the structure of the protocol stack of the radio | wireless interface which concerns on embodiment. It is a figure which shows the relationship between the bit number of the positional information which concerns on embodiment, the distance which can be notified, and the time when a value makes a round at 60 km / h. It is a figure which shows the resource allocation based on the positional information which concerns on 1st Embodiment. It is a figure which shows the 1st example of the compression process of the positional information which concerns on 1st Embodiment. It is a figure which shows the 2nd example of the compression process of the positional information which concerns on 1st Embodiment. It is a figure which shows an example of the relationship between the moving speed of UE, and the time (elapsed time) when the value which shows the latitude changes. It is a figure which shows the resource allocation based on the positional information which concerns on 2nd Embodiment. It is a figure which shows the 1st example of the process which determines the transmission timing of the positional information which concerns on 2nd Embodiment. It is a figure which shows the 2nd example of the process which determines the transmission timing of the positional information which concerns on 2nd Embodiment. It is a figure which shows the 3rd example of the process which determines the transmission timing of the positional information which concerns on 2nd Embodiment. It is a figure which shows the resource allocation based on the positional information which concerns on 3rd Embodiment.

(Configuration of mobile communication system)
A configuration of the mobile communication system according to the embodiment will be described. The mobile communication system according to the embodiment is an LTE (Long Term Evolution) system based on the 3GPP standard.

FIG. 1 is a diagram illustrating a configuration of an LTE (Long Term Evolution) system. As shown in FIG. 1, the LTE system includes a radio terminal (UE: User Equipment) 100, a radio access network (E-UTRAN: Evolved-UMTS Terrestrial Radio Access Network) 10, and a core network (EPC: Evolved Packet Core) 20. Is provided.

UE 100 is a mobile communication device. The UE 100 performs radio communication with the eNB 200 that manages a cell (serving cell) in which the UE 100 is located. The UE 100 may be a vehicle-mounted UE (V-UE: Vehicle UE).

The E-UTRAN 10 includes a base station (eNB: evolved Node-B) 200. The eNB 200 is connected to each other via the X2 interface. The eNB 200 manages one or a plurality of cells. eNB200 performs radio | wireless communication with UE100 which established the connection with the cell which eNB200 manages. The eNB 200 has a radio resource management (RRM) function, a routing function of user data (hereinafter simply referred to as “data”), a measurement control function for mobility control / scheduling, and the like. “Cell” is used as a term indicating a minimum unit of a wireless communication area. The “cell” is also used as a term indicating a function or resource for performing wireless communication with the UE 100.

The EPC 20 includes a mobility management entity (MME) and a serving gateway (S-GW) 300. MME performs various mobility control etc. with respect to UE100. The S-GW performs data transfer control. The MME / S-GW is connected to the eNB 200 via the S1 interface.

FIG. 2 is a diagram illustrating a configuration of the UE 100 (wireless terminal). As illustrated in FIG. 2, the UE 100 includes a reception unit 110, a transmission unit 120, a control unit 130, and a GNSS (Global Navigation Satellite System) receiver 140.

The receiving unit 110 performs various types of reception under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 130.

The transmission unit 120 performs various transmissions under the control of the control unit 130. The transmission unit 120 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output from the control unit 130 into a radio signal and transmits it from the antenna.

The control unit 130 performs various controls in the UE 100. The control unit 130 includes at least one processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor includes a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of the baseband signal. The CPU performs various processes by executing programs stored in the memory. The processor executes processing to be described later.

The GNSS receiver 140 receives a GNSS satellite signal under the control of the control unit 130 and outputs position information indicating the geographical position of the UE 100 to the control unit 130. GNSS may be read as GPS (Global Positioning System). The position information includes latitude and longitude information. The UE 100 may include at least one sensor (for example, a gyro sensor or an acceleration sensor) that can be used for correcting position information, measuring a moving speed, and measuring a moving distance.

FIG. 3 is a diagram illustrating a configuration of the eNB 200 (base station). As illustrated in FIG. 3, the eNB 200 includes a transmission unit 210, a reception unit 220, a control unit 230, and a backhaul communication unit 240.

The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output from the control unit 230 into a radio signal and transmits it from the antenna.

The receiving unit 220 performs various types of reception under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

The control unit 230 performs various controls in the eNB 200. The control unit 230 includes at least one processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor includes a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of the baseband signal. The CPU performs various processes by executing programs stored in the memory. The processor executes processing to be described later.

The backhaul communication unit 240 is connected to the neighboring eNB 200 via the X2 interface. The backhaul communication unit 240 is connected to the MME / S-GW 300 via the S1 interface. The backhaul communication unit 240 is used for communication performed on the X2 interface, communication performed on the S1 interface, and the like.

FIG. 4 is a diagram showing a configuration of a protocol stack of a radio interface in the LTE system. As shown in FIG. 4, the radio interface protocol is divided into the first to third layers of the OSI reference model. The first layer is a physical (PHY) layer. The second layer includes a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. The third layer includes an RRC (Radio Resource Control) layer.

The physical layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the physical layer of the UE 100 and the physical layer of the eNB 200 via a physical channel.

The MAC layer performs data priority control, retransmission processing by hybrid ARQ (HARQ), random access procedure, and the like. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the eNB 200 via a transport channel. The MAC layer of the eNB 200 includes a scheduler. The scheduler determines the uplink / downlink transport format (transport block size, modulation / coding scheme (MCS)) and the resource blocks allocated to the UE 100.

The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the physical layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the eNB 200 via a logical channel.

The PDCP layer performs header compression / decompression and encryption / decryption.

The RRC layer is defined only in the control plane that handles control information. Messages for various settings (RRC messages) are transmitted between the RRC layer of the UE 100 and the RRC layer of the eNB 200. The RRC layer controls the logical channel, the transport channel, and the physical channel according to establishment, re-establishment, and release of the radio bearer. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the eNB 200, the UE 100 is in the RRC connected mode. Otherwise, the UE 100 is in RRC idle mode.

The NAS (Non-Access Stratum) layer located above the RRC layer performs session management and mobility management.

(Resource allocation based on location information)
In the embodiment, a scenario in which V2V communication using the vehicle-mounted UE 100 is performed is assumed. In the V2V communication technology, it is assumed that the occurrence of interference is suppressed by changing radio resources used for transmission according to the position of the UE 100. UE100 transmits the positional information which shows own geographical position to eNB200. The eNB 200 allocates radio resources to the UE 100 based on the location information. The allocation of radio resources is performed using, for example, downlink control information (DCI). UE100 transmits data to other UE100 using the link between UE (side link) using the radio | wireless resource allocated from eNB200. Such dynamic side link communication resource allocation may be referred to as “Mode 1”.

In the embodiment, the position information is latitude and longitude information. As an example, the latitude is an integer (INTEGER) within a range of 0 ° to 90 ° and a value of 0 to 8388607. The latitude is configured as 23-bit length information. As for the latitude, the value of INTEGER changes by one with a movement of about 1.2 m. On the other hand, the longitude is an integer (INTEGER) within a range of −180 ° to 180 ° and has a value of −8388608 to 8388607. The longitude is configured as 24-bit length information. As for the longitude, the value of INTEGER changes by one with a movement of about 2.4 m.

In the latitude and longitude information, the upper bits do not change unless the UE 100 moves a sufficient distance. The information of the lower bits is very detailed as compared with the GPS / GNSS accuracy, and may be too detailed as information for the eNB 200 to use for resource allocation based on the location information.

(First embodiment)
A first embodiment will be described. The first embodiment is an embodiment that can efficiently reduce the number of bits of position information transmitted from the UE 100 to the eNB 200 in resource allocation based on position information (latitude and longitude information). In 1st Embodiment, the case where UE100 transmits a positional information to eNB200 periodically is mainly assumed. However, the position information may be transmitted by an event trigger instead of the periodic position information transmission.

UE100 which concerns on 1st Embodiment performs the process (Geo-information reporting) which transmits the positional information which shows own geographical position to eNB200. The location information is used for the eNB 200 to allocate radio resources to the UE 100. The UE 100 performs a compression process for reducing the number of bits of position information based on at least one of its own moving distance and moving speed. eNB200 grasps the position of UE100 based on position information. The eNB 200 receives the compressed position information from the UE 100. The eNB 200 grasps the latest position of the UE 100 based on the grasped position information and the compressed position information.

As an example, the UE 100 transmits only some bits of position information by compression processing until it moves a certain distance. Here, the “partial bits” may be lower-order bits of the position information. The “certain distance” may be set from the eNB 200 to the UE 100. The upper bits of the position information do not change unless the UE 100 moves a sufficient distance. Therefore, the number of bits of the position information can be efficiently reduced by omitting the transmission of the upper bits. The UE 100 transmits complete position information in response to moving a certain distance. Thereby, it can prevent eNB200 misrecognizing the position of UE100.

As another example, the UE 100 receives setting information for setting a compression processing method from the eNB 200. UE100 performs a compression process based on setting information. The setting information indicates information indicating whether or not the position information can be compressed, information indicating the bit number / bit range (bit position) of the position information to be transmitted by the UE 100, and accuracy of the position information to be transmitted by the UE 100 (for example, in units of 10 m). At least one of the information is included. The eNB 200 may set the UE 100 not to transmit the number of upper bits of the position information that will not change based on the size of its own cell. The UE 100 determines whether or not to perform compression processing based on information indicating whether or not position information can be compressed. The UE 100 determines the number of bits / bit range (bit position) of the position information to be transmitted to the eNB 200 based on the information indicating the number of bits / bit range (bit position) of the position information and / or information indicating the accuracy of the position information. To do. Thereby, UE100 can perform the positional information transmission suitable for the positional information which the eNB200 requires, and its precision.

As another example, the UE 100 determines a compression processing method based on at least one of its moving distance and moving speed. That is, even if the compression processing method is not specified from the eNB 200, the UE 100 autonomously determines the compression processing method based on the moving distance, the moving speed, its own capability (positioning capability, etc.), and the like. Specifically, the UE 100 autonomously determines at least one of the position information compression propriety, the number of bits / bit range (bit position) of the position information to be transmitted by the UE 100, and the accuracy of the position information. In this case, the UE 100 includes at least one of information indicating whether the position information is compressed, information indicating the number of bits / bit range (bit position) of the position information, and information indicating the accuracy of the position information together with the position information. You may transmit to eNB200. Thereby, UE100 can transmit a positional information appropriately according to an own condition.

As another example, the UE 100 transmits only the difference between the current position information and the complete position information by a compression process within a predetermined time after transmitting the complete position information. The “difference” may be expressed by a moving direction and a moving distance. The “predetermined time” may be a certain time. The “certain time” may be set from the eNB 200 to the UE 100. Alternatively, the “predetermined time” may be a time required to move a certain distance as described above.

The above-described examples are not limited to being implemented separately and may be implemented by combining two or more examples.

FIG. 5 is a diagram showing the relationship between the number of bits of position information, the distance that can be notified, and the time for which the value makes a round at 60 km / h. Here, a case is assumed in which lower-order bits of position information are transmitted to eNB 200. As shown in FIG. 5, the position information can be notified as the number of bits of the position information decreases. On the other hand, the greater the number of bits, the longer the position information can be notified. In other words, if the moving distance of the UE 100 is short, only a small number of bits are changed, so that the position information to be transmitted needs only a small number of bits. As the position information has a smaller number of bits, the time required for the value to go around becomes shorter. On the other hand, as the number of bits of the position information increases, the time for the value to go around becomes longer. In other words, if the moving speed of the UE 100 is low, an accurate value can be expressed even with a small number of bits, so that the position information to be transmitted needs only a small number of bits.

FIG. 6 is a diagram showing resource allocation based on position information according to the first embodiment.

As shown in FIG. 6, in step S <b> 11, the eNB 200 transmits setting information for setting transmission of position information to the UE 100. The eNB 200 may transmit the setting information by RRC signaling (dedicated RRC signaling or broadcast RRC signaling). The setting information includes various setting parameters described later. The dedicated RRC signaling may be an RRC Connection Reconfiguration message. Broadcast RRC signaling may be a system information block (SIB). The SIB may be SIB type 18 (SIB 18) for side link communication, or SIB type 21 (SIB 21) for V2V.

In step S12, the UE 100 acquires its position information (latitude and longitude information) using the GNSS receiver 140. The UE 100 may acquire the position information without using the GNSS receiver 140. As an example, the UE (V-UE) 100 may acquire position information based on information obtained from sensors provided in the UE 100 and / or information obtained from a vehicle. Such information includes acceleration information, speed information, information indicating the steering wheel rotation angle of the vehicle, direction information using an electronic compass (geomagnetic sensor), map information of a car navigation system, and an in-vehicle camera mounted on the vehicle. The information of the road sign contained in the obtained image is mentioned. Or UE100 may acquire position information using the intensity and the arrival angle of a radio signal. The same applies to the acquisition of the following position information.

The condition for starting acquisition of the location information may be that the eNB 200 is set to transmit the location information in Step S11 or that the transmission resource of Mode 1 is set.

In step S13, the UE 100 calculates its moving distance and / or moving speed. The movement distance is a movement distance based on the position when the position information was transmitted last time. The moving speed may be calculated based on the position information. The moving speed may be calculated using a sensor. Step S12 may be executed after step S13.

In step S14, the UE 100 determines whether or not to compress the position information based on the movement distance and / or movement speed of the UE 100. Whether the moving distance is used, whether the moving speed is used, and / or whether the compression process is performed may be set from the eNB 200 to the UE 100. When the position information compression process is not performed (step S14: NO), in step S17, the UE 100 transmits complete position information (that is, uncompressed position information) to the eNB 200.

On the other hand, when the position information compression process is performed (step S14: YES), in step S15, the UE 100 determines a compression method of the position information. UE100 may determine the compression method according to the setting information from eNB200. The UE 100 may autonomously determine the compression method. In step S16, the UE 100 performs position information compression processing. The position information compression process may be a process of extracting some bits of the position information. The position information compression process may be a process of calculating a difference (direction and distance) from the previous position information. In step S17, the UE 100 transmits the compressed position information to the eNB 200. The location information may be transmitted to the eNB 200 by RRC signaling (for example, Sidelink UEInformation or UE Assistance Information message), or may be transmitted to the eNB 200 as a MAC control element (CE).

ENB200 receives the compressed location information from UE100. The eNB 200 grasps the latest position of the UE 100 based on the grasped position information and the compressed position information. In step S18, the eNB 200 selects a radio resource (time / frequency resource) corresponding to the latest position of the UE 100. The eNB 200 transmits resource allocation information indicating the selected radio resource to the UE 100. The resource allocation information may be transmitted to the UE 100 as downlink control information (DCI). The resource allocation information may be transmitted to the UE 100 by RRC signaling.

In step S19, the UE 100 identifies an assigned radio resource based on the resource assignment information. The UE 100 transmits data (and a control signal) on the side link using the specified assigned radio resource. The other UEs on the receiving side know the transmission radio resource candidates in advance, and receive data (and control signals) from the UE 100 by trying to receive all the transmission radio resources.

FIG. 7 is a diagram showing a first example of position information compression processing. As shown in FIG. 7, in step S111, the UE 100 transmits complete position information to the eNB 200. In step S112, the UE 100 initializes a movement distance counter and starts counting the movement distance. In step S113, based on the value of the counter, the UE 100 determines whether or not the moving distance after transmitting complete position information exceeds a certain distance. The certain distance (distance threshold) may be set from the eNB 200 to the UE 100. If “NO” in the step S113, in the step S114, the UE 100 compresses the current position information, and transmits the compressed position information to the eNB 200. After transmitting the compressed position information, the process returns to step S113. On the other hand, if “YES” in the step S113, the process returns to the step S111, and the UE 100 transmits complete position information to the eNB 200.

FIG. 8 is a diagram showing a second example of position information compression processing. As illustrated in FIG. 8, in step S121, the UE 100 transmits complete position information to the eNB 200. In step S122, the UE 100 initializes an elapsed time timer and starts measuring the elapsed time. In step S123, based on the value of the counter, the UE 100 determines whether or not an elapsed time after transmitting complete position information exceeds a certain time. The certain time (time threshold value) may be set from the eNB 200 to the UE 100. If “NO” in the step S123, in the step S124, the UE 100 compresses the current position information, and transmits the compressed position information to the eNB 200. After transmitting the compressed position information, the process returns to step S123. On the other hand, if “YES” in the step S123, the process returns to the step S121, and the UE 100 transmits complete position information to the eNB 200.

As described above, according to the first embodiment, in resource allocation based on position information (latitude and longitude information), the number of bits of position information transmitted from the UE 100 to the eNB 200 can be efficiently reduced.

(Second Embodiment)
A second embodiment will be described. However, differences from the first embodiment will be mainly described, and redundant description will be omitted. The second embodiment is an embodiment in which position information can be transmitted from the UE 100 to the eNB 200 at an appropriate timing in resource allocation based on position information (latitude and longitude information).

There are two patterns of position information transmission timing: a timing at which a predetermined event occurs (that is, an event trigger) or a periodic timing.

In the event trigger pattern, a method of transmitting position information triggered by a change in a value indicating latitude or a value indicating longitude is conceivable. In the example described above, the value indicating latitude changes with a movement of about 1.2 [m], and the value indicating latitude changes with a movement of about 2.4 [m]. FIG. 9 is a diagram illustrating an example of the relationship between the moving speed of the UE 100 and the time (elapsed time) when the value indicating the latitude changes. As illustrated in FIG. 9, the lower the moving speed of the UE 100, the lower the frequency of updating the position information, and the higher the moving speed of the UE 100, the higher the frequency of updating the position information. Therefore, the UE 100 that is moving at high speed may be frequently triggered to transmit the location information.

On the other hand, in the periodic timing pattern, the transmission cycle of the position information can be set from the eNB 200 to the UE 100. However, considering the possibility that the UE 100 moves at high speed, it is considered that the position information transmission cycle must be set short.

However, frequent transmission of location information causes an increase in overhead in both event trigger and periodic patterns.

Therefore, the UE 100 according to the second embodiment determines the transmission timing of the position information based on at least one of its movement distance and movement speed.

As an example, the UE 100 receives the movement distance threshold value from the eNB 200, and transmits position information in response to the movement distance of the UE 100 exceeding the movement distance threshold value. Thereby, since UE100 should just transmit position information, only when it moves the distance designated from eNB200, it can prevent the frequent transmission of position information efficiently.

As another example, the UE 100 periodically transmits location information (Periodic reporting). The UE 100 stops the transmission of the periodic position information in response to the fact that the UE 100 is stopped or the moving speed is low. The threshold for determining that the vehicle is stopped or the moving speed is low may be set from the eNB 200 to the UE 100. As a result, even if the UE 100 is configured to transmit periodic location information, if the UE 100 is stopped or moving at a very low speed (for example, in a traffic jam or waiting for a signal), the UE 100 stops or is very slow. Location information is not sent while moving with. Thereby, frequent transmission of position information can be efficiently prevented.

As another example, the UE 100 periodically transmits location information (Periodic reporting). In response to the fact that the UE 100 is stopped, the UE 100 transmits a notification indicating that it is stopped to the eNB 200 instead of the location information. The said notification may be transmitted to eNB200 by RRC signaling, and may be transmitted to eNB200 as a MAC control element (CE). The notification may be a 1-bit flag. Thereby, even if position information is transmitted frequently, an increase in overhead can be suppressed.

As another example, the UE 100 periodically transmits location information (Periodic reporting). UE100 changes the transmission cycle of position information according to a moving speed. The correspondence relationship between the moving speed and the transmission cycle may be set from the eNB 200 to the UE 100. As a result, even if the UE 100 is configured to transmit periodic location information, the location information can be transmitted in a cycle suitable for its own moving speed, thereby efficiently preventing frequent transmission of location information. can do.

FIG. 10 is a diagram showing resource allocation based on position information according to the second embodiment. The description of the same operations as those in the first embodiment described above will be omitted.

As illustrated in FIG. 10, in step S <b> 21, the eNB 200 transmits setting information for setting transmission of position information to the UE 100. The setting information includes various setting parameters described later. The setting information may include information indicating whether transmission of position information is an event trigger or periodic. When setting periodic position information transmission, the setting information may include information indicating a transmission cycle of position information.

In step S22, the UE 100 acquires its own location information (latitude and longitude information). In step S23, the UE 100 calculates its moving distance and / or moving speed.

In step S24, the UE 100 determines whether or not to transmit position information based on its own moving distance and / or moving speed. When the position information is not transmitted (step S24: NO), the process returns to step S22.

On the other hand, when transmitting location information (step S24: YES), in step S25, the UE 100 transmits location information to the eNB 200.

The eNB 200 grasps the latest position of the UE 100 based on the received position information. In step S26, the eNB 200 selects a radio resource (time / frequency resource) corresponding to the latest position of the UE 100. The eNB transmits resource allocation information indicating the selected radio resource to the UE 100.

In step S27, the UE 100 identifies an assigned radio resource based on the resource assignment information. The UE 100 transmits data (and a control signal) on the side link using the allocated radio resource.

FIG. 11 is a diagram illustrating a first example of processing for determining the transmission timing of position information. In the first example, the eNB 200 sets the movement distance threshold value to the UE 100. The unit of the movement distance is any one of “m”, “degree”, and “value based on INTEGER expressing latitude / longitude”. As illustrated in FIG. 11, in step S211, the UE 100 transmits location information to the eNB 200. In step S212, the UE 100 initializes a movement distance counter and starts counting the movement distance. In step S213, based on the value of the counter, the UE 100 determines whether or not the moving distance since the previous transmission of the position information has exceeded a certain distance. The certain distance (distance threshold) may be set from the eNB 200 to the UE 100. The UE 100 may calculate the difference between the previously transmitted position information and the latest position information acquired this time as the movement distance. Thereby, a case (for example, a U-turn or a multi-story parking lot) where the moving distance is long but has not greatly changed geographically can be excluded. When it is "YES" at Step S213, processing returns to Step S211 and UE100 transmits position information to eNB200. The UE 100 may transmit the position information in response to receiving a request from the eNB 200 even when the moving distance does not exceed the moving distance threshold.

FIG. 12 is a diagram illustrating a second example of processing for determining the transmission timing of position information. A 2nd example assumes the case where transmission of periodic position information is set to UE100. The eNB 200 may set the UE 100 to permit the stop of the transmission of the periodic position information. eNB200 may set the threshold value for determining that it is stopping or the moving speed is low in UE100. As illustrated in FIG. 12, in step S221, the UE 100 starts a timer that defines a transmission cycle of position information. In step S222, the UE 100 determines whether or not the timer has expired. If “YES” in the step S222, in the step S223, the UE 100 determines whether or not the moving speed is equal to or higher than a threshold value. When it is "YES" at Step S223, UE100 transmits position information to eNB200 in Step S224. On the other hand, when “NO” in step S223 (that is, when the UE 100 is stopped or the moving speed is low), the UE 100 skips transmission of position information. Thereafter, the process returns to step S221.

FIG. 13 is a diagram illustrating a third example of processing for determining the transmission timing of position information. The third example assumes a case where transmission of periodic location information is set in the UE 100. The eNB 200 sets a plurality of timer values associated with the moving speed range in the UE 100. Each of the plurality of timer values defines a transmission cycle of position information. As illustrated in FIG. 13, in step S231, the UE 100 selects any one of a plurality of timer values set from the eNB 200 according to its own moving speed. Specifically, the UE 100 compares the speed range corresponding to each timer value with its moving speed. And UE100 selects the timer value corresponding to the speed range to which own moving speed belongs. In step S232, the UE 100 starts a timer in which the selected timer value is set. In step S233, the UE 100 determines whether or not the timer has expired. When it is "YES" at Step S233, UE100 transmits position information to eNB200 in Step S234. Thereafter, the process returns to step S231.

(Third embodiment)
A third embodiment will be described. However, differences from the first and second embodiments will be mainly described, and redundant description will be omitted. The third embodiment is an embodiment in which resource allocation methods based on position information (latitude and longitude information) can be properly used.

UE100 which concerns on 3rd Embodiment performs the process which transmits the positional information which shows own geographical position to eNB200. The location information is used for the eNB 200 to allocate radio resources to the UE 100. UE100 performs the process switched to a specific system based on at least one of own moving distance and moving speed. The specific method is a method in which the UE 100 autonomously selects a radio resource based on the position information without transmitting the position information. Thereby, for example, it is not necessary to transmit the location information to the eNB 200 while the UE 100 is moving at high speed, so that frequent transmission of the location information can be efficiently prevented.

The method in which the eNB 200 allocates radio resources to the UE 100 based on the location information may be referred to as “Mode 1”. On the other hand, a method of autonomously selecting radio resources for the UE 100 based on the location information may be referred to as “Mode 2”. In Mode 2, the UE 100 converts the position information into a zone ID using a predetermined rule (for example, modulo calculation). The eNB 200 notifies the UE 100 of the correspondence relationship between the zone ID and the resource pool. UE100 specifies the resource pool corresponding to zone ID obtained from own position information, and selects the radio | wireless resource used for transmission from the specified resource pool.

FIG. 14 is a diagram showing resource allocation based on position information according to the third embodiment. The description of the same operations as those in the first and second embodiments described above will be omitted. Here, the description will be made assuming that Mode 1 is initially set in the UE 100.

As shown in FIG. 14, in step S31, the eNB 200 transmits setting information for setting transmission of position information to the UE 100. The setting information may include a moving speed threshold value. When assuming an event trigger pattern, the eNB 200 may set a recommended minimum transmission time interval (transmission cycle) as a threshold value. In this case, the UE 100 may determine that the UE 100 is moving at high speed when the transmission of the position information is triggered before the set time interval elapses.

In step S32, the UE 100 acquires its own location information (latitude and longitude information). In step S33, the UE 100 calculates its moving speed.

In step S34, the UE 100 determines whether or not its own moving speed is equal to or higher than a moving speed threshold value. The moving speed threshold may be set from the eNB 200 to the UE 100. When the own moving speed is less than the moving speed threshold (step S34: NO), Mode 1 is maintained.

On the other hand, when the own moving speed is equal to or higher than the moving speed threshold (step S34: YES), the UE 100 determines to switch to Mode 2 in step S35. In step S36, the UE 100 transmits a notification to that effect to the eNB 200. The notification may be transmitted to the eNB 200 by RRC signaling (for example, Sidelink UEInformation message). The notification may be transmitted to the eNB 200 as a MAC CE.

In step S37, the eNB 200 sets the transmission resource pool information for Mode 2 in the UE 100. The resource pool information may include a plurality of combinations of zone IDs and transmission resource pools. The resource pool information may be transmitted to the UE 100 by dedicated RRC signaling (for example, RRC Connection Reconfiguration message) or MAC CE. Alternatively, when a transmission resource pool is preset in the UE 100, the eNB 200 may instruct the UE 100 to use the preset transmission resource pool. The eNB 200 may cause the UE 100 to transition to the RRC idle mode.

In step S38, the UE 100 selects a radio resource from the transmission resource pool. In step S39, the UE 100 transmits data (and a control signal) on the side link using the selected radio resource.

The UE 100 may switch from Mode 2 to Mode 1 when the moving speed of the UE 100 falls below the threshold.

14, whether or not to switch to Mode 2 is determined based on the moving speed of the UE 100, but the determination may be performed in consideration of the moving distance. As an example, the UE 100 determines that the mode 1 is maintained when the moving speed is fast (the moving speed is equal to or greater than the threshold) but is not separated as an absolute distance from the position where the complete position information has been transmitted in the past. May be. Such a condition may be set from the eNB 200 to the UE 100.

(Other embodiments)
In each embodiment mentioned above, the scenario which performs V2V communication using vehicle-mounted UE100 was mainly assumed. However, a scenario for performing D2D communication using a normal UE 100 may be assumed. Although a scenario in which the eNB 200 performs resource allocation for V2V communication is assumed, a scenario in which the eNB 200 performs resource allocation for cellular communication (uplink communication or downlink communication) may be assumed.

Not only when each embodiment mentioned above is implemented independently, you may implement combining two or more embodiments. For example, a part of the configuration according to one embodiment may be added to another embodiment. Alternatively, some configurations according to one embodiment may be replaced with some configurations according to another embodiment.

In the above-described embodiment, the LTE system is exemplified as the mobile communication system. However, the present disclosure is not limited to LTE systems. The present disclosure may be applied to a system other than the LTE system.

The entire contents of US Provisional Application No. 62/372912 (filed on August 10, 2016) are incorporated herein by reference.

This disclosure is useful in the mobile communication field.

Claims

A wireless terminal for a mobile communication system,
A control unit that performs processing for transmitting position information indicating a geographical position of the wireless terminal to a base station;
The location information is used by the base station to allocate radio resources to the radio terminal,
The said control part is a radio | wireless terminal which performs the compression process for reducing the bit number of the said positional information to transmit based on at least one of the movement distance and movement speed of the said radio | wireless terminal.
The control unit transmits only some bits of the position information by the compression process until it moves a certain distance,
The wireless terminal according to claim 1, wherein the control unit transmits complete position information in response to movement of the certain distance.
The control unit receives setting information for setting the compression processing method from the base station,
The wireless terminal according to claim 1, wherein the control unit performs the compression processing based on the setting information.
The wireless terminal according to claim 1, wherein the control unit determines the compression processing method based on at least one of a moving distance and a moving speed of the wireless terminal.
The wireless terminal according to claim 1, wherein the control unit transmits only a difference between the current position information and the complete position information by the compression process within a predetermined time after transmitting the complete position information.
A wireless terminal for a mobile communication system,
A control unit that performs processing for transmitting position information indicating a geographical position of the wireless terminal to a base station;
The location information is used by the base station to allocate radio resources to the radio terminal,
The said control part is a radio | wireless terminal which determines the transmission timing of the said positional information based on at least one of the movement distance and the movement speed of the said radio | wireless terminal.
The control unit receives a movement distance threshold from the base station,
The wireless terminal according to claim 6, wherein the control unit transmits the position information in response to the movement distance exceeding the movement distance threshold.
The control unit periodically transmits the position information,
The wireless terminal according to claim 6, wherein the control unit stops transmission of periodic position information in response to the wireless terminal being stopped or the moving speed being low.
The control unit periodically transmits the position information,
The wireless terminal according to claim 6, wherein the control unit transmits a notification indicating that the wireless terminal is stopped, instead of the position information, to the base station in response to the wireless terminal being stopped.
The control unit periodically transmits the position information,
The wireless terminal according to claim 6, wherein the control unit changes a transmission cycle of the position information according to the moving speed.
A wireless terminal for a mobile communication system,
A control unit that performs processing for transmitting position information indicating a geographical position of the wireless terminal to a base station;
The location information is used by the base station to allocate radio resources to the radio terminal,
The control unit performs a process of switching to a specific method based on at least one of a moving distance and a moving speed of the wireless terminal,
The specific method is a method in which the wireless terminal autonomously selects a wireless resource based on the position information without transmitting the position information.