WO2017154160A1

WO2017154160A1 - Base station, terminal, radio communication system and processing method

Info

Publication number: WO2017154160A1
Application number: PCT/JP2016/057479
Authority: WO
Inventors: 中村　道春
Original assignee: 富士通株式会社
Priority date: 2016-03-09
Filing date: 2016-03-09
Publication date: 2017-09-14

Abstract

A terminal (120) transmits a random access signal by use of a first radio resource. A base station (110) receives the random access signal transmitted thereto by use of the first radio resource and identifies, on the basis of the received random access signal, the terminal (120) having transmitted the random access signal. The base station (110) then transmits a response signal that is responsive to the random access signal and that permits the identified terminal (120) to transmit data to the base station (110) by use of a second radio resource different from the first radio resource. The terminal (120) transmits, on the basis of the response signal transmitted from the base station (110), the data to the base station (110) by use of the second radio resource. The base station (110) receives the data transmitted from the terminal (120) by use of the second radio resource.

Description

Base station, terminal, wireless communication system and processing method

The present invention relates to a base station, a terminal, a wireless communication system, and a processing method.

Conventionally, mobiles such as LTE corresponding to third generation mobile communication system (3G), LTE corresponding to 3.9 generation mobile communication system, LTE-Advanced corresponding to fourth generation mobile communication system, and fifth generation mobile communication system (5G) Communication systems are known. LTE is an abbreviation for Long Term Evolution.

In addition, in mobile communication systems, random access in which a terminal connects to a base station using RACH (Random Access Channel) is known (for example, see Patent Documents 1 to 10 below).

JP2013-192251A JP 2012-186841 A Japanese Patent Application Laid-Open No. 2010-200337 JP 2013-55461 A International Publication No. 2012/108046 International Publication No. 2012/077237 Special table 2014-522205 gazette JP2015-65485A JP 2011-205242 A JP 2010-98707 A

However, in the conventional random access technique described above, since many control signals are transmitted and received between the terminal and the base station, there is a problem that it takes time until transmission of data is possible after transmission data is generated. There is.

In one aspect, an object of the present invention is to provide a base station, a terminal, a wireless communication system, and a processing method that can shorten the time until data transmission is possible.

In order to solve the above-described problems and achieve the object, according to one aspect of the present invention, a terminal transmits a random access signal using a first radio resource, and a base station transmits using the first radio resource. The random access signal to the received local station is received, the terminal that has transmitted the random access signal is identified based on the received random access signal, and a response signal to the random access signal is identified. The terminal transmits a response signal permitting data to be transmitted to the local station using a second radio resource different from the first radio resource, and the terminal is based on the response signal transmitted from the base station. The base station transmits data to the base station using the second radio resource, and the base station transmits data transmitted from the terminal using the second radio resource. Base station receiving terminal, a wireless communication system and processing method are proposed.

According to one aspect of the present invention, it is possible to shorten the time until data transmission is possible.

FIG. 1 is a diagram illustrating an example of a wireless communication system according to an embodiment. FIG. 2 is a diagram illustrating another example of the wireless communication system according to the embodiment. FIG. 3 is a diagram illustrating an example of a configuration of a radio frame in the radio communication system according to the embodiment. FIG. 4 is a diagram illustrating another example of a configuration of a radio frame in the radio communication system according to the embodiment. FIG. 5 is a flowchart illustrating an example of processing in the wireless communication system according to the embodiment. FIG. 6 is a diagram of an example of the base station according to the embodiment. FIG. 7 is a diagram illustrating an example of a terminal according to the embodiment. FIG. 8 is a flowchart illustrating an example of processing performed by the base station according to the embodiment. FIG. 9 is a flowchart illustrating another example of processing performed by the base station according to the embodiment. FIG. 10 is a flowchart illustrating an example of processing performed by the terminal according to the embodiment. FIG. 11 is a flowchart illustrating another example of processing performed by the terminal according to the embodiment. FIG. 12 is a diagram illustrating an example of a radio frame according to the first embodiment. FIG. 13 is a flowchart of an example of processing in the wireless communication system according to the first embodiment. FIG. 14 is a diagram illustrating an example of a configuration of a radio frame in the radio communication system according to the second embodiment. FIG. 15 is a flowchart of an example of processing in the wireless communication system according to the third embodiment. FIG. 16 is a flowchart of an example of processing in the wireless communication system according to the fourth embodiment. FIG. 17 is a diagram of an example of the first radio resource according to the sixth embodiment. FIG. 18 is a diagram illustrating an example of a sequence of a random access signal according to the sixth embodiment. FIG. 19 is a diagram of an example of the first radio resource according to the seventh embodiment. FIG. 20 is a diagram of an example of the first radio resource according to the eighth embodiment.

Embodiments of a base station, a terminal, a wireless communication system, and a processing method according to the present invention will be described in detail below with reference to the drawings.

(Embodiment)
(Radio communication system according to embodiment)
FIG. 1 is a diagram illustrating an example of a wireless communication system according to an embodiment. As shown in FIG. 1, a radio communication system 100 according to the embodiment includes a base station 110 and a terminal 120. The base station 110 is a radio base station that forms a cell and can perform radio communication with terminals located in the formed cell. The terminal 120 is located in the cell of the base station 110 and is a wireless terminal capable of wireless communication with the base station 110 by connecting to the base station 110.

The base station 110 includes a receiving unit 111, a specifying unit 112, and a transmitting unit 113. The receiving unit 111 receives the random access signal transmitted to the own station transmitted by the first radio resource, and outputs the received random access signal to the specifying unit 112. The random access signal is, for example, a random access preamble in a random access procedure.

The first radio resource is a radio resource that the base station 110 broadcasts in its own cell as a radio resource for transmitting a random access signal to the base station 110, for example. Alternatively, the first radio resource may be a radio resource that is set in advance in the radio communication system 100 and is known in the base station 110 and the terminal 120. A radio resource is a combination of a frequency resource and a time resource.

The identifying unit 112 identifies the terminal 120 that has transmitted the random access signal based on the random access signal output from the receiving unit 111. The identification of the terminal 120 is identification of the identifier of the terminal 120, for example. The identifier of the terminal 120 is an identifier such as IMSI or IMEI. IMSI stands for International Mobile Subscriber Identity (International Mobile Subscriber Identifier). IMEI is an abbreviation for International Mobile Equipment Identity (international mobile equipment identifier).

For example, the random access signal transmitted by the terminal 120 is a random access signal of a specific sequence assigned only to the terminal 120. The sequence is a bit string (bit pattern) used for a random access signal (preamble). In this case, the specifying unit 112 can specify the terminal 120 based on the result of assigning a specific sequence to the terminal 120 and the sequence of the random access signal output from the receiving unit 111. The assignment result of the specific sequence to the terminal 120 is correspondence information that associates the specific sequence with the identifier of the terminal 120.

Alternatively, the random access signal transmitted by the terminal 120 is a radio resource included in the first radio resource, and may be a random access signal transmitted by a specific radio resource allocated only to the terminal 120. Good. In this case, the specifying unit 112 can specify the terminal 120 based on the result of assignment of a specific radio resource to the terminal 120 and the radio resource to which the random access signal output from the receiving unit 111 is transmitted. . The assignment result of the specific radio resource to the terminal 120 is correspondence information that associates the specific radio resource with the identifier of the terminal 120.

Alternatively, the random access signal transmitted by the terminal 120 is a random access signal of a specific sequence assigned to the terminal 120 and is transmitted by a specific radio resource assigned to the terminal 120. It may be. In this case, the combination of the specific sequence and the specific radio resource is a combination assigned only to the terminal 120. The identifying unit 112 can identify the terminal 120 based on the allocation result of the specific sequence and the specific radio resource to the terminal 120 and the radio resource to which the sequence of the random access signal and the random access signal are transmitted. The assignment result of the specific sequence and the specific radio resource to the terminal 120 is correspondence information that associates the combination of the specific sequence and the specific radio resource with the identifier of the terminal 120.

The allocation of the specific sequence and the specific radio resource to the terminal 120 is, for example, when the terminal 120 performs initial access to the base station 110 or when the terminal 120 performs location registration via the base station 110. The base station 110 can perform this. In this case, the base station 110 notifies the terminal 120 of a specific sequence assigned to the terminal 120 and a specific radio resource.

When data to be transmitted to the base station 110 is generated, the terminal 120 transmits a random access signal to the base station 110 using a specific sequence or a specific radio resource notified from the base station 110. Thereby, the identifying unit 112 of the base station 110 can identify the terminal 120 based on the random access signal transmitted by the terminal 120.

However, the method for identifying the terminal 120 based on the random access signal is not limited to these. For example, a specific sequence or a specific radio resource may be allocated to the terminal 120 in advance based on the contract content of the user of the terminal 120. In this case, information indicating a specific sequence or a specific radio resource allocated in advance to the terminal 120 is stored in the memory of the terminal 120. Then, the terminal 120 transmits a random access signal using a specific sequence or a specific radio resource based on the information stored in the memory. Correspondence information that associates a specific sequence or a specific radio resource assigned to terminal 120 in advance with the identifier of terminal 120 is stored in the memory of base station 110. Then, the base station 110 identifies the terminal 120 based on the correspondence information stored in the memory.

The identifying unit 112 notifies the transmitting unit 113 of the identification result when the terminal 120 can be identified based on the random access signal. The case where the terminal 120 can be specified is, for example, a case where a random access signal transmitted from the terminal 120 is normally received and a specific sequence can be identified.

The transmission unit 113 transmits a response signal to the random access signal from the terminal 120 to the terminal 120 based on the identification result notified from the identification unit 112. The response signal transmitted by the transmission unit 113 is transmitted as an individual control signal from the base station 110 to the terminal 120, for example. Alternatively, the response signal transmitted by the transmission unit 113 may be transmitted by a predetermined radio resource that is uniquely determined from the first radio resource to which the random access signal is transmitted. Thereby, the terminal 120 can receive the response signal transmitted by the transmission unit 113.

Further, the transmission unit 113 transmits a response signal to be transmitted to the terminal 120 when the identifying unit 112 has identified the terminal 120, and data transmission that allows the terminal 120 to transmit data to the own station using the second radio resource. Use permission signal. The second radio resource is a radio resource different from the first radio resource. Further, the second radio resource may be notified to terminal 120 by a data transmission permission signal, or may be notified to terminal 120 in advance by broadcast information from base station 110 or the like.

On the other hand, the terminal 120 can transmit data (for example, user data) to the base station 110 using the second radio resource allocated from the base station 110 based on the response signal received from the base station 110. . In this case, the reception unit 111 of the base station 110 receives data transmitted from the terminal 120 using the second radio resource.

The terminal 120 includes a transmission unit 121 and a reception unit 122. Transmitter 121 transmits a random access signal to base station 110 using the first radio resource described above. For example, the transmission unit 121 identifies the first radio resource from the broadcast information from the base station 110, and transmits a random access signal to the base station 110 using the identified first radio resource.

The reception unit 122 receives a response signal from the base station 110 to the random access signal transmitted by the transmission unit 121, and outputs the received response signal to the transmission unit 121. When the response signal output from the reception unit 122 is a data transmission permission signal that allows the terminal to transmit data to the base station 110 using the second radio resource, the transmission unit 121 transmits the second radio signal. Data (user data) is transmitted to the base station 110 by the resource.

As described above, according to the wireless communication system 100, when the base station 110 can identify the terminal 120 based on the random access signal, the terminal 120 is permitted to transmit data using a response signal to the random access signal. it can. Thereby, a part of the random access procedure is omitted, and the time until data transmission from the terminal 120 to the base station 110 becomes possible can be shortened.

In addition, when the identifying unit 112 cannot identify the terminal 120, the transmitting unit 113 of the base station 110 sets the response signal transmitted to the terminal 120 as a random access signal retransmission request signal. The case where the terminal 120 could not be identified is a case where the random access signal transmitted by the terminal 120 could not be normally received due to the influence of reception power, interference, etc., and a specific sequence could not be identified.

The random access signal retransmission request signal is a signal for requesting the terminal 120 to retransmit the random access signal using the third radio resource. The third radio resource is, for example, a radio resource different from the first radio resource. As a result, retransmission of the random access signal is performed in a radio resource that does not compete with the initial transmission of the random access signal, and the success rate of retransmission of the random access signal can be improved. Also, the third radio resource may be notified to terminal 120 by a random access signal retransmission request signal, or may be notified to terminal 120 in advance by broadcast information from base station 110 or the like.

When the transmission unit 121 of the terminal 120 outputs a response signal including information indicating the third radio resource for the terminal itself to retransmit the random access signal to the base station 110, the response signal output from the reception unit 122 is Then, the random access signal is retransmitted by the third radio resource.

As described above, according to the wireless communication system 100, when the base station 110 cannot identify the terminal 120 based on the random access signal, the terminal 120 randomly generates the third wireless resource different from the first wireless resource. The access signal can be retransmitted. As a result, the random access signal can be retransmitted using the radio resource used only by the terminal 120 that failed to transmit the random access signal. For this reason, the success rate of retransmission of a random access signal can be improved, and the time until data transmission from the terminal 120 to the base station 110 becomes possible can be shortened.

Further, when the terminal 120 that has transmitted the random access signal can be identified by the identifying unit 112, the base station 110 allocates the third radio resource to communication between another terminal different from the terminal 120 and the own station. Also good. As a result, the third radio resource that is not used for retransmission of the random access signal can be used for communication between the other terminal and the own station, and the utilization efficiency of the radio resource can be improved.

Further, the random access signal transmitted by the terminal 120 may include information on data (user data) transmitted from the terminal 120 to the base station 110 in addition to the random access preamble. Thereby, the information regarding the data transmitted from the terminal 120 to the base station 110 can be efficiently transmitted to the base station 110.

Information related to data can be, for example, information indicating at least one of the presence of data to be transmitted from the terminal 120 to the base station 110 and the amount of data to be transmitted from the terminal 120 to the base station 110. For example, the base station 110 notifies the base station 110 of the amount of data to be transmitted from the terminal 120 to the base station 110 by using a random access signal, so that the base station 110 can transmit the second wireless signal without excess or deficiency with respect to data transmission from the terminal 120 Resources can be allocated. For this reason, the utilization efficiency of a radio | wireless resource can be improved.

Further, the random access signal transmitted by the terminal 120 may include at least a part of data (user data) transmitted from the terminal 120 to the base station 110. Thereby, data transmitted from terminal 120 to base station 110 can be efficiently transmitted to base station 110.

FIG. 2 is a diagram illustrating another example of the wireless communication system according to the embodiment. The radio communication system 200 shown in FIG. 2 includes a base station 210 and terminals 221 to 224. A cell 211 is a cell of the base station 210. Terminals 221 to 224 are terminals located in the cell 211. The terminal 221 is an information terminal such as a mobile phone or a smartphone that communicates with the base station 210 using an application such as a web browser.

The terminal 222 is a communication terminal applied to a thermometer, and transmits information indicating the measurement result of the thermometer to the base station 210, for example. The terminal 223 is a communication terminal applied to a monitoring device such as a monitoring camera, and transmits, for example, image data and moving image data obtained by photographing with the monitoring camera to the base station 210. The terminal 224 is a communication terminal applied to the fire alarm, and transmits information for notifying the discovery of a fire to the base station 210, for example.

Conventionally, in a cellular radio communication system such as the radio communication system 200, for example, a base station controls radio resources used by a terminal, and the terminal communicates with the base station using radio resources instructed to the base station. The radio resource given to the terminal is basically exclusive with other terminals, so that a plurality of terminals can communicate with the base station without competing radio resources.

In a cellular radio communication system, it is necessary to request allocation of radio resources for transmitting data from a terminal side to a base station in various situations. In such a situation, for example, when the mobile phone terminal starts a call, or when the user temporarily stops communication while the user is browsing the web, For example, requesting page data.

Also, in such a scene, for example, the terminal is a sensor such as a thermometer, a rain gauge, and a power meter, and the terminal is ready to start transmitting data sensed. In such a scene, the terminal may be a monitoring device such as detecting a suspicious person or finding a fire, and may notify the abnormality when the terminal detects the abnormality.

In the above example, the data transmitted from the terminal to the base station is, for example, data indicating that the data for the next page of the web is requested, temperature, rainfall, power measurement data, suspicious persons or fires are detected. There is data to show that we did. These are data at the application level. On the communication system, further control the communication, such as data indicating the application, data indicating the source and destination of the data on the network, data indicating the order of the data, and data for detecting that there is an error. Data to which each piece of information is added is transmitted.

Also, in a wireless system, in general, in order to have tolerance against errors in a communication channel, communication channel coding is performed on data to be transmitted. Hereinafter, the data transmitted / received on the radio resource by the terminal or the base station refers to data after, for example, data for controlling communication is added to application level data and further processing for channel coding is performed. And

“Overall description; Stage 2” of TS36.300 of 3GPP defines a random access procedure for the purpose of requesting allocation of radio resources for transmitting data from the terminal side to the base station. 3GPP is an abbreviation for 3rd Generation Partnership Project.

Also, 3GPP TS36.211 defines a waveform of a random access preamble that is actually used. The random access preamble defined in TS 36.211 is a time waveform obtained by IFFT of a Zadoff Chu sequence having a bit length of 839 or 139. IFFT is an abbreviation for Inverse Fast Fourier Transform (Inverse Fast Fourier Transform).

It is defined that 64 different random access preambles are used for each cell by cyclically shifting this random access preamble or changing the route of the Zadoff Chu sequence.

The base station has a known waveform of 64 random access preambles used. For this reason, the base station can detect which random access preamble is transmitted among the 64 random access preambles by performing a correlation operation between the received signal and the known random access preamble.

According to the procedure defined by the specifications of the 3GPP cellular radio communication system, the terminal first transmits one random access preamble randomly selected from 64 random access preambles as message 1 (MSG1). In response to this, the base station returns a random access response as message 2 (MSG2). At this stage, a plurality of terminals may select and transmit the same random access preamble, and it is not specified which terminal communicates with the base station.

Next, the terminal transmits a connection request signal (also called Scheduled Transmission) including its own ID as message 3 (MSG3), and the base station starts a procedure for specifying the received ID and putting the terminal in a connected state. .

The terminal transmits a scheduling request signal after the connection procedure including its own ID is started and becomes connected. The terminal can transmit data using the specified radio resource only after receiving a transmission grant (UL grant) in which the radio resource used for data transmission is specified from the base station.

When the random access preamble conflicts, the terminal may not start the connection procedure for its own ID even if it transmits a connection request signal including its own ID for the obtained random access response. In such a case, the terminal starts over from transmission of the random access preamble. Even when the procedure up to the connection state has already been executed and the terminal is in the connection state, the procedure after the transmission of the scheduling request (SR) signal is required.

On the other hand, in a wireless system that multiplexes by the CSMA method typified by a wireless LAN, there is no equivalent to a base station in a cellular wireless system that manages wireless resources, and a terminal transmits data by self-judgment. LAN is an abbreviation for Local Area Network. CSMA is an abbreviation for Carrier Sense Multiple Access (carrier sense multiple access).

For example, in the CSMA scheme, a terminal receives a radio resource to be transmitted for a certain period according to a certain random number, and performs transmission when it is determined that the radio resource is unused. After the transmission, if the terminal does not receive a reception acknowledgment signal (ACK) from the transmission destination partner, the terminal determines that the transmission has competed with another terminal and performs retransmission.

When retransmitting, the terminal selects a reception time of radio resources to determine whether or not transmission is possible with a random number from the extended period. As a result, it is possible to reduce the probability that terminals that have competed for transmission compete again. Before the terminal transmits, it confirms that the radio resource is unused for the time according to the random number, so it takes inevitably the time when the radio resource is unused, and the average time generates a random number. It becomes the average of time. This average time becomes longer when transmission competition by a plurality of terminals occurs.

The base station 110 shown in FIG. 1 can be realized by the base station 210, for example. The terminal 120 shown in FIG. 1 can be realized by each of the terminals 221 to 224, for example. As a result, it is possible to shorten the time from when the data to be transmitted to the base station 110 is generated in the terminals 221 to 224 until the data is transmitted to the base station 110.

(Configuration of Radio Frame in Radio Communication System According to Embodiment)
FIG. 3 is a diagram illustrating an example of a configuration of a radio frame in the radio communication system according to the embodiment. In FIG. 3, the horizontal axis indicates the time of the radio resource, and the vertical axis indicates the frequency of the radio resource. Here, a case will be described in which transmission with DL (Down Link) and transmission with UL (Up Link) are performed separately in time. In the example illustrated in FIG. 3, the

periods

311 and 313 are DL periods, and the

periods

312 and 314 are UL periods.

The radio resource 301 is a radio resource in the DL period 311. The radio resource 301 is a radio resource assigned to downlink control information or broadcast information. The downlink control information or broadcast information of the radio resource 301 is information indicating an arrangement of a radio resource 302 (first radio resource) described later. The radio resource 302 is a radio resource in the UL period 312. Radio resource 302 is a radio resource (first radio resource) for transmitting a random access signal.

The radio resource 303 is a radio resource in the DL period 313. The radio resource 303 is a radio resource for transmitting a response signal for the random access signal. The response signal transmitted by the radio resource 303 is a data transmission permission signal indicating a radio resource 304 (second radio resource) described later or a random access signal retransmission request indicating a radio resource 305 (third radio resource) described later. Signal.

The wireless resource 304 is a wireless resource in the UL period 314. The radio resource 304 is a radio resource (second radio resource) for transmitting data (user data). The radio resource 305 is a radio resource in the UL period 314. The radio resource 305 is a radio resource (third radio resource) for retransmitting the random access signal.

For example, as in the example illustrated in FIG. 3, the radio resource 305 (third radio resource) for the terminal 120 to retransmit the random access signal is set to a period 314 immediately after the period 313 for notifying the radio resource 305. Thereby, for example, the terminal 120 can retransmit the random access signal earlier than waiting for the next radio resource 301. For this reason, the time until the terminal 120 can transmit data to the base station 110 can be shortened.

FIG. 4 is a diagram illustrating another example of a configuration of a radio frame in the radio communication system according to the embodiment. In FIG. 4, the same parts as those shown in FIG. In the example shown in FIG. 4,

radio resources

301 and 401 are radio resources in

DL periods

311 and 313, respectively.

Radio resources

301 and 401 are radio resources allocated to downlink control information. The downlink control information of the radio resource 301 is information indicating the arrangement of the radio resource 402 (broadcast information) and the arrangement of the radio resource 303.

The radio resource 402 is a radio resource in the

DL periods

311 and 313. Radio resource 402 is a radio resource assigned to broadcast information. The broadcast information of the radio resource 402 is information indicating the arrangement of the radio resource 302 (first radio resource).

(Processing in Radio Communication System According to Embodiment)
FIG. 5 is a flowchart illustrating an example of processing in the wireless communication system according to the embodiment. In the wireless communication system 100, for example, each step shown in FIG. 5 is executed. First, the base station 110 determines a radio resource arrangement (for example, see FIGS. 3 and 4) on a radio frame (step S501). However, the radio resource arrangement on the radio frame may be determined in advance at the time of system design. In this case, in step S501, the base station 110 reads information on radio resource arrangement on the radio frame determined at the time of system design and stored in the memory of the base station 110.

The radio resource allocation determined in step S501 is notified from the base station 110 to the terminal 120 using downlink control information and broadcast information. For example, the radio resource allocation determined in step S501 may be all notified to the terminal 120 before data to be transmitted by the terminal 120 is generated, or each time data to be transmitted by the terminal 120 is generated, the terminal 120 May be notified.

Next, it is assumed that data to be transmitted has occurred in the terminal 120 (step S502). Next, the terminal 120 transmits a random access signal to the base station 110 using the first radio resource notified from the base station 110 in order to obtain permission to transmit data (step S503). Based on the random access signal transmitted in step S503, the base station 110 attempts to identify the terminal 120 that has transmitted the random access signal.

When the base station 110 can identify the terminal 120 that has transmitted the random access signal, the base station 110 permits data transmission to the terminal 120 after step S503 (step S504). The data transmission permission in step S504 is performed, for example, by transmitting a data transmission permission signal indicating the second radio resource to the terminal 120.

Next, the terminal 120 transmits data to the base station 110 in accordance with the data transmission permission in step S504 (step S505), and the series of processing ends. The data transmission in step S505 is performed by the second radio resource indicated by the data transmission permission signal from the base station 110, for example.

When the base station 110 cannot identify the terminal 120 that has transmitted the random access signal, the base station 110 requests the terminal 120 to retransmit the random access signal (step S506), and returns to the process of step S503. . The retransmission request for the random access signal in step S506 is performed, for example, by transmitting a random access signal retransmission request signal indicating the third radio resource to the terminal 120. Also, the retransmission of the random access signal by the terminal 120 upon returning from step S506 to step S503 is performed by the third radio resource indicated by the random access signal retransmission request signal from the base station 110.

(Base station according to the embodiment)
FIG. 6 is a diagram of an example of the base station according to the embodiment. As shown in FIG. 6, the base station 110 according to the embodiment includes, for example, a processor 610, a memory 620, a transmission signal generator 631, a transmitter 632, a transmission / reception signal separator 640, an antenna 650, A receiver 661 and a received signal processor 662 are provided.

The processor 610 is a CPU (Central Processing Unit) that controls the entire base station 110, for example. The memory 620 includes, for example, a main memory and an auxiliary memory. The main memory is, for example, a RAM (Random Access Memory). The main memory is used as a work area for the processor 610. The auxiliary memory is, for example, a nonvolatile memory such as a magnetic disk, an optical disk, or a flash memory. Various programs for operating the base station 110 are stored in the auxiliary memory. The program stored in the auxiliary memory is loaded into the main memory and executed by the processor 610.

By the processor 610, for example, a radio resource allocation control unit 611, a control information / broadcast information generation unit 612, a random access signal detection unit 613, a data decoding unit 614, a data transmission permission / random access retransmission determination unit 615, Is realized. However, the processor 610 is not limited to these, and each processing unit for operating the base station 110 is realized.

The radio resource allocation control unit 611 determines radio resource arrangement (for example, see FIGS. 3 and 4) on the radio frame. Radio resource allocation control section 611 outputs arrangement information indicating the determined arrangement of radio resources to control information / notification information generation section 612.

Control information / broadcast information generating section 612 generates DL control information and broadcast information transmitted from base station 110, and outputs a signal including the generated control information and broadcast information to transmission signal generator 631. For example, the control information / broadcast information generation unit 612 stores the arrangement information output from the radio resource allocation control unit 611 in the DL control information or broadcast information to be generated. The control information / broadcast information generation unit 612 stores the data transmission permission signal and the random access signal retransmission request signal output from the data transmission permission / random access retransmission determination unit 615, which will be described later, in the control information of the DL to be generated. .

The transmission signal generator 631 arranges various information such as control information and broadcast information included in the signal output from the processor 610 on a radio frame and converts the information into a radio signal. Then, the transmission signal generator 631 outputs the signal converted into the radio signal to the transmitter 632.

The transmitter 632 performs transmission processing of the signal output from the transmission signal generator 631. The transmission processing by the transmitter 632 includes, for example, conversion from a digital signal to an analog signal, frequency conversion from a baseband band to an RF (Radio Frequency) band, amplification, and the like. The transmitter 632 outputs the signal subjected to the transmission process to the transmission / reception signal separator 640.

The transmission / reception signal separator 640 outputs the DL signal output from the transmitter 632 to the antenna 650, and outputs the UL signal output from the antenna 650 to the receiver 661, whereby the DL signal and the UL signal are output. And isolate. The antenna 650 wirelessly transmits the signal output from the transmission / reception signal separator 640 to the terminal 120. Antenna 650 receives a signal wirelessly transmitted from terminal 120, and outputs the received signal to transmission / reception signal separator 640.

The receiver 661 performs reception processing of the signal output from the transmission / reception number separator 640. The reception processing by the receiver 661 includes, for example, amplification, frequency conversion from the RF band to the baseband, conversion from an analog signal to a digital signal, and the like. The receiver 661 outputs the signal subjected to the reception process to the reception signal processor 662.

Received signal processor 662 demodulates the signal output from receiver 661. Thereby, a random access signal and a signal including data are obtained. Reception signal processor 662 outputs the signal obtained by demodulation to processor 610.

The random access signal detector 613 realized by the processor 610 detects a random access signal included in the signal output from the received signal processor 662. Then, the random access signal detection unit 613 determines the sequence of the detected random access signal. Also, the random access signal detection unit 613 notifies the data transmission permission / random access retransmission determination unit 615 of the detection and determination results.

The data decoding unit 614 decodes and extracts UL data (for example, user data) included in the signal output from the reception signal processor 662.

The data transmission permission / random access retransmission determination unit 615 determines the response content to be returned to the terminal 120 from the sequence of the determined random access signal. For example, the data transmission permission / random access retransmission determination unit 615 identifies the terminal 120 based on the random access signal described above.

Then, when the terminal 120 can be identified, the data transmission permission / random access retransmission determination unit 615 outputs a data transmission permission signal to the terminal 120 indicating the second radio resource to the control information / broadcast information generation unit 612. In addition, if the terminal 120 cannot be identified, the data transmission permission / random access retransmission determination unit 615 transmits a random access signal retransmission request signal to the terminal 120 indicating the third radio resource to the control information / broadcast information generation unit 612. Output.

1 can be realized by an antenna 650, a transmission / reception signal separator 640, a receiver 661, a reception signal processor 662, a random access signal detection unit 613, and a data decoding unit 614, for example. The specifying unit 112 illustrated in FIG. 1 can be realized by the data transmission permission / random access retransmission determination unit 615, for example. The transmission unit 113 illustrated in FIG. 1 can be realized by, for example, a control information / broadcast information generation unit 612, a transmission signal generator 631, a transmitter 632, a transmission / reception signal separator 640, and an antenna 650.

(Terminal according to the embodiment)
FIG. 7 is a diagram illustrating an example of a terminal according to the embodiment. As illustrated in FIG. 7, the terminal 120 according to the embodiment includes, for example, a processor 710, a memory 720, a transmission signal generator 731, a transmitter 732, a transmission / reception signal separator 740, an antenna 750, and a reception. Machine 761 and a received signal processor 762.

The processor 710 is a CPU that controls the entire terminal 120, for example. The memory 720 includes, for example, a main memory and an auxiliary memory. The main memory is, for example, a RAM. The main memory is used as a work area for the processor 710. The auxiliary memory is a non-volatile memory such as a magnetic disk or a flash memory. Various programs for operating the terminal 120 are stored in the auxiliary memory. The program stored in the auxiliary memory is loaded into the main memory and executed by the processor 710.

The processor 710 implements, for example, a transmission data generation detection unit 711, a random access signal generation unit 712, a data transmission unit 713, and a control information / broadcast information analysis unit 714. However, the processor 710 is not limited to these, and each processing unit for operating the terminal 120 is realized.

The transmission data generation detection unit 711 detects the generation of data to be transmitted from the terminal 120 to the base station 110 from various sensors and monitoring devices. When the transmission data generation detection unit 711 detects the generation of data to be transmitted, the transmission data generation detection unit 711 notifies the random access signal generation unit 712 of the generation of data to be transmitted, and outputs the generated data to be transmitted to the data transmission unit 713. To do.

When the generation of data to be transmitted is notified from the transmission data generation detection unit 711, the random access signal generation unit 712 generates a random access signal. For example, the random access signal generation unit 712 generates a random access signal based on a specific sequence or a specific radio resource assigned and notified in advance from the terminal 120. Then, the random access signal generation unit 712 outputs the generated random access signal to the transmission signal generator 731.

As the random access signal generated by the random access signal generation unit 712, for example, a signal conforming to the random access preamble defined in TS36.211 which is the specification of the cellular radio communication system defined by 3GPP can be used. By using a Zadoff Chu sequence of a route different from the Random Access Preamble defined in TS 36.211, a random access signal having a purpose different from the purpose defined in TS 36.211 can be obtained.

The random access signal is not limited to such a random access signal, and various sequences can be used. However, it is desirable that a plurality of specific sequences in the random access signal are orthogonal to each other. Being orthogonal to each other means that the correlation becomes zero when a correlation operation is performed with a sequence that does not match.

As an example, a Walsh code {0000, 0101, 0110, 0011} can be used for a random access signal. If the length of the code of the random access signal is increased, more orthogonal codes can be obtained. In general, N orthogonal codes can be obtained if a length N code is used.

Further, the random access signal of a specific sequence may be unique so that the terminal 120 can be completely specified. However, when the number of the terminals 120 in the wireless communication system 100 is large, several terminal groups are configured. May be. In this case, a radio resource for transmitting a random access signal may be determined for each terminal group, and a random access signal that identifies a terminal in the terminal group that uses the radio resource may be used.

The data transmission unit 713 adds data for controlling communication to application level data (user data) or performs processing of channel coding. The application level data includes, for example, data output from the transmission data generation detection unit 711. The data transmission unit 713 outputs a signal obtained by the channel coding process to the transmission signal generator 731.

The transmission signal generator 731 arranges a random access signal or data included in the signal output from the processor 710 on a wireless frame and converts it into a wireless signal. Then, the transmission signal generator 731 outputs the signal converted into the radio signal to the transmitter 732.

The transmitter 732 performs transmission processing of the signal output from the transmission signal generator 731. The transmission processing by the transmitter 732 includes, for example, conversion from a digital signal to an analog signal, frequency conversion from a baseband to an RF band, amplification, and the like. The transmitter 732 outputs the signal subjected to the transmission process to the transmission / reception signal separator 740.

The transmission / reception signal separator 740 outputs the UL signal output from the transmitter 732 to the antenna 750 and outputs the DL signal output from the antenna 750 to the receiver 761, whereby the UL signal and the DL signal are output. And isolate. The antenna 750 wirelessly transmits the signal output from the transmission / reception signal separator 740 to the base station 110. The antenna 750 receives a signal wirelessly transmitted from the base station 110 and outputs the received signal to the transmission / reception signal separator 740.

The receiver 761 performs reception processing of the signal output from the transmission / reception signal separator 740. The reception processing by the receiver 761 includes, for example, amplification, frequency conversion from the RF band to the baseband, conversion from an analog signal to a digital signal, and the like. The receiver 761 outputs the signal subjected to the reception process to the reception signal processor 762.

The reception signal processor 762 demodulates the signal output from the receiver 761. As a result, a signal including a control signal and broadcast information from the base station 110 is obtained. Reception signal processor 762 outputs a signal obtained by demodulation to processor 710.

The control information / notification information analysis unit 714 realized by the processor 710 extracts a control signal and notification information included in the signal output from the reception signal processor 762. Then, the control information / notification information analysis unit 714 analyzes the extracted control signal and notification information. For example, the control information / broadcast information analysis unit 714 notifies the random access signal generation unit 712 of radio resources for initial transmission of the random access signal indicated by the control signal or broadcast information from the base station 110. In this case, the random access signal generation unit 712 generates a random access signal transmitted for the first time using the radio resource notified from the control information / broadcast information analysis unit 714.

Also, the control information / broadcast information analysis unit 714 outputs a data transmission permission signal indicating the second radio resource included in the control signal or broadcast information from the base station 110 to the data transmission unit 713. In this case, the data transmission unit 713 generates a data signal using the second radio resource indicated by the data transmission permission signal output from the control information / broadcast information analysis unit 714.

Also, the control information / broadcast information analysis unit 714 outputs a random access signal retransmission request signal indicating the third radio resource included in the control signal or broadcast information from the base station 110 to the random access signal generation unit 712. In this case, the random access signal generation unit 712 generates a retransmission random access signal using the third radio resource indicated by the random access signal retransmission request signal output from the control information / broadcast information analysis unit 714.

1 can be realized by a random access signal generation unit 712, a transmission signal generator 731, a transmitter 732, a transmission / reception signal separator 740, an antenna 750, and a data transmission unit 713, for example. The receiving unit 122 illustrated in FIG. 1 can be realized by, for example, the antenna 750, the transmission / reception signal separator 740, the receiver 761, the received signal processor 762, and the control information / broadcast information analyzing unit 714.

(Processing by the base station according to the embodiment)
FIG. 8 is a flowchart illustrating an example of processing performed by the base station according to the embodiment. The base station 110 according to the embodiment executes, for example, each step shown in FIG. First, the base station 110 determines a radio resource arrangement on a radio frame (step S801). Next, the base station 110 determines a sequence of a random access signal used by the terminal (for example, the terminal 120) and notifies the terminal of the random access signal (step S802).

Next, the base station 110 transmits first radio resource arrangement information as broadcast information (step S803). Next, the base station 110 performs a random access signal reception process using the first radio resource and the third radio resource (step S804).

Next, the base station 110 determines whether or not a random access signal is detected by the reception process in step S804 (step S805). When a random access signal is not detected (step S805: No), the base station 110 allocates a radio resource that is scheduled to be used when a random access signal is detected as a resource for communication of another terminal. (Step S806). The radio resource that is scheduled to be used when the random access signal is detected is, for example, a radio resource that is scheduled to be used for response transmission of a random access signal, permission to transmit data, or retransmission of random access. After step S806, the base station 110 returns to step S803.

In step S805, when a random access signal is detected (step S805: Yes), the base station 110 determines whether the terminal 120 that has transmitted the detected random access signal has been identified (step S807). When the terminal 120 that has transmitted the random access signal has not been identified (step S807: No), the base station 110 transmits a random access signal retransmission request signal including the arrangement information of the third radio resource (step S808). Return to step S804. By returning to step S804 from step S808 and performing reception processing of the random access signal, it is possible to cope with a case where another terminal 120 transmits a new random access signal.

In step S807, when the terminal 120 that has transmitted the random access signal can be identified (step S807: Yes), the process proceeds to step S809. That is, the base station 110 transmits a data transmission permission signal including the second radio resource arrangement information to the terminal 120 (step S809). Next, the base station 110 receives data transmitted from the terminal 120 using the second radio resource (step S810), and ends a series of processes.

FIG. 9 is a flowchart illustrating another example of processing by the base station according to the embodiment. The base station 110 according to the embodiment may execute the steps shown in FIG. 9, for example. Steps S901 and S902 shown in FIG. 9 are the same as steps S801 and S802 shown in FIG. Subsequent to step S902, the base station 110 transmits arrangement information of the first radio resource, the second radio resource, and the third radio resource as broadcast information (step S903).

Steps S904 to S907 shown in FIG. 9 are the same as steps S804 to S807 shown in FIG. In step S907, when the terminal 120 that has transmitted the random access signal cannot be identified (step S907: No), the base station 110 transmits a random access signal retransmission request signal (step S908), and returns to step S904. In the example shown in FIG. 9, since the arrangement information of the third radio resource is broadcast in step S903, the random access signal retransmission request signal transmitted in step S908 includes the arrangement information of the third radio resource. It does not have to be.

In step S907, when the terminal 120 that has transmitted the random access signal can be identified (step S907: Yes), the base station 110 transmits a data transmission permission signal to the terminal 120 (step S909). In the example illustrated in FIG. 9, the second radio resource arrangement information is notified in step S903, and therefore the data transmission permission signal transmitted in step S909 includes the second radio resource arrangement information. It does not have to be. Next, the base station 110 receives data transmitted from the terminal 120 using the second radio resource (step S910), and ends a series of processes.

As shown in FIG. 9, the base station 110 may previously notify the arrangement information of the second radio resource and the third radio resource in the cell by the broadcast information. In this case, for example, when there are a plurality of terminals 120 in the radio communication system 100, the second radio resource and the third radio resource become a radio resource common to the plurality of terminals 120.

Even in such a case, for example, when it is unlikely that data transmission from a plurality of terminals 120 will occur simultaneously, the same second radio resource or the same third radio resource is used by the plurality of terminals 120. It is unlikely to be done. Therefore, the base station 110 can receive data using the second radio resource or receive a retransmitted random access signal using the third radio resource.

(Processing by the terminal according to the embodiment)
FIG. 10 is a flowchart illustrating an example of processing performed by the terminal according to the embodiment. For example, when the base station 110 performs the processing shown in FIG. 8, the terminal 120 according to the embodiment executes, for example, each step shown in FIG. First, the terminal 120 receives random access signal sequence information indicating a specific sequence of random access signals to be used from the base station 110 (step S1001).

Step S1001 can be performed, for example, when the terminal 120 is connected to the base station 110 for the first time or when the location of the terminal 120 is registered. In this case, in the initial connection of the terminal 120 to the base station 110 and the location registration of the terminal 120, by performing a normal random access procedure, the terminal 120 can be connected even before a specific sequence is assigned to the terminal 120. A connection to the base station 110 can be made.

Next, the terminal 120 determines whether or not data to be transmitted is generated (step S1002), and waits until data to be transmitted is generated (step S1002: No loop). When data to be transmitted is generated (step S1002: Yes), the terminal 120 acquires the first radio resource arrangement information from the base station 110 (step S1003). The acquisition of the placement information in step S1003 can be performed by receiving broadcast information from the base station 110, for example.

Next, the terminal 120 transmits a random access signal using the first radio resource based on the arrangement information of the first radio resource received in step S1003 (step S1004). In step S1004, the terminal 120 transmits a random access signal using a specific sequence indicated by the random access signal sequence information received in step S1001.

Next, the terminal 120 performs a reception process of a response from the base station 110 with respect to the transmitted random access signal (step S1005). Next, the terminal 120 determines whether or not the response of the base station 110 has been received by the reception process of step S1005 (step S1006). When the response has not been received (step S1006: No), the terminal 120 returns to step S1003.

If a response is received in step S1006 (step S1006: Yes), terminal 120 determines whether or not the response received in step S1005 is a data transmission permission signal including second radio resource arrangement information ( Step S1007). When the received response is not a data transmission permission signal including the second radio resource arrangement information (step S1007: No), the terminal 120 proceeds to step S1008. That is, terminal 120 determines whether or not the response received in step S1005 is a random access signal retransmission request signal including third radio resource arrangement information (step S1008).

In step S1008, when the received response is not a random access signal retransmission request signal including the arrangement information of the third radio resource (step S1008: No), the terminal 120 returns to step S1003. When the received response is a random access signal retransmission request signal including the arrangement information of the third radio resource (step S1008: Yes), the terminal 120 proceeds to step S1009. That is, terminal 120 transmits (retransmits) a random access signal to base station 110 using the third radio resource based on the arrangement information of the third radio resource (step S1009), and returns to step S1005.

In step S1007, when the received response is a data transmission permission signal including the second radio resource arrangement information (step S1007: Yes), the terminal 120 proceeds to step S1010. That is, terminal 120 transmits data using the second radio resource based on the arrangement information of the second radio resource (step S1010), and ends a series of processes.

FIG. 11 is a flowchart illustrating another example of processing performed by the terminal according to the embodiment. For example, when the base station 110 performs the process shown in FIG. 9, the terminal 120 according to the embodiment may execute the steps shown in FIG. 11, for example. First, the terminal 120 receives random access signal sequence information indicating a sequence of random access signals to be used from the base station 110 (step S1101).

Next, the terminal 120 acquires the arrangement information of the first radio resource, the second radio resource, and the third radio resource from the broadcast information of the base station 110 (step S1102). The acquisition of arrangement information in step S1102 can be performed by receiving broadcast information from the base station 110, for example.

Next, the terminal 120 determines whether or not data to be transmitted is generated (step S1103), and waits until data to be transmitted is generated (step S1103: No loop). When data to be transmitted is generated (step S1103: Yes), the terminal 120 proceeds to step S1104.

Steps S1104 to S1106 shown in FIG. 11 are the same as steps S1004 to S1006 shown in FIG. If a response is received in step S1106 (step S1106: Yes), the terminal 120 determines whether or not the response received in step S1105 is a data transmission permission signal (step S1107). When the received response is not a data transmission permission signal (step S1107: No), the terminal 120 determines whether or not the response received in step S1105 is a random access signal retransmission request signal (step S1108).

In step S1108, when the received response is not a random access signal retransmission request signal (step S1108: No), the terminal 120 returns to step S1104. When the received response is a random access signal retransmission request signal (step S1108: Yes), the terminal 120 proceeds to step S1109. That is, terminal 120 transmits a random access signal to base station 110 using the third radio resource based on the arrangement information of the third radio resource acquired in step S1102 (step S1109), and returns to step S1105. .

In step S1107, when the received response is a data transmission permission signal (step S1107: Yes), the terminal 120 proceeds to step S1110. That is, the terminal 120 transmits data using the second radio resource based on the arrangement information of the second radio resource acquired in step S1102 (step S1110), and ends a series of processes.

As described above, according to the wireless communication system 100 according to the embodiment, when the base station 110 can identify the terminal 120 based on the random access signal, the terminal is permitted to transmit data using the response signal for the random access signal. 120. Thereby, a part of the random access procedure is omitted, and the time until data transmission from the terminal 120 to the base station 110 becomes possible can be shortened.

In addition, when the base station 110 cannot identify the terminal 120 based on the random access signal, the random access signal can be retransmitted from the terminal 120 using the third radio resource different from the first radio resource. As a result, the success rate of retransmission of the random access signal can be improved, and the time until data transmission from the terminal 120 to the base station 110 becomes possible can be shortened.

Example 1
(Radio frame according to the first embodiment)
FIG. 12 is a diagram illustrating an example of a radio frame according to the first embodiment. 12, parts similar to those shown in FIGS. 3 and 4 are given the same reference numerals and description thereof is omitted. A radio frame 1211 (n) illustrated in FIG. 12 is an n-th radio frame including a DL period 311 and a UL period 312. The radio frame 1212 (n + 1) is an (n + 1) th radio frame configured by a DL period 313 and a UL period 314.

When the data to be transmitted occurs and the terminal 120 needs to allocate radio resources for transmitting data, the terminal 120 determines the arrangement information of the radio resources 302 from the control information or broadcast information of the radio resources 301 of the radio frame 1211 (n). To get. The radio resource 302 is a first radio resource for transmitting a random access signal in the UL of the radio frame 1211. The terminal 120 transmits a random access signal in the radio resource 302 based on the acquired arrangement information.

The base station 110 receives the random access signal from the terminal 120 and attempts to identify the terminal 120 that has transmitted the received random access signal. If the base station 110 can identify the terminal 120, the base station 110 transmits a data transmission permission signal to the terminal 120 using the DL radio resource 303 of the radio frame 1212 (n + 1). This data transmission permission signal includes information on the radio resource 304 (second radio resource) for the terminal 120 to transmit data in the UL of the radio frame 1212 (n + 1).

The terminal 120 that has received a transmission permission signal including information related to the radio resource 304 from the base station 110 transmits data to the base station 110 using the UL radio resource 304 in the radio frame 1212.

When the base station 110 cannot identify the terminal 120 that has transmitted the random access signal, the base station 110 transmits a random access signal retransmission request signal to the terminal 120 in the DL radio resource 303 of the radio frame 1212. The random access signal retransmission request signal includes information on the radio resource 305 (third radio resource) for retransmitting the random access signal. The terminal 120 that has received the random access signal retransmission request signal retransmits the random access signal in the UL radio resource 305 in the radio frame 1212.

The radio resource 1201 in the DL of the radio frame 1211 (n) is used to transmit a response signal from the base station 110 to the random access signal transmitted from the terminal 120 during the UL period of the (n−1) th radio frame. A radio resource 1202 (second radio resource) in the UL of the radio frame 1211 (n) is used for data transmission from the terminal 120 based on a response signal by the radio resource 1201. The radio resource 1203 (third radio resource) in the UL of the radio frame 1211 (n) is used for retransmission of a random access signal from the terminal 120 based on the response signal by the radio resource 1201.

The radio resource 1204 in the DL of the radio frame 1212 (n + 1) is used for control information or broadcast information indicating the radio resource 1205 (first radio resource) in the UL of the radio frame 1212. The response to the random access signal transmitted by the UL radio resource 1205 of the radio frame 1212 (n + 1) is transmitted by the radio resource in the DL period of the (n + 2) th radio frame.

Thus, the radio resources 302 and 1205 (first radio resource) for transmitting the random access signal when the transmission data is generated and the radio resources 305 and 1203 (third radio resource) for retransmitting the random access signal are transmitted. Are placed as separate resources. As a result, a collision between a random access signal transmitted first in a certain radio frame and a random access signal transmitted in an earlier radio frame but retransmitted because data transmission permission was not obtained can be detected. Can be avoided.

However, if it is not considered that a plurality of terminals transmit random access signals at the same time, grant permission for data transmission to some terminals, and request retransmission of random access signals to the remaining terminals, the first radio resource and the second The three radio resources may be shared. For example, the wireless resource 302 and the wireless resource 1203 may be the same wireless resource. Also, the radio resource 1205 and the radio resource 305 may be the same radio resource.

In addition, when the base station 110 does not detect a random access signal, the

radio resources

304, 305, 1202, and 1203 may be assigned for data transmission of other terminals that are already in communication.

(Processing in the wireless communication system according to the first embodiment)
FIG. 13 is a flowchart of an example of processing in the wireless communication system according to the first embodiment. In the wireless communication system 100, for example, each step shown in FIG. 13 is executed. First, the base station 110 determines a radio resource arrangement (for example, see FIGS. 3 and 4) on a radio frame (step S1301).

Next, the base station 110 transmits arrangement information indicating the arrangement of the first radio resource among the radio resource arrangements determined in step S1301 to the terminal 120 (step S1302). Step S1302 is performed using, for example, downlink control information and broadcast information.

On the other hand, it is assumed that data to be transmitted is generated in the terminal 120 (step S1303). Next, the terminal 120 acquires the arrangement information of the first radio resource transmitted from the base station 110 using the downlink control information and broadcast information in step S1302 (step S1304).

Next, the terminal 120 transmits a random access signal to the base station 110 to request data transmission permission (step S1305). The transmission of the random access signal in step S1303 is performed by the first radio resource based on the arrangement information received in step S1304, for example. In addition, the transmission of the random access signal in step S1303 is performed using a specific sequence or a specific radio resource assigned to the terminal 120 in advance.

Next, the base station 110 receives the random access signal transmitted in step S1305 (step S1306). Based on the random access signal received in step S1306, the base station 110 determines whether the terminal 120 that has transmitted the random access signal has been identified (step S1307).

In step S1307, when the terminal 120 that has transmitted the random access signal can be identified (step S1307: Yes), the base station 110 proceeds to step S1308. That is, base station 110 transmits a data transmission permission signal including second radio resource arrangement information to terminal 120 as a response to the random access signal received in step S1306 (step S1308).

In step S1307, when the terminal 120 that has transmitted the random access signal has not been identified (step S1307: No), the base station 110 proceeds to step S1309. That is, base station 110 transmits a random access signal retransmission request signal including third radio resource arrangement information to terminal 120 as a response to the random access signal received in step S1306 (step S1309).

Next, the terminal 120 receives a response from the base station 110 transmitted in step S1308 or step S1309 to the random access signal transmitted in step S1305 (step S1310).

Next, the terminal 120 determines whether or not the response received in step S1310 is a data transmission permission signal including the second radio resource arrangement information (step S1311). When the received response is not a data transmission permission signal including the arrangement information of the second radio resource (step S1311: No), the response received by the terminal 120 in step S1310 is a random including the arrangement information of the third radio resource. This is an access signal retransmission request signal. In this case, the terminal 120 returns to step S1305 to retransmit the random access signal.

In step S1311, when the received response is a data transmission permission signal including the second radio resource arrangement information (step S1311: Yes), the terminal 120 proceeds to step S1312. That is, the terminal 120 transmits data using the second radio resource based on the arrangement information of the second radio resource (step S1312). Next, the base station 110 receives the data transmitted in step S1312 (step S1313), and ends a series of processing.

(Example 2)
(Configuration of radio frame in radio communication system according to second embodiment)
FIG. 14 is a diagram illustrating an example of a configuration of a radio frame in the radio communication system according to the second embodiment. In FIG. 14, the same parts as those shown in FIG. In the second embodiment, the

radio resources

301 and 1204 in the

DL periods

311 and 313 are used for transmission of control information including broadcast information and information on the arrangement of response signals with respect to random access signals.

The

radio resources

1401 and 1402 in the

DL periods

311 and 313 are used for transmission of broadcast information including information on the arrangement of the radio resources 302 and 1205 (first radio resources) for the terminal 120 to transmit a random access signal. .

The terminal 120 receives the control information of the radio resource 301 in the DL period 311 of the radio frame 1211 (n), thereby acquiring the broadcast information arrangement information of the radio resource 1401. And the terminal 120 can acquire the information regarding arrangement | positioning of the radio | wireless resource 302 (1st radio | wireless resource) by receiving the alerting | reporting information of the radio | wireless resource 1401 based on the acquired arrangement | positioning information.

In addition, in the UL period 312 of the radio frame 1211 (n), the terminal 120 that has transmitted the random access signal by the radio resource 302 receives the DL radio resource 1204 of the radio frame 1212 (n + 1). Thereby, the terminal 120 can acquire information on where the response (the radio resource 303) is arranged on the radio frame. And the terminal 120 can receive the response of the radio | wireless resource 303 with respect to random access based on the acquired information.

(Example 3)
(Processing in the wireless communication system according to the third embodiment)
FIG. 15 is a flowchart of an example of processing in the wireless communication system according to the third embodiment. In the wireless communication system 100, for example, each step shown in FIG. 15 is executed. Steps S1501 and S1502 shown in FIG. 15 are the same as steps S1301 and S1302 shown in FIG. However, in step S1502, the base station 110 transmits arrangement information indicating the arrangement of the first radio resource among the radio resource arrangements determined in step S1501 as broadcast information in the own cell (step S1502).

On the other hand, the terminal 120 acquires first radio resource arrangement information from the broadcast information transmitted from the base station 110 in step S1502 (step S1503). Next, it is assumed that data to be transmitted is generated in the terminal 120 (step S1504). Next, the terminal 120 proceeds to step S1505. Steps S1505 to S1513 shown in FIG. 15 are the same as steps S1305 to S1313 shown in FIG.

Thus, the base station 110 determines the first radio resource for the terminal 120 to transmit random access as being quasi-fixed over a number of radio frames, and notifies the terminal 120 as broadcast information. The terminal 120 acquires information related to the arrangement of the first radio resource with the broadcast information transmitted in the radio frame before the transmission data is generated. Then, when data to be transmitted is generated, the terminal 120 transmits a random access signal using the first radio resource that can be used immediately.

(Example 4)
(Processing in Radio Communication System According to Embodiment 4)
FIG. 16 is a flowchart of an example of processing in the wireless communication system according to the fourth embodiment. In the wireless communication system 100 according to the fourth embodiment, for example, each step illustrated in FIG. 16 is executed. Steps S1601 and S1602 shown in FIG. 16 are the same as steps S1501 and S1502 shown in FIG. However, in step S1602, the base station 110 broadcasts the arrangement information indicating the arrangement of the first radio resource, the second radio resource, and the third radio resource in the determined radio resource arrangement to the own cell. It transmits as information (step S1602).

On the other hand, the terminal 120 acquires the arrangement information of the first radio resource, the second radio resource, and the third radio resource from the broadcast information transmitted from the base station 110 in step S1602 (step S1603), The process moves to step S1604. Steps S1604 to S1613 shown in FIG. 16 are the same as steps S1504 to S1513 shown in FIG.

However, the data transmission permission signal transmitted in step S1608 may not include the second radio resource arrangement information. In this case, in step S1612, the terminal 120 transmits data using the second radio resource based on the arrangement information of the second radio resource acquired in step S1603.

The random access signal retransmission request signal transmitted in step S1609 may not include the third radio resource arrangement information. In this case, when returning from step S1611 to step S1605, terminal 120 retransmits the random access signal using the third radio resource based on the arrangement information of the third radio resource acquired in step S1603.

In this way, the base station 110 determines all or part of the first radio resource, the second radio resource, and the third radio resource as being quasi-fixed over a number of radio frames, and broadcasts it as broadcast information. May be notified to the terminal 120. When data to be transmitted is generated, the terminal 120 transmits a random access signal using the first radio resource that can be used immediately.

When the base station 110 can identify the terminal 120 based on the random access signal from the terminal 120, the base station 110 transmits a data transmission permission signal to the terminal 120 as a response to the random access signal. In addition, when the base station 110 cannot identify the terminal 120 based on the random access signal from the terminal 120, the base station 110 transmits a random access signal retransmission request signal to the terminal 120 as a response to the random access signal. Thereby, the amount of control information exchanged after data generation in step S1604 can be reduced.

(Example 5)
In the radio communication system 100 according to the fifth embodiment, it is assumed that the arrangement of all or part of the first radio resource, the second radio resource, and the third radio resource is fixed in advance by the system. As a result, for example, transmission of information related to the arrangement of each radio resource in the first to fourth embodiments becomes unnecessary. For this reason, the amount of control information exchanged after data generation in the terminal 120 can be reduced.

For example, in the example shown in FIG. 16, it is possible to omit the steps S1601 to S1603. In this case, in first steps S1605 and S1606 shown in FIG. 16, the base station 110 and the terminal 120 transmit and receive a random access signal using the first radio resource fixed in advance in the radio communication system 100.

Also, in the first steps S1612 and S1613 shown in FIG. 16, the base station 110 and the terminal 120 perform transmission / reception of a random access signal using the second radio resource fixed in advance in the radio communication system 100.

Further, in steps S1605 and S1606 after the second time shown in FIG. 16, base station 110 and terminal 120 perform transmission / reception (retransmission) of a random access signal using a third radio resource fixed in advance in radio communication system 100. .

(Example 6)
(First radio resource according to the sixth embodiment)
FIG. 17 is a diagram of an example of the first radio resource according to the sixth embodiment. The first radio resource for the terminal 120 to transmit a random access signal can be, for example, a 4 [bit] radio resource 1700 shown in FIG. With 4 [bit] radio resource 1700, for example, 2 ^ 4 = 16 sequences at maximum can be prepared.

(Sequence of Random Access Signal According to Embodiment 6)
FIG. 18 is a diagram illustrating an example of a sequence of a random access signal according to the sixth embodiment. In the 4 [bit] sequence transmitted by the terminal 120 using the radio resource 1700, for example, four sequences shown in the table 1800 of FIG. 18 are prepared as the specific sequence described above.

For example, when the terminal 120 connects to the base station 110, the base station 110 gives the terminal 120 one of the numbers “1” to “4”. After that, when data to be transmitted is generated, the terminal 120 transmits a sequence of numbers given from the base station 110 as a random access signal using the first radio resource.

For example, when the number “2” is given from the base station 110, the terminal 120 transmits “0101” as a random access signal using the radio resource 1700. On the other hand, the base station 110 performs a correlation calculation between the received random access signal and the four types of sequences shown in the table 1800. The correlation can be calculated as “1” when the bits match and “−1” when they do not match.

For example, when the correlation between the random access signal (“0101”) received by the base station 110 and “0000”, which is the first sequence in the table 1800, is calculated, two matches and two mismatches are calculated. There are pieces. For this reason, the result of the correlation calculation is 1 + (− 1) +1 + (− 1) = 0.

Further, when the correlation between the random access signal (“0101”) received by the base station 110 and “0101”, which is the second sequence in the table 1800, is calculated, there are four matches. For this reason, the result of the correlation calculation is 1 + 1 + 1 + 1 = 4.

Further, when calculating the correlation between the random access signal (“0101”) received by the base station 110 and “0011”, which is the third sequence in the table 1800, two matches and 2 does not match. It is a piece. For this reason, the result of the correlation calculation is 1 + (− 1) + (− 1) + 1 = 0.

Further, when the correlation between the random access signal (“0101”) received by the base station 110 and “0110”, which is the fourth sequence in the table 1800, is calculated, two matches and two not match. It is a piece. For this reason, the result of the correlation calculation is 1 + 1 + (− 1) + (− 1) = 0.

From the above, the base station 110 can determine that “0101”, which is the second sequence in the table 1800 having the largest correlation calculation result, is the sequence transmitted by the terminal 120 as a random access signal. Here, as long as the second sequence is not given to a plurality of terminals, the base station 110 can specify which terminal has transmitted the random access sequence.

In the example shown in FIGS. 17 and 18, a 4 [bit] long sequence is taken as an example of the random access signal, but the random access signal is not limited to this. For example, as a random access signal, it is possible to use a sequence that is as long as the ratio of the first radio resource in the radio frame allows.

(Example 7)
(First radio resource according to the seventh embodiment)
FIG. 19 is a diagram of an example of the first radio resource according to the seventh embodiment. The first radio resource for the terminal 120 to transmit a random access signal can be, for example, three 4 [bit] radio resources 1901 to 1903 shown in FIG. The terminal 120 selects one radio resource from the radio resources 1901 to 1903, and transmits a 4 [bit] sequence as a random access signal using the selected radio resource. The sequence transmitted by the terminal 120 using the selected radio resource is the same as the example shown in FIGS. 17 and 18, for example.

For example, when the terminal 120 is connected to the base station 110, a specific radio resource to be used in the radio resources 1901 to 1903 is given to the terminal 120 together with one of the numbers “1” to “4” in the table 1800. Notice. At this time, different terminals with the same radio resource are prevented from being given the same sequence number. When data to be transmitted is generated, the terminal 120 transmits a sequence of numbers notified from the base station 110 as a random access signal using a specific radio resource notified from the base station 110 among the radio resources 1901 to 1903. To do.

The base station 110 detects whether a signal is received by each of the radio resources 1901 to 1903, and if it is detected that the signal is received, performs a correlation operation between the received signal and four types of sequences. Do. This makes it possible to determine which sequence is transmitted with which radio resource. Therefore, the base station 110 can specify which terminal has transmitted the random access signal as a terminal that has given the set by the set of the radio resource from which the signal is received and the detected sequence number.

In the example shown in FIG. 19, a 4 [bit] long sequence is taken as an example of the random access signal, but the random access signal is not limited to this. For example, as a random access signal, it is possible to use a sequence that is as long as the ratio of the first radio resource in the radio frame allows.

(Example 8)
FIG. 20 is a diagram of an example of the first radio resource according to the eighth embodiment. The first radio resource for the terminal 120 to transmit a random access signal can be, for example, an 8-bit radio resource 2000 shown in FIG. The radio resource 2000 includes a sequence unit 2001 and an information unit 2002.

The sequence part 2001 is a 4 [bit] part to which the terminal 120 sends a random access signal sequence. The information part 2002 is a 4 [bit] part to which the terminal 120 sends information related to data. The sequence transmitted by the terminal 120 by the sequence unit 2001 is the same as the example shown in FIGS. 17 and 18, for example.

For example, the information part 2002 can store all or part of data to be transmitted by the terminal 120. Further, the information section 2002 may store information related to the amount of data to be transmitted. For example, a data amount corresponding to a number (0 to 15) indicated by 4 [bits] is determined, and the terminal 120 sets any number from 0 to 15 in the information unit 2002 according to the amount of data to be transmitted. It transmits to the base station 110 by the information part 4 [bit].

Thereby, when the base station 110 transmits the data transmission permission signal including the arrangement information of the second radio resource to the terminal 120, the amount of the second radio resource according to the amount of data transmitted from the terminal 120 Can be secured.

Although the case where 4 [bit] is assigned to the information unit 2002 has been described, the configuration is not limited to this. For example, in order to improve the transmission error characteristic of the information unit 2002, it is possible to set the net information of the information unit 2002 to 2 [bit] and to repeat 4 times to 4 [bit].

In the example illustrated in FIG. 20, the case where 4 [bit] lengths are assigned as the sequence unit 2001 and the information unit 2002 is taken as an example, but the sequence unit 2001 and the information unit 2002 are not limited thereto. For example, as the sequence unit 2001, it is possible to use a sequence unit that is as long as the ratio of the first radio resource in the radio frame allows. In addition, as illustrated in FIG. 19, a plurality of radio resources can be set as the first radio resource. In addition, when the information unit 2002 becomes longer to some extent, it is possible to apply encoding having error correction performance with good characteristics to the information unit 2002.

As described above, according to the base station, the terminal, the wireless communication system, and the processing method, it is possible to shorten the time until data transmission becomes possible.

For example, according to the specifications of the conventional 3GPP cellular radio, as described above, an event (such as start of a call, operation of a terminal by a user, completion of sensor sensing, detection of an abnormality of a monitoring device, etc.) is started at a terminal. It takes time until data is actually transmitted after it occurs. For example, according to TR36.912 of 3GPP, 50 [ms] until the terminal enters the connection state, and 9.5 [ms] from the time when the scheduling request (SR) signal is transmitted until the data transmission becomes possible It is reported that.

Also, if contention occurs in the transmission of the random access preamble and the execution of the connection procedure fails, the process starts again from the transmission of the random access preamble. For this reason, when contention occurs in transmission of the random access preamble, there is a possibility that the time until data transmission becomes possible may be further increased.

Also, in applications that communicate with M2M (Machine to Machine) without human intervention, such as sensors and monitoring devices, after communication events occur, communication is started and data is transmitted. Such time may be a problem. For example, in TR22.885 of 3GPP, as an example of Pre-crash Sensing Warning, when a car detects that a collision is unavoidable, it needs to transmit the information within 20 [ms] to the surroundings. .

Also, even when a person is involved, there may be an interactive communication such as a remote operation of a PC (Personal Computer) via communication. For example, data indicating a keyboard or mouse operation performed by a user is transmitted to a remote PC via a communication path, and data for displaying a character input by a human or moving a mouse pointer as a response is remote. It is transmitted from the PC to the user's screen. At this time, if the time from when the user performs an operation until the result of the operation is reflected on the user's screen is long, the operability by the user is significantly impaired, and in some cases, it may be painful for the operating human Become.

In other words, depending on the application, communication is required to be performed with a delay time shorter than the data transmission delay time provided by the current cellular radio standard. If the delay time is reduced by new means, the application of cellular communication This can contribute to widening the width.

Also, for example, a radio resource for performing data transmission to a terminal is constantly given, and transmission is performed using the resource as the transmission data is generated at the terminal, thereby enabling low-delay data transmission. However, if the data to be transmitted does not always occur, such as a sensor that does not always operate or a monitoring device that does not always have an abnormality, radio resources when there is no data to be transmitted are wasted. Therefore, the radio resource utilization efficiency is not good.

Also, for example, increasing the resources used for the random access preamble ensures radio resources for transmission of random access preambles that do not always occur, and limits the radio resources that can be used for normal data transmission. Will be. For this reason, the utilization efficiency of radio resources is not good.

On the other hand, according to the above-described embodiment, when base station 110 can identify terminal 120 based on a random access signal, data transmission permission is given to terminal 120 using a response signal to the random access signal. be able to. Thereby, a part of the random access procedure is omitted, and the time until data transmission from the terminal 120 to the base station 110 becomes possible can be shortened. Moreover, the utilization efficiency of the radio | wireless resource for enabling the data transmission from the terminal 120 to the base station 110 can be improved.

100, 200

Wireless communication system

110, 210

Base station

111, 122 Receiver 112

Identification unit

113, 121

Transmitter

120, 221 to 224 Terminal 211 Cell 301 to 305, 401, 402, 1201 to 1205, 1401, 1402, 1700, 1901 to 1903, 2000 Radio resource 311 to 314 Period 610,710 Processor 611 Radio resource allocation control unit 612 Control information / broadcast information generation unit 613 Random access signal detection unit 614 Data decoding unit 615 Data transmission permission / random access

retransmission determination unit

620 , 720 memory 631,731 transmission signal generator 632,732 transmitter 640,740 transmission / reception signal separator 650,750 antenna 661,761 receiver 662,762 reception signal processor 711 transmission Data generation detector section 712 the random access signal generator 713 the data transmission unit 714 control information and the broadcast information analysis unit 1211 radio frames 1800 table 2001 sequence portion 2002 information unit

Claims

A receiving unit for receiving a random access signal to the local station transmitted by the first radio resource;
A specifying unit for specifying a terminal that has transmitted the random access signal based on the random access signal received by the receiving unit;
A response signal to the random access signal, the response signal permitting the terminal specified by the specifying unit to transmit data to the own station using a second radio resource different from the first radio resource; A transmission unit for transmitting,
The receiving unit receives data transmitted from the terminal by the second radio resource;
A base station characterized by that.
The random access signal is a specific sequence of random access signals assigned to the terminal;
The specifying unit specifies the terminal based on an allocation result of the specific sequence to the terminal and a sequence of the random access signal;
The base station according to claim 1.
The random access signal is a random access signal transmitted by a specific radio resource included in the first radio resource and allocated to the terminal;
The specifying unit specifies the terminal based on an allocation result of the specific radio resource to the terminal and a radio resource to which the random access signal is transmitted;
The base station according to claim 1 or 2, characterized in that
The transmitting unit is a response signal to the random access signal when the terminal that has transmitted the random access signal by the specifying unit is not specified, and the terminal uses the third radio resource to transmit the random access signal. Send a response signal requesting that
The receiving unit receives a random access signal from the terminal to the local station retransmitted by the third radio resource;
The base station according to any one of claims 1 to 3, wherein:
The base station according to claim 4, wherein the third radio resource is a radio resource different from the first radio resource.
When the terminal that has transmitted the random access signal can be specified by the specifying unit, the third radio resource is allocated to communication between another terminal different from the terminal that has transmitted the random access signal and the own station. The base station according to claim 4 or 5, wherein
The base station according to any one of claims 1 to 6, wherein the transmission unit transmits broadcast information for broadcasting information indicating the first radio resource in the own cell.
The base station according to any one of claims 1 to 7, wherein the random access signal includes information on the data transmitted from the terminal to the own station.
The base station according to claim 8, wherein the information related to the data is information indicating at least one of the presence of the data and the amount of the data.
The base station according to any one of claims 1 to 9, wherein the random access signal includes at least a part of the data transmitted from the terminal to the own station.
The base station according to any one of claims 1 to 10, wherein the random access signal is a random access preamble in a random access procedure.
A transmission unit for transmitting a random access signal to the base station using the first radio resource;
A response signal from the base station to the random access signal transmitted by the transmitter, wherein the terminal transmits data to the base station using a second radio resource different from the first radio resource. A receiving unit that receives a response signal that permits
The transmission unit transmits data to the base station using the second radio resource based on the response signal received by the reception unit.
A terminal characterized by that.
A terminal that transmits a random access signal using a first radio resource;
Receiving the random access signal to the local station transmitted by the first radio resource, identifying the terminal that has transmitted the random access signal based on the received random access signal, to the random access signal A base station that transmits a response signal that is a response signal that permits the identified terminal to transmit data to the local station using a second radio resource different from the first radio resource, and
The terminal transmits data to the base station using the second radio resource based on the response signal transmitted from the base station,
The base station receives data transmitted by the second radio resource from the terminal;
A wireless communication system.
A processing method by a base station,
Receiving a random access signal to the local station transmitted by the first radio resource;
Identify the terminal that transmitted the random access signal based on the received random access signal,
A response signal to the random access signal, the response signal permitting the identified terminal to transmit data to the own station by a second radio resource different from the first radio resource;
Receiving data transmitted by the second radio resource from the terminal;
A processing method characterized by the above.
A terminal processing method,
Transmitting a random access signal to the base station by the first radio resource;
A response signal from the base station to the transmitted random access signal, the response signal permitting the terminal to transmit data to the base station using a second radio resource different from the first radio resource Receive
Based on the received response signal, data is transmitted to the base station by the second radio resource.
A processing method characterized by the above.