JP2010177874A - Radio base station and communication control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance certainty of processing of a signal from a radio terminal. <P>SOLUTION: A radio base station 1 measures a delay time of the signal from the radio terminal. When the delay time is equal to or longer than the time length of one guard time, and also equal to or longer than (n) times as long as the time length of the guard time and shorter than (n+1) times as long as the guard time, the radio base station 1 combines a first up time slot and (n) second up time slots together to form a combined up time slot. Then the base station 1 delays the head part of the combined up time slot by a total time length of (n) guard times behind the head part of the first time slot and then allocates the time slot to the radio terminal being the transmission source of the delay exceeding signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio base station that transmits signals to a plurality of radio terminals by time division multiplexing, and a communication control method in the radio base station.

  In a wireless communication system that performs time division duplex (TDD) and time division multiplexing (TDMA) communication between a plurality of wireless terminals and a wireless base station, the distance between each wireless terminal and the wireless base station is different for each wireless terminal. Different. For this reason, even though different time slots are assigned to the respective radio terminals, the radio base station may simultaneously receive burst signals from the respective radio terminals due to a propagation delay caused by a difference in distance. is there.

  In order to prevent such simultaneous reception (collision) of burst signals, for example, in the techniques described in Patent Literature 1 and Patent Literature 2, a radio base station transmits a control signal for preventing collision to each radio terminal. . Each wireless terminal forcibly adjusts the transmission timing of the burst signal based on the received control signal. Such control is referred to as time alignment control.

JP 2001-169343 A JP 2002-77087 A

  However, when the wireless terminal moves from the vicinity to the distance with respect to the wireless base station, the time position of the burst signal received by the wireless base station is a signal at the wireless base station even if the time alignment control as described above is performed. There may be cases where it falls outside the possible range of processing. Thus, if there is a burst signal whose reception timing at the radio base station is extremely delayed, it becomes difficult for the radio base station to normally process the burst signal.

  In particular, in a PHS (Personal Handy Phone System) wireless communication system, the change in the distance between a wireless terminal and a wireless base station is large due to the formation of a macro cell.

  In view of the above problems, an object of the present invention is to provide a radio base station and a communication control method that improve the reliability of processing of a signal from a radio terminal.

  In order to solve the above-described problems, the present invention has the following features. First, the first aspect of the present invention includes a plurality of uplink time slots, a plurality of downlink time slots, and a plurality of guard times located between the uplink time slots and between the downlink time slots. A radio base station (radio base station) that assigns the plurality of uplink time slots and the downlink time slots to a plurality of radio terminals and transmits signals to the plurality of radio terminals (radio terminals 2A to 2D) in a time zone. A reception unit (reception processing unit 152) for receiving a signal from a first wireless terminal to which the first uplink time slot is assigned, and a delay time of the signal received by the reception unit A delay time measurement unit (delay time measurement unit 154) that measures the delay time, and the delay time measured by the delay time measurement unit is greater than or equal to the length of the guard time The first upstream time slot and the second upstream time slot after the first upstream time slot have a total time length, and the head portion is the head portion of the first upstream time slot. And a first allocation control unit (time slot allocation control unit 156) that allocates a third uplink time slot delayed to the first radio terminal.

  In the radio base station, when the delay time of the signal from the first radio terminal to which the first uplink time slot is assigned is equal to or longer than the guard time, the signal from the first radio terminal is The signal enters the second uplink time slot after one uplink time slot, and signal processing at the radio base station becomes difficult.

  Therefore, when the delay time is equal to or longer than the guard time, the radio base station has a total time length of the first uplink time slot and the second uplink time slot, and the first portion is the first portion. A third uplink time slot delayed from the beginning of the uplink time slot is assigned to the first wireless terminal. That is, the radio base station combines the first uplink time slot and the second uplink time slot to form a third uplink time slot, and the head portion is more than the head portion of the first uplink time slot. After the delay, the first wireless terminal is assigned.

  Thereby, in the radio base station, the signal from the first radio terminal comes to be located in the third uplink time slot assigned to the first radio terminal, and the radio base station It becomes possible to process reliably.

  According to a second aspect of the present invention, the first allocation control unit is configured such that the delay time measured by the delay time measurement unit is equal to or longer than a total time length of the n guard times and n + 1 A total time length of the first uplink time slot and the n second uplink time slots after the first uplink time slot when the guard time is less than the total time length. The first part is assigned to the first wireless terminal with the third upstream time slot delayed by a total length of n guard times from the first part of the first upstream time slot. To do.

  The gist of the third aspect of the present invention is that it includes a first transmission unit (wireless terminal transmission control unit 158) that transmits information specifying the third uplink time slot to the first wireless terminal. .

  A fourth aspect of the present invention is the first downlink time slot allocated to the first radio terminal when the delay time measured by the delay time measuring unit is equal to or longer than the time length of the guard time. And a third downlink time slot having a total time length of the first downlink time slot and the second downlink time slot after the first downlink time slot, the leading portion being coincident with the leading portion of the first downlink time slot. The gist of the present invention is to include a second allocation control unit (time slot allocation control unit 156) allocated to the first wireless terminal.

  According to a fifth aspect of the present invention, the second allocation control unit is configured such that the delay time measured by the delay time measurement unit is equal to or greater than a total time length of the m guard times, and m + 1 When the guard time is less than the total time length, the third time length has a total time length of the first downlink time slot and the m second downlink time slots after the first downlink time slot. The gist is to assign a downlink time slot to the first wireless terminal.

  The sixth aspect of the present invention is characterized by comprising a second transmission unit (wireless terminal transmission control unit 158) that transmits information specifying the third downlink time slot to the first wireless terminal. .

  A seventh aspect of the present invention is a time zone composed of a plurality of uplink time slots, a plurality of downlink time slots, and a plurality of guard times located between the uplink time slots and between the downlink time slots. A communication control method in a radio base station for allocating the plurality of uplink time slots and the downlink time slots to a plurality of radio terminals and transmitting signals to and from the plurality of radio terminals, the radio base station Receiving a signal from a first radio terminal to which a first uplink time slot is assigned, measuring a delay time of the received signal by the radio base station, and the radio base station If the measured delay time is equal to or longer than the guard time, the first uplink time slot and the first uplink time A third uplink time slot having a total time length with the second uplink time slot after the slot and having a head portion delayed from the head portion of the first uplink time slot is transmitted to the first wireless terminal. And a step of assigning.

  The eighth aspect of the present invention provides the first downlink time slot assigned to the first radio terminal when the radio base station has the measured delay time equal to or longer than the guard time. And a third downlink time slot having a total length of the first downlink time slot and the second downlink time slot after the first downlink time slot, the leading portion being coincident with the leading portion of the first uplink time slot. The gist includes providing a step of assigning to the first wireless terminal.

  According to the present invention, it is possible to improve the reliability of processing of signals from a wireless terminal in a wireless base station.

1 is an overall schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. It is a figure which shows the structure of the flame | frame which concerns on embodiment of this invention. It is a figure which shows the structure of the downlink time slot | zone and uplink time slot | zone of the frame which concern on embodiment of this invention. It is a schematic block diagram of the radio base station which concerns on embodiment of this invention. It is a functional block block diagram of the control part and radio | wireless communication part in a wireless base station based on embodiment of this invention. It is a 1st flowchart which shows operation | movement of the wireless base station which concerns on embodiment of this invention. It is a 2nd flowchart which shows operation | movement of the wireless base station which concerns on embodiment of this invention. It is a figure which shows the structure of the reception data which concern on embodiment of this invention. It is a figure which shows the formation procedure of the joint uplink time slot in the wireless base station based on embodiment of this invention. It is a figure which shows the formation procedure of the joint downlink time slot in the wireless base station based on embodiment of this invention. It is a figure which shows the formation procedure of the joint uplink time slot in the radio | wireless terminal based on embodiment of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings. Specifically, (1) the configuration of the radio communication system, (2) the operation of the radio base station, (3) the operation and effect, and (4) other embodiments will be described. In the description of the drawings in the following embodiments, the same or similar parts are denoted by the same or similar reference numerals.

(1) Configuration of Radio Communication System First, the configuration of the radio communication system according to the embodiment of the present invention will be described in the order of (1.1) Overall schematic configuration of radio communication system, (1.2) Configuration of radio base station. To do.

(1.1) Overall Schematic Configuration of Radio Communication System FIG. 1 is an overall schematic configuration diagram of a radio communication system 10 according to an embodiment of the present invention.

  As shown in FIG. 1, the radio communication system 10 is a PHS radio communication system. The radio communication system 10 includes a radio base station 1, a radio terminal 2A, a radio terminal 2B, a radio terminal 2C, and a radio terminal 2D. In FIG. 1, radio terminals 2A to 2D are located in a cell 3 provided by the radio base station 1. The radio base station 1 and the radio terminals 2A to 2D transmit signals by time division duplex and time division multiplexing.

  Prior to communication with the radio terminals 2A to 2D, the radio base station 1 allocates a downlink time slot and an uplink time slot in the frame to the radio terminals 2A to 2D. The radio terminals 2A to 2D receive signals from the radio base station 1 using the assigned downlink time slots, and transmit signals to the radio base station 1 using the assigned uplink time slots.

  FIG. 2 is a diagram illustrating a frame configuration. As shown in FIG. 2, the frame includes a downlink time zone used for communication in the downlink direction (direction from the radio base station 1 toward the radio terminals 2A to 2D), and an uplink direction (radio terminal 2A) following the downlink time zone. To the uplink time zone used for communication in the direction from 2D to the radio base station 1).

  FIG. 3 is a diagram illustrating a configuration of a downlink time zone and an uplink time zone of a frame. As shown in FIG. 3A, the frame downlink time zone is composed of four downlink time slots D1 to D4 and guard times DG1 to DG4. The guard times DG1 to DG4 are located between the downlink time slots D1 to D4 and behind the downlink time slot D4.

  As shown in FIG. 3B, the upstream time slot of the frame is composed of four upstream time slots U1 to U4 and guard times UG1 to UG4. The guard times UG1 to UG4 are located between the upstream time slots U1 to U4 and behind the downstream time slot U4.

  The downlink time slots D1 to D4 and the uplink time slots U1 to U4 have the same time length. Further, the guard times DG1 to DG4 and the guard times UG1 to UG4 are shorter than the downlink time slots D1 to D4 and the uplink time slots U1 to U4.

(1.2) Configuration of Radio Base Station Next, regarding the configuration of the radio base station 1, (1.2.1) schematic configuration of the radio base station, (1.2.2) detailed configuration of the radio base station. explain.

(1.2.1) Schematic Configuration of Radio Base Station FIG. 4 is a schematic configuration diagram of the radio base station 1. As illustrated in FIG. 4, the wireless base station 1 includes a control unit 102, a storage unit 103, a wired communication unit 104, a wireless communication unit 106, and an antenna 108.

  The control unit 102 is configured by a CPU, for example, and controls various functions provided in the radio base station 1. The storage unit 103 is configured by a memory, for example, and stores various types of information used for control and the like in the radio base station 1.

  The wired communication unit 104 communicates with a gateway server or the like in an upper network (not shown). The wireless communication unit 106 includes an RF circuit, a baseband circuit, etc., performs modulation and demodulation, encoding and decoding, etc., and transmits and receives wireless signals via the antenna 108.

(1.2.2) Detailed Configuration of Radio Base Station Next, a detailed configuration of the radio base station 1, specifically, functional block configurations of the control unit 102 and the radio communication unit 106 will be described. FIG. 5 is a functional block configuration diagram of the control unit 102 and the radio communication unit 106 of the radio base station 1.

  As illustrated in FIG. 5, the wireless communication unit 106 includes a reception processing unit 152 and a delay time measurement unit 154. The control unit 102 includes a time slot allocation control unit 156 and a wireless terminal transmission control unit 158.

  The reception processing unit 152 in the wireless communication unit 106 transmits each signal transmitted from each of the wireless terminals 2A to 2D via the uplink time slot in the time division multiplexing communication method assigned to each of the wireless terminals 2A to 2D. Receive.

  Further, the reception processing unit 152 demodulates and decodes each received signal to generate reception data, and outputs the reception data to the delay time measurement unit 154 each time.

  The delay time measuring unit 154 in the wireless communication unit 106 inputs each received data. Further, the delay time measuring unit 154 detects the time position of the unique word (UW) included in each input received data. Here, the unique word (see FIG. 8) is identification information of a wireless terminal that is a signal transmission source. Further, the delay time measuring unit 154 measures the delay time of the signal corresponding to the unique word based on the time position of the unique word.

  Specifically, the delay time measurement unit 154 calculates the difference between the time position of the unique word and the reference time position (reference time position) determined for the unique word as the delay time. Here, the reference time position indicates the time position of the unique word in the received data corresponding to the received signal when it is assumed that there is no delay in the signal received by the radio base station 1.

  The delay time measurement unit 154 outputs the measured delay time and the unique word to the time slot allocation control unit 156 in the control unit 102.

  The output delay time is input to the time slot allocation control unit 156 in the control unit 102. Next, the time slot allocation control unit 156 determines whether or not the delay time is equal to or longer than the length of one guard time.

  When the delay time is equal to or longer than the length of one guard time, the time slot allocation control unit 156 further delays the delay time to n times or more of the guard time and less than n + 1 times the guard time. An integer n is specified (hereinafter, for the description of the time slot allocation control unit 156, also refer to the description of S105 in FIG. 6).

  When the integer n is specified, the delay time is greater than or equal to the total time length of n guard times and less than the total time length of n + 1 guard times.

  Next, the time slot allocation control unit 156 outputs a signal (delay excess signal) whose delay time is not less than the total time length of n guard times and less than the total time length of n + 1 guard times. Combining the uplink time slot (first uplink time slot) allocated to the source wireless terminal at that time and n consecutive uplink time slots after the first uplink time slot (second uplink time slot) Thus, a combined uplink time slot is formed. Specifically, the time slot allocation control unit 156 forms a combined uplink time slot having a total time length of the first uplink time slot and the n second uplink time slots.

  If any of the n second uplink time slots has already been assigned to a wireless terminal (other wireless terminal) other than the wireless terminal that has transmitted the excess delay signal, the time slot allocation control unit 156 Reassigns uplink time slots other than the first uplink time slot and the n second uplink time slots to other wireless terminals. As a result, the n second uplink time slots are in an unassigned state. Thereafter, the time slot allocation control unit 156 forms a combined uplink time slot having a total time length of the first uplink time slot and the n second uplink time slots.

  Next, the time slot allocation control unit 156 delays the head part of the combined uplink time slot by a total time length of n guard times from the head part of the first uplink time slot. Thereby, the time length and timing of the combined uplink time slot are set.

  Next, the time slot allocation control unit 156 continues to the downlink time slot (first downlink time slot) allocated to the wireless terminal that is the transmission source of the excess delay signal and the first downlink time slot and thereafter. The n downlink time slots (second downlink time slots) are combined to form a combined downlink time slot. Specifically, the time slot allocation control unit 156 forms a combined downlink time slot having a total time length of the first downlink time slot and the n second downlink time slots.

  If any of the n second downlink time slots has already been assigned to a wireless terminal (other wireless terminal) other than the wireless terminal that has transmitted the excess delay signal, a time slot allocation control unit 156 reassigns downlink time slots other than the first downlink time slot and the n second downlink time slots to other wireless terminals. As a result, the n second downlink time slots are in an unallocated state. Thereafter, the time slot allocation control unit 156 forms a combined uplink time slot having a total length of the first downlink time slot and the n second downlink time slots.

  Next, the time slot allocation control unit 156 matches the head part of the combined downlink time slot with the head part of the first downlink time slot. Thereby, the time length and timing of the combined downlink time slot are set.

  Next, the time slot allocation control unit 156 allocates the above-described combined uplink time slot and combined downlink time slot to the wireless terminal that is the source of the excess delay signal.

  Next, the time slot allocation control unit 156 determines the number of uplink time slots (uplink combination number) constituting the combined uplink time slot and the number of combined downlink time slots (downlink combination number) constituting the combined downlink time slot. Including time slot specifying information is generated. Further, the time slot allocation control unit 156 outputs the time slot specifying information and the unique word to the wireless terminal transmission control unit 158.

  The wireless terminal transmission control unit 158 transmits the time slot identification information to the wireless terminal that is the transmission source of the excess delay signal via the wireless communication unit 106 and the antenna 108. The wireless terminal that is the source of the excess delay signal can be specified by a unique word.

(2) Operation of Radio Base Station Next, the operation of the radio base station 1 will be described. FIG. 6 is a first flowchart showing the operation of the radio base station 1, and FIG. 7 is a second flowchart showing the operation of the radio base station 1. In the following, it is assumed that, in the initial state, the radio base station 1 assigns the downlink time slot D1 and the uplink time slot U1 in the frame shown in FIG. 3 to the radio terminal 2A. Further, it is assumed that the downlink time slots D2 to D4 and the uplink time slots U2 to U4 are in an unallocated state.

  The radio terminal 2A transmits a signal to the radio base station 1 using the assigned uplink time slot U1. In step S101, the radio communication unit 106 in the radio base station 1 inputs a signal transmitted from the radio terminal 2A and received by the antenna 108.

  In step S102, the wireless communication unit 106 detects the time position of the unique word included in the received data obtained by demodulating and encoding the signal. Here, the time position of the unique word indicates the detection time of the unique word.

  FIG. 8 is a diagram illustrating a configuration of received data. The received data shown in FIG. 8 has a bit length of 240 bits. The received data includes, in order from the top, a 4-bit long ramp time for transient response (R), a 2-bit long start symbol (SS), a 6-bit long preample (PR), a 16-bit long unique word (UW). ), 180-bit information, 16-bit CRC (Cyclic Redundancy Check), and 16-bit guard.

  Again, referring back to FIG. In step S103, the control unit 102 in the radio base station 1 calculates the difference between the detected time position of the unique word and the reference time position corresponding to the unique word as the delay time of the signal from the radio terminal 2A. To do.

  In step S104, the control unit 102 determines whether or not the delay time of the signal from the wireless terminal 2A is equal to or longer than the time length of one guard time. When the delay time of the signal from the wireless terminal 2A is less than the length of one guard time, the control unit 102 ends the series of operations.

  On the other hand, when the delay time of the signal from the wireless terminal 2A is equal to or longer than the length of one guard time, the signal from the wireless terminal 2A is assigned to the wireless terminal 2A as shown in FIG. The second uplink time slot (in this case, uplink time slot U2) after the first uplink time slot (in this case, uplink time slot U1) is entered, and signal processing in radio base station 1 becomes difficult.

  In this case, in step S105, the control unit 102 specifies an integer n whose delay time is not less than n times the guard time length and less than n + 1 times the guard time.

  Thereafter, the operation proceeds to the operation shown in FIG. 7, and in step S201, the control unit 102 combines the first uplink time slot and the n consecutive second uplink time slots after the first uplink time slot. , Forming a combined upstream time slot.

  Next, in step S202, the control unit 102 delays the head part of the combined uplink time slot by a total time length of n guard times from the head part of the first uplink time slot.

  For example, when the integer n is 1, in other words, when the delay time is greater than or equal to the time length of one guard time and less than the total time length of two guard times, FIG. ), The control unit 102 combines the uplink time slot U1 allocated to the radio terminal 2A and the uplink time slot U2 to form a combined uplink time slot. Further, the control unit 102 delays the head part of the combined uplink time slot by the time length of one guard time from the head part of the uplink time slot U1.

  When the integer n is 2, in other words, when the delay time is not less than the total time length of the two guard times and less than the total time length of the three guard times, FIG. As shown in (c), the control unit 102 combines the uplink time slot U1 allocated to the radio terminal 2A and the uplink time slots U2 and U3 to form a combined uplink time slot. Further, the control unit 102 delays the head part of the combined uplink time slot by the total length of two guard times from the head part of the uplink time slot U1.

  When the integer n is 3, in other words, when the delay time is not less than the total time length of the three guard times and less than the total time length of the four guard times, FIG. As shown in (d), the control unit 102 combines the uplink time slot U1 allocated to the radio terminal 2A and the uplink time slots U2 to U4 to form a combined uplink time slot. Furthermore, the control unit 102 delays the head part of the combined uplink time slot by a total time length of three guard times from the head part of the uplink time slot U1.

  Again, returning to FIG. In step S203, the control unit 102 combines the first downlink time slot and the n downlink consecutive time slots after the first downlink time slot, A combined downlink time slot having a total time length with the second downlink time slot is formed.

  Next, in step S204, the control unit 102 matches the head part of the combined downlink time slot with the head part of the first downlink time slot.

  For example, when the integer n is 1, in other words, when the delay time is greater than or equal to the time length of one guard time and less than the total time length of two guard times, FIG. ), The control unit 102 combines the downlink time slot D1 allocated to the radio terminal 2A and the downlink time slot D2 to form a combined downlink time slot. Further, the control unit 102 matches the head part of the combined downlink time slot with the head part of the downlink time slot D1 shown in FIG.

  When the integer n is 2, in other words, when the delay time is not less than the total time length of the two guard times and less than the total time length of the three guard times, FIG. As shown in (c), the control unit 102 combines the downlink time slot D1 allocated to the radio terminal 2A and the downlink time slots D2 and D3 to form a combined downlink time slot. Furthermore, the control unit 102 matches the head part of the combined downlink time slot with the head part of the downlink time slot D1.

  When the integer n is 3, in other words, when the delay time is not less than the total time length of the three guard times and less than the total time length of the four guard times, FIG. As shown in (d), the control unit 102 combines the downlink time slot D1 allocated to the radio terminal 2A and the downlink time slots D2 to D4 to form a combined downlink time slot. Furthermore, the control unit 102 matches the head part of the combined downlink time slot with the head part of the downlink time slot D1.

  Again, returning to FIG. In step S205, the control unit 102 allocates the combined uplink time slot and the combined downlink time slot described above to the wireless terminal 2A that is the transmission source of the excess delay signal. Thereafter, the radio base station 1 tries to receive a signal from the radio terminal 2A at the timing of the combined uplink time slot and transmits a signal to the radio terminal 2A at the timing of the combined downlink time slot.

  Further, in step S206, the control unit 102 generates time slot specifying information including the uplink coupling number and the downlink coupling number, and transmits the time slot specifying information to the wireless terminal 2A that is the transmission source of the excess delay signal.

  The radio terminal 2A receives the time slot specifying information. Next, the radio terminal 2A specifies the combined uplink time slot based on the uplink combination number in the received time slot specifying information. Specifically, the radio terminal 2A forms a combined uplink time slot having a total time length of the number of uplink time slots corresponding to the uplink combination number. Furthermore, the radio terminal 2A matches the head part of the combined uplink time slot with the head part of the first uplink time slot assigned to itself.

  For example, when the uplink combination number is 2, as shown in FIG. 11B, the radio terminal 2A forms a combined uplink time slot having a total time length of two uplink time slots. Furthermore, the wireless terminal 2A matches the head part of the combined upstream time slot with the head part of the upstream time slot U1 shown in FIG.

  When the number of combinations is 3, as shown in FIG. 11C, the radio terminal 2A forms a combined uplink time slot having a total time length of three uplink time slots. Further, the radio terminal 2A matches the head part of the combined uplink time slot with the head part of the uplink time slot U1.

  When the number of combinations is 4, as illustrated in FIG. 11D, the radio terminal 2A forms a combined uplink time slot having a total time length of four uplink time slots. Further, the radio terminal 2A matches the head part of the combined uplink time slot with the head part of the uplink time slot U1.

  Also, the radio terminal 2A changes the downlink time slot based on the downlink combination number in the received time slot specifying information. Specifically, the wireless terminal 2A shifts the timing of the downlink time slot allocated to itself backward by the total time length of the guard times that is one less than the number of downlink combinations. In this case, the radio terminal 2A may extend the downlink time slot to the total time length of the number of downlink time slots corresponding to the number of downlink combinations. Alternatively, the wireless terminal 2A extends the time length of the downlink time slot allocated to itself backward by the total time length of the guard times that is one less than the number of downlink combinations.

  Thereafter, the radio terminal 2A transmits a signal to the radio base station 1 at the timing of the combined downlink time slot and attempts to receive a signal from the radio base station 1 at the timing of the changed downlink time slot.

(3) Operation / Effect In the radio communication system 10 according to the embodiment of the present invention, the radio terminals 2A to 2D transmit signals using uplink time slots assigned to themselves. The radio base station 1 receives this signal and obtains received data by demodulation and decoding. Next, the radio base station 1 detects the time position of the unique word included in the received data, and measures the difference between the time position of the unique word and the reference time position as a delay time. When the delay time is equal to or longer than one guard time, and more than n times the guard time, and less than n + 1 times the guard time, the radio base station 1 One uplink time slot and n second uplink time slots are combined to form a combined uplink time slot. Next, the radio base station 1 delays the head part of the combined uplink time slot by the total length of n guard times from the head part of the first uplink time slot, and then transmits an over-delay signal. Assign to the original wireless terminal. Furthermore, the radio base station 1 generates time slot specifying information including the number of uplink couplings, and transmits the time slot specifying information to the radio terminal that is the source of the excess delay signal.

  As a result, in the radio base station 1, the signal from the radio terminal that is the source of the excess delay signal is located in the combined uplink time slot, and the radio base station 1 can reliably process the signal. It becomes possible.

  When the delay time is equal to or longer than one guard time, and more than n times the guard time, and less than n + 1 times the guard time, the radio base station 1 The first downlink time slot and the n second downlink time slots are combined to form a combined downlink time slot. Next, the radio base station 1 makes the head part of the combined downlink time slot coincide with the head part of the first downlink time slot, and assigns it to the radio terminal that is the source of the excess delay signal. Furthermore, the radio base station 1 generates time slot specifying information including the number of downlink couplings, and transmits the time slot specifying information to the radio terminal that is the source of the excess delay signal.

  As a result, the signal transmitted from the wireless base station 1 to the wireless terminal that is the source of the excess delay signal can be located in the combined downlink time slot in the wireless terminal that is the source of the excess delay signal. The terminal can reliably process the signal.

(4) Other Embodiments As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the above-described embodiment, as illustrated in FIGS. 2 and 3, the case where the uplink time slot is divided into four uplink time slots and the downlink time slot is divided into four downlink time slots has been described as an example. The present invention can be applied in the same way even when it is divided into more uplink time slots and downlink time slots.

  It should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

  INDUSTRIAL APPLICABILITY The radio base station and communication control method of the present invention can improve the reliability of processing of signals from each radio terminal in the radio base station, and are useful as a radio base station and a communication control method.

  DESCRIPTION OF SYMBOLS 1 ... Wireless base station, 2A-2D ... Wireless terminal, 3 ... Cell, 10 ... Wireless communication system, 102 ... Control part, 103 ... Memory | storage part, 104 ... Wired communication part, 106 ... Wireless communication part, 108 ... Antenna, 152 ... Reception processing unit, 154 ... Delay time measurement unit, 156 ... Time slot allocation control unit, 158 ... Radio terminal transmission control unit

Claims (8)

In a time zone constituted by a plurality of uplink time slots, a plurality of downlink time slots, and a plurality of guard times located between the uplink time slots and between the downlink time slots, the plurality of uplink time slots and A radio base station that assigns the downlink time slot to a plurality of radio terminals and performs signal transmission with the plurality of radio terminals,
A receiving unit for receiving a signal from the first wireless terminal to which the first uplink time slot is assigned;
A delay time measuring unit for measuring a delay time of the signal received by the receiving unit;
When the delay time measured by the delay time measurement unit is equal to or longer than the guard time, the first uplink time slot, and the second uplink time slot after the first uplink time slot, A first allocation control unit that allocates to the first wireless terminal a third uplink time slot having a total time length of the first uplink time slot that is delayed from the beginning of the first uplink time slot. Radio base station.   The first allocation control unit is configured such that the delay time measured by the delay time measurement unit is greater than or equal to the total time length of the n guard times and less than the total time length of the n + 1 guard times. In some cases, the first uplink time slot has a total length of the second uplink time slots after the first uplink time slot and the first uplink time slot has a total length of the first uplink time slot. 2. The radio base station according to claim 1, wherein the third uplink time slot that is delayed by a total time length of the n guard times from the head part of the time slot is allocated to the first radio terminal.   3. The radio base station according to claim 1, further comprising a first transmission unit configured to transmit information specifying the third uplink time slot to the first radio terminal.   A first downlink time slot assigned to the first wireless terminal and the first downlink time slot when the delay time measured by the delay time measuring unit is equal to or longer than the guard time. A third downlink time slot having a total time length with a subsequent second downlink time slot and having a leading portion coincident with the leading portion of the first downlink time slot is assigned to the first wireless terminal. The radio base station according to claim 1, further comprising two allocation control units.   The second allocation control unit is not less than a total time length of the m guard times and less than a total time length of the m + 1 guard times measured by the delay time measurement unit. In some cases, the third downlink time slot having a total time length of the first downlink time slot and the m second downlink time slots after the first downlink time slot is the first downlink time slot. The radio base station according to claim 4, further comprising a second assignment control unit assigned to the radio terminal.   The radio base station according to claim 4 or 5, further comprising a second transmission unit configured to transmit information specifying the third downlink time slot to the first radio terminal. In a time zone constituted by a plurality of uplink time slots, a plurality of downlink time slots, and a plurality of guard times located between the uplink time slots and between the downlink time slots, the plurality of uplink time slots and A communication control method in a radio base station that assigns the downlink time slot to a plurality of radio terminals and performs signal transmission with the plurality of radio terminals,
The radio base station receiving a signal from a first radio terminal to which a first uplink time slot is assigned;
The radio base station measuring a delay time of the received signal;
The wireless base station, when the measured delay time is equal to or longer than the guard time, the first uplink time slot, and the second uplink time slot after the first uplink time slot; Assigning to the first wireless terminal a third uplink time slot having a total time length of the first uplink time slot delayed from the beginning of the first uplink time slot;
A communication control method comprising:   A first downlink time slot assigned to the first radio terminal and the first downlink time slot when the measured delay time is equal to or longer than the guard time. A step of allocating to the first wireless terminal a third downlink time slot having a total time length with a subsequent second downlink time slot, the leading portion of which coincides with the leading portion of the first uplink time slot A communication control method according to claim 7.

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