JPWO2008087724A1 - Wireless communication system and base station - Google Patents

Abstract

The radio communication system according to the present invention includes a base station host apparatus (2) and a plurality of base stations (3), and the reception timing deviates from the transmission delay allowable range (Ttw) of the base station (3). When the base station (3) receives the user data (UD2), the transmission timing of the user data (UD2) from the base station host apparatus (2) is adjusted. Further, the base station (3) measures the reception timing distribution by measuring the reception timing of the user data (UD2) and the number of reception timings for a predetermined period, and the reception timing distribution measurement unit (31). A transmission delay allowable range changing unit (32) capable of changing the transmission delay allowable range (Ttw) based on the timing distribution is provided.

Description

  The present invention relates to a radio communication system, for example, applied to a radio communication system including a base station host apparatus that transmits user data and a base station that receives the user data and transmits the user data to a mobile radio terminal. can do.

  Conventionally, in a wireless communication system, communication between a wireless base station (hereinafter simply referred to as a base station) and a mobile station has been wireless transmission / reception of data (synchronized) with a certain period. On the other hand, the communication between the base station host apparatus and the base station is data transmission / reception using an asynchronous line such as an ATM line or an IP line.

  Therefore, it is necessary to keep the data transmission / reception period constant in communication between the base station host apparatus and the base station so that the base station can transmit / receive data to / from the mobile station at a constant period. For this reason, a data transmission / reception timing control method is required between the base station host apparatus and the base station.

  In the conventional user data transmission timing control method between a base station host apparatus and a base station in a conventional radio communication system, both the base station host apparatus and the base station have counters of the same period. Then, the base station host apparatus transmits user data by adding a counter value at the time when the base station performs data transmission to the mobile station.

  In the base station, the user data is once stored in the buffer, and the base station counter value is set to the counter value added to the user data before the user data processing period in the base station. The station retrieves user data from the buffer. Then, after performing necessary processing, the base station wirelessly transmits user data to the mobile station at a timing when the counter value of the base station becomes the counter value added to the user frame.

  By transmitting and receiving user data using the user data transmission timing control method as described above, user data is transmitted from the base station host apparatus to the base station even if the counters of the base station and the base station host apparatus are not synchronized. Control is performed such that the difference between the transmission timing and the timing at which the base station wirelessly transmits user data is a fixed time.

  By the way, in the technique according to Patent Document 1, in order to absorb the transmission delay between the base station host apparatus and the base station, a reception window width (transmission delay allowable range) having a certain width is set in the base station. ing. When the timing at which user data is received from the base station host apparatus deviates from the reception window width, the base station issues a user data transmission timing correction request. In response to the user data transmission timing correction request from the base station, the base station host apparatus corrects (adjusts) the timing for transmitting user data.

JP2003-102053

  However, in Patent Document 1, the reception window width set in the base station is fixed. For this reason, when a line in which the amount of variation in transmission delay varies greatly depending on the line load is used as a line between the base station host apparatus and the base station, there are the following problems.

  That is, when the reception window width set in the base station is smaller than the fluctuation amount of the transmission delay, user data transmission timing correction requests are frequently issued from the base station to the base station host apparatus. This causes a problem of increasing the line load and discarding a large amount of data that is out of the reception window width.

  On the other hand, when the reception window width set in the base station is larger than the fluctuation amount of the transmission delay, even if the line load decreases and the transmission delay amount becomes smaller, the user data transmission timing correction request is issued until the large reception window width is exceeded. Not done. Therefore, there is a problem that a wasteful delay occurs.

  Therefore, the present invention is a radio that can dynamically (adaptively) avoid quality degradation due to discarding user data and quality degradation due to useless transmission delay, even in a line in which the amount of variation in transmission delay varies greatly. An object is to provide a communication system.

  In order to achieve the above object, a wireless communication system according to claim 1 of the present invention is transmitted from a base station host apparatus (2) that transmits user data (UD2) and the base station host apparatus. A plurality of base stations (3) that receive the user data and wirelessly transmit the received user data, and at a reception timing that is out of a transmission delay allowable range (Ttw) of the base station In a wireless communication system that can adjust the transmission timing of the user data from the base station host apparatus when the base station receives the user data, the base station is configured to receive the user data reception timing and the user data The reception timing distribution is measured by measuring the number of times the user data is received at the reception timing for a predetermined period. Distribution measurement section (31), based on the reception timing distribution, transmission delay allowable range changing unit capable of changing the transmission delay tolerance and (32), are provided.

  A radio communication system according to claim 6 of the present invention receives a base station host apparatus (2) that transmits user data (UD2) and the user data transmitted from the base station host apparatus, A plurality of base stations (3) for wirelessly transmitting the received user data, and the base station receives the user data at a reception timing that is out of an allowable transmission delay range of the base station In the wireless communication system capable of adjusting the transmission timing of the user data from the base station host apparatus, the base station host apparatus transmits an inquiry frame to the base station. ), A transmission timing indicating the transmission timing of the inquiry frame included in the inquiry frame, and a response in response to the inquiry frame. A transmission delay between the base station host apparatus and the base station by measuring a difference from the reception timing at which the base station received the inquiry frame included in the response frame transmitted from the base station a plurality of times. A delay fluctuation amount calculation unit (22) for calculating a fluctuation amount of the amount, and changing to a transmission delay allowable range determined based on the fluctuation amount of the transmission delay amount calculated by the delay fluctuation amount calculation unit. A transmission delay allowable range change request issuing unit (23) that requests the base station, and the base station transmits the transmission delay allowable range transmitted from the transmission delay allowable range change request issuing unit. In response to the change request, the set transmission delay allowable range is changed to the transmission delay allowable range determined based on the fluctuation amount of the transmission delay amount.

  The radio communication system according to claim 8 of the present invention receives a base station host apparatus (2) that transmits user data (UD2) and the user data transmitted from the base station host apparatus, A plurality of base stations (3) for wirelessly transmitting the received user data, and the base station at a reception timing deviating from a transmission delay allowable range (Tta, Ttb, Ttc, Ttd) of the base station. In a radio communication system capable of adjusting the transmission timing of the user data from the base station host apparatus when a station receives the user data, the base station host apparatus is configured such that the base station transmits the transmission delay. When the user data is received out of an allowable range, a transmission timing correction request transmitted from the base station to the base station host apparatus is transmitted in advance. A transmission timing calculation unit (27) that measures the frequency of reception by the base station host apparatus, and changes to the transmission delay allowable range determined based on the measurement result of the transmission timing calculation unit for the base station A transmission delay allowable range change request issuing unit (28), and the base station responds to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit. Then, the set transmission delay allowable range is changed to the transmission delay allowable range determined based on the measurement result of the transmission timing calculation unit.

  The wireless communication system according to claim 1 of the present invention is a transmission delay in which a base station can change a transmission delay allowable range based on a reception timing distribution measurement unit that measures the reception timing distribution and the reception timing distribution. And an allowable range changing unit.

  Therefore, even if the fluctuation amount of the transmission delay between the base station host apparatus and the base station changes according to the load on the transmission line, the transmission delay allowable range corresponding to the delay fluctuation amount can be reset as needed. Therefore, when the delay fluctuation amount is large, the user data discard rate can be kept low, and when the delay fluctuation amount is small, communication with low delay is possible.

  Further, in the wireless communication system according to claim 6 of the present invention, the base station host apparatus sets a plurality of differences between the inquiry issuing unit that transmits the inquiry frame, the inquiry frame transmission timing, and the inquiry frame reception timing. By calculating the variation amount of the transmission delay amount by measuring the number of times, and requesting a change to the transmission delay allowable range determined based on the calculated variation amount of the transmission delay amount, A transmission delay allowable range change request issuing unit. The base station changes the set transmission delay allowable range in response to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit.

  Therefore, even if the fluctuation amount of the transmission delay between the base station host apparatus and the base station changes according to the load on the transmission line, the transmission delay allowable range corresponding to the delay fluctuation amount can be reset as needed. Therefore, when the delay fluctuation amount is large, the user data discard rate can be kept low, and when the delay fluctuation amount is small, communication with low delay is possible.

  Moreover, in the radio communication system according to claim 8 of the present invention, the base station host apparatus measures the frequency of receiving a transmission timing correction request from the base station, and based on the measurement result A transmission delay allowable range change request issuing unit that requests to change to the determined transmission delay allowable range. The base station changes the set transmission delay allowable range in response to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit.

  Therefore, even if the fluctuation amount of the transmission delay between the base station host apparatus and the base station changes according to the load on the transmission line, the transmission delay allowable range corresponding to the delay fluctuation amount can be reset as needed. Therefore, when the delay fluctuation amount is large, the user data discard rate can be kept low, and when the delay fluctuation amount is small, communication with low delay is possible.

  The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

It is the schematic which shows the structure of a radio | wireless communications system. 3 is a functional block diagram showing an internal configuration of a base station according to Embodiment 1. FIG. 6 is a diagram for explaining a variation operation of an allowable transmission delay range in the radio communication system according to Embodiment 1. FIG. 6 is a diagram for explaining a variation operation of an allowable transmission delay range in the radio communication system according to Embodiment 1. FIG. 6 is a diagram for explaining a variation operation of an allowable transmission delay range in the radio communication system according to Embodiment 1. FIG. 6 is a diagram for explaining a changing operation of the radio communication system according to Embodiment 1. FIG. FIG. 10 is a functional block diagram showing an internal configuration of a base station host apparatus and a base station according to Embodiment 3. FIG. 12 is a diagram for explaining a variation operation of the allowable transmission delay range in the wireless communication system according to the third embodiment. FIG. 10 is a functional block diagram showing an internal configuration of a base station host apparatus and a base station according to Embodiment 4. FIG. 10 is a diagram for explaining a variation operation of the allowable transmission delay range in the wireless communication system according to the fourth embodiment. FIG. 10 is a diagram for explaining a variation operation of the allowable transmission delay range in the wireless communication system according to the fourth embodiment.

  In a wireless communication system typified by a mobile phone or a PHS, an area where communication can be performed in one wireless base station (hereinafter simply referred to as a base station) is limited. Therefore, by configuring an area (cell) in which a plurality of base stations can cover communication and complementing each other, mobile wireless communication can be performed from any location.

  When a mobile terminal (hereinafter, simply referred to as a terminal) performs wireless communication, communication is performed using a base station responsible for communication within a cell to which the mobile terminal belongs. However, when moving to another cell beyond the range of the cell to which it originally belonged during communication, it becomes necessary to perform communication using a base station existing in the destination cell. At that time, if the terminal can use only one base station, there is a problem that communication is momentarily interrupted at the moment of switching the base station to be used.

  In order to avoid such a problem, in a wireless communication system, when a terminal exists in the vicinity of a boundary between a plurality of cells, it is possible to perform communication simultaneously with a plurality of base stations.

  In order to enable such a technique, timing control is performed so that a plurality of base stations existing near the terminal receive user data, and the user data arrives at the terminal simultaneously from each base station to the terminal. There must be. The role of the timing control is generally played by a base station host apparatus (base station control apparatus). When receiving the user data to the terminal, the base station host apparatus duplicates the data and controls the transmission timing to each base station so that the user data arrives simultaneously at a plurality of base stations.

  FIG. 1 is a conceptual diagram showing the configuration of a general (mobile) wireless communication system (more specifically, the relationship between base station host apparatus 2, base station 3, and terminal 4).

  In the radio communication system shown in FIG. 1, the base station host apparatus 2 receives user data UD1 from the core network 1. Then, the base station host apparatus 2 duplicates the user data UD1, and transmits the duplicated user data UD2 to the plurality of base stations 3 (3-1, 3-2, 3-3). The plurality of base stations 3-1, 3-2 and 3-3 transmit user data UD 2 as user data UD 3 wirelessly. Then, the user data UD3 is transmitted to the terminal 4.

  Here, as described in the background art, the data transmission / reception cycle is constant also in communication between the base station host apparatus 2 and the base station 3 so that the base station 3 can transmit / receive data to / from the terminal 4 at a constant cycle. Need to keep on. For this reason, a data transmission / reception timing control method is required between the base station host apparatus 2 and the base station 3.

  In the user data UD2 transmission timing control method between the base station host apparatus 2 and the base station 3 in the wireless communication system, both the base station host apparatus 2 and the base station 3 have counters of the same period. Then, the base station host apparatus 2 transmits user data UD2 with a counter value added when the base station 3 transmits data to the terminal 4.

  In the base station 3, the user data UD2 is once stored in the buffer, and only before the processing period of the user data UD2 in the base station 3 from the timing when the counter value of the base station 3 becomes the counter value added to the user data UD2. The base station 3 takes out the user data UD2 from the buffer at the time. Then, after performing the necessary processing, the base station 3 wirelessly transmits the user data UD3 to the terminal 4 at a timing when the counter value of the base station 3 becomes the counter value added to the user frame UD2.

  By transmitting and receiving user data using the user data transmission timing control method as described above, even if the counters of the base station 3 and the base station host apparatus 2 are not synchronized, the base station host apparatus 2 can change the base station 3 to the base station 3. The difference between the timing at which user data is transmitted to the base station 3 and the timing at which the base station 3 wirelessly transmits user data UD3 is controlled to be a fixed time.

  Further, in the wireless communication system, in order to absorb transmission delay between the base station host apparatus 2 and the base station 3, the base station 3 has a receivable window having a certain width and a transmission delay allowable range. Has been.

  The receivable window is a timing range in which the user data UD2 can be received, which is determined from the internal processing time of the base station 3 and the size of the reception buffer. The transmission delay allowable range is a range within the range of the receivable window by the base station 3, and is a range that dynamically changes as will be described later. The base station 3 transmits the user data UD2 received at the timing within the receivable window at the designated transmission timing regardless of whether the transmission delay allowable range is inside or outside. On the other hand, the base station 3 discards the user data UD2 received at a timing outside the receivable window.

  When the timing at which the user data UD2 is received from the base station host apparatus 2 is out of the allowable transmission delay range, the base station 3 issues a user data transmission timing correction request. The base station host apparatus 2 receives the user data transmission timing correction request from the base station 3 and corrects (adjusts) the timing for transmitting the user data UD2.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

<Embodiment 1>
The radio communication system according to the present embodiment measures the reception timing distribution of user data UD2 at base station 3. Then, based on the reception timing distribution, the allowable transmission delay range set in the base station 3 is dynamically changed. When the base station 3 receives the user data UD2 at a reception timing that is outside the transmission delay allowable range after the change, the base station host apparatus 2 corrects the user data transmission timing as described above.

  Hereinafter, the configuration of the base station 3 according to the present embodiment will be specifically described. FIG. 2 is a functional block diagram showing the internal configuration of the base station 3.

  As shown in FIG. 2, the base station 3 includes a reception timing distribution measurement unit 31, a timing correction amount calculation unit (also known as a transmission delay allowable range change unit) 32, a timing correction request issue unit 33, and a storage unit 34. Has been.

  The reception timing distribution measurement unit 31 receives the user data UD2 obtained with reference to a predetermined timing (in the present embodiment, when the user data UD3 is transmitted), and the number of times the user data UD2 is received at the reception timing. Are measured for a predetermined period. As a result, the reception timing distribution measuring unit 31 measures (creates) the reception timing distribution (see FIG. 3 described later).

  The timing correction amount calculation unit (which can also be grasped as a transmission delay allowable range changing unit) 32 can change the width of the transmission delay allowable range based on the reception timing distribution.

  The timing correction amount calculation unit 32 calculates a first transmission timing correction amount. Here, the first transmission timing correction amount is an end portion (end portion T24 in FIG. 4 to be described later) on the side where reception timing of user data is late in the transmission delay allowable range after the change. It is possible to coincide with the time (T21 in FIG. 4 described later) that is just before the user data processing period in the base station 3 from the time of wireless transmission timing (T20 in FIG. 4 described later) (see FIG. 5). This is the correction amount.

  The timing correction request issuing unit 33 can transmit the first transmission timing correction amount to the base station host apparatus 2. The base station host apparatus 2 corrects (adjusts) the transmission timing of the user data UD2 based on the first transmission timing correction amount. Thereby, the position of the allowable transmission delay range at a predetermined timing coordinate can be moved from the state of FIG. 4 described later to the state of FIG. 5 described later.

  The storage unit 34 stores a table. The table is composed of user data types (which can also be understood as service types) and reference values determined according to the user data types.

  The reception timing distribution measuring unit 31 obtains a normal distribution that best matches the reception timing distribution based on the reception timing distribution. Then, the timing correction amount calculation unit (transmission delay allowable range changing unit) 32 changes the width of the transmission delay allowable range based on the distribution shape of the normal distribution and a preset reference value.

  Here, the timing correction amount calculation unit 32 uses the above criteria based on the type of the current user data being used (in other words, the type of service to be provided) and the table stored in the storage unit 34. Select a value. Further, the changed transmission delay allowable range is determined so that the positions where the normal distribution is symmetric are the end portions (T24, T25) (see FIG. 4).

  Next, regarding the operation for changing the allowable transmission delay range and the moving operation at the timing coordinates of the allowable transmission delay range according to the present embodiment, the reception timing of user data UD2 at base station 3 shown in FIGS. This will be described with reference to the drawings.

  Here, FIGS. 3 to 5 are diagrams showing a timing coordinate system in the base station 3 starting from the radio transmission timing T20 of the user data UD3. The left side of FIGS. 3 to 5 is the transmission time side of the user data UD2 from the base station host apparatus 2, and the right side is the wireless transmission side of the user data UD3 from the base station 3 as described above.

  First, in FIG. 3, the receivable window and the current allowable transmission delay range are set in the base station 3. Here, the end of the range of the receivable window on the side where the reception timing is late coincides with the timing (timing) T21 that is just before the processing period of the user data UD2 in the base station 3 from the radio transmission timing T20. Similarly, the end of the transmission delay allowable range on the side where the reception timing is late coincides with the timing (timing) T21 that is before the processing period of the user data UD2 in the base station 3 from the radio transmission timing T20. Note that “the end on the side where the reception timing is late” is an end on the side close to the radio transmission timing T20.

  In the state where the receivable window and the current transmission delay allowable range are set, as shown in FIG. 3, the reception timing distribution measuring unit 31 displays the header area of the user data UD2 received from the base station host apparatus 2. The difference (difference time Td) between the included radio transmission timing T20 of the user data UD3 and the base station 3 reference timing T22 at the time when the base station 3 receives the user data UD2 is calculated. That is, the reception timing at the base station 3 of the user data UD2 obtained based on a predetermined timing (radio transmission timing T20) is calculated.

  Then, the reception timing distribution measurement unit 31 measures the number of receptions of the user data UD2 for each difference time Td. The number of receptions is counted for the timing update period Tn (which can be grasped as a predetermined period). The state after the aggregation is represented by a bar graph in FIG. Each time the counting for the timing update period Tn is completed, the counting result is cleared.

  Next, the reception timing distribution measuring unit 31 obtains the most suitable normal distribution based on the reception timing distribution shown by the bar graph shown in FIG. 3 (see FIG. 3).

  Next, the timing correction amount calculation unit (transmission delay allowable range changing unit) 32 changes the transmission delay allowable range based on the distribution shape of the normal distribution and a preset reference value (new transmission delay). It can also be understood that the width of the allowable range Ttw is determined). As shown in FIG. 4, the transmission delay is changed to a new allowable transmission delay range Ttw.

  Here, the storage unit 34 of the base station 3 has a table composed of user data types and the reference values determined according to the user data types. The timing correction amount calculation unit 32 selects the reference value based on the type and table of user data used during the processing.

  Note that if the transmission delay allowable range Ttw is determined based on the distribution shape of the normal distribution and the reference value, the timing correction amount calculation unit 32, as shown in FIG. The changed transmission delay allowable range Ttw is set (determined) so as to be the end portions T24 and T25. That is, the end portions T24 and T25 of the transmission delay allowable range Ttw after the change are set to positions that are symmetric with respect to the symmetry axis O of the normal distribution.

  Next, the timing correction amount calculation unit 32 transmits the end portion T24 on the side where the reception timing of the user data UD2 is late in the transmission delay allowable range Ttw after the change from the wireless transmission timing T20 when the user data UD3 is transmitted over the radio. The base station 3 can be made to coincide with the time T21 that is just before the processing period of the user data UD2 (that is, the end T24 can be made to coincide with the time T21), and the first transmission timing correction amount Tf is calculated. To do.

  Thereafter, the timing correction request issuing unit 33 of the base station 3 transmits the calculated first transmission timing correction amount Tf to the base station host apparatus 2.

  The base station host apparatus 2 corrects the transmission timing of the user data UD2 based on the received first transmission timing correction amount Tf. With this correction, as shown in FIG. 5, the reception timing distribution (normal distribution) of the user data UD2 in the base station 3 moves. Then, the new transmission delay allowable range Ttw that has been changed based on the normal distribution and fixed to the normal distribution also moves to a position where the end T24 coincides with the time T21 due to the correction (see FIG. 5). ).

  Here, as can be seen from FIG. 5, the user data UD2 received at the timing T20 from the end T24 is discarded in the base station 3 (in other words, the user data UD2 distributed in the area Sa is discarded. ) This is because the user data UD2 is received at a timing outside the receivable window as described above.

  It is understood that the area Sa indicates the number of user data UD2 to be discarded. Accordingly, it can be understood that the determination of the allowable transmission delay range Ttw in the timing correction amount calculation unit 32 described above is determined based on the discard amount of the user data UD2. Therefore, the table including the reference value stored in the storage unit 34 is allowed to discard the user data UD2 type (service type at the time of channel setting) and the user data UD2 of a certain type in the base station 3. It is created in advance from the point of view.

  For example, in the user data UD2 (service) in which the delay time is important like voice data but some data omission is allowed, the transmission delay allowable range Ttw (in other words, so that the area Sa is increased) Ends T24 and T25) with respect to the normal part are set (area Sa is 0.01 times the total area of the normal distribution). On the other hand, in the user data UD2 (service) that is allowed to have a delay as in packet data but has a large influence of the data loss, the transmission delay allowable range Ttw (in other words, the area Sa is reduced). Then, end portions T24 and T25) with respect to the normal portion are set (the area Sa is 0.0001 times the total area of the normal distribution).

  As described above, in the radio communication system according to the present embodiment, the transmission delay allowable range is dynamically changed according to the variation in the reception timing of user data UD2 in base station 3 (distribution of user data UD2 reception timing). I am letting.

  Therefore, even if the fluctuation amount of the transmission delay between the base station host apparatus 2 and the base station 3 changes according to the load of the transmission line, the transmission delay allowable range corresponding to the delay fluctuation amount can be reset as needed. Therefore, when the delay fluctuation amount is large, the discard rate of the user data UD2 can be kept low, and when the delay fluctuation amount is small, communication with a low delay is possible.

  In other words, when the fluctuation amount of the transmission delay is large, the reception timing of the user data UD2 is within the transmission delay allowable range Ttw, and the frequency of data discarding can be kept low. Further, when the fluctuation amount of the transmission delay is small, the transmission delay allowable range Ttw is set to be narrow, so that communication with a low delay is possible. Therefore, by performing transmission timing control of the user data UD2 using the transmission delay allowable range obtained from the reception timing distribution, it is possible to perform timing control that takes into account the amount of variation in transmission delay that changes depending on the transmission line load at that time. is there.

  Further, in the wireless communication system according to the present embodiment, the timing correction amount calculation unit (transmission delay allowable range changing unit) 32 is based on the distribution shape of the normal distribution and the preset reference value, The range Ttw is changed. Here, the reference value is determined, for example, according to the user data UD2 type (service type).

  Therefore, it is suitable for each of user data UD2 (service) that places importance on low delay even if some data is discarded, and user data UD2 (service) where it is better to discard data even if the delay is large. The transmission delay allowable range Ttw can be changed.

  In the radio communication system according to the present embodiment, the end portion T24 of the transmission delay allowable range Ttw is made coincident with the time T21 based on the first transmission timing correction amount Tf.

  Therefore, in the base station 3, it is possible to minimize the buffer period of the user data UD2 from when the user data UD2 is received until wireless transmission. Therefore, it is possible to suppress occurrence of useless delay in the base station 3.

  Note that the transmission delay between the base station host apparatus 2 and the base station 3 is considered to be substantially the same for channels with the same QoS setting. For this reason, the distribution information of the reception timing of the user data UD2 may be aggregated using distribution information of other channels with the same QoS setting. In this case, the timing information of the existing channel can be applied to the newly set channel, and the user data UD2 can be received at the optimal timing from the beginning.

  Even in a state before a channel for user data UD2 communication is set, a common channel for transmitting common information is always set. For this reason, it is also possible to perform timing control of the user data communication channel that is initially set using the transmission delay distribution information of the common channel.

  In addition, for the transmission delay allowable range Ttw that is adaptively set in the base station 3, a reception allowable window (not shown) limited by the signal processing performance and buffer amount on the base station host apparatus 2 side is separately set, It is also conceivable that the base station 3 controls the transmission delay allowable range Ttw within the range of the reception allowable window.

  In addition, the load on the line can be predicted to some extent depending on the time of day and season. Therefore, it is conceivable to refer to time information and past statistical data to predict load fluctuations and to control the allowable transmission delay range in order to cope with changes in the fluctuation amount of transmission delay in advance.

<Embodiment 2>
In the radio communication system according to the present embodiment, when the user data UD2 is received at a timing deviating from the changed transmission delay allowable range Ttw described in the first embodiment, the base station 3 transmits to the base station host apparatus 2 On the other hand, it is possible to request correction (adjustment) of the transmission timing of the user data UD2.

  Hereinafter, the transmission timing correction operation in the wireless communication system according to the present embodiment will be described with reference to FIG.

  First, after the situation illustrated in FIG. 5 is obtained by the operation described in the first embodiment, the base station 3 continuously changes the transmission delay tolerance changed a predetermined number of times (the number can be arbitrarily selected). It is assumed that the user data UD2 is received out of the range Ttw toward the one end T24 side or the other end T25 side. Then, the timing correction amount calculation unit 32 illustrated in FIG. 2 determines the second timing correction amount (second user) based on the reception timing of the user data UD2 received out of the changed transmission delay allowable range Ttw. Data transmission timing correction amount) Tp is calculated.

  For example, as shown in FIG. 6, it is assumed that the base station 3 continuously receives the user data UD2 a predetermined number of times at a timing deviating from the end portion T25 of the transmission delay allowable range Ttw (out-of-range reception). Here, it is assumed that the user data UD2 is continuously received a predetermined number of times at a timing that deviates from the end T25 of the allowable transmission delay range Ttw by a predetermined threshold value or more by further imposing conditions. (Receiving out of range).

  In this case, the timing correction amount calculation unit 32 calculates the average reception timing of the user data UD2 received out of the range. Thereby, as shown in FIG. 6, the average timing T30 of the user data UD2 received out of range of the user data UD2 is determined.

  Next, the timing correction amount calculation unit 32 calculates a difference between the end portion T25 of the transmission delay allowable range Ttw after the change and the average timing T30 of out-of-range reception of the user data UD2. The calculated value is the above-described second timing correction amount Tp.

  Thereafter, the timing correction request issuing unit 33 transmits the second transmission timing correction amount tp to the base station host apparatus 2. Then, the base station host apparatus 2 corrects (adjusts) the transmission timing of the user user UD2 based on the second transmission timing correction amount Tp (specifically, delays the transmission timing by the correction amount Tp).

  As described above, in the radio communication system according to the present embodiment, the second transmission timing correction amount Tp is obtained as described above, and the base station host apparatus 2 determines the user data UD2 based on the correction amount Tp. The transmission time is adjusted (corrected).

  Therefore, it is possible to avoid erroneous control of the transmission timing of user data UD2 due to a sudden timing shift in transmission delay. Furthermore, when out-of-range reception occurs continuously, it is possible to finally allow the base station 3 to receive the user data UD2 at a timing within the changed transmission delay allowable range Ttw. It is.

  In the above description, the timing correction amount calculation unit 32 calculates the second transmission timing correction amount Tp. However, the timing correction request issuing unit 33 that can function as a reception timing evaluation unit calculates the second transmission timing correction amount Tp in the same manner as described above using the changed transmission delay allowable range, It is also possible to configure so that the second transmission timing correction amount tp is transmitted to the base station host apparatus 2.

<Embodiment 3>
In the radio communication system according to Embodiment 1, the allowable transmission delay range is changed on the base station 3 side based on the reception timing distribution of the user data UD2 measured on the base station 3 side.

  In the radio communication system according to the present embodiment, base station host apparatus 2 determines the allowable transmission delay range based on the amount of change in transmission delay calculated on the base station host apparatus 2 side. Then, the base station host apparatus 2 issues a request for changing the allowable transmission delay range to the base station 3, thereby dynamically (adaptively) changing the allowable transmission delay range on the base station 3 side. Do.

  When the base station 3 receives the user data UD2 at a reception timing outside the allowable transmission delay range of the base station 3, as described in the first embodiment, user data from the base station host apparatus 2 is used. The transmission timing of UD2 is corrected (adjusted).

  FIG. 7 is a functional block diagram showing the internal configuration of base station host apparatus 2 and the internal configuration of base station 3 in the radio communication system according to the present embodiment.

  As shown in FIG. 7, the base station host apparatus 2 includes a reception timing inquiry issuing unit 21, a delay variation calculating unit 22, a transmission delay allowable range change request issuing unit 23, a user data transmitting unit 24, and a transmission timing correcting unit 25. It has. On the other hand, the base station 3 includes a reception timing inquiry response unit 35, a transmission delay allowable range changing unit 36, and a timing correction request issuing unit 37.

  First, the configuration of the base station host apparatus 2 will be described.

  The reception timing inquiry issuing unit 21 is a part that can periodically transmit an inquiry frame to the base station 3, for example.

  The delay variation calculation unit 22 measures (calculates) a difference between a transmission timing included in the inquiry frame and a reception timing included in a response frame described later. Here, the transmission timing indicates the timing at which the base station host apparatus 2 transmits an inquiry frame. The response frame is a frame transmitted from the base station 3 in response to the inquiry frame. Further, the reception timing indicates the timing at which the base station 3 receives the inquiry frame included in the response frame.

  Further, the delay variation calculation unit 22 measures the difference a plurality of times (a predetermined number, which can be arbitrarily set), thereby reducing the transmission delay between the base station host apparatus 2 and the base station 3. A fluctuation amount (hereinafter referred to as a delay fluctuation amount) is calculated. Here, the calculation of the delay amount fluctuation amount may be determined assuming a normal distribution as described in the first embodiment. Further, it may be determined from the maximum value and the minimum value of the transmission delay amount.

  The transmission delay allowable range change request issuing unit 23 requests the base station 3 to change to the transmission delay allowable range determined based on the delay amount variation calculated by the delay variation calculation unit 22.

  The user data transmission unit 24 is a part that transmits user data UD2 to the base station 3, and the transmission timing correction unit 25 responds to the transmission timing correction request transmitted from the base station 3, and the user data UD2 This is a part for correcting (adjusting) the transmission timing.

  Next, the configuration of the base station 3 will be described.

  The reception timing inquiry response unit 35 is a part that receives an inquiry frame transmitted from the base station host apparatus 2 and transmits a response frame in response to the reception. As described above, the response frame includes the timing at which the inquiry frame is received at the base station 3.

  The transmission delay allowable range changing unit 36 is a part that changes a transmission delay allowable range before the request to a new transmission delay allowable range in response to a transmission delay allowable range change request transmitted from the base station host apparatus 2. That is, in accordance with the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit 23, the set transmission delay allowable range is represented by the delay amount variation calculated by the delay variation calculation unit 22. To a transmission delay allowable range determined based on

  The timing correction issuing unit 37 can function as a reception timing evaluation unit as described in the latter part of the second embodiment. That is, when the user data UD2 is received at a timing outside the transmission delay allowable range after the change, the correction amount of the transmission timing of the user data UD2 from the base station host apparatus 2 is calculated. Then, the timing correction issuing unit 37 transmits the calculated correction amount to the base station host apparatus 2. The timing correction issuance unit 37 also accepts reception of user data UD2 transmitted from the base station host apparatus 2.

  Next, the operation for changing the allowable transmission delay range in the radio communication system according to the present embodiment will be described.

  The reception timing inquiry issuing unit 21 of the base station host apparatus 2 issues an inquiry frame to the base station 3 every transmission range allowable range update period T in order to make a reception timing inquiry. Here, in order to measure the delay fluctuation amount, the inquiry frame is continuously transmitted a plurality of times. As described above, the inquiry frame includes the timing at which the base station host apparatus 2 transmits the inquiry frame.

  Next, the reception timing inquiry response unit 35 of the base station 3 receives the inquiry frame. Then, the reception timing inquiry response unit 35 transmits a response frame to the base station host apparatus 2 in response to the reception of the inquiry frame. Here, as described above, the response frame includes the timing at which the base station 3 receives the inquiry frame. For example, the reception timing inquiry response unit 35 can add the received timing to the received inquiry frame as a response frame to the base station host apparatus 2.

  Next, the delay variation calculation unit 22 of the base host apparatus 2 receives the response frame. Here, it is assumed that the response frame includes a transmission timing ST at which the base station host apparatus 2 transmits the inquiry frame and a reception timing RT at which the base station 3 receives the inquiry frame.

  After receiving the response frame, the delay variation calculation unit 22 calculates the difference between the transmission timing ST and the reception timing RT. The delay variation calculation unit 22 calculates a transmission delay amount between the base station host apparatus 2 and the base station 3 by calculating the difference as many times as the number of times the inquiry frame is transmitted. As described above, the calculation of the delay variation amount may be determined on the assumption of a normal distribution as described in the first embodiment, or may be determined from the maximum value and the minimum value of the transmission delay amount. .

  Next, the transmission delay allowable range change request issuing unit 23 of the base station host apparatus 2 receives the delay fluctuation amount calculated by the delay fluctuation amount calculation unit 22 and determines a new transmission delay determined based on the delay fluctuation amount. A command to change to an allowable range is transmitted to the base station 3.

  Here, as shown in FIG. 8, a time T61 that is just before the time required for processing the user data UD2 in the base station 3 from the radio transmission timing T60 of the user data UD3 in the base station 3, and the changed transmission The user data transmission unit 24 of the base station host apparatus 2 transmits the user data UD2 at a timing at which the end portion on the side where the reception timing of the allowable delay range is late can coincide.

  Next, the transmission delay allowable range changing unit 36 of the base station 3 receives the transmission delay allowable range change command. The transmission delay allowable range changing unit 36 changes the currently set transmission delay allowable range to a new transmission delay allowable range based on the change command.

  Here, when the amount of delay variation in the transmission path between the base station host apparatus 2 and the base station 3 is large, a relatively wide transmission delay allowable range (end T63-end T61) is set. . On the other hand, when the amount of delay variation in the transmission line is small, a relatively narrow transmission delay allowable range (end portion T62-end portion T61) is set.

  Thereafter, the timing correction issuing unit 37 of the base station 3 calculates (evaluates) a correction amount so that the user data UD2 can be received at the timing within the changed transmission delay allowable range, and calculates the correction amount. Transmit to the base station host apparatus 2.

  The transmission timing correction unit 25 that has received the correction amount controls the user data transmission unit 25 based on the correction amount. Thus, the transmission timing of the user data UD2 transmitted from the user data transmission unit 24 is corrected (adjusted).

  As described above, the radio communication system according to the present embodiment dynamically changes the allowable transmission delay range according to the delay variation amount between the base station host apparatus 2 and the base station 3.

  Therefore, it has the same effect as the first embodiment. Specifically, when the transmission line load is low and the delay fluctuation amount is small, the delay amount can be reduced and the delay quality can be maintained. On the other hand, when the load on the transmission line is high and the amount of delay fluctuation is large, quality degradation due to missing user data UD2 can be reduced even if the delay quality is somewhat sacrificed.

  As described in the first embodiment, the transmission delay between the base station host apparatus 2 and the base station 3 is considered to be substantially the same for channels with the same QoS setting. Accordingly, the calculation of the delay variation amount may be performed in common for the same QoS setting service. In this case, the timing information of the existing channel can be applied to the newly set channel. Therefore, the base station 3 can receive the user data UD2 at the optimal timing from the beginning.

  In addition, for the transmission delay allowable range that is adaptively set in the base station 3, a reception allowable window limited by the signal processing performance and buffer amount of the base station host apparatus side 2 may be set separately. In this case, the base station 3 may control the transmission delay allowable range within the range of the reception allowable window.

  In addition, the line load between the base station host apparatus 2 and the base station 3 can be expected to vary to some extent depending on the time zone, season, and the like. Accordingly, it is conceivable to control the allowable transmission delay range in order to predict fluctuations in the line load with reference to time information and past statistical data and to cope with changes in the delay fluctuation amount in advance.

  In the above description, a method of newly adding a call control message is also conceivable as means for dynamically changing the allowable transmission delay range of the base station 3 set at the time of channel setting. However, a control command related to a request for changing the allowable transmission delay range may be newly added to the frame of the user data UD2.

  Further, as shown in FIG. 8, by performing control to fix the slow end portion of the new allowable transmission delay range at time T61, as described in Embodiment 1, the base station 3 allows the user to The buffer period of the user data UD2 from the reception of the data UD2 to the wireless transmission can be minimized. Therefore, it is possible to suppress occurrence of useless delay in the base station 3.

<Embodiment 4>
The radio communication system according to the present embodiment monitors the occurrence frequency of a user data transmission timing correction request from the base station 3 between the base station host apparatus 2 and the base station 3 in the same configuration as in FIG. Estimate the amount of delay variation in the transmission line. As a result, in the wireless communication system, the transmission delay allowable range of the base station 3 can be changed dynamically (adaptively).

  When the base station 3 receives the user data UD2 at a reception timing outside the allowable transmission delay range of the base station 3, as described in the first embodiment, user data from the base station host apparatus 2 is used. The transmission timing of UD2 is corrected (adjusted).

  FIG. 9 is a functional block diagram showing an internal configuration of base station host apparatus 2 and an internal configuration of base station 3 in the radio communication system according to the present embodiment.

  As shown in FIG. 9, the base station host apparatus 2 includes a user data transmission unit 26, a transmission timing calculation unit 27, and a transmission delay allowable range change request issue unit 28. On the other hand, the base station 3 includes a reception timing evaluation unit (which can be grasped as a timing correction request issuing unit) 38 and a transmission delay allowable range changing unit 39.

  First, the configuration of the base station host apparatus 2 will be described.

  The user data transmission unit 26 is a part that transmits user data UD2 to the base station 3.

  The transmission timing calculation unit 27 is a part that measures the frequency at which the transmission timing transmission unit 27 of the base station host apparatus 2 receives a transmission timing correction request transmitted from the base station 3. Here, the transmission timing correction request is transmitted from the base station 3 when the base station 3 receives the user data UD2 at a timing outside the allowable transmission delay range.

  The transmission delay allowable range change request issuing unit 28 is a part that requests the base station 3 to change to the transmission delay allowable range determined based on the measurement result of the transmission timing calculation unit 27.

  Next, the configuration of the base station 3 will be described.

  If the reception timing evaluation unit 38 receives the user data UD2 at a timing outside the allowable transmission delay range (including those after the change), the correction amount of the transmission timing of the user data UD2 from the base station host apparatus 2 Calculate Then, the timing correction issuing unit 37 transmits the calculated correction amount to the base station host apparatus 2. The reception timing evaluation unit 38 also accepts reception of user data UD2 transmitted from the base station host apparatus 2.

  The transmission delay allowable range changing unit 39 is a part that changes the transmission delay allowable range before the request to a new transmission delay allowable range in response to a transmission delay allowable range change request transmitted from the base station host apparatus 2. That is, the set transmission delay allowable range is determined based on the measurement result of the transmission timing calculation unit 27 in response to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit 28. Change to the allowable transmission delay range.

  Next, the operation for changing the allowable transmission delay range in the radio communication system according to the present embodiment will be described.

  The reception timing evaluation unit 38 of the base station 3 evaluates the reception timing of the user data UD2 transmitted from the user data transmission unit 26 of the base station host apparatus 2. And the reception timing evaluation part 38 calculates the correction amount of the transmission timing of the user data UD2 from the base station host apparatus 2 when the user data UD2 is received at a timing outside the allowable transmission delay range. Thereafter, the reception timing evaluation unit 38 transmits a user data transmission timing correction request including the correction amount to the base station host apparatus 2.

  Next, the transmission timing calculation unit 27 of the base station host apparatus 2 corrects (adjusts) the transmission timing of the user data UD2 according to the correction amount transmitted from the reception timing evaluation unit 38 of the base station 3.

  In addition, the transmission timing calculation unit 27 aggregates the reception frequency of the timing correction requests transmitted from the base station 3. Then, the transmission timing calculation unit 27 instructs the transmission delay allowable range change request issuing unit 28 to change the transmission delay allowable range according to the aggregation result.

  For example, as shown in FIG. 10, it is assumed that the illustrated normal distribution is created in a state where the allowable transmission delay range Tta is set. Here, the said normal distribution is calculated | required so that it may follow the bar graph distribution which consists of the reception timing and the frequency | count that the base station 3 receives user data UD2.

  When the base station 3 receives the user data UD2 in a region outside the allowable transmission delay range Tta (the shaded region in FIG. 10), the reception timing evaluation unit 38 corrects the transmission timing every time reception is outside the range. Send a request.

  As described above, the transmission timing calculation unit 27 measures the frequency of the transmission timing correction request. When the reception frequency of the transmission timing correction request is equal to or greater than the first threshold value set in advance, the transmission timing calculation unit 27 sets the transmission delay variation amount (delay variation amount) to the current transmission delay allowable range Tta. Judged to be large. Here, the said 1st threshold value is set in the transmission timing calculation part 27 as arbitrary values, for example.

  When the transmission timing calculation unit 27 makes the above determination, the transmission timing calculation unit 27 issues a transmission delay allowable range change request so as to widen the transmission delay allowable range according to the reception frequency of the transmission timing correction request. The unit 28 is instructed to change the range (that is, an instruction to change to the new allowable transmission delay range Ttb).

  Here, the end of the reception delay side in the new transmission delay allowable range Ttb is before the processing period of the user data UD2 in the base station 3 from the wireless transmission timing T70 when the user data UD3 is transmitted over the radio. The transmission timing calculation unit 27 adjusts the transmission time of the user data UD2 from the user data transmission unit 26 so that it can coincide with the time T71 (see FIG. 10).

  On the other hand, as shown in FIG. 11, it is assumed that the illustrated normal distribution is created in a state where the allowable transmission delay range Ttc is set. Here, the said normal distribution is calculated | required so that it may follow the bar graph distribution which consists of the reception timing and the frequency | count that the base station 3 receives user data UD2.

  When the base station 3 receives the user data UD2 in an area outside the allowable transmission delay range Ttc, the reception timing evaluation unit 38 transmits a transmission timing correction request each time the out-of-range reception is performed. As described above, the transmission timing calculation unit 27 measures the frequency of the transmission timing correction request. When the reception frequency of the transmission timing correction request is equal to or less than the second threshold value set in advance, the transmission timing calculation unit 27 sets the transmission delay variation amount (delay variation amount) to the current transmission delay allowable range Ttc. Judged to be small. Here, the said 2nd threshold value can be set in the transmission timing calculation part 27 as arbitrary values, for example.

  When the transmission timing calculation unit 27 makes the above determination, the transmission timing calculation unit 27 issues a transmission delay allowable range change request so as to narrow the transmission delay allowable range according to the reception frequency of the transmission timing correction request. The unit 28 is instructed to change the range (that is, an instruction to change to the new allowable transmission delay range Ttd).

  Here, the end of the reception timing later in the new transmission delay allowable range Ttd is just before the processing period of the user data UD2 in the base station 3 from the wireless transmission timing T70 when the user data UD3 is transmitted over the radio. The transmission timing calculation unit 27 adjusts the transmission time of the user data UD2 from the user data transmission unit 26 so that it can coincide with the time T75 (see FIG. 11). In other words, the transmission timing of the user data UD2 is controlled so that the timing coincides.

  Thereafter, the transmission delay allowable range change request issuing unit 28 issues a transmission delay allowable range change request to the base station 3 in accordance with the change instruction from the transmission timing calculating unit 27. The transmission delay allowable range change request is a call control message newly added to dynamically change the transmission delay allowable range.

  Next, the transmission delay allowable range changing unit 39 of the base station 3 receives the change request from the base station host apparatus 2 and changes the transmission delay allowable range as illustrated in FIGS. Then, the transmission delay allowable range changing unit 39 transmits the changed transmission delay allowable range to the reception timing evaluating unit 38. The reception timing evaluation unit 38 may newly change the transmission delay allowable range determined according to the measurement result of the transmission timing calculation unit 27 in accordance with an instruction from the transmission delay allowable range change unit 39.

  As described above, in the wireless communication system according to the present embodiment, the frequency of receiving the user data UD2 outside the transmission delay allowable range set before the change in the transmission delay allowable range in the base station 3 (this is It is dynamically changed according to the delay variation in the transmission line).

  Therefore, it has the same effect as the first embodiment. Specifically, when the transmission line load is low and the delay fluctuation amount is small, the delay amount can be reduced and the delay quality can be maintained. On the other hand, when the load on the transmission line is high and the amount of delay fluctuation is large, quality degradation due to missing user data UD2 can be reduced even if the delay quality is somewhat sacrificed.

  As described in the first embodiment, the transmission delay between the base station host apparatus 2 and the base station 3 is considered to be substantially the same for channels with the same QoS setting. Therefore, measurement (aggregation) of the reception frequency of the transmission timing correction request may be performed in common for the same QoS setting service. In this case, the timing information of the existing channel can be applied to the newly set channel. Therefore, the base station 3 can receive the user data UD2 at the optimal timing from the beginning.

  In addition, for the transmission delay allowable range that is adaptively set in the base station 3, a reception allowable window limited by the signal processing performance and buffer amount of the base station host apparatus side 2 may be set separately. In this case, the base station 3 may control the transmission delay allowable range within the range of the reception allowable window.

  In addition, the line load between the base station host apparatus 2 and the base station 3 can be expected to vary to some extent depending on the time zone, season, and the like. Accordingly, it is conceivable to control the allowable transmission delay range in order to predict fluctuations in the line load with reference to time information and past statistical data and to cope with changes in the delay fluctuation amount in advance.

  In the above description, a method of newly adding a call control message is also conceivable as means for dynamically changing the allowable transmission delay range of the base station 3 set at the time of channel setting. However, a control command related to a request for changing the allowable transmission delay range may be newly added to the frame of the user data UD2.

  As shown in FIGS. 10 and 11, as described in the first embodiment, control is performed to fix the slow end portions of the new allowable transmission delay ranges Ttb and Ttd at times T71 and T75. The base station 3 can minimize the buffer period of the user data UD2 from when the user data UD2 is received until wireless transmission is performed. Therefore, it is possible to suppress occurrence of useless delay in the base station 3.

  Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

The present invention relates to a radio communication system and a base station , for example, a radio communication comprising a base station host apparatus that transmits user data and a base station that receives the user data and transmits it to a mobile radio terminal. Can be applied to the system.

Therefore, the present invention is a radio that can dynamically (adaptively) avoid quality degradation due to discarding user data and quality degradation due to useless transmission delay, even in a line in which the amount of variation in transmission delay varies greatly. An object is to provide a communication system and a base station .

The radio communication system according to claim 8 of the present invention receives a base station host apparatus (2) that transmits user data (UD2) and the user data transmitted from the base station host apparatus, A plurality of base stations (3) for wirelessly transmitting the received user data, and the base station at a reception timing deviating from a transmission delay allowable range (Tta, Ttb, Ttc, Ttd) of the base station. In a radio communication system capable of adjusting the transmission timing of the user data from the base station host apparatus when a station receives the user data, the base station host apparatus is configured such that the base station transmits the transmission delay. When the user data is received out of an allowable range, a transmission timing correction request transmitted from the base station to the base station host apparatus is transmitted in advance. A transmission timing calculation unit (27) that measures the frequency of reception by the base station host apparatus, and changes to the transmission delay allowable range determined based on the measurement result of the transmission timing calculation unit for the base station A transmission delay allowable range change request issuing unit (28), and the base station responds to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit. Then, the set transmission delay allowable range is changed to the transmission delay allowable range determined based on the measurement result of the transmission timing calculation unit.
The base station according to claim 10 of the present invention receives user data sent from the outside, and transmits the received user data by radio in a base station that transmits the received user data and the user data A reception timing distribution measuring unit that measures the reception timing distribution by measuring the number of times the user data is received at the reception timing for a predetermined period, and a transmission delay allowable range is changed based on the reception timing distribution. A transmission delay allowable range changing unit capable of

Claims (9)

A base station host apparatus (2) that transmits user data (UD2), and a plurality of base stations (3) that receive the user data transmitted from the base station host apparatus and transmit the received user data by radio When the base station receives the user data at a reception timing outside the transmission delay allowable range (Ttw) of the base station, the user data from the base station host apparatus is In a wireless communication system capable of adjusting transmission timing,
The base station
A reception timing distribution measurement unit (31) for measuring a reception timing distribution by measuring a reception timing of the user data and the number of times the user data is received at the reception timing for a predetermined period;
A transmission delay allowable range changing unit (32) capable of changing the transmission delay allowable range based on the reception timing distribution,
A wireless communication system. The reception timing distribution measurement unit
Based on the reception timing distribution, obtain a normal distribution,
The transmission delay allowable range changing unit,
Based on the distribution shape of the normal distribution and a preset reference value, change the transmission delay allowable range,
The wireless communication system according to claim 1. The base station
A table composed of the type of user data and the reference value determined according to the type of user data;
The transmission delay allowable range changing unit,
Selecting the reference value based on the type of the user data being received and the table;
The wireless communication system according to claim 2. The transmission delay allowable range after the change is determined so that the position where the normal distribution is symmetric is at each end (T24, T25),
The transmission delay allowable range changing unit,
Processing of the user data in the base station from the time of radio transmission timing (T20) at which the user data is transmitted over the radio at the end on the side where the reception timing of the user data is late in the transmission delay allowable range after the change Calculating a first transmission timing correction amount (Tf) that can be matched with a time (T21) that is just before the period;
The base station
A timing correction request issuing unit (33) for transmitting the first transmission timing correction amount to the base station host apparatus;
The base station host apparatus is
Correcting the transmission timing of the user data based on the first transmission timing correction amount;
The wireless communication system according to claim 2. The base station is
When the user data is received by deviating from the changed transmission delay allowable range to one end side or the other end side continuously for a predetermined number of times, the transmission delay allowable range is deviated. A reception timing evaluation unit (32 or 33) that calculates a second timing correction amount (Tp) based on the reception timing of the user data received
The timing correction request issuing unit
Transmitting the second transmission timing correction amount to the base station host apparatus;
The base station host apparatus is
Correcting the transmission timing of the user user based on the second transmission timing correction amount;
The wireless communication system according to claim 4. A base station host apparatus (2) that transmits user data (UD2), and a plurality of base stations (3) that receive the user data transmitted from the base station host apparatus and transmit the received user data by radio And when the base station receives the user data at a reception timing out of the transmission delay allowable range of the base station, the transmission timing of the user data from the base station host device is In a wireless communication system that can be adjusted,
The base station host apparatus is
An inquiry issuing unit (21) for transmitting an inquiry frame to the base station;
Transmission timing indicating transmission timing of the inquiry frame included in the inquiry frame, and reception timing when the base station receives the inquiry frame included in the response frame transmitted from the base station in response to the inquiry frame A delay fluctuation amount calculation unit (22) that calculates a fluctuation amount of a transmission delay amount between the base station host apparatus and the base station by measuring a difference between the base station host device and the base station,
Transmission delay allowable range change request issuing unit that requests the base station to change to a transmission delay allowable range determined based on the variation of the transmission delay calculated by the delay variation calculating unit ( 23), and
The base station
The set transmission delay allowable range is determined based on the variation amount of the transmission delay amount in response to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit. Change to the allowable transmission delay range,
A wireless communication system. The base station host apparatus is
The base station from the radio transmission timing (T60) at which the user data is transmitted over the radio, with the end portion of the transmission delay allowable range determined based on the fluctuation amount of the transmission delay amount being delayed. Controlling the transmission timing of the user data so that it can coincide with the time (T61) which is just before the processing period of the user data in
The wireless communication system according to claim 6. A base station host apparatus (2) that transmits user data (UD2), and a plurality of base stations (3) that receive the user data transmitted from the base station host apparatus and transmit the received user data by radio When the base station receives the user data at a reception timing that is out of the transmission delay allowable range (Tta, Ttb, Ttc, Ttd) of the base station, the base station host apparatus In a wireless communication system capable of adjusting the transmission timing of the user data from
The base station host apparatus is
Frequency at which the base station host apparatus receives a transmission timing correction request that the base station transmits to the base station host apparatus when the base station receives the user data outside the allowable transmission delay range. A transmission timing calculation unit (27) for measuring
A transmission delay allowable range change request issuing unit (28) that requests the base station to change to the transmission delay allowable range determined based on a measurement result of the transmission timing calculation unit. ,
The base station
In response to the transmission delay allowable range change request transmitted from the transmission delay allowable range change request issuing unit, the set transmission delay allowable range is determined based on the measurement result of the transmission timing calculation unit. Change to the transmission delay allowable range,
A wireless communication system. The base station host apparatus is
The end on the side with the later reception timing in the transmission delay allowable range determined based on the measurement result of the transmission timing calculation unit is transmitted from the wireless transmission timing (T70) at which the user data is transmitted over the radio to the base. Controlling the transmission timing of the user data so that it can coincide with the time (T71, T75) that is just before the processing period of the user data in the station,
The wireless communication system according to claim 8.

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