JP3796485B2 - Uplink quality measurement equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, bidirectional wireless communication between a single base station and a single or a plurality of subscriber stations is performed using a TDD (Time Division Duplex) / TDMA (Time Division Multiple Access) system or FDD (Frequency Division Duplex). TECHNICAL FIELD The present invention relates to an uplink quality measuring apparatus for calculating uplink quality in transmission of an uplink radio frame from a subscriber station to a base station in a wireless communication system using the / TDMA method.
[0002]
[Prior art]
Conventionally, the transmission quality of data transmission has been defined by a bit error rate (= number of erroneously received bits / total number of transmitted bits) or a block error rate (= number of erroneously received blocks / total number of transmitted blocks) (non-patent literature). 1).
[0003]
The uplink quality of a wireless communication system in which a single base station with a fixed installation location and a single or a plurality of subscriber stations are connected by the TDD / TDMA method has been measured as follows.
[0004]
First, the subscriber station performs error correction using a Reed-Solomon code or the like on each packet of a single packet or a plurality of packets included in the uplink radio frame, and transmits the packet to the base station as an uplink radio frame.
[0005]
Next, in the base station, for each subscriber station, the total number of packets (the number of received packets) included in the received uplink radio frame, and the number of packets that are detected and discarded among these packets (the number of discarded packets) The wireless packet discard rate is calculated from the number of received packets).
[0006]
This wireless packet discard rate is calculated by the number of discarded received packets ÷ the number of received packets.
[0007]
[Non-Patent Document 1]
Iwao Hosaka, “Introduction to Data Communication Systems”, Ohmsha, December 10, 1985, p. 103-p. 105
[0008]
[Problems to be solved by the invention]
By the way, the bit error rate, the block error rate, or the wireless packet discard rate described above is calculated on the assumption that all transmission data transmitted from the transmission side is normally received on the reception side.
[0009]
However, in the case of wireless data transmission, the quality of the transmission line is generally poorer than that of wired data transmission. In some cases, it becomes impossible to receive the uplink radio frame on the side. In some cases, the base station cannot receive the uplink radio frame due to a momentary interruption of the transmission path due to a radio wave obstacle such as a bird or laundry, or disconnection for a certain period.
[0010]
In such a case, the radio packet discard rate described above is based on the premise that all packets constituting the uplink radio frame transmitted from each subscriber station can be received by the base station. No consideration is given to a packet that could not be received or a packet that was disconnected for a certain period of time and thus could not be received, a so-called missing packet. For this reason, there is a problem that the value of the wireless packet discard rate becomes small and the actual uplink quality cannot be reflected in detail.
[0011]
In order to measure the missing packet, a counter that measures the number of uplink packets transmitted to the subscriber station is provided, and a counter that measures the number of uplink packets received is provided at the base station, and the difference is measured by providing a counter. It is conceivable to measure the number of defects.
[0012]
However, in this case, when the difference is measured, it is extremely difficult to control the base station counter and the subscriber station counter simultaneously because the base station and the subscriber station are separated from each other. is there.
[0013]
In order to control both counters at the same time, both counters are reset at the same time before the subscriber station transmits the upstream packet, and then the upstream packet transmission is started. Thus, it is necessary to collect the count values of both counters and calculate the difference between them.
[0014]
However, during operation of the wireless communication system, that is, while an uplink packet is constantly being transmitted from the subscriber station at random, a missing packet in the uplink packet cannot be measured. Further, it is necessary to notify the base station of the count value of the counter of the subscriber station that is far away, and the number of packet loss cannot be measured instantaneously.
[0015]
The present invention has been made in view of such problems, and an object of the present invention is to provide an uplink quality measuring apparatus that can calculate uplink quality in more detail.
[0016]
In addition, the present invention provides an uplink quality measuring apparatus that can measure the number of packet loss of an uplink packet even during operation of the wireless communication system, that is, while the uplink packet is randomly transmitted. With the goal.
[0017]
Further, according to the present invention, in the uplink quality information, for example, in calculating the radio packet discard rate, the base station could not receive the uplink packet due to an instantaneous interruption of the radio transmission path due to rain / snowfall or an obstacle, or for some reason. It is an object of the present invention to provide an uplink quality measuring apparatus capable of reflecting information on a case.
[0018]
[Means for Solving the Problems]
An uplink quality measuring apparatus according to the present invention is an uplink quality measuring apparatus for a wireless communication system in which a single base station and a single or a plurality of subscriber stations are connected by a TDD scheme or an FDD scheme. Counts the number of uplink packets allocated to the subscriber station and outputs the number of allocated packets, and counts the number of uplink packets received from the specific subscriber station and outputs the number of received packets Received packet counter and , With The number of lost packets is calculated as (number of assigned packets−number of received packets) from the number of assigned packets and the number of received packets. (Invention of Claim 1)
[0019]
According to the present invention, since the number of allocated packets allocated at the base station and the number of received packets received from the subscriber station are obtained, for example, the number that could not be received even though the base station allocated to the subscriber station That is, the number of lost packets in the wireless transmission path between the base station and the subscriber station can be measured by the difference (number of assigned packets−number of received packets).
[0020]
In this case, since the number of packet loss can be measured based only on the information obtained at the base station, the packet loss of the upstream packet is also during operation of the wireless communication system, that is, while the upstream packet is randomly transmitted. Numbers can be easily measured.
[0021]
The packet loss count reflects information when the base station cannot receive an uplink packet due to a momentary interruption of the wireless transmission path due to rain / snow, an obstacle, etc., or more detailed uplink quality information. can get.
[0022]
In this case, further, an error detector that detects an error in the received uplink packet and outputs an error detection signal, and an erroneously received packet number counter that counts using the error detection signal as a trigger and outputs the number of erroneously received packets When , With From the number of erroneously received packets and the number of lost packets, the number of discarded wireless packets is obtained as (number of erroneously received packets + number of lost packets). Thus, the uplink quality can be measured in more detail (the invention according to claim 2).
[0023]
For example, the wireless packet discard rate is further calculated from the number of assigned packets, the number of received packets, and the number of erroneously received packets: {number of erroneously received packets + (number of assigned packets−number of received packets)} / (assigned packets) By providing a wireless packet discard rate calculator that is calculated as (number), a more detailed packet discard rate can be calculated (the invention according to claim 3). As described above, (number of assigned packets−number of received packets) means the number of lost packets that could not be received at the subscriber station.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0025]
FIG. 1 shows an overall configuration of a wireless communication system 10 to which an embodiment of the present invention is applied.
[0026]
The wireless communication system 10 is used as a P-MP (Point To Multi-Point) type that provides a fixed wireless access service to a plurality of subscribers.
[0027]
The wireless communication system 10 is basically capable of two-way communication with a base station 11 fixed to a building or a utility pole, and the fixed base station 11 via a wireless line. A plurality of subscriber stations 21 (1) to 21 (3) (referred to as subscriber stations 21 as representatives) distributed in a company or home.
[0028]
The wireless line is established through wireless communication between the antenna 12 of the base station 11 and the antennas of the plurality of subscriber stations 21.
[0029]
Each subscriber station 21 is connected to terminals 20 (1) to 20 (3) (typically referred to as terminals 20) such as personal computers by wire or wirelessly. Each terminal 20 and each subscriber station 21 can be integrated. On the other hand, the base station 11 can be connected to a terminal 14 having a function of a personal computer, and is connected to a network 13 mainly by wire. The terminal 14 of the base station 11 is operated by an administrator of the radio communication system 10, for example. The terminal 14 of the base station 11 can be always connected via the network 13.
[0030]
Each subscriber station 21 can access the network 13 via the radio line and the base station 11. As the network 13, an IP (Internet Protocol) network connected to a WWW (World Wide Web) server or the like (not shown) can be used.
[0031]
For communication between the base station 11 and the plurality of subscriber stations 21, bidirectional communication employing the TDD / TDMA scheme is possible. In this case, a common radio frequency, for example, a 26 [GHz] band is assigned between the base station 11 and the plurality of subscriber stations 21, and efficient communication is possible due to a difference in time slots to be used.
[0032]
For communication between the base station 11 and the plurality of subscriber stations 21, an FDD / TDMA system, which will be described later, can be adopted instead of the TDD / TDMA system. In either case of the TDD / TDMA scheme or the FDD / TDMA scheme, the downlink direction is a TDM (Time Division Multiplex) scheme, and the uplink direction is a TDMA scheme.
[0033]
FIG. 2 shows a configuration of a radio frame (one radio frame) based on the TDD scheme for performing communication between a plurality of subscriber stations 21 and the base station 11. The period of one radio frame is selected to be a fixed period, for example, 1 [ms], etc., of the order of 1 to 10 [ms]. Of course, a shorter period or a longer period can be selected as the period of one radio frame in relation to hardware or the like. The frame of one radio frame having a fixed period is different from a frame such as a variable-length ether frame.
[0034]
One radio frame includes a downlink area, an uplink area, and a guard time TS16. The downlink region includes a downlink header region TS11 and a downlink data region TS12. The uplink region includes a DMF (Delay Measurement Frame) region TS13, a slot demand region TS14, and an uplink data region TS15 that are time zones for measuring propagation delay between the base station 11 and each subscriber station 21. . The DMF region TS13 calculates the downlink radio packet discard rate calculated on the subscriber station 21 side or the downlink radio packet discard rate when measuring the propagation delay of each subscriber station 21. Data necessary for the transmission is transmitted from each subscriber station 21 to the base station 11. The DMF region TS13 also has a control channel function.
[0035]
In the downlink area of one radio frame, the downlink header area TS11 includes a preamble area TS17 for generating a reception synchronization signal for each radio frame, a base station number area TS18, a frame position designation area TS19, and DMF transmission permission. The command area TS20 includes control commands such as, and the slot allocation area TS21.
[0036]
In the downlink region of one radio frame, the remaining downlink data region TS12 is divided into a plurality of time slots, and a fixed downlink packet (also simply referred to as a packet) Pd is assigned to each. Each downlink fixed length packet Pd includes a subscriber station number Pd1, control information Pd2 such as adjacent packet presence / absence information, fixed length data Pd3 which is actual data, and an error detection code Pd4.
[0037]
In the uplink region of one radio frame, the uplink data region TS15 is divided into a plurality of time slots, and an uplink fixed length packet (also simply referred to as a packet) Pu is allocated to each. Each uplink fixed length packet Pu is composed of guard time Pu1, preamble Pu2, subscriber station number Pu3, control information Pu4 including adjacent packet presence / absence information, fixed length data Pu5 that is actual data, and error detection code Pu6. ing.
[0038]
Note that the configurations of the upper and lower data areas TS12 and TS15 are common to the TDD / TDMA system and the FDD / TDMA system.
[0039]
The data length of one downlink fixed length packet Pd or one uplink fixed length packet Pu is selected to be 64 bytes or 128 bytes, for example.
[0040]
FIG. 3 shows the configuration of each subscriber station 21 as an example. The subscriber station 21 basically includes an antenna 22, a high frequency circuit 32, and a communication control circuit 33 connected to the high frequency circuit 32 and the terminal 20.
[0041]
The high frequency circuit 32 includes a receiver 41, a transmitter 42, and a changeover switch 43 disposed between the transceivers 41 and 42 and the antenna 22.
[0042]
The transmitter 42 of the high frequency circuit 32 converts the intermediate frequency signal supplied from the communication control circuit 33 into a radio frequency signal by a built-in mixer and converts the radio frequency high frequency signal with a built-in power amplifier. The power is amplified and supplied to the antenna 22 via the changeover switch 43.
[0043]
The receiver 41 of the high-frequency circuit 32 inputs a radio frequency high-frequency signal (a radio frame modulation signal) received by the antenna 22 through the change-over switch 43, amplifies it with a built-in low noise amplifier, and then incorporates it. The frequency is converted into an intermediate-frequency radio frame by the mixer, and supplied to the modulation / demodulation circuit 51 of the communication control circuit 33.
[0044]
The demodulating unit constituting the modem circuit 51 demodulates the data in the downlink region in the radio frame received by the receiver 41 by an A / D converter (not shown) and a PSK demodulator (not shown), and has a fixed downlink length. The packet Pd is supplied to a TDD-TDM / TDMA control circuit (hereinafter referred to as a TDD / TDMA control circuit) 52. The TDD / TDMA control circuit 52 includes a downlink radio packet discard rate calculation device 202.
[0045]
The downlink fixed length packet Pd demodulated by the modem circuit 51 is hereinafter referred to as a received packet (downlink fixed length packet) Pd.
[0046]
Further, the modulation unit constituting the modem circuit 51 converts the data in the uplink region in the radio frame supplied from the TDD / TDMA control circuit 52 into a D / A converter (not shown) and a PSK modulator (not shown). Modulates and supplies to the transmitter 42.
[0047]
In addition to the modem circuit 51 and the TDD / TDMA control circuit 52, the communication control circuit 33 includes a communication interface circuit 53, a downlink reception buffer 61, an uplink transmission buffer 62, and a packet number measurement unit 63 connected to the terminal 20.
[0048]
The packet number measuring unit 63 periodically measures the number of packets accumulated in the uplink transmission buffer 62 for each period of one radio frame, and transmits this to the TDD / TDMA control circuit 52 as information on the slot demand 71. Information on the slot demand 71 is notified from the TDD / TDMA control circuit 52 to the base station 11 through the modulation / demodulation circuit 51, the transmitter 42, the changeover switch 43 and the antenna 22 in the time zone of the slot demand area TS14 of one radio frame in FIG. Is done.
[0049]
FIG. 4 shows an example of the configuration of the downlink quality measuring apparatus 200 of this embodiment that constitutes the subscriber station 21. Downlink quality measuring apparatus 200 includes modulation / demodulation circuit 51 and downlink radio packet discard rate calculation apparatus 202 in TDD / TDMA control circuit 52.
[0050]
The wireless packet discard rate calculating apparatus 202 includes a frame period signal output circuit 204 and a synchronization number counter 206 for receiving one reception synchronization signal output from the modulation / demodulation circuit 51 (one pulse) for each received wireless frame. In addition to an error detector 208 and a received packet number counter 212, a frame number counter 210, an erroneously received packet number counter 214, and a wireless packet discard rate calculator 216 are provided.
[0051]
The frame cycle signal output circuit 204 includes a timer 205. When the radio frame received by the receiver 41 is normally demodulated by the modulation / demodulation circuit 51, one reception synchronization signal is sent from the modulation / demodulation circuit 51 every 1 [ms] corresponding to one radio frame. At this time, the frame period signal output circuit 204 outputs one (one pulse) frame period signal (referred to as a reception frame period signal) corresponding to the normal reception synchronization signal.
[0052]
At the same time, the frame cycle signal output circuit 204 counts and counts the system clock by the timer 205 and creates a self-running frame cycle signal (referred to as a free-running frame cycle signal) every 1 [ms]. . If the next reception synchronization signal is not input even after 1 [ms] has elapsed since the reception frame period signal was output, the free-running frame period signal is output as the frame period signal. In this case, the received frame period signal corresponds to the number of radio frames transmitted from the base station 11 and actually received and demodulated normally by the subscriber station 21, and the free-running frame period signal is transmitted from the base station 11. This corresponds to the number of radio frames (referred to as the number of missing frames) that could not be normally demodulated by the subscriber station 21.
[0053]
The frame number counter 210 counts frame period signals (received frame period signal and free-running frame period signal), and outputs the number of frames as a count value to the wireless packet discard rate calculator 216.
[0054]
The synchronization number counter 206 counts the reception synchronization signal and outputs the number of synchronizations that is a count value to the wireless packet discard rate calculator 216. In this case, the number of times of synchronization matches the count value of the received frame period signal.
[0055]
The error detector 208 performs error detection and correction of the received packet (downlink fixed-length packet) Pd, which is the downlink fixed-length packet Pd demodulated by the modem circuit 51, and detects an error and detects the error. One (one pulse) error detection signal corresponding to one received packet (downlink fixed length packet) Pd is output to the erroneous received packet number counter 214. The error detector 208 supplies the fixed-length data Pd3 to the downlink reception buffer 61, which is normal in the received packet (downlink fixed-length packet) Pd and which is normal after correcting the error.
[0056]
The erroneously received packet counter 214 counts using the error detection signal as a trigger, and uses the count value (one count value for one error detection signal) as the number of erroneously received packets as a radio packet discard rate calculator 216. Output to.
[0057]
The reception packet number counter 212 counts the number of packets included in one downlink radio frame in synchronization with the reception synchronization signal, and outputs the count value to the radio packet discard rate calculator 216 as the number of received packets.
[0058]
The wireless packet discard rate calculator 216 is configured to measure the number of frames and the synchronization by the frame number counter 210 during a measurement period (for example, every minute, one minute can be arbitrarily set) according to a counter control signal output by itself. Based on the number of synchronizations by the number counter 206, the number of erroneously received packets by the erroneously received packet number counter 214, and the number of received packets by the received packet number counter 212, the wireless packet discard rate in the downlink direction shown in the following equation (1) is calculated. .
Wireless packet discard rate = {number of erroneously received packets + (number of frames−number of synchronizations) × N} ÷ {number of received packets + (number of frames−number of synchronizations) × N} (1)
[0059]
As described above, in equation (1), (number of frames−number of synchronizations) is a frame that could not be demodulated by the modem circuit 51, that is, a frame that could not be received by the antenna 22 and the receiver 41 of the subscriber station 21. Therefore, the expression (1) can be replaced with the expression (2).
Wireless packet discard rate = {number of erroneously received packets + number of missing frames × N} ÷ {number of received packets + number of missing frames × N} (2)
[0060]
Here, N is the number of downlink fixed-length packets Pd for each subscriber station 21 included in one radio frame. When the number of packets is always fixed, a fixed value and the number of packets fluctuate dynamically. If so, set the expected value.
[0061]
The calculated wireless packet discard rate or the number of erroneously received packets, the number of frames, the number of synchronizations, the number N of fixed-length packets in the frame, and the number of received packets for calculating this wireless packet discard rate Each subscriber station 21 can be included in the DMF region TS13 output in a predetermined order and transmitted to the base station 11. In this case, the base station 11 that has received this information calculates, for example, the wireless packet discard rate for each subscriber station 21 in the terminal 14 and stores it in the storage device. Quality can be managed.
[0062]
FIG. 5 shows a configuration of the base station 11 as an example. The base station 11 basically includes an antenna 12, a high frequency circuit 132, and a communication control circuit 34 connected to the high frequency circuit 132 and the network 13.
[0063]
The configuration and operation of the high-frequency circuit 132 are the same as those of the high-frequency circuit 32 of the subscriber station 21 shown in FIG.
[0064]
The communication control circuit 34 includes a modulation / demodulation circuit 151, a TDD-TDM / TDMA (referred to as TDD / TDMA) control circuit 152 having a built-in uplink radio packet discard rate calculation device 302, a communication interface circuit 153 connected to the network 13, A slot allocation unit 54, a reception buffer 64 for each uplink subscriber station, a transmission buffer 65 for each downlink subscriber station, and a packet number measurement unit 66 are provided.
[0065]
The packet number measurement unit 66 periodically measures the number of packets for each subscriber station 21 stored in the transmission buffer 65 for each downlink subscriber station for each period of one radio frame, and transmits this to the slot allocation unit 54. . The TDD / TDMA control circuit 152 extracts information on the slot demand 71 of each subscriber station 21 notified in the time zone of the slot demand region TS14 of one radio frame in FIG. 2 and transmits the information to the slot allocation unit 54.
[0066]
The slot allocation unit 54 determines information on the slot allocation 72 based on the number of packets for each subscriber station 21 and the information on the slot demand 71 and notifies the TDD / TDMA control circuit 152 of the information.
[0067]
The allocation of time slots in the uplink direction (referred to as the number of allocated packets) for each subscriber station 21 is notified in the time slot of the slot allocation area TS21 in one radio frame in FIG.
[0068]
FIG. 6 shows a configuration example of the uplink quality measuring apparatus 300 of this embodiment constituting the base station 11. Uplink quality measuring apparatus 300 includes modulation / demodulation circuit 151 and uplink radio packet discard rate calculation apparatus 302 in TDD / TDMA control circuit 152.
[0069]
The radio packet discard rate calculating apparatus 302 performs one (one pulse) for each received radio frame, for each time slot of the uplink data region TS15 from the modulation / demodulation circuit 151, more specifically, for each uplink fixed length packet Pu. ) In addition to the error detector 308 and the received packet number counter 312 for inputting the received reception synchronization signals, the allocated packet number counter 310, the erroneous received packet number counter 314, and the uplink radio packet discard rate calculator 316 are provided. I have.
[0070]
The allocation packet number counter 310 counts the number of uplink packets (number of time slots) allocated to each subscriber station based on the slot allocation 72 supplied from the slot allocation unit 54, and counts each subscriber station as a count value. Is output to the wireless packet discard rate calculator 316.
[0071]
The error detector 308 detects and corrects the received packet (uplink fixed-length packet) Pu, which is the uplink fixed-length packet Pu demodulated by the modem circuit 51, and detects an error and detects the error. One (one pulse) error detection signal corresponding to one received packet (uplink fixed length packet) Pu is output to the erroneous received packet number counter 314. The error detector 308 sends the fixed length data Pu5 of the received packet (uplink fixed length packet) Pu that is normal and the error corrected one to the reception buffer 64 for each uplink subscriber station. To supply.
[0072]
The erroneous reception packet number counter 314 counts using the error detection signal as a trigger, and the wireless packet discard rate calculator 316 uses the count value (one count value for one error detection signal) as the number of erroneous reception packets. Output to.
[0073]
The received packet number counter 312 counts the number of packets included in one uplink radio frame in synchronization with the reception synchronization signal, and outputs the count value to the radio packet discard rate calculator 316 as the number of received packets. Since the reception synchronization signal is generated at 1: 1 in synchronization with the preamble Pu2 constituting the fixed uplink packet Pu, the reception packet number counter 312 counts only this reception synchronization signal and counts the count value as the number of received packets. May be configured to output to the wireless packet discard rate calculator 316, or only the received packet (uplink fixed length packet) Pu demodulated by the modem circuit 51 without counting the reception synchronization signal is counted and the count value is calculated. The number of received packets may be output to the wireless packet discard rate calculator 316.
[0074]
The wireless packet discard rate calculator 316 receives a received packet (uplink fixed-length packet) Pu during a measurement period (for example, every minute, one minute can be arbitrarily set) according to a counter control signal output by itself. The subscriber station number Pu3 is determined from the received packet number counter 310, the assigned packet number for each subscriber station 21 by the assigned packet number counter 310, the erroneously received packet number for each subscriber station 21 by the erroneously received packet number counter 314, and the received packet number counter. Based on the number of received packets for each subscriber station 21, the uplink radio packet discard rate for each subscriber station 21 shown in the following equation (3) is calculated.
Wireless packet discard rate = {number of erroneously received packets + (number of assigned packets−number of received packets)} ÷ (number of assigned packets) (3)
[0075]
In Equation (3), (number of assigned packets−number of received packets) is the number of lost packets that could not be demodulated by the modem circuit 151, that is, the packets that could not be received by the antenna 12 and the receiver 141 of the base station 11. Since they are equal, equation (3) can be replaced by equation (4).
Wireless packet discard rate = (number of erroneously received packets + number of lost packets) / (number of allocated packets) (4)
[0076]
The calculated uplink wireless packet discard rate is supplied to the terminal 14 and can be confirmed on the display of the terminal 14 and stored in the storage device. Uplink quality can be managed. The TDD / TDMA control circuits 52 and 152 and the communication interface circuits 53 and 153 of the subscriber stations 21 and the base station 11 include a CPU (Central Processing Unit) and are configured by a microcomputer or the like. Each program has a configuration in which various programs are installed in a ROM (Read Only Memory) and executed by the CPU, and when configured as hardware, an ASIC (Application Specific Integrated Circuit) is formed and a predetermined function is executed. The
[0077]
The wireless communication system 10 to which an embodiment of the present invention is applied is basically configured as described above. Next, the overall operation and the details of the uplink quality measuring apparatus 300 will be described. This will be described in the order of operation.
[0078]
General overall operation
For example, randomly generated variable-length data such as an Ethernet frame supplied from the terminal 20 to the subscriber station 21 is divided into uplink fixed-length packets Pu by the communication interface circuit 53 of the subscriber station 21. Is done. At this time, the communication interface circuit 53 further adds control information Pu4 including recombination information such as adjacent packet presence information, error detection code Pu6, and the like to each uplink fixed-length packet Pu.
[0079]
Each uplink fixed length packet Pu is assigned a slot according to the contents of the slot assignment area TS21 from the base station 11, and is transmitted from each subscriber station 21 functioning as a transmission side device through a wireless line.
[0080]
Each uplink fixed-length packet Pu received at the base station 11 functioning as a receiving-side device is recombined by the communication interface circuit 153 based on the control information Pu4 and the like, and the presence or absence of a packet is detected. If there is no omission, the recombined frame is output as data to the network 13 side.
[0081]
On the other hand, the same applies to the data supplied from the network 13 to the base station 11. In this case, the data is divided into fixed downlink packets Pd by the communication interface circuit 153 of the base station 11 functioning as a transmitting side device. At this time, recombining information such as adjacent packet presence / absence information is added to each downlink fixed length packet Pd as control information Pd2 and transmitted to a subscriber station 21 functioning as a receiving side device through a wireless line.
[0082]
The downlink fixed-length packet Pd received by the communication interface circuit 53 of the corresponding subscriber station 21 is recombined based on the control information Pd2, the presence or absence of a packet is detected, and when there is no packet loss It is transmitted to the terminal 20.
[0083]
The above description is a general description of the overall operation of the radio communication system 10, and then the detailed operation of the uplink quality measuring apparatus 300 will be described.
[0084]
At this time, first, a counter control signal for starting counting is output from the wireless packet discard rate calculator 316. By this counter control signal, the counter values of the allocated packet number counter 310, the erroneously received packet number counter 314 and the received packet number counter 312 are reset to zero values.
[0085]
When the modulation / demodulation circuit 151 of the base station 11 receives the uplink radio frame received through the antenna 12 via the diplexer 144 and the receiver 141, the modulation / demodulation circuit 151 is a reception pull-in signal that is synchronized with the preamble Pu2 of the uplink fixed-length packet Pu. The reception synchronization signal is output to error detector 308 and received packet number counter 312. Also, the modem circuit 51 outputs a received packet (uplink fixed-length packet) Pu to the error detector 308 and the received packet number counter 312 in synchronization with the output of the reception synchronization signal.
[0086]
On the other hand, the allocated packet number counter 310 indicates the number of allocated packets in the uplink data area TS15 to which the slot allocation unit 54, which is a scheduler, allocates transmission with reference to the slot demand 71 of the slot demand area TS14 from each subscriber station 21. Counting from the information of the slot allocation 72, the number of allocated packets for each subscriber station 21 is output to the wireless packet discard rate calculator 316. The allocation packet number counter 310 actually outputs the allocation packet number for each subscriber station 21 to the radio packet discard rate calculator 316 because the count of the allocated packets from the radio packet discard rate calculator 316 is counted. This is the arrival time of the counter control signal instructing termination.
[0087]
When the error detector 308 receives a reception packet (uplink fixed length packet) Pu synchronized with the reception synchronization signal at 1: 1, it performs error correction and discards the received packet (uplink fixed length packet) Pu that could not be corrected. At the same time, an error detection signal is output to the erroneously received packet number counter 314. The normally demodulated received packet (uplink fixed-length packet) Pu and the error-corrected received packet (uplink fixed-length packet) Pu are sent to the receive buffer 64 for each uplink subscriber station.
[0088]
The erroneously received packet counter 314 increments the erroneously received packet count for each subscriber station 21 using the error detection signal as a trigger.
[0089]
The received packet number counter 312 increments the number of received packets by the number of received packets (uplink fixed length packet) Pu for each subscriber station 21 using the reception synchronization signal or the received packet (uplink fixed length packet) Pu as a trigger. . The reception packet number counter 312 has a function of demodulating the subscriber station number Pu3 based on a reception synchronization signal synchronized with the preamble Pu2.
[0090]
Then, when the counter control signal indicating the end of counting is output from the wireless packet discard rate calculator 316, the count values of the allocated packet number counter 310, the erroneously received packet number counter 314, and the received packet number counter 312 are latched and latched. The number of assigned packets, the number of erroneously received packets, and the number of received packets, which are count values for each subscriber station 21, are taken into the wireless packet discard rate calculator 316.
[0091]
At this time, the radio packet discard rate calculator 316 calculates the uplink radio packet discard rate of the above-described equations (3) and (4).
[0092]
Then, after the count value is taken into the wireless packet discard rate calculator 316, a counter control signal for starting counting is output again from the wireless packet discard rate calculator 316 at a predetermined time, and the allocated packet number counter 310, the counter values of the erroneously received packet number counter 314 and the received packet number counter 312 are reset to zero, and counting for the next wireless packet discard rate calculation is started.
[0093]
The above description is the detailed operation of the uplink quality measuring apparatus 300.
[0094]
Next, FIG. 7 shows a configuration example of the FDD subscriber station 21A. FIG. 8 shows a configuration example of the FDD base station 11A. FIG. 9 shows the configuration of an FDD radio frame.
[0095]
7 of the FDD system and the subscriber station 21 of FIG. 3 of the TDD system, the base station 11A of FIG. 8 of the FDD system, the base station 11 of FIG. 5 of the TDD system, and the FDD system In the radio frame of FIG. 9 and the radio frame of FIG. 2 of the TDD system described above, the same reference numerals are given to corresponding elements, and detailed description thereof is omitted.
[0096]
Since the FDD scheme is frequency multiplexing, different radio frequencies are used in the uplink direction and the downlink direction. Therefore, in the FDD system, the change-over switches 43 and 143 constituting the TDD type high frequency circuits 32 and 132 are replaced with diplexers 44 and 144, respectively, as shown in FIGS. As is well known, the diplexers 44 and 144 are composed of a band-pass filter for reception frequency and a band-pass filter for transmission frequency. The diplexers 44 and 144 lead output signals from the transmitters 42 and 142 to the antennas 12 and 22, respectively. The signal transmitted and received by the antennas 12 and 22 is guided to the receivers 41 and 141 side.
[0097]
On the other hand, as is clear from FIG. 2 and FIG. 9, one radio frame is divided into a downlink and an uplink in series in the TDD scheme, whereas in the FDD scheme, the radio frame is divided. The downlink radio frame and the uplink radio frame are configured in parallel.
[0098]
Note that the downlink data area in the downlink radio frame shown in FIG. 9 has the same configuration as the downlink fixed length packet Pd shown in the downlink data area TS12 of FIG.
[0099]
Similarly, the uplink data area in the uplink radio frame shown in FIG. 9 has the same configuration as the uplink fixed length packet Pu shown in the uplink data area TS15 in FIG.
[0100]
For this reason, the uplink quality measuring apparatus 300 (modulation / demodulation circuit 151 and radio packet discard rate calculating apparatus 302) shown in FIG. 6 uses the more detailed uplink radio packet discard shown in equation (3) as in the TDD scheme. The rate can be calculated.
[0101]
As described above, in the above-described embodiment, the base station 11, 11A performs uplink frame slot allocation 72 to the subscriber stations 21, 21A based on the slot demand 71 from the subscriber stations 21, 21A. The present invention is applied to the P-MP type wireless communication system 10. In this case, the allocated packet number counter 310 for measuring the number of allocated packets allocated to the specific subscriber stations 21 and 21A to the base station 11 and the received packets (uplink fixed length) received from the specific subscriber stations 21 and 21A. A received packet number counter 312 that measures the number of packets) Pu and an error detector 308 that detects and corrects errors in received packets (uplink fixed-length packets) Pu are provided.
[0102]
The counters of the allocated packet number counter 310, the received packet number counter 312 and the erroneously received packet number counter 314 are started and stopped by the counter control signals from the radio packet discard rate calculator 316 of the base stations 11 and 11A. Measured value reading and counter reset (clear) are performed simultaneously. The wireless packet discard rate calculator 316 subtracts the number of received packets from the number of assigned packets in the read measurement value, so that it is transmitted from the specific subscriber station 21 or 21A, but the lost uplink direction Find the number of missing packets.
[0103]
Next, the radio packet discard rate in the uplink direction of the specific subscriber station 21, 21A by the above equation (4), that is, the radio packet discard rate = (number of erroneously received packets + number of lost packets) / (number of allocated packets) Ask for. In this way, the uplink radio packet discard rate can be obtained only from the information in the base stations 11 and 11A. Therefore, it is possible to easily measure the packet loss number of the uplink packet during operation of the wireless communication system 10, that is, while the uplink packet is randomly transmitted.
[0104]
In addition, according to this embodiment, the radio packet discard rate in the downlink direction shown in the above equations (1) and (2) can be obtained as necessary. That is, the upstream frame from the subscriber station 21, 21A to which transmission of the upstream frame is allocated is received on the base station 11, 11A side, for example, due to a momentary disconnection of the transmission path due to weather conditions such as rain or snow, or disconnection for a certain period of time. If it cannot be received, or if it cannot be received by the base station 11 or 11A due to a momentary interruption of the transmission path due to a radio wave obstruction such as a bird or laundry, or disconnection for a certain period of time, further some other factors Even when the base station 11 or 11A cannot receive the signal, the fact that the downstream frame is lost is detected by the free-running frame period signal which is the free-running output of the timer 205 built in the frame period signal output circuit 204. Since this is added to the downlink quality information, more detailed downlink quality information can be obtained. This detailed downlink quality information is known from the terminal 14 on the base station 11, 11 A side by transmitting from the subscriber station 21, 21 A side to the base station 11, 11 A side using the uplink radio frame DMF region TS 13. You can also.
[0105]
As described above, since the base station 11 and 11A can obtain the radio packet discard rates in both the uplink and downlink directions, for example, the radio packet discard rates of the specific subscriber stations 21 and 21A are the other subscribers. When it is larger than the stations 21 and 21A, it becomes easy for the administrator of the radio communication system 10 on the base station 11 and 11A side to investigate the cause and isolate the problem. The effect that an effective measure for reducing the size can be established at an early stage is achieved.
[0106]
The present invention is not limited to the above-described embodiment, and may be applied to, for example, a bidirectional optical line in which a base station and a subscriber station are connected by an optical fiber instead of a wireless line as a transmission line. Of course, various configurations can be adopted without departing from the gist of the present invention.
[0107]
【The invention's effect】
As described above, according to the present invention, the base station can measure the number of lost packets (number of assigned packets−number of received packets) lost in the wireless transmission path between the base station and the subscriber station.
[0108]
For this reason, it is possible to easily measure the packet loss number of the uplink packet even during operation of the wireless communication system, that is, while the uplink packet is being transmitted at random.
[0109]
As a result, more detailed uplink quality information can be obtained as compared with the prior art.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a wireless communication system to which an embodiment of the present invention is applied.
FIG. 2 is a configuration diagram of a TDD radio frame.
FIG. 3 is a block diagram showing a configuration of a TDD subscriber station.
FIG. 4 is a block diagram showing a configuration of a downlink quality measuring apparatus according to this embodiment.
FIG. 5 is a block diagram showing a configuration of a TDD base station.
FIG. 6 is a block diagram showing a configuration of an uplink quality measuring apparatus according to this embodiment.
FIG. 7 is a block diagram showing a configuration of an FDD subscriber station.
FIG. 8 is a block diagram illustrating a configuration of an FDD base station.
FIG. 9 is a configuration diagram of an FDD radio frame.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Wireless communication system 11, 11A ... Base station
12, 22 ... Antenna 13 ... Network
14, 20 ... Terminal 21, 21A ... Subscriber station
32, 132 ... high frequency circuit 33, 34 ... communication control circuit
41, 141 ... receiver 42, 142 ... transmitter
43, 143 ... changeover switch 44, 144 ... diplexer
51, 151 ... modulation / demodulation circuit
52, 152 ... TDD / TDMA control circuit
53, 153 ... Communication interface circuit
54 ... Slot allocation unit 61 ... Downlink reception buffer
62 ... Upstream transmission buffer 63 ... Number of packets measuring unit
64: Receive buffer for each upstream subscriber station
65: Transmission buffer for each downlink subscriber station
71 ... Slot demand 72 ... Slot allocation
200 ... Downlink quality measuring device
202, 302 ... Wireless packet discard rate calculation device
204... Frame period signal output circuit
205: Timer 206: Synchronization counter
208, 308 ... error detector 210 ... frame number counter
212, 312 ... Received packet number counter
214, 314 ... Number of erroneously received packets counter
216, 316 ... Wireless packet discard rate calculator
310 ... Number of assigned packets counter

Claims (3)

In an uplink quality measuring apparatus of a radio communication system in which a single base station and a single or a plurality of subscriber stations are connected by a TDD scheme or an FDD scheme,
To the base station,
An allocation counter that counts the number of uplink packets allocated to a specific subscriber station and outputs the number of allocated packets;
The specific counts the number of the uplink packets received from the subscriber station, the number of received packet counter for outputting the number of received packets comprises,
From the number of allocated packets and the number of received packets, the number of lost packets is
(Number of allocated packets-number of received packets)
An uplink quality measuring apparatus characterized by being obtained as follows. In the uplink quality measuring apparatus according to claim 1,
further,
An error detector for detecting an error in the received upstream packet and outputting an error detection signal;
The counted by the error detection signal as a trigger, with a false received packet counter outputs a count erroneous received packets, and
From the number of erroneously received packets and the number of lost packets, the number of discarded wireless packets is
(Number of erroneously received packets + number of missing packets)
Upstream channel quality measuring apparatus according to claim Rukoto determined as. The uplink quality measuring apparatus according to claim 2, wherein
further,
From the number of assigned packets, the number of received packets, and the number of erroneously received packets, a radio packet discard rate is
{Number of erroneously received packets + (number of allocated packets-number of received packets)} ÷ (number of allocated packets)
An uplink quality measuring apparatus, comprising: a wireless packet loss rate calculator obtained as follows.

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