JP2005012469A - Quality analyzer and quality measurement method for radio communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a configuration and to realize flexible adaptation to the expansion and change of a system, in a radio communication quality analyzer for evaluating transmission quality in a radio transmission system and in a radio communication quality measurement method. <P>SOLUTION: The radio communication quality analyzer comprises a monitoring means, a normality discriminating means, and a transmission quality evaluation means. The monitoring means monitors the time length of first and second radio packets received in the order of time series and the period length from the rear edge of the first radio packet and the front one of the second radio packet. The normality discriminating means discriminates that the length of the first radio packet is at least specified time length, and whether both the time length and period one of the second radio packet belong to a prescribed range for indicating that the second radio packet corresponds to a radio packet for notifying that the first radio packet is normally received by a reception station. The transmission quality evaluation means evaluates the transmission quality of the first radio packet as ratio, where a discrimination result becomes true or fault. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless communication quality analysis apparatus that evaluates transmission quality of a wireless transmission system to which a predetermined communication procedure is applied, and a wireless communication quality measurement method that realizes the wireless communication quality analysis apparatus.
[0002]
[Prior art]
In recent years, wireless LAN can greatly relax the restrictions on installation and movement of terminals, and can flexibly and inexpensively access a desired network. In recent years, it has been combined with high-speed digital wireless transmission technology. As a result, technologies for ensuring transmission information concealment and other security have been applied, and the technology is rapidly spreading.
[0003]
Further, among the above-described wireless LAN systems, a system that achieves a transmission rate of 6 megabits / second to 54 megabits / second by applying a 2.4 GHz band or 5 GHz band radio frequency (for example, IEEE802). .11a, conforming to the IEEE802.11g standard.) Is a method that can be adapted to the demand for broadband to realize “transmission speed exceeding 10 megabits / second”, so that the cost reduction and development of equipment can be reduced. It is being actively promoted.
[0004]
By the way, in such a wireless LAN, it is assumed that the transmitting end has a certain length including a prescribed word generated by dividing transmission information (here, for simplicity, it is 1518 bytes long). ) Packet (hereinafter referred to as “data packet”) based on the CSMA / CA (Carrier Sense Multiple Access with Collision Aidance) method (FIG. 6 (1)).
[0005]
Note that, under this CSMA / CA scheme, the transmitting end specifies an opportunity for a data packet to be transmitted based on the following procedure.
A determination (carrier sense) (hereinafter referred to as “first determination”) is performed as to whether or not transmission by another transmission end is performed on the wireless transmission path.
If the result of the first determination is true, it is determined whether or not the packet transmitted in this way is a data packet addressed to the own station (hereinafter referred to as “second determination”). I do.
[0006]
-If one of the first discrimination and the second discrimination described above is false, the process shifts to a "standby state" and generates a random number based on a predetermined algorithm. The point in time when “the time equal to the random number” has elapsed from the “when the result of“ is determined ”is identified as the trigger described above.
On the other hand, only when the above-described data packet is normally received, the receiving end only receives a predetermined time (in this case, “16 for the sake of simplicity” from the time of the trailing edge of the data packet (FIG. 6 (2)). Assuming that it is “microseconds”), a short packet (hereinafter referred to as an “ACK packet”) that means that and has been configured in a prescribed format (FIG. 6 (3)). It is sent out (FIG. 6 (4)).
[0007]
This ACK packet is monitored in parallel by the above-described transmitting end and transmitting ends other than the transmitting end.
Further, of these transmitting ends, the transmitting end having any data packet to be transmitted subsequently, transmits a specified time (for example, “34” from the time of the trailing edge of the corresponding ACK packet (FIG. 6 (5)). Assuming that it is “microseconds”), the transmission trigger is identified from the point in time (FIG. 6 (6)), and the data packet is transmitted after the identification.
[0008]
The modulation scheme applied to the generation of the data packet and the ACK packet and the length of the data packet (here, it is assumed that it is 1518 bytes long as described above) are transmitted by these packets. For each of the obtained transmission rates of 6 megabit / second, 9 megabit / second, 12 megabit / second, 18 megabit / second, 24 megabit / second, 36 megabit / second, 48 megabit / second and 54 megabit / second, FIG. It is set as shown in.
[0009]
Further, in the conventional wireless communication quality analyzing apparatus used for evaluating the transmission quality of such a wireless LAN, the transmission quality is required by performing the following series of processes.
-For any wireless packet received via the wireless transmission path, by performing demodulation processing, the information placed in a predetermined field of the wireless packet is referred to, and the corresponding data packet and ACK packet are applicable. Identify one.
[0010]
The transmission quality is obtained as the ratio of the total number of ACK packets and data packets identified in this way.
[Non-Patent Document 1]
http: // www. toyo. co. jp / sniffer / toyoctcpr11_6_3. html
[0011]
[Problems to be solved by the invention]
However, the radio frequency band inherently allocated to the above-described wireless LAN is expanded by “many manufacturers who manufacture devices constituting the wireless LAN” or conforms to the IEEE802.11a standard. Nevertheless, there is a commercially available device that can expand the transmission capacity to a value that is twice the value that conforms to the standard by an optional function added by the manufacturer.
[0012]
Therefore, in the conventional wireless communication quality analysis device, evaluation of transmission quality of all existing wireless LANs has not been realized unless any of the following measures are taken.
Standardization that can perform demodulation and other processing suitable for any wireless LAN system that continues to evolve in a complex manner, and a system that is applied to a wireless LAN whose transmission quality should be actually evaluated Certainly identified.
[0013]
-At least one wireless communication quality analyzer that can be adapted to each method applied to an existing wireless LAN is secured.
An object of the present invention is to provide a wireless communication quality analysis apparatus and a wireless communication quality measurement method that have a simplified configuration and that can be flexibly adapted to system expansion and change.
[0014]
[Means for Solving the Problems]
In the first aspect of the present invention, the monitoring means includes the time lengths of the first radio packet and the second radio packet received in time-series order, and the second radio packet from the trailing edge of the first radio packet. Monitor the length of time to the leading edge of the radio packet. The normality determining means notifies that the second wireless packet is normally received by the receiving station when the length of the first wireless packet is equal to or longer than a predetermined time length. It is determined whether or not both the time length and the period length of the second wireless packet belong to a specified value range indicating that the packet corresponds to the wireless packet. The transmission quality evaluation means evaluates the transmission quality of the first wireless packet as a ratio at which the determination result is true or false.
[0015]
In other words, the above-described ratio is either the execution of demodulation processing that conforms to the modulation scheme applied to the generation of the first radio packet and the second radio packet, or the reference of transmission information transmitted as these radio packets. Sought without being done.
Therefore, in addition to specifying such a modulation method, the configuration is simplified compared to the conventional example in which the analysis of the first wireless packet and the second wireless packet based on the modulation method must be performed. Therefore, flexible adaptation to various modulation schemes that can be actually applied is achieved, and the above-described transmission quality is required with high accuracy.
[0016]
In the invention according to claim 2, the monitoring means includes the time lengths of the first radio packet and the second radio packet received in the order of time series, and the second radio packet from the trailing edge of the first radio packet. Monitor the length of time to the leading edge of the radio packet. When the length of the first wireless packet is equal to or longer than a predetermined time length, the normality determining means specifies the modulation method corresponding to the length based on the time length of the first wireless packet, The second radio packet falls within a predetermined range indicating that the first radio packet corresponds to a radio packet for notifying that the first radio packet has been successfully received by the receiving station under this modulation scheme. It is determined whether the time length of the wireless packet and the length of the period belong. The transmission quality evaluation means evaluates the transmission quality of the first wireless packet for each modulation method as a ratio at which the determination result is true or false under the specified modulation method.
[0017]
That is, the modulation method applied to the generation of the first wireless packet is automatically identified, and the transmission quality is evaluated for each first wireless packet having the same modulation method.
Therefore, even when the modulation schemes that can be applied to the generation of the first radio packet are various and can be changed under some communication control, the evaluation of the transmission quality is achieved stably and accurately. .
[0018]
According to a third aspect of the present invention, in the wireless communication quality analyzing apparatus according to the first or second aspect, the monitoring means occupies the occupied bandwidth of the first wireless packet and the second wireless packet. Based on the band components in which the main components of the band can be distributed, the time length and the length of the period of these first and second radio packets are monitored.
[0019]
That is, since the time lengths of the first wireless packet and the second wireless packet described above and the above-described period are obtained based on the main components of these wireless packets, these lengths and periods Compared to the case where is determined based on the power distributed over the entire occupied band of the first wireless packet and the second wireless packet, the signal to be processed by the normality determining means and the transmission quality evaluating means Bandwidth is reduced.
[0020]
Therefore, it is possible to reduce the amount of processing in conjunction with the simplification of the configuration of the normality determination unit and the transmission quality evaluation unit.
According to a fourth aspect of the present invention, in the wireless communication quality analyzing apparatus according to the first or second aspect, the monitoring unit is configured to calculate an instantaneous value of an envelope component between the first wireless packet and the second wireless packet. The sequence is smoothed in chronological order, and the time lengths of the first radio packet and the second radio packet and the length of the above-described period are obtained from the resulting pulse train.
[0021]
That is, it is possible to avoid errors in these lengths and periods due to noise or the like.
Therefore, the accuracy of evaluation of transmission quality is improved.
In the invention according to claim 5, the temporal lengths of the first radio packet and the second radio packet received in chronological order, and the trailing edge of the first radio packet before the second radio packet. The length of the period leading to the edge is monitored. When the length of the first wireless packet is equal to or longer than the predetermined time length, the second wireless packet corresponds to a wireless packet for notifying that the first wireless packet has been normally received by the receiving station. It is determined whether or not the time length and the period length of the second wireless packet belong to a specified value range indicating the above. The transmission quality of the first wireless packet is evaluated as the ratio at which the determination result is true or false.
[0022]
In other words, the above-described ratio is either the execution of demodulation processing that conforms to the modulation scheme applied to the generation of the first radio packet and the second radio packet, or the reference of transmission information transmitted as these radio packets. Sought without being done.
Therefore, in addition to specifying such a modulation method, the configuration is simplified compared to the conventional example in which the analysis of the first wireless packet and the second wireless packet based on the modulation method must be performed. Therefore, flexible adaptation to various modulation schemes that can be actually applied is achieved, and the above-described transmission quality is required with high accuracy.
[0023]
In the invention according to claim 6, the temporal lengths of the first radio packet and the second radio packet received in the order of time series, and the leading edge of the second radio packet from the trailing edge of the first radio packet. The length of the period leading to the edge is monitored. When the length of the first wireless packet is equal to or longer than the predetermined time length, the modulation method corresponding to the length of the first wireless packet is specified based on the time length of the first wireless packet, and the second wireless packet is The second wireless packet is set to a predetermined value range indicating that the first wireless packet corresponds to a wireless packet for notifying that the first wireless packet has been normally received by the receiving station under the modulation scheme. It is determined whether the time length of the wireless packet and the length of the period belong to each other. The transmission quality of the first wireless packet is evaluated for each modulation method as a ratio at which the determination result is true or false under the specified modulation method.
[0024]
That is, the modulation method applied to the generation of the first wireless packet is automatically identified, and the transmission quality is evaluated for each first wireless packet having the same modulation method.
Therefore, even when the modulation schemes that can be applied to the generation of the first radio packet are various and can be changed under some communication control, the evaluation of the transmission quality is achieved stably and accurately. .
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the basic principle of the present invention will be described.
When the modulation scheme (64QAM R = 3/4) that realizes a transmission rate of 54 megabits / second is applied, the length of the data packet described above is 248 microseconds as shown in FIG. .
[0026]
On the other hand, the length of the ACK packet is about 44 microseconds even when the modulation scheme (BPSK R = 1/2) that realizes the lowest transmission rate of 6 megabits / second is applied.
[0027]
Therefore, for each wireless packet, it can be estimated whether it corresponds to a data packet or an ACK packet based on such a difference in length.
In addition, with regard to the trigger for transmitting the ACK packet, it is generally defined that the time elapsed from the time point of the trailing edge of the data packet is a specified time (16 microseconds).
[0028]
Therefore, for a combination of a previously transmitted data packet and an ACK packet sent as a response to the data packet, a subsequent packet (ACK pulse can be estimated from the time of the trailing edge of such a data packet. ) Based on the time to the leading edge point of time).
As shown in FIG. 7, the length of the data packet is a different value corresponding to each applied modulation scheme (transmission rate realized based on the modulation scheme).
[0029]
Here, the modulation system means a method for realizing various transmission speeds realized in combination with a multi-value technology such as BPSK, QPSK, 16QAM, 64QAM, and an error correction coding rate. .
Therefore, such a modulation scheme can be estimated based on the maximum value of the length of the received radio packet.
[0030]
FIG. 1 is a diagram showing first to third embodiments of the present invention.
In the figure, a cascade-connected amplifier 12, filter 13, A / D converter 14 and determination circuit 15 are connected to the feeding point of the antenna 11, and the determination circuit 15 is connected to an input port of the control unit 16. The Transmission quality described later is output to the output port of the control unit 16, and the output of the clock generator 17 is connected to the clock terminal of the A / D converter 14.
[0031]
FIG. 2 is an operation flowchart of the first embodiment of the present invention.
The operation of the first embodiment of the present invention will be described below with reference to FIG. 1 and FIG.
In a specific storage area of the main memory of the control unit 16, a packet length table configured as a sequence of records having the following fields individually corresponding to all the modulation schemes shown in FIG. 16T is stored in advance (see FIG. 3).
[0032]
A “modulation scheme” field in which individual modulation schemes shown in FIG. 7 (records corresponding to ACK packets are represented by a symbol “−” here) are stored in advance.
“Transmission rate” in which the transmission rate achieved by the modulation method indicated by the content of the “Modulation method” field (records corresponding to ACK packets are also indicated by the symbol “−”) is stored in advance. field
A “mark period length” in which a lower limit value and an upper limit value of a range that can be taken by the time length of a data packet (or ACK packet) transmitted in the modulation scheme indicated by the value of this “modulation scheme” field are stored in advance. "field
The antenna 11 is installed at a point where a wireless packet transmitted via the above-described wireless LAN arrives, and the amplifier 12 amplifies the wireless packet received through the antenna 11 to a predetermined level.
[0033]
The filter 13 extracts a component of the occupied band of each wireless packet amplified in this way, thereby generating a baseband signal indicating an envelope component of these wireless packets.
The A / D converter 14 generates a code string that discretely indicates the instantaneous value of the baseband signal described above in accordance with a clock signal having a predetermined frequency (= 1 / Δt) given by the clock generator 17. It is assumed here that the period Δt of such a clock signal is 1 μsec for simplicity.
[0034]
The determination circuit 15 sequentially discriminates the magnitude relationship between the instantaneous value indicated by the code sequence and the prescribed threshold value, thereby indicating the sequence of instantaneous values in chronological order, and the data packet or ACK packet described above. A binary pulse signal having a logical value of “1” is generated only during a period in which the signal is received.
[0035]
In the main memory of the control unit 16, the following counters and registers that are referred to or updated as appropriate in the course of processing performed by the control unit 16 are arranged in advance.
The length m of the period in which the logical value of the pulse signal described above is “0” (hereinafter referred to as “space period”) (here, normalized for the period Δt of the clock signal described above for simplicity) Counter m provided for timing)
The length n of the period (hereinafter referred to as “mark period”) in which the logical value of the pulse signal is “1” (here, for the sake of simplicity, a value normalized with the above-described clock signal period Δt) Counter n provided for timing)
• Used to count the number of times an ACK packet was sent from the receiving end (that is, the transmission of the data packet was successfully realized) as a response to the data packet transmitted by the transmitting end and successfully received by the receiving end. Counter L1
A counter L2 used for counting the number of times the above data packet has not been received by the receiving end or has not been received normally.
Registers K1 and K2 in which the upper limit value and the lower limit value of the pulse width of data packets transmitted via the wireless LAN are to be stored
A space period from the time of the trailing edge of the data packet to be transmitted via the wireless LAN (FIG. 6 (2)) to the time of the leading edge of the ACK packet following the data packet (FIG. 6 (3)). Register K3 in which the upper limit value k3 of the length is to be stored
Registers K4 and K5 for storing the upper limit value and the lower limit value of the pulse width of the ACK packet to be transmitted via the wireless LAN, respectively.
Furthermore, the following values are given in advance to the control unit 16 as known information.
[0036]
• “From the time of the trailing edge of the data packet transmitted based on the respective first modulation scheme that can be applied to the transmission of the data packet” to “the ACK packet transmitted from the receiving end in response to the data packet. Upper limit value k3 of the length of "period leading to the time of the leading edge"
An ACK to be transmitted via a wireless LAN based on an individual second modulation scheme (which may be set to a modulation scheme different from the first modulation scheme described above) that can be applied to transmission of an ACK packet The upper limit value k4 and the lower limit value k5 control unit 16 of the pulse width of the packet performs processing as described below at the time of starting or starting.
[0037]
(1) Perform the following initial settings.
The count values of the counter m, the counter n, the counter L1, and the counter L2 are set to “0”.
Of the records of the packet length table 16T described above, the first modulation method to which the value of the “modulation method” field is actually applied (in this case, for the sake of simplicity, it is designated in advance via a man-machine interface or the like) And the upper limit value and the lower limit value stored in the “mark period length” field of the record are stored in the registers K1 and K2, respectively.
[0038]
As described above, of the known information and the predetermined upper limit value k3, the upper limit value k3 corresponding to the first modulation method is stored in the register K3.
Similarly, the second modulation method that is actually applied in the pair of the upper limit value k4 and the lower limit value k5 given in advance as known information (here, for the sake of simplicity, it is specified via a man-machine interface or the like). The upper limit value k4 and the lower limit value k5 included in the pair corresponding to (2) are stored in the registers K4 and K5, respectively.
[0039]
(2) By sequentially referring to the logical value of the pulse signal generated as described above by the determination circuit 15 with the above-described clock period Δt, any one of the following four states is identified in time series.
Since the logical value of the pulse signal is “0” in the same way as the logical value at the time that precedes Δt on the time axis, any wireless packet (including both the above-described data packet and ACK packet) is received. "Space period" presumed to be not done
Since the logical value of the pulse signal is “1” in the same way as the logical value when Δt precedes on the time axis, any wireless packet (any of the above-described data packet and ACK packet may be applicable). ) "Mark period" estimated to be received
-Since the logical value of the pulse signal has changed to "1", which is different from the logical value "0" at the time that precedes by Δt on the time axis, any wireless packet (both data packets and ACK packets described above are applicable) The leading edge period during which the leading edge is estimated to have been received.
-Since the logical value of the pulse signal has changed to "0", which is different from the logical value "1" at the time that precedes by Δt on the time axis, any wireless packet (both data packets and ACK packets described above are applicable) ) "Rear edge period" where the trailing edge is estimated to have been received
(3) When the period identified in this way corresponds to any of the above-mentioned “space period”, “mark period” and “rear edge period”, the following individually corresponding to these periods: Process.
[0040]
When the “space period” is identified, the length of the “space period” is updated by incrementing the counter m (FIG. 2 (1)).
When the “mark period” is identified, the length of the “mark period” is updated by incrementing the counter n (FIG. 2 (2)).
When the “rear edge period” is identified, it means that the start point of the “space period” following the preceding “mark period” has been detected, so the count value of the counter m is initialized to “1”. (FIG. 2 (3)), and the serial number i given to the received wireless packet (both data packet and ACK packet can be applicable) in chronological order is incremented (FIG. 2 (4)). ) And the count value of the counter n at that time is preserved as the mark period length N (i) corresponding to the serial number i incremented in this way (FIG. 2 (5)).
[0041]
(4) However, when the identified period is the above-described “front edge period”, the following processing is performed.
This means that the start point of the “mark period” following the preceding “space period” has been detected, so the count value of the counter n is initialized to “1” (FIG. 2 (6)).
[0042]
As the length M (i) of the space period following the wireless packet corresponding to the serial number i described above, the count value of the counter m at that time is maintained (FIG. 2 (7)).
The length N (i−1) of the mark period associated with the serial number (i−1) which is smaller by “1” than the serial number i at this time and maintained as described above, and the registers K1, K2 First determination as to whether or not the following inequality holds for the upper limit value k1 and the lower limit value k2 stored as described above (whether a data packet having a pulse width satisfying the following inequality has been received) (Meaning determination of whether or not) (FIG. 2 (8)). Of the processes performed by the control unit 16 when the “leading edge period” is identified, such a first determination and a series of processes performed following the first determination will be described below. Then, for simplicity, it is called “normality determination processing”.
[0043]
k1 ≧ N (i−1)> k2
When the result of the first determination is false, all the remaining processes that should be performed as the “normality determination process” are omitted.
The length N (i) of the mark period maintained in association with the serial number i at this time, and the upper limit value k4 and the lower limit value k5 stored as described above in the registers K4 and K5 Second determination as to whether or not the following inequality holds (after receiving a data packet for which the result of the first determination is true, an ACK packet to be received as a response to the data packet is normally received) Is determined) (FIG. 2 (9)).
[0044]
k4 ≧ N (i)> k5
-If the result of the second determination is false, it can be estimated that after the data packet is received, the ACK packet to be received as a response to the data packet has not been received normally. Therefore, the count value of the counter L2 is incremented (FIG. 2 (10)), and all the remaining processes to be performed as the “normality determination process” are omitted.
[0045]
However, if the result of the second determination is true, the maintenance is performed as described above in association with the continuous number (i−1) which is smaller by “1” than the continuous number i at this time. The third determination of whether or not the following inequality holds for the length M (i−1) of the space period thus determined and the upper limit value k3 stored in the register K3 (after the data packet described above) This means that it is determined whether or not the length of the period from the edge time point to the front edge time point of the ACK packet is an appropriate value equal to or less than the upper limit value k3 (FIG. 2 (11)).
[0046]
M (i−1) ≦ k3
-If the result of the third determination is false, “after the data packet was received, the ACK packet to be received as a response to the data packet was not received in a proper period”. This means that the count value of the counter L2 is incremented (FIG. 2 (12)), and all the remaining processes to be performed as the “normality determination process” are omitted.
[0047]
However, if the result of the third determination is true, “the period in which the ACK packet is to be received is appropriate in addition to the pulse width of the data packet and the ACK packet described above. Therefore, the count value of the counter L1 is incremented (FIG. 2 (13)).
In addition, the control unit 16 performs the following processing every time the above-described “normality determination processing” is performed for a specified number of times or at predetermined intervals, whereby the count value L1 of the counter L1 and the counter L2 With reference to the count value L2, both or one of the success rate S and the failure rate F represented by the following equations is calculated for these count values L1 and L2.
[0048]
S = L1 / (L1 + L2)
F = L2 / (L1 + L2)
Such a success rate S and failure rate F are obtained by referring to the lengths of these data packets and ACK packets and the ACK as a response to the data packets without referring to any transmission information indicated by the data packets and ACK packets. This is obtained based on the result of the determination as to whether or not all the lengths of the periods during which the packets are to be received are appropriate.
[0049]
Therefore, in addition to the reliable identification of the modulation scheme (transmission scheme) applied to the transmission of data packets and ACK packets, analysis of these data packets and ACK packets based on the modulation scheme must be performed. Compared to the conventional example, even if any modification or improvement is applied to such a modulation method, the transmission quality of the wireless LAN can be evaluated with high accuracy and at low cost.
[0050]
In this embodiment, even if the second modulation method is not necessarily the same as the first modulation method, if the data packet and the ACK packet can be identified from the time length of the radio packet, Good. Thus, for example, if the time required to transmit an ACK packet in the modulation method with the slowest transmission rate is sufficiently shorter than the time required to transmit a data packet of 1518 bytes in the modulation method with the fastest transmission rate, A specific relationship may not be established between the second modulation method and the first modulation method.
[0051]
Further, in the present embodiment, the “space period” and the “mark period” are defined to be the same as the logical value at the time point when the logical value of the pulse signal described above precedes Δt on the time axis. Based on prompt identification.
However, the present invention is not limited to such a configuration. For example, when the control unit 16 performs processing different from the processing described above in the following points, in addition to avoiding the occurrence of errors due to noise or the like, The accuracy related to the identification of the “space period” and the “mark period” may be increased, and the accuracy of the transmission quality evaluation may be increased.
[0052]
The pulse signal logic value is sequentially accumulated over a predetermined period (assumed to be an integer multiple of Δt for the sake of simplicity).
A “space period” is identified when all of the preceding plural (= k6) logical values are “0”, and all of the preceding plural (= k7) logical values are “1”. Sometimes the “mark period” is identified.
[0053]
When the “rear edge period” is identified, the above-described plural (= k7) is applied as the initial value of the counter m instead of “1” (FIG. 4 (3)), and increment As the length N (i) of the mark period corresponding to the serial number i, the value represented by the following expression is maintained (FIG. 4 (5)).
N (i) = n−k6 + 1
When the “leading edge period” is identified, the above-described plural (= k6) is applied as the initial value of the counter n instead of “1” described above (FIG. 4 (6)), and As the length M (i) of the space period following the wireless packet corresponding to the serial number i described above, the value represented by the following expression is maintained (FIG. 4 (7)).
[0054]
M (i) = m−k7 + 1
Furthermore, in the present embodiment, the “normality determination process” is performed only when the “front edge period” is identified.
However, such “normality determination processing” may be performed only when the “rear edge period” is identified.
[0055]
In addition, this “normality determination processing” is referred to in the process of “normality determination processing”, for example, during a period in which all wireless packets to be evaluated for transmission quality are being transmitted. All the information that should be stored is sequentially maintained, and when the transmission is completed, the information may be referred to collectively.
Further, in this embodiment, the transmission quality is evaluated by performing the above-described processing in real time according to the logical value of the pulse signal given by the determination circuit 15.
[0056]
However, such evaluation of transmission quality is performed, for example, after a column of logical values (or instantaneous values) of a pulse signal given by the determination circuit 15 is accumulated in a certain storage device and then these logical values and instantaneous values are stored. This may be realized by collectively performing the above-described processing on the value column.
FIG. 5 is an operation flowchart of the second embodiment of the present invention.
[0057]
Hereinafter, the operation of the second embodiment of the present invention will be described with reference to FIG. 1, FIG. 3, and FIG.
The feature of the present embodiment is the processing procedure performed by the control unit 16 and replacing the following processing.
・ Initial settings described above
・ Normality discrimination processing
A process for calculating either or both of the success rate S and the failure rate F
In the present embodiment, the procedure performed prior to the “normality determination process” when the “leading edge period” is identified is the same as the procedure in the first embodiment described above. Therefore, the description thereof is omitted here.
[0058]
In addition, in the following, for the sake of simplicity, individual records whose values in the “transmission rate” field are “54 megabits / second” to “6 megabits / second” among the records of the packet length table 16T have the value “ Assume that a record pointer p that is "0" to "7" indicates.
Furthermore, the upper limit value and the lower limit value stored in the “mark period length” field of the record indicated by the record pointer p (= 0 to 7) in the records of the packet length table 16T will be described below. The values of the record pointer p are expressed as k1 [p] and k2 [p], respectively.
[0059]
Further, in the main memory of the control unit 16, instead of the counters L1 and L2, the counters L1 [0] to L1 [individually corresponding to the values (= 0 to 7) that can be taken by the record pointer p described above are possible. 7] and L2 [0] to L2 [7] are arranged.
In the initial setting process performed at the time of start-up or startup, the control unit 16 does not perform the following processing performed in the first embodiment described above, and instead of the count values of the counter L1 and the counter L2. All the count values of the counters L1 [0] to L1 [7] and L2 [0] to L2 [7] described above are set to “0”.
[0060]
-Processing to store upper and lower limit values in registers K1 and K2
Further, the control unit 16 performs “normality determination processing” based on the following procedure.
(A) The value of the record pointer p is initialized to “0”.
(B) Among the records of the packet length table 16T, a record corresponding to the current value of the record pointer p (hereinafter referred to as “current record”) is specified and stored in the “mark period length” field of the record. The upper limit value k1 [p] and the lower limit value k2 [p] are acquired.
[0061]
(C) The length N (i−1) of the mark period maintained as described above in association with the serial number (i−1) which is smaller by “1” than the serial number i at this time point, A first determination as to whether or not the following inequality is satisfied with respect to the upper limit value k1 [p] and the lower limit value k2 [p] acquired as follows (a data packet having a pulse width that satisfies the following inequality is This means that it has been received or not) (FIG. 5 (1)).
[0062]
k1 [p] ≧ N (i−1)> k2 [p]
(D) If the result of the first determination is false, it is determined whether or not the value of the record pointer p is “7” (hereinafter referred to as “censoring determination”). As long as the result is false, after the record pointer p is incremented, the above processes (b) to (d) are repeated.
[0063]
(E) However, if the result of this abortion determination is true, the remaining processing to be performed as “normality determination processing” is omitted.
(F) If the result of the first determination described above is true, the length N (i) of the mark period maintained in association with the serial number i at this time and the upper limit value described above Second determination as to whether or not the following inequality holds for k4 and lower limit k5 (after receiving a data packet for which the result of the first determination is true, it is received as a response to the data packet) This means that it is determined whether or not the ACK packet to be received has been normally received (FIG. 5 (3)).
[0064]
k4 ≧ N (i)> k5
-If the result of the second determination is false, it can be estimated that after the data packet is received, the ACK packet to be received as a response to the data packet has not been received normally. Therefore, the count value of the counter L2 [p] is incremented (FIG. 5 (4)), and all the remaining processes to be performed as the “normality determination process” are omitted.
[0065]
However, if the result of the second determination is true, the maintenance is performed as described above in association with the continuous number (i−1) which is smaller by “1” than the continuous number i at this time. The third determination as to whether or not the following inequality is satisfied with respect to the length M (i−1) of the generated space period and the upper limit k3 described above (ACK from the time of the trailing edge of the data packet described above) This means that it is determined whether or not the length of the period up to the time point of the leading edge of the packet is an appropriate value equal to or less than the upper limit value k3 (FIG. 5 (5)).
[0066]
M (i−1) ≦ k3
-If the result of the third determination is false, it is estimated that "after the data packet was received, the ACK packet to be received as a response to the data packet was not received in an appropriate period" Since it is possible, the count value of the counter L2 [p] is incremented (FIG. 5 (6)), and the remaining processing to be performed as “normality determination processing” is omitted.
[0067]
However, if the result of the third determination is true, “the period in which the ACK packet is to be received is appropriate in addition to the pulse width of the data packet and the ACK packet described above. Therefore, the count value of the counter L1 [p] is incremented (FIG. 5 (7)).
[0068]
Further, the control unit 16 performs the following processing every time such “normality determination processing” is repeated a prescribed number of times or at a predetermined cycle.
Of the counters L1 [0] to L1 [7] and the counters L2 [0] to L2 [7], the counter value L1 [p] and the counter L2 [p] of the counter L1 [p] corresponding to the current pointer p The count value L2 [p] is referred to, and either or both of the success rate S [p] and the failure rate F [p] represented by the following formulas for these count values L1 [p] and L2 [p] Either one is calculated.
[0069]
S [p] = L1 [p] / (L1 [p] + L2 [p])
F [p] = L2 [p] / (L1 [p] + L2 [p])
That is, in the present embodiment, the modulation scheme applied to the transmission of the data packet and the ACK packet is automatically determined, and in addition to the first to third determinations described above, the success rate S [p] and the failure rate The calculation of F [p] is reliably performed under a criterion adapted to the modulation scheme thus determined.
[0070]
Therefore, according to the present embodiment, even when there are various modulation schemes that can be applied and can be changed under some communication control, the transmission quality can be evaluated stably and with high accuracy.
In the present embodiment, the counter values L1 [p] and L2 [p] of the counters L1 [p] and L2 [p] corresponding to the modulation method indicated by the record pointer p for which the first determination result is true. ], The success rate S [p] and the failure rate F [p] are required.
[0071]
However, such a success rate or failure rate is, for example, a value that can be taken by the record pointer p (= 0 to 7) regardless of the record pointer p for which the result of the first determination described above is true. Success rates S [0] to S [7] and failure rates F [0] to F [7] individually corresponding to all of the above may be obtained in parallel.
The operation of the third embodiment of the present invention will be described below with reference to FIG.
[0072]
The feature of this embodiment lies in the following processing performed by the filter 13 shown in FIG.
The filter 13 is a baseband signal indicating, in a baseband region, a component that passes through a band that satisfies all of the following conditions among components of a wireless packet that is received via the antenna 11 and is subject to transmission quality evaluation. Is generated.
[0073]
Regardless of the modulation method to be applied to the transmission of the above-described wireless packet, main components are distributed in the occupied band of the wireless packet.
• It is guaranteed that the distortion that can accompany the baseband signal is small enough to be tolerated.
That is, the transmission quality of a wireless packet is evaluated based on the main components of the wireless packet.
[0074]
Therefore, according to the present embodiment, compared with the case where the above-described passband is set unnecessarily wide, the power saving and the overall reliability are reduced in addition to the simplification of the hardware and software configuration in the following points. Can be improved.
The frequency of the clock signal to be supplied to the A / D converter 14 can be set low.
[0075]
It is possible to reduce the total processing amount of the determination circuit 15 and the control unit 16.
In each of the above-described embodiments, the present invention is applied to evaluation of transmission quality related to a wireless LAN to which the CSMA / CA method is applied.
However, the present invention is not limited to such a wireless LAN. The length of the first wireless packet transmitted in advance and the second wireless packet to be transmitted from the receiving end as a response to the first wireless packet. Based on the length of the radio packet and the length of the period from the trailing edge of the first radio packet to the leading edge of the second radio packet, As long as it is possible to determine whether or not the transmission is normally completed, the present invention can be applied to a wireless transmission system to which any communication procedure, modulation scheme, and multiple access scheme are applied.
[0076]
Further, in each of the above-described embodiments, the above-described processing is performed by the control unit 16 on the logical value sequence of the pulse signal generated by binarizing the instantaneous value of the envelope component of the wireless packet. However, as long as a process equivalent to such a process is realized, each process may be performed in either the analog domain or the digital domain.
Furthermore, such an equivalent process may be directly performed on the envelope component of a wireless packet that is indicated by multiple values of three or more values instead of binary values.
[0077]
Further, in each of the above-described embodiments, the success rate or failure rate is determined without determining the length of the period from the time point of the trailing edge of the ACK packet to the time point of the leading edge of the data packet subsequent to the ACK packet. Is required.
However, according to the present invention, the accuracy of the success rate and the failure rate described above may be increased by determining whether such a period is appropriate.
[0078]
Further, in each of the above-described embodiments, the present invention is applied to the evaluation of the transmission quality of a wireless LAN in which an ACK packet is sent out one by one by the receiving end of the data packet as a response to a single-length data packet. Yes.
However, according to the present invention, for example, even when a single ACK packet is transmitted as a comprehensive response to a plurality of continuously transmitted data packets, whether or not all of these packets are normally transmitted. As long as this determination is possible based on the length of each wireless packet and the value of the interval, the same applies.
[0079]
In each of the above-described embodiments, the present invention is applied to a wireless LAN in which both a data packet and an ACK packet are transmitted via a common wireless transmission path.
However, the present invention provides an envelope component for each packet transmitted through these wireless transmission paths even when the wireless transmission paths used for transmission of these data packets and ACK packets are different. As long as it can be monitored, the same applies.
[0080]
Furthermore, the radio network transmission quality analysis apparatus according to each of the above-described embodiments is configured by including a filter 13 in addition to the antenna 11 and the amplifier 12.
However, the wireless channel transmission quality analysis apparatus according to the present invention can flexibly adapt to an applicable wireless LAN or wireless transmission system (including frequency arrangement, zone configuration, etc.) in conjunction with reduction of restrictions on transportation. For the purpose, all or part of the antenna 11, the amplifier 12 and the filter 13 may be provided separately or detachably.
[0081]
In the above-described embodiments, the above-described processing performed by the filter 13, the A / D converter 14, the determination circuit 15, and the control unit 16 is a single or a plurality of general-purpose processors as long as they are equivalent to the processing. (It may be a DSP (Digital Sinal Processor)) and / or dedicated hardware, and may be performed under any function distribution or load distribution.
[0082]
Furthermore, the present invention is not limited to the above-described embodiments, and various embodiments can be made within the scope of the present invention, and any or all of the components may be improved. .
[0083]
【The invention's effect】
As described above, in the first and fifth aspects of the invention, in addition to specifying the modulation method applied to the generation of the first wireless packet and the second wireless packet, the first based on the modulation method is provided. Compared to the conventional example in which the analysis of the radio packet and the second radio packet had to be performed, the configuration can be simplified and flexible adaptation to various modulation schemes that can be actually applied is achieved. At the same time, the transmission quality described above is required with high accuracy.
[0084]
In the invention according to claim 2 and claim 6, even when the modulation schemes that can be applied to the generation of the first radio packet are various and can be changed under some communication control, In addition, transmission quality can be evaluated with high accuracy.
[0085]
According to the third aspect of the present invention, it is possible to reduce the amount of processing as the configuration is simplified.
In the invention according to claim 4, the accuracy of evaluation of transmission quality is increased.
Therefore, in the wireless transmission system to which these inventions are applied, even when the transmission methods of the wireless transmission system are variously different, the transmission quality can be evaluated flexibly and inexpensively, and the adjustment, maintenance and In addition to reducing the costs associated with operation, labor can be saved.
[Brief description of the drawings]
FIG. 1 is a diagram showing first to third embodiments of the present invention.
FIG. 2 is an operation flowchart of the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a configuration of a packet length table.
FIG. 4 is an operation flowchart showing another operation of the first embodiment of the present invention.
FIG. 5 is an operation flowchart of the second embodiment of the present invention.
FIG. 6 is a diagram illustrating an example of a wireless packet transmitted via a wireless LAN.
FIG. 7 is a diagram illustrating a correspondence between modulation schemes and data packet lengths.
[Explanation of symbols]
11 Antenna
12 Amplifier
13 Filter
14 A / D converter
15 Judgment circuit
16 Control unit
16T packet length table
17 Clock generator

Claims (6)

A time length of the first wireless packet and the second wireless packet received in time-series order, and a length of a period from the trailing edge of the first wireless packet to the leading edge of the second wireless packet; Monitoring means for monitoring
When the length of the first wireless packet is equal to or longer than a predetermined time length, the second wireless packet is a wireless packet for notifying that the first wireless packet has been normally received by the receiving station. Normality determining means for determining whether or not both of the time length of the second wireless packet and the length of the period belong to a specified range indicating that it corresponds to:
A wireless communication quality analyzing apparatus comprising: transmission quality evaluation means for evaluating the transmission quality of the first wireless packet as a ratio at which the determination result is true or false. A time length of the first wireless packet and the second wireless packet received in time-series order, and a length of a period from the trailing edge of the first wireless packet to the leading edge of the second wireless packet; Monitoring means for monitoring
When the length of the first wireless packet is equal to or longer than a predetermined time length, the modulation method corresponding to the length is specified based on the time length of the first wireless packet, and the second wireless packet is The second wireless packet is in a predetermined range indicating that the wireless packet corresponds to a wireless packet for notifying that the first wireless packet has been normally received by the receiving station under this modulation scheme. Normality determining means for determining whether or not the length of time and the length of the period belong,
Transmission quality evaluation means for evaluating the transmission quality of the first radio packet for each modulation method as a ratio at which the determination result is true or false under the specified modulation method. A wireless communication quality analyzer. In the wireless communication quality analysis device according to claim 1 or 2,
The monitoring means includes
Based on the band components in which the main components of the occupied band can be distributed among the occupied bands of the first wireless packet and the second wireless packet, these first wireless packet and second wireless packet A wireless communication quality analyzing apparatus for monitoring a time length of a packet and a length of the period. In the wireless communication quality analysis device according to claim 1 or 2,
The monitoring means includes
The sequence of instantaneous values of envelope components of the first radio packet and the second radio packet are smoothed in order of time series, and the first radio packet and the second radio packet are obtained from the resulting pulse train. A wireless communication quality analyzing apparatus characterized by obtaining a time length of a wireless packet and a length of the period. A time length of the first wireless packet and the second wireless packet received in time-series order, and a length of a period from the trailing edge of the first wireless packet to the leading edge of the second wireless packet; Monitor
When the length of the first wireless packet is equal to or longer than a predetermined time length, the second wireless packet is a wireless packet for notifying that the first wireless packet has been normally received by the receiving station. It is determined whether or not the time length of the second wireless packet and the length of the period belong to a specified range indicating that it corresponds to
A wireless communication quality measuring method, wherein the transmission quality of the first wireless packet is evaluated as a ratio at which the determination result is true or false. The time length of the first radio packet and the second radio packet received in chronological order, and the length of the period from the trailing edge of the first radio packet to the leading edge of the second radio packet Monitor
When the length of the first wireless packet is equal to or longer than a predetermined time length, the modulation method corresponding to the length is specified based on the time length of the first wireless packet, and the second wireless packet is The second wireless packet is in a predetermined range indicating that the wireless packet corresponds to a wireless packet for notifying that the first wireless packet has been normally received by the receiving station under this modulation scheme. To determine whether or not the length of time and the length of the period belong,
A wireless communication quality measurement method, comprising: evaluating a transmission quality of the first wireless packet for each modulation method as a ratio at which the determination result is true or false under the specified modulation method.

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