EP1417816A1 - Dispositif et procede pour le controle de qualite de paquets de donnees transmis par l'intermediaire d'une voie radio - Google Patents

Dispositif et procede pour le controle de qualite de paquets de donnees transmis par l'intermediaire d'une voie radio

Info

Publication number
EP1417816A1
EP1417816A1 EP02754228A EP02754228A EP1417816A1 EP 1417816 A1 EP1417816 A1 EP 1417816A1 EP 02754228 A EP02754228 A EP 02754228A EP 02754228 A EP02754228 A EP 02754228A EP 1417816 A1 EP1417816 A1 EP 1417816A1
Authority
EP
European Patent Office
Prior art keywords
data packets
transmission channel
error
metric
quality
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02754228A
Other languages
German (de)
English (en)
Inventor
Martin Krüger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Infineon Technologies AG
Original Assignee
Infineon Technologies AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Infineon Technologies AG filed Critical Infineon Technologies AG
Publication of EP1417816A1 publication Critical patent/EP1417816A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector

Definitions

  • the invention relates to a device for the detection of poorly or unreliably transmitted data packets in a radio receiver, in particular in a mobile radio receiver, and a method for the detection of poorly or unreliably transmitted data packets.
  • the user data stream to be transmitted is broken down into data packets on the transmitter side, which are then transmitted to the receiver.
  • the received packets are first fed to a deinterleaver, which performs a permutation of the data symbols of this data block for each transmitted data block.
  • the output of the deinterleaver is connected to the input of the Viterbi decoder on the receiver side, which decodes the incoming data stream.
  • the GSM mobile radio standard differentiates between three classes of useful bits, namely classes la, Ib and II. While the transmitted bits of class la are transmitted together with an associated error protection word, no such error protection word is provided for the bits of class Ib.
  • the bits of class II differ from the bits of classes la and Ib in that they are passed past the Viterbi decoder after de-interleaving and can be processed further without further decoding.
  • a CRC check is therefore only carried out for the useful bits of class la (and thus only for a certain fraction of the total transmitted useful bits). Depending on the result of the CRC check, the data packet is either accepted or discarded.
  • the error probability of the bits of the frames not rejected is still too great in many cases.
  • the ETSI European Telecommunications Standards Institute
  • RBER residual bit error rate
  • FER frame erasure rate
  • the specification for the residual error probability RBER is the more difficult to meet. Since only the Ia bits can be checked for errors with a checksum test and therefore only a small part of the transmitted bits is recorded, the probability of undetected faulty bits of classes Ib and II is quite large, often greater than permissible.
  • the number of bit errors determined for a data packet or for a group of data packets is referred to as a metric. If the metric exceeds a certain predefined threshold value or if the checksum test carried out in parallel is unsuccessful, the frame is discarded. In any case, this increases the framework committee rate FER; the residual error probability RBER is reduced.
  • this method in which the metric is compared with a predetermined threshold value, has the disadvantage that the residual error probability RBER is still subject to strong fluctuations.
  • This object is achieved by a device for the detection of poorly or unreliably transmitted data packets according to claim 1, by a mobile radio receiver according to claim 14 and by a method for the detection of poorly or unreliably transmitted data packets in a mobile radio receiver according to claim 15.
  • the device according to the invention for the detection of badly or unreliably transmitted data packets in a radio receiver comprises a convolutional decoder for decoding the received data packets, means for evaluating the quality of the decoded data packets and comparison means which parameters characteristic of the quality of the decoded data packets
  • the device for detecting badly or unreliably transmitted data packets comprises means for determining the type of transmission channel, which determine whether the current transmission channel is a rapidly changing or a slowly changing transmission channel, and means for determining the threshold values for the Comparison means depending on the determined transmission channel type.
  • the invention is based on the knowledge that the transmission behavior of slowly changing (mobile) radio channels differs fundamentally from the transmission behavior of rapidly changing (mobile) radio channels.
  • a slowly changing transmission channel is, for example, the transmission channel that is between a mobile phone pedestrian in an urban environment and the closest base station (Typical Urban 3 km / h, TU3).
  • Slowly changing transmission channels alternate between long periods of good and bad transmission quality. This means that the transmission quality usually remains constant during the transmission of a data packet - either consistently good or constantly bad. As a result of this, the received data either have no or very few errors after they have been decoded, or they have a great many errors.
  • the transmission quality of the channel changes at shorter intervals. Time intervals with good transmission quality alternate in quick succession with time intervals with poor transmission quality. For this reason, the transmission quality usually changes several times during the transmission of a data packet. Since the useful data bits are transmitted with a certain redundancy, incorrectly transmitted parts of a data packet can generally be reconstructed in the convolutional decoder on the basis of other, error-free transmitted parts of the data packet. In the case of rapidly changing transmission channels, the majority of the decoded data packets contain some errors; In contrast, data packets with a very large number of errors are rare with rapidly changing transmission channels. Completely error-free data packets also rarely occur, because a sufficiently good transmission quality must be provided for this during the entire period required for the transmission of the data packet. This rarely happens with fast changing transmission channels.
  • the residual error probability RBER that is, the probability of errors in the bits that cannot be explicitly checked for errors.
  • the basic principle is that if there is a good transmission period, no errors occur. If, on the other hand, bit errors were found for some of the checked bits, the residual error probability for the unchecked bits is very high for slowly changing transmission channels, because it can be assumed that the entire data packet was transmitted during a bad transmission period. In the case of rapidly changing transmission channels, on the other hand, if some bit errors have already been detected, the residual error probability is significantly lower.
  • the threshold values for the quality of the decoded data packets are matched to the previously determined type of transmission channel in the device according to the invention for the detection of poorly or unreliably transmitted data packets. If it is determined that there is a slowly changing transmission channel, then strict thresholds for the quality check are set. Because even if only a few errors occur within the checked part of the transmitted user data, it must be assumed with slowly changing transmission channels that the entire data packet was transmitted incorrectly. Therefore, even if only a few errors were found within the verified fraction of the user data, the data packet should be discarded.
  • the threshold values for the quality of the decoded data packets may be set more generously. In this case, even if there are some errors within the verified fraction of the user data sequence, it can still be assumed that large parts of the data packet have been transmitted correctly. With the aid of the adaptation of the threshold values according to the invention depending on the transmission channel type determined, it can be achieved that the residual error probability can be kept at an approximately constant value even under changing transmission conditions. This leads to a more uniform transmission quality; Fluctuating bit error rates can be avoided by using the solution according to the invention. With the solution according to the invention, an optimal balance can also be established between the residual error probability RBER and the relative number of frames rejected, the frame reject rate FER.
  • the decisive factor for these successes achieved with the aid of the solution according to the invention is the distinction between slowly changing and rapidly changing transmission channels and an understanding of the different transmission behavior caused thereby.
  • the distinction as to whether there is a slowly changing or a rapidly changing transmission channel can be made simply and quickly using some of the criteria disclosed in this patent application.
  • the circuitry for implementing means for determining the transmission channel type is low.
  • the means for evaluating the quality of the decoded data packets comprise a convolutional encoder for re-encoding the decoded data.
  • the Viterbi algorithm is used to determine, based on the data received via the mobile radio channel, which user data sequence was most likely the basis of the transmission.
  • the decoded data are re-encoded by means of an additional folding encoder.
  • the original, encoded bit stream, which had been fed to the Viterbi decoder can be compared with the re-encoded bit stream. The number of bit errors per data packet can be determined from the comparison of the two bit streams.
  • the number of The deviations or bit errors determined in the data packet are referred to below as metrics.
  • This metric which is obtained by convolutionally coding the decoded data again, represents a meaningful key figure for the quality of the decoded data packets and is therefore particularly suitable for checking the transmission quality.
  • the means for evaluating the quality of the decoded data packets comprise an error counter which counts the number of errors as the number of deviations between the received data and the data re-encoded by the convolutional encoder.
  • the encoded data stream of the received data and the data stream of re-encoded data generated by the convolutional encoder are compared bit by bit, and the error counter counts the number of deviations.
  • the error counter supplies the metric of the data packet for each received data packet, that is, the number of errors determined for the data packet. If the deviations between the received data and the data re-encoded by the convolutional encoder are detected using an XOR gate then the error counter counts how often the signal value "1" occurs at the output of the XOR gate.
  • the number of errors determined by the error counter is compared by the comparison means with at least one threshold value and, depending on the comparison result, the data packets are accepted, rejected or modified.
  • the number of errors or metric is a meaningful parameter for the quality of the decoded data packets. The higher the metric, the poorer the quality of the decoded data packet.
  • the metric threshold value defines the just acceptable number of errors in the data packet. If the number of errors or metrics of the data packet is below the threshold value, the decoded data can be trusted. If, on the other hand, the number of errors determined by the error counter exceeds the threshold value, the data packet must be discarded. The retransmission of the data packet can then be requested.
  • a conventional checksum test (CRC; Cyclic Redundancy Check) can also be carried out for a part of the transmitted bits, for example for the bits of class la.
  • CRC Cyclic Redundancy Check
  • the checksum test can be used to assess whether or not bit errors have occurred within the bits of class la. If both the metric was determined and a CRC check was carried out for a received data packet, then the data packet is only accepted if both tests classify the data as trustworthy.
  • the received data packet must be discarded.
  • a quality check based on the Metrics of the data packets can therefore be easily combined with the well-established CRC checks, parity checks or checksum tests.
  • the means for determining the transmission channel type open up the transmission channel type on the basis of the distribution of the frequencies of the various error numbers determined for the data packets.
  • the distribution of the frequencies of the number of errors can be used to determine whether there is a rapidly changing or a slowly changing transmission channel.
  • the associated number of errors is determined for a set of data packets for each data packet.
  • the frequency ni of their occurrence in the considered quantity of data packets is then determined for each possible number of errors i.
  • a histogram is obtained which has specific peculiarities depending on the type of the physical transmission channel.
  • the histogram of the number of errors decreases monotonically from zero.
  • the frequency of a zero metric is particularly high with slowly changing channels, higher than with rapidly changing channels. This is due to the fact that a zero metric is only achieved if good transmission conditions prevail throughout the entire time period required for the transmission of the data packet. This case occurs much more frequently with slowly changing channels than with rapidly changing channels, in which good and bad transmission periods alternate rapidly during the transmission of a data packet.
  • the properties of the physical transmission channel can are therefore recognized and taken into account on the basis of the histogram of the metrics.
  • the means for determining the transmission channel type determine the transmission channel type on the basis of the proportion of error-free data packets.
  • a high proportion of data packets with zero metric is a typical feature of a slowly varying transmission channel. Slowly varying and rapidly varying transmission channels can be easily distinguished from one another on the basis of this feature. For this purpose, the data packets with the metric zero only have to be determined and counted within a predetermined number of data packets.
  • the means for determining the transmission channel type comprise a zero metric counter which counts the error-free data packets within a predetermined number of data packets. During the reception of a predetermined number of data packets, the zero metric counter is incremented by one for each data packet for which the metric has the value zero. Such a zero metric counter can be implemented easily and with little effort in hardware. On the basis of the result provided by the zero metric counter, the different types of physical transmission channels can be distinguished in a simple manner.
  • the means for determining the transmission channel type comprise at least one comparator that compares the number or proportion of error-free data packets with a zero metric limit value, the comparison result being used to determine whether a rapidly changing or a slowly changing one Transmission channel is present. If the proportion of error-free data packets within the received data packets exceeds the zero metric limit value, then there is a slowly changing transmission channel. With slowly changing transmission channels There are long time intervals with good transmission quality and data packets that are transmitted within these time intervals have no or only a few bit errors. If, on the other hand, the proportion of error-free data packets is below the zero metric limit value, it can be concluded that the transmission channel is changing quickly.
  • a comparator can be easily implemented as a comparator circuit, the implementation effort is low. On the basis of the result provided by the comparator, a reliable distinction between the different types of physical channels is possible.
  • the threshold values for the comparison means are set to lower values than for the case that the number or the proportion of error-free data packets is below the zero metric limit. If the number or proportion of error-free data packets is above the zero metric limit, the transmission channel is a slowly changing transmission channel. In this respect, a higher quality of the data packets received must be required. This means that the data packets should be discarded even with a relatively small number of errors, and therefore the threshold values for the comparison means must be set to relatively low values. If the metric exceeds these relatively low threshold values, the data packet is discarded.
  • the proportion of error-free data packets is below the zero metric limit, then it is a matter of a rapidly changing transmission channel. Accordingly, the quality requirements are less rigorous, and in this respect the threshold values, beyond which the corresponding data packet is discarded, can be set to comparatively higher values.
  • the comparison means for determining badly received data packets carry out a comparison between the parameters characteristic of the quality of the data packets and a first threshold value.
  • the means of comparison for determining Reliably received data packets carry out a comparison between the parameters characteristic of the quality of the data packets and a second threshold value, the second threshold value being smaller than the first threshold value.
  • the "unreliable frame” class is also introduced.
  • a rate for the unreliable frames (UFR, unreliable frame rate) and a residual error rate URBER for the unreliable frames can be defined.
  • the frame As soon as the error rate of a data packet exceeds the smaller, second threshold value, the frame is classified as unreliable. If the higher first threshold value is also exceeded, then it is also a bad framework that must be rejected in any case. With regard to the unreliable frames, it would be possible, for example, to either keep or discard these frames, depending on the current frequency of discarded frames. With the introduction of the additional class "unreliable frame", an even more uniform quality of data transmission can be achieved.
  • the transmission channel is a half rate channel and in particular a half rate voice channel.
  • data packets with 456 bits are used for full-rate channels, while data packets with 228 bits are provided for half-rate channels.
  • both the frame reject rate FER and the residual error probability RBER are checked particularly strictly here.
  • a voice frame is only distributed over two instead of four time slots. If such a speech frame is transmitted via a slowly changing transmission channel, then the quality requirements are increased when using the solution according to the invention. If namely the transmission of the speech frame completely within a time interval with bad Transmission conditions is made, then the probability of a frequent occurrence of transmission errors is very high.
  • the invention is particularly suitable for a low-effort implementation on an integrated circuit in a mobile radio receiver.
  • the method according to the invention for the detection of badly or unreliably transmitted data packets in a radio receiver in particular in a mobile radio receiver, it is first determined whether there is a rapidly changing or a slowly changing transmission channel. Then, depending on the determined type of transmission channel, threshold values for the required quality of the data packets are defined. A comparison of parameters characteristic of the quality of the decoded data packets with the defined threshold values is then carried out. Depending on the comparison result, the data packets are accepted, rejected or modified.
  • the threshold values for the required quality of the data packets are adapted depending on the type of the transmission channel.
  • the threshold values for slowly changing transmission channels are set to lower values than the threshold values for rapidly changing transmission channels.
  • the parameters characteristic of the quality of the decoded data packets, for example the metric are compared with the defined threshold values. If the threshold values are exceeded, the data packets are discarded.
  • FIG. 3 shows a plot of the frequency of occurrence of various metric values in the form of a histogram for a slowly changing channel and for a rapidly changing channel;
  • FIG. 4 shows a block diagram of the device according to the invention for the detection of poorly or unreliably transmitted data packets; such as
  • FIG. 5 shows a more detailed circuit diagram of the device according to the invention, from which in particular the mode of operation of the state machine also shown in FIG. 4 emerges.
  • the curve labeled TU3 relates to the transmission channel type "Typical Urban 3 km / h", that is, to a mobile radio station that is moved at a speed of approx. 3 km / h in an urban environment. A pedestrian who moves in an urban environment and thereby uses mobile phones sets up a transmission channel of this type with the base station.
  • the transmission channel type TU3 (without frequency hopping) is a slowly changing Chen transmission channel, because the transmission conditions change only comparatively slowly due to the slow walking speed of the pedestrian.
  • the transmission channel type "Static" in which the mobile radio subscriber does not move at all, is one of the slowly changing transmission channels.
  • the rapidly changing transmission channels include all transmission channels in which a frequency hopping method (FH: Frequency Hopping) is used.
  • FH Frequency Hopping
  • the transmission frequency is changed at short intervals on the transmitter and receiver side in accordance with a defined scheme, in order to improve the robustness of the transmission channel against various types of interference.
  • the TU3 transmission channel, Ideal FH is therefore one of the rapidly changing transmission channels due to the frequency hopping method used.
  • a frequency hopping method comparatively high speeds of the mobile radio subscriber can also result in the transmission channel changing rapidly. For this reason, the transmission channel types TU20, RA250 and HT100 are to be counted among the rapidly changing transmission channel types even if no frequency hopping method is used.
  • the transmission channel type TU20 (Typical Urban 20 km / h) refers to a participant who moves at a speed of approx. 20 km / h in an urban environment.
  • a cell phone subscriber who moves by car or train at up to 250 km / h in a rural environment is described by the RA250 (Rural Area 250 km / h) transmission channel type.
  • HT100 Hilly Terrain 100 km / h
  • HT100 Hilly Terrain 100 km / h
  • the metric plotted on the right axis in FIG. 1 indicates the number of errors determined for a specific data packet, which is obtained by bit-wise comparison of the Viterbi-decoded and subsequently encoded data stream with the original, encoded data stream. If the transmission conditions are bad during the transmission of a data packet, then the received data packet has a large number of bit errors after it has been decoded. This results in a high value of the metric or number of errors. The higher the metric value, the worse the quality of the received data. It can also be seen from FIG. 1 that the bit error rate determined for part of the transmitted bits, namely for bits of class Ib, increases monotonically with the metric or number of errors. The worse the transmission ratios are, the higher the metric value or the number of errors will be, and the higher the bit error rate for the bits of class Ib will be.
  • bit errors occur frequently with slowly changing data channels. If a relatively high metric value is determined for a certain data packet, it can be assumed that a large part of the transmitted bits of the data packet is incorrect. Therefore, in the case of slowly changing transmission channels, the bit error rate determined for a specific metric value is higher than the bit error rate determined for the same metric value in the case of a rapidly changing transmission channel.
  • a metric threshold is defined, this means that the metric or number of errors is determined for each received data packet and compared with the predefined metric threshold. Only data packets with a metric below the metric threshold are accepted. All data packets whose metrics exceed the metric threshold are discarded.
  • the residual bit error rate plotted in FIG. 2 as a function of the metric threshold therefore indicates the residual bit error rate of the accepted data packets, that is to say the residual bit error rate of the data packets whose metric lies below the metric threshold.
  • the residual error rate for the metric threshold with the value 30
  • all data packets are used whose metrics are below the metric threshold of 30.
  • all data packets with a metric of 30 or more are discarded.
  • the slowly changing transmission channels (TU3) have a significantly higher residual bit error rate than the rapidly changing transmission channels (TU20). The reasons for this had already been described in connection with FIG. 1.
  • TU 3 shows the frequency of the occurrence of certain metric values as a function of the metric for a rapidly changing channel (TU20) and for a slowly changing channel (TU3).
  • TU20 rapidly changing channel
  • TU3 slowly changing channel
  • the frequency of a zero metric is particularly high in the case of slowly changing channels.
  • the reason for this is that with slowly changing channels, good transmission conditions are often present during the entire time period required for the transmission of the data packet.
  • the metric is determined for each incoming data packet and a zero metric counter is incremented by one for each data packet with the metric zero.
  • a large number of data packets must be evaluated. It has proven useful to set the observation period for counting the zero metrics to a super frame which comprises 300 data packets.
  • the number of zero metrics determined in this way can then be compared with a predetermined zero metric limit value, which should be placed between the number of zero metrics expected for rapidly changing transmission channels and the number of zero metrics expected for slowly changing channels. If this zero metric limit is undershot, then there is a high probability that the transmission channel is changing rapidly. If, on the other hand, the zero metric limit value is exceeded, there is a high probability that the transmission channel is slowly changing. With the help of this criterion, after receiving approximately 300 data packets, it is clear which type of transmission channel is present.
  • the metric threshold for a slowly changing transmission channel must be set to a significantly lower value than the metric threshold for rapidly changing transmission channels (TU20).
  • the quality requirements for slowly changing transmission channels must be chosen more strictly than for rapidly changing transmission channels. If it is determined that there is a slow transmission channel (eg TU3), the metric threshold value will be set to a stricter, ie lower, value. On the other hand, if there is a rapidly changing transmission channel, the metric threshold is set to a higher value. Only data packets with a metric below the specified metric threshold are accepted. Data packets for which the determined metric exceeds the threshold value must be discarded and then possibly requested again.
  • FIG. 4 Detection of badly or unreliably transmitted data packets is shown in FIG. 4.
  • the stream of received data which, in addition to the interleaved, encoded bits 1, also includes additional information 2 on this data, is fed to a deinterleaver 3.
  • the deinterleaver 3 performs a permutation of the data symbols belonging to a specific data packet in order to bring them into the correct order for the subsequent decoding.
  • a stream of deinterleaved bits 4 and additional information 5 relating to this data can be tapped.
  • the incoming bits are divided by the demultiplexer 6 into the stream 7 of encoded class I bits, into the additional information 8 for the class I bits and into the stream 9 of class II bits. There is no additional information on the class II bits (10).
  • the class I bits are encoded data that must be decoded by the Viterbi decoder 11.
  • Class II bits are not encoded and are therefore not supplied to the Viterbi decoder 11.
  • Class II bits can be used directly.
  • the Viterbi decoder 11 decodes the incoming stream 7 of encoded bits of class I and thus generates a stream 12 of decoded bits of class I, as well as additional information 13 for this data.
  • the additional information 13 includes, for example, reliability values (soft outputs) for the individual decoded bits.
  • the stream 12 of decoded bits of class I and the additional information 13 are fed to the demultiplexer and checksum tester 14.
  • the demultiplexer From the stream 12 of decoded bits of class I, the demultiplexer generates two bit streams, namely the stream 15 of bits of class la and the stream 16 of bits of class Ib.
  • There is an error protection word for checking the data integrity for the bits of class la and in this respect the demultiplexer and checksum tester 14 can carry out a checksum test or CRC check (Cyclic Redundancy Check) for these bits of class la. If the checksum test reveals that the bits of class la have bit errors, then signal 17, which indicates a negative checksum test, is set to "1".
  • There is no error protection word for the bits of class Ib There is no error protection word for the bits of class Ib, and so the The data integrity of these bits cannot be checked using a checksum test.
  • the current 12 of decoded class I bits which can be tapped at the output of the Viterbi decoder 11 is fed to the convolutional encoder 18.
  • the convolutional encoder 18 generates a stream 19 of class I bits again convolutionally coded, which is present at the first input of the XOR gate 20.
  • the current 7 of encoded bits of class I which can be tapped off at the input of the Viterbi decoder 11 is present at the second input of the XOR gate 20.
  • a bit-wise comparison of the stream 7 of encoded bits and the stream 19 of again convolutionally encoded bits is carried out in the XOR gate 20.
  • the output 21 of the XOR gate 20 is connected to the input of the
  • Error counter 22 connected. Each time the value "1" appears at the output 21, the counter reading of the error counter 22 is incremented by one.
  • the error counter 22 can be used to record the number of bit errors occurring in a data packet, the so-called metric M 22 after a data packet has been transmitted, a frame pulse 23 is transmitted, which serves as a reset / readout pulse for the error counter 22. Each time a frame pulse 23 occurs, the counter reading of the error counter 22 is switched through as a metric value M to the output of the error counter 22. In addition, the count of the error counter 22 is reset to zero.
  • the state machine 24 is supplied with both the frame pulse 23 and the metric value M.
  • the state machine 24 determines the proportion of the data packets with the metric zero and thus determines whether there is a slowly changing or a rapidly changing transmission channel.
  • the state machine 24 sets the threshold value ⁇ B for the detection of bad frames and the threshold value ⁇ u for the detection of unreliable frames.
  • Both the metric value M and the threshold value ⁇ B are fed to the metric comparator 25.
  • the metric comparator 25 makes a comparison of M and ⁇ B and sets the comparison signal 26 for bad frames to “1 ⁇ if M> gilt B applies. In this case, the determined exceeds Metric or number of errors M the permissible threshold value ⁇ B , and the associated data frame must be rejected.
  • the bad frame comparison signal 26 is connected to an input of the OR gate 27.
  • Signal 17, which indicates a negative result of the checksum test, is present at the other input of OR gate 27. If at least one of the two signals 17 or 26 is at "1", then the BFI signal 28 (bad frame indication) which can be tapped at the output of the OR gate 27 also assumes the value "1".
  • the BFI signal 28 indicates that the data packet just received is a bad data packet that has to be discarded.
  • the state machine 24 also sets the threshold value ⁇ T for the detection of unreliable frames as a function of the type of transmission channel.
  • the state machine 24 supplies the threshold value ⁇ u to the metric comparator 29, which carries out a comparison of M and ⁇ u and sets the comparison signal 30 for unreliable frames to “1” when M> ⁇ u.
  • the comparator signal 30 is for unreliable frames therefore to "1" if the metric M of the data packet exceeds the threshold value ⁇ u.
  • the unreliable frame comparator signal 30 is supplied to the OR gate 31.
  • the BFI signal 28 is present at the second input of the OR gate 31, which assumes the value “1” when there is a bad data packet.
  • the UFI signal 32 that can be tapped at the output of the OR gate 31 takes the value "1” when there is a data packet classified as unreliable.
  • the UFI signal 32 assumes the value "1" when the comparator signal 30 for unreliable frames or the BFI signal 28 (or both signals) are set.
  • the BFI signal 28 has the value "1" because, for example, a negative result of the checksum test or CRC check is present, this automatically leads to the UFI signal 32 assuming the value "1".
  • every bad frame is also classified as an unreliable frame, while, conversely, not every unreliable frame also has to be a bad frame.
  • the mode of operation of the state machine 24 is to be illustrated below with reference to FIG. 5.
  • the state machine 24 is supplied with the metric values M determined for the various data packets.
  • the counter reading of the zero metric counter 35 is counted up by one during each data packet occurring with a metric 0 during a predetermined observation period of N data packets. At the end of the observation period, the counter reading of the zero metric counter 35 indicates the number Z of the zero metrics that occurred during the observation period.
  • the duration of the observation period is recorded with the aid of the frame counter 36, the counter reading of which is incremented by one with each frame pulse 23 that occurs.
  • This reset / readout pulse 38 is fed to the zero metric counter 35, which outputs the counter reading Z reached at the time of the occurrence of the reset / readout pulse at its output.
  • the reset / readout pulse 38 is also fed to the frame counter 36, where it causes the number F of the frames previously counted to be reset to zero.
  • the number Z of the zero metrics present at the end of the observation period is transmitted both to the zero metric comparator 39 for bad frames and to the zero metric comparator 40 for unreliable frames.
  • the comparator result i is present at the output of the zero metric comparator 39.
  • Z> ⁇ L that is, for the case of a slowly changing transmission channel
  • i assumes the value "1". If, on the other hand, Z ⁇ applies to the number Z of the zero metrics, then there is a rapidly changing transmission channel and the comparator result i takes the value "0".
  • the comparator result i is fed to the threshold value table 41.
  • ⁇ Bf0 and ⁇ B , ⁇ stored in the threshold value table 41 the following therefore applies: ⁇ B , 0 > ⁇ B , I - If the metric M exceeds the respective threshold value ⁇ B , ⁇ , the metric comparator 25 signals, that there is a bad framework.
  • a strictly rer threshold value 0,1 0.1 is selected than in the case of a rapidly changing transmission channel, so that u u, ⁇ ⁇ 0,0 0.0 applies.
  • the threshold value is fed to the metric comparator 29 for unreliable frames, which compares the metric M and the threshold value ⁇ , k . If M> ⁇ U (k applies, then the metric comparator 29 signals the presence of an unreliable frame.

Landscapes

  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Detection And Prevention Of Errors In Transmission (AREA)

Abstract

L'invention concerne un dispositif et un procédé servant à détecter des trames incorrectes ou non fiables dans un récepteur radio. Selon l'invention, les valeurs de seuil pour le nombre d'erreurs ou la métrique sont adaptées en fonction du type de voie de transmission. La qualité exigée pour des voies de transmission à variation lente est supérieure à celle exigée pour des voies de transmission à variation rapide. Le type de voie de transmission actuel peut être déduit de la proportion de paquets de données à métrique égale à zéro.
EP02754228A 2001-08-16 2002-06-18 Dispositif et procede pour le controle de qualite de paquets de donnees transmis par l'intermediaire d'une voie radio Withdrawn EP1417816A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10140114A DE10140114A1 (de) 2001-08-16 2001-08-16 Vorrichtung und Verfahren zur Qualitätsprüfung von über einen Funkkanal übertragenen Datenpaketen
DE10140114 2001-08-16
PCT/DE2002/002217 WO2003019887A1 (fr) 2001-08-16 2002-06-18 Dispositif et procede pour le controle de qualite de paquets de donnees transmis par l'intermediaire d'une voie radio

Publications (1)

Publication Number Publication Date
EP1417816A1 true EP1417816A1 (fr) 2004-05-12

Family

ID=7695562

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02754228A Withdrawn EP1417816A1 (fr) 2001-08-16 2002-06-18 Dispositif et procede pour le controle de qualite de paquets de donnees transmis par l'intermediaire d'une voie radio

Country Status (5)

Country Link
US (1) US20040157595A1 (fr)
EP (1) EP1417816A1 (fr)
CN (1) CN1543736A (fr)
DE (1) DE10140114A1 (fr)
WO (1) WO2003019887A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1330151C (zh) * 2003-04-04 2007-08-01 智邦科技股份有限公司 一种测量封包型网络传输的目标播放质量的方法
DE50302716D1 (de) * 2003-08-05 2006-05-11 Tektronix Int Sales Gmbh Verfahren und Vorrichtung zum Ermitteln mindestens eines Übertragungsparameters in einem Übertragungssystem
JP4417733B2 (ja) * 2004-01-15 2010-02-17 ソニー・エリクソン・モバイルコミュニケーションズ株式会社 伝送方法及び装置
US20070086550A1 (en) * 2005-10-18 2007-04-19 Matsushita Electric Industrial Co., Ltd. Receiving apparatus, mobile communication terminal, and communication system
US20070183330A1 (en) * 2006-02-08 2007-08-09 Metin Salt Methods, systems, and apparatus for reducing real time data traffic in a multi-layer network
FI20065699A0 (fi) * 2006-11-06 2006-11-06 Nokia Corp HARQ-vastaanotto moniradiolaitteessa
JP5573053B2 (ja) * 2009-09-04 2014-08-20 ソニー株式会社 無線通信装置および無線通信方法
US8543891B2 (en) * 2011-09-21 2013-09-24 Apple Inc. Power-optimized decoding of linear codes
JP2018113630A (ja) * 2017-01-13 2018-07-19 富士ゼロックス株式会社 中継装置、エラー情報管理システムおよびプログラム

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4521886A (en) * 1983-07-08 1985-06-04 At&T Bell Laboratories Quasi-soft decision decoder for convolutional self-orthogonal codes
US6092230A (en) * 1993-09-15 2000-07-18 Motorola, Inc. Method and apparatus for detecting bad frames of information in a communication system
US6004028A (en) * 1994-08-18 1999-12-21 Ericsson Ge Mobile Communications Inc. Device and method for receiving and reconstructing signals with improved perceived signal quality
GB2306866B (en) * 1995-10-26 1998-08-05 Bosch Gmbh Robert Method of obtaining information about the residual errors in a transmitted channel-decoded digital signal
US5815507A (en) * 1996-04-15 1998-09-29 Motorola, Inc. Error detector circuit for digital receiver using variable threshold based on signal quality
US6578162B1 (en) * 1999-01-20 2003-06-10 Skyworks Solutions, Inc. Error recovery method and apparatus for ADPCM encoded speech

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
None *
See also references of WO03019887A1 *

Also Published As

Publication number Publication date
CN1543736A (zh) 2004-11-03
US20040157595A1 (en) 2004-08-12
WO2003019887A1 (fr) 2003-03-06
DE10140114A1 (de) 2003-03-13

Similar Documents

Publication Publication Date Title
DE60311593T2 (de) System und Verfahren zur Erkennung von Sprach und DTX Moden
EP1121762B1 (fr) Procede et dispositif de codage ou de decodage
DE60017867T2 (de) Detektionsgerät und -verfahren für datenrate in einer mobilen kommunikationsanordnung
EP0090210A1 (fr) Système pour l'installation automatique d'une communication par ondes courtes à signaux télégraphiques
EP1005734B1 (fr) Procede pour la transmission de donnees dans un systeme de transmission numerique en service de commutation de paquets
EP1198913A1 (fr) Procede pour empecher les erreurs dans un train de bits d'information
EP0659002A1 (fr) Méthode et circuit pour la transmission des signaux vocaux
EP1629632B1 (fr) Procédé et appareil de controle permettant de determiner un taux d'erreur
WO2003019887A1 (fr) Dispositif et procede pour le controle de qualite de paquets de donnees transmis par l'intermediaire d'une voie radio
DE10297176T5 (de) Verfahren und Anordnungen in ein Digital-Kommunikationssystem betreffenden Anwendungen
DE60120158T2 (de) Detektor für hörbare fehler und steuerung unter verwendung der kanalqualität und der iterativen synthese
DE602004009092T2 (de) Indikator für falsche rahmen in einem gsm-mobilsystem
DE69825274T2 (de) Bitdetektionsverfahren in einem funkkommunikationssystem
EP0946015A1 (fr) Procédé et dispositif d'estimation de la qualité de transmission
DE60035099T2 (de) Verfahren zur bestimmung der rahmenfrequenz eines datenrahmens in einem kommunikationssystem
EP1142185B1 (fr) Procede et systeme pour le codage de canaux ou le decodage d'informations a structure de trame
EP1252716B1 (fr) Procede et systeme pour le decodage d'informations
EP1046254A1 (fr) Procede et dispositif pour le codage, le decodage et la transmission de donnees, par decodage de voie a commande source
DE19844702C2 (de) Verfahren, Empfangseinrichtung und Funkstation zur Erkennung eines Nutzdatenblocks mit fehlerhaften Nutzdatensymbolen
EP1512242A1 (fr) Pointillage identique pour donnees d'identification d'equipement utilisateur et pour donnees utiles de canal hs-scch
DE10339832A1 (de) Verfahren zum verbesserten Erkennen der Gültigkeit von IEEE 802.11a Signalen sowie Schaltungsanordnung zur Durchführung des Verfahrens
EP0542065B1 (fr) Procédé de décodage de signaux binaires
WO2003094416A1 (fr) Procede et dispositif de gestion d'une memoire destinee a la memorisation temporaire de blocs de donnees dans le cas de systemes de transmission arq
DE102004057194A1 (de) Verfahren und Vorrichtung zur Feststellung der Zuverlässigkeit eines Flagwerts
WO2009095001A2 (fr) Procédé et dispositif d'évaluation de paramètres de canaux

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20040119

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

AX Request for extension of the european patent

Extension state: AL LT LV MK RO SI

17Q First examination report despatched

Effective date: 20040527

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RBV Designated contracting states (corrected)

Designated state(s): DE DK FI FR GB IT

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20070630