Be used to select whether to refuse the Apparatus and method for of the data segment that receives at the communication station place
Technical field
Present invention relates in general to a kind ofly be used for determining that refusal still is the method that is received in the data of the data segment that communication station place (for example mobile radio station with EDGE ability of GPRS/EDGE cellular communication system) receives.More specifically, the present invention relates to a kind of equipment and correlation technique, be used for determining the content of this data segment is refused as invalid content in response to the measurement to the BER (bit error rate) of the header portion of data segment, the content of still accepting this data segment is effective content.
If the header portion that carries out the FEC protection by forward error correction (FEC) coding presents the BER than selected threshold difference, think that then this data segment is invalid and it is abandoned.Only utilize data segment payload CRC (cyclic redundancy code) to analyze to determine whether that to accept data segment be that the traditional scheme of valid data section tends to pass through mistakenly CRC check.The BER of the header portion by the measurement data section, and use this to measure the content that determines whether this data segment and refuse, thereby avoided because the data segment of accepting mistakenly that the CRC check of the wrong payload portions of passing through data segment causes is the valid data section as invalid content.
Background technology
Digital communication technology is widely used in the communication system of number of different types.Compare with using traditional analog communication techniques, the use of digital communication technology allows to communicate by letter with the efficiency in data of significant data throughput and Geng Gao more usually.The information translation that will transmit or be provided as digital form.Typically, come data are formatd according to all known standardized format scheme of the receiving station of the dispatching station of data initiation place and data termination.Dispatching station and receiving station by transmit data based on communication channel interconnect.In radio communications system, limit communication channel based on the radio link that between communication station, extends at least in part.
In actual communication systems, communication channel is incomplete.That is to say that during the data based on communication channel transmitted, data are distortion sometimes.When the receiving station place received data, the information content of these data was distortions.If distortion is comparatively serious, then can't recover the information content of these data.
The various schemes of the method that is used to provide method that distortion that data are introduced corrects or this distortion is compensated have been developed.The digital coding that being used to before data transmit improved data redudancy is a kind of scheme of such type.In addition, also use sending of sequence to determine whether the data that receive at the receiving station place to have been carried out abundant decoding sometimes to known value or value.
A kind of exemplary digital cellular communication system, i.e. GPRS/EDGE (GPRS/enhanced data-rates GSM evolution) cellular communication system is according to the realization of EDGE communication service and transmit coded data between dispatching station and receiving station.The data that dispatching station will be formatted as radio block are sent to receiving station.Radio block comprises header portion and payload portions.In addition, the header portion of radio block comprises the CRC (cyclic redundancy code) of 12 bits, and is subjected to the FEC protection alternatively.The header portion of radio block comprises the CRC of 8 bits, and compares with payload portions and to be subjected to stronger FEC (forward error correction) protection.The CRC of the payload portions of radio block is used for determining whether payload portions is correctly decoded.Yet,, determine possible errors that also this payload portions is correctly decoded even sometimes when payload portions is decoded improperly.That is to say, made wrong determining.Utilize the CRC of 12 bit lengths, CRC check may appear once passing through mistakenly in random data block in per 4,096 times.In tediously long transfer of data, may receive tens thousand of radio blocks.Under relatively poor signal conditioning, the bad radio block of minority will be by CRC check, and is accepted as the valid wireless piece mistakenly.
When data are accepted as valid data, these data are passed to higher logical layer to form the part of data block, i.e. PDU (Packet Data Unit).Typically, the data block of higher level is made of the radio block of many lower levels.If relatively poor (promptly bad) radio block has constituted the part of higher layer data block, then the data block of this higher level becomes bad piece.When detecting bad piece, will cause taking place in succession complete re-transmission, thereby cause serious time delay and many unnecessary retransmission all radio blocks of this higher layer data block.In addition, the retry of higher level is based on overtime sometimes.The bad piece at higher level place is blocking data stream further, ends the also re-transmission of trigger data piece up to timer.The data flow that gets clogged has caused relatively poor data throughput.
Therefore, a kind of method that can guarantee bad radio block not to be accepted as mistakenly effective radio block preferably will be useful.
According to transmitting relevant background technology, developed important improvement of the present invention with the data of using digital communication technology.
Summary of the invention
Therefore, the present invention provides a kind of equipment and correlation technique valuably, be used for determining the data of refusal in the data segment that communication station (for example mobile radio station with EDGE ability of GPRS/EDGE cellular communication system) locates to receive, still these data accepted as valid data.
By the operation of embodiments of the invention, a kind of method is provided, utilize this method, in response to the measurement to the BER (bit error rate) of the header portion of data segment, the content of determining to accept this data segment is effective content, still refuses the content of this data segment.
In one aspect of the invention, if determine to demonstrate BER than selected threshold difference by the header portion that forward error correction (FEC) coding is subjected to the data segment that FEC protects, then refuse this data segment, promptly not accepting this data segment is valid data.This data segment comprises header portion and payload portions.For example, header portion and payload portions are protected by FEC all, and compare with payload portions, and header portion is subjected to stronger FEC protection.
In another aspect of this invention, when receiving data segment, the bit error rate measuring appliance is measured the bit error rate of the header portion of this data segment.In typical communication scenes, receive lot of data section, radio block continuously.In this scene, the bit error rate measuring appliance is measured the bit error rate of each data segment that receives at the communication station place.In other is realized, constituted other quality status stamp by the header portion of data segment and measured.
In another aspect of this invention, when the bit error rate measuring appliance has been measured the bit error rate of header portion of data segment, this bit error rate and threshold value are compared.If this bit error rate than threshold difference, is then refused this data segment as the invalid data section.That is to say, if the BER of the header portion of data segment, then makes the conclusion that the payload portions of this data segment correspondingly has relatively poor quality than threshold difference.Correspondingly the refusal have poor quality data segment.The refusal of this data segment got rid of by other mechanism come mistakenly to determine the effective possibility of this data segment.
In another aspect of this invention, the threshold value that is used for comparing with measured bit error rate is optional.That is to say that this threshold value is the set point value that is selected from a plurality of different threshold values.Based on selection, partly determine whether independently and data segment should be refused as invalid data threshold value.In one implementation, come data segment is encoded according to the selected encoding scheme in a plurality of encoding schemes.Different encoding schemes has different coding parameters.For example, to the selection of threshold value in response to the encoding scheme that is used for the data of data segment are encoded.In the process of the typical scene that transmits a plurality of data segments continuously, if be used for the encoding scheme that data segment is encoded has been changed, the threshold value that then is used to compare can correspondingly change.
In another aspect of this invention, measure at the bit error rate measuring appliance before the bit error rate of header portion, at first carry out CRC check based on the payload portions of data segment.If passed through the CRC check to the payload portions of data segment, then the bit error rate measuring appliance is measured the bit error rate of the header portion of this data segment.In addition, measured bit error rate and threshold value are compared, determining to accept this data segment is the valid data section, still refuses this data segment.Therefore, in order to be accepted as the valid data section, this data segment must be by measuring test based on the CRC check of payload portions and based on the bit error rate of the header portion of this data segment.Owing to data segment is accepted as mistakenly the valid data section and can't causes the most at last that this data segment is accepted as the valid data section by what CRC check caused mistakenly, this be because to carry out also that bit error rate is measured and with the comparison of threshold value.When having passed through CRC check, only be to accept this data segment conditionally.In order to be accepted as the valid data section, this data segment also must pass through the bit error rate of the header portion of this data segment is measured test.Alternatively, at first carry out BER and measure, to determine whether BER is better than threshold value.If be better than threshold value, then carry out CRC check based on payload portions.
In another aspect of this invention, radio block is made of header portion and payload portions.Header portion and payload portions all are protected by FEC and CRC.Yet, to compare with payload segment, header portion has been subjected to stronger FEC protection.Because to the stronger FEC protection of header portion,, the BER of header portion measured still keep reliable even the distortion of payload portions makes the CRC check of payload portions become unreliable.For example, except based on the performed CRC check of payload portions, as additional verification, the BER measurement is based on that the header portion of radio block carries out.
In another aspect of this invention, when accepting data segment and be the valid data section, this data segment is passed to higher logical layer, and these data (being payload segment) are used for the part of composition data piece, for example PDU (Packet Data Unit).The bit error rate of the header portion by determining low logical layer is better than threshold value, comprises that the data block of higher level of the data of the data segment that is transmitted can not comprise bad data.Thereby caused improved communication performance.
Therefore, aspect these and other, it is the equipment and the correlation technique of valid data section that a kind of data segment that is used to select whether to accept to be received is provided.This data segment has header portion and payload portions.The header portion error meter is applicable to the header portion of analyzing data segment.The configuration of header portion error meter is used to measure the bit error rate of header portion.It is the valid data section that the configuration of data segment recipient is used for selectively accepting data segment in response to the bit error rate of the measured header portion of header portion error meter at least in part.
Description of drawings
Fig. 1 shows the functional block diagram that embodiments of the invention can operate in radio communications system wherein;
Fig. 2 shows the procedure chart of the operating process of expression embodiments of the invention;
Fig. 3 shows the method flow diagram of the method for operation of expression embodiments of the invention.
Embodiment
Therefore, at first with reference to Fig. 1, provide with the communication system shown in 10 generally and mobile radio station that mobile radio station 12 is represented between radio communication.
Executive communication between mobile radio station and network portion (representing by radio access network (RAN) 14 here).By realize communication by line segment 16 represented radio air interfaces, the data of network being initiated based on this interface are sent to mobile radio station 12, and will move the communication equipment that the data of initiation are sent to radio access network and are coupled to this radio access network by this radio air interfaces.Radio access network is coupled to external network (being expressed as packet data network (PDN) 18 here).Communication equipment (for example communication equipment 22) is positioned at and the communicating to connect of this packet data network.This communication equipment represents to be used for the communication end point that communicates according to communication session and mobile radio station 12.
In exemplary realization, the radio portion of this communication system is drawn together GSM/GPRS/EDGE (global mobile communication system/general grouping wireless service/enhanced data-rates GSM evolution) cellular communication system that high speed data communication services is provided.More specifically, the wireless part of communication system divides any one in the plurality of communication systems that the communication of expression by data segment provides data service.In exemplary realization, sometimes this data segment is called the EDGE radio block, each radio block is made of header portion and payload portions.Therefore, though following explanation will be described the exemplary operation about the exemplary realization of cellular communication system that the EDGE communication service is provided, instruction of the present invention also can be applied to the communication system of other type similarly.In addition, downlink communication has been described.Uplink communication is similarly, though and do not illustrate respectively, be similar exercisable in the operation of the entity of the Network Dept. office of system 10.
Mobile radio station comprises transceiver circuit, here by receiving (Rx) part 26 and launching (Tx) part 28 and represent this transceiver circuit.Receive the data that are sent to mobile radio station in this acceptance division office, and assign to launch the data that transmit by mobile radio station by emission part.When mobile radio station is used in the realization of foundation data communication service, receive radio block (being data segment) at the mobile radio station place.Owing to fade condition, noise, receiver front end distortion and make other distortion reason of value distortion of data segment, the value of the data segment of mobile radio station place operation when sending analog value and difference.If mobile radio station can not or retransmit by its correction and compensate this distortion, then will produce communication issue.As mentioned previously, when carrying out CRC (cyclic redundancy code) analysis, exist wrong radio block to be accepted as the possibility of effective radio block.When the data block that will be received as the valid data piece is passed to higher logical layer, the communication issue that passes through to have caused higher level to the wrong data block of accepting of quilt, and in the time that the data block that constitutes by many radio blocks must be retransmitted, may cause serious communication delay.
According to the operation of embodiments of the invention, mobile radio station 12 also comprises generally the equipment with the embodiments of the invention shown in 36.Equipment 36 is made of the functional entity that can realize in the mode (for example by the executable algorithm of treatment circuit) of any desired.For example, the controller that the performed function of the entity of this equipment can also be by mobile radio station or locate at an arbitrary position to realize as the part of the transceiver circuit of mobile radio station.
Here, this equipment comprises payload portions error meter 38, header portion error meter 42, comparator 44, threshold value selector 46 and data segment recipient 48.
In Fig. 1, also data segment 52 (being radio block) is illustrated with its header portion 54 and payload portions 56.When receiving data segment at the mobile radio station place, receiving unit detects its transmission at this mobile radio station place.In addition, provide the indication to this data segment (here by line 61 expressions) to the payload portions error meter.In this exemplary realization, the payload portions error meter comprises and is used for CRC check device that the CRC that payload portions comprised that receives data segment is carried out verification.If CRC check is qualified, promptly passed through CRC check, then provide the indication that CRC check is passed through (here by line 64 expressions) to header portion error meter 42.Also will offer the header portion error meter by the indication that line 62 is provided to detecting data segment.The operation of this error meter is used to measure the bit error rate of the header portion of the radio block that provides to this error meter.In addition, provide indication on online 72 to measurement result.In this exemplary realization, the header portion error meter is only just operated when the payload portions error meter provides successfully indication by CRC check.
At the comparator place will by the measured bit error rate value of header portion error meter 42 be expressed as the threshold value that is provided by line 76 here and compare.In this exemplary realization, this threshold value is can be by the optional value of threshold value selector 46 selections.Here offer data segment recipient 48 by line 82 comparative result that comparator is performed.。Whether the data segment recipient is selected to accept by line 62 is the valid data section to its data segment that provides.If this data segment is accepted as the valid data section, then transmit this data segment, here by line 84 expressions.If comparative result indicates the bit error rate of header portion of this data segment than the selected threshold difference that applies on online 76, then not accept this data segment be the valid data section to the data segment recipient, on the contrary, use the refusal that is produced on online 66 to indicate and refuse this data segment.Here, line 66 extends to the radiating portion of mobile radio station, should refuse indication herein and return network, so that the data segment that request retransmission is refused.Owing to error is detected at lower logical layer place, therefore this error is proofreaied and correct apace, and do not have possibility with only delay that the detected error in higher logical-layer place is associated (when the whole group of radio block that will constitute by data segment be combined to Packet Data Unit or other data block of constituting by a plurality of data segments similarly in the time).In alternative embodiment, before the CRC check performed based on payload portions, the BER that carries out header portion measures and analyzes.
In this exemplary realization, carry out the operation that is used for threshold value selector that the threshold value that is applied to comparator 44 by line 76 is selected in response to the input that is applied to the threshold value selector by line 92.Line 92 has been indicated the coding grade of the data segment that detects in the receiving unit place of mobile radio station.Encoding scheme in the communication session that the EDGE data are provided is one of nine coding grades that are designated as MCS-1 to MCS-9.In response to employed encoding scheme, the threshold value that the selection of threshold value selector will be used in response to this encoding scheme.Therefore, the selected threshold value of this selector is also correspondingly partly depended in the operation of comparative result and recipient 48.
Fig. 2 shows generally the procedure chart with the operating process of the expression embodiments of the invention of 102 expressions.This process is with detection (by the frame 106 indications) beginning (by 104 indications of beginning frame) to the data segment such as the EDGE piece.
Carry out CRC check (shown in frame 108) based on the payload portions of the data segment that is detected.Determine then whether the payload portions of this data segment has passed through CRC check (shown in judgement frame 112).If no, then adopt "No" branch, and refuse this data segment (shown in frame 114).On the contrary, if passed through CRC check, then adopt "Yes" branch.Passing through of CRC check only is acceptance with good conditionsi to this data segment."Yes" branch extends to frame 116, and carries out the bit error rate of the header portion of the data segment that receives is measured.Then, shown in frame 118, between measured bit error rate and selected threshold value, compare.Determine that then comparative result indication bit error rate is to be better than or to be worse than selected threshold value (shown in judgement frame 122).If be worse than selected threshold value, then adopt and lead to the refusal branch of refusing frame 114.Otherwise, accept branch if adopt, then accepting this data segment is the valid data section, and this data segment is forwarded to higher logical layer (shown in frame 126).When data segment was passed to higher logical layer, this data segment became the part of bigger data block, for example Packet Data Unit.
Fig. 3 shows generally with method flow diagram 132 expressions, that represent the methods of operation of embodiments of the invention.The data segment that this method helps selecting whether to accept to be received is the valid data section.This data segment has header portion and payload portions.
At first, shown in frame 134, measure the bit error rate of the header portion of this data segment.Then, shown in frame 136, determine whether the bit error rate of this header portion is better than the first selected threshold value.
Thereafter, shown in frame 138, be better than the definite of the first selected threshold value in response to the bit error rate to this header portion at least in part, this data segment is effective.
Therefore, providing a kind of is used for based on the method for the measurement of the bit error rate of the header portion of data segment being determined the validity of this data segment.By additional (or alternative) analysis to the bit error rate of header portion, traditional scheme to the analysis that only utilizes the CRC that is comprised in the payload portions to data segment has carried out replenishing or improving, and this traditional scheme tends to mistakenly this data segment is accepted as the valid data section.Reduced and the data in the bad data segment have been accepted relevant problem as the mistake of valid data.