Capture indication detection method and mobile terminal
Technical Field
The present invention relates to the field of channel indication detection technologies, and in particular, to a capture indication detection method and a mobile terminal.
Background
In the prior art, in a WCDMA communication system, the process of random access of a mobile terminal generally includes:
the mobile terminal transmits a corresponding access prefix to the base station to request access to a corresponding channel. The access prefixes of different mobile terminals are identified through signatures of the access prefixes;
and after receiving the access prefix sent by the mobile terminal, the base station analyzes the signature and allocates corresponding network resources. The base station notifies the mobile terminal of the corresponding network resource allocation situation in a manner of issuing an Acquisition Indicator (AI) to the mobile terminal. The mobile terminal obtains corresponding network resource allocation by analyzing the signature of the AI signal and accesses a corresponding channel according to the allocated network resource.
Accordingly, in the prior art, the base station may issue an Extended Acquisition Indicator (EAI) to the mobile terminal, and the mobile terminal also obtains some additional channel configuration information included in the EAI by parsing a signature of the EAI, and further configures and accesses the channel according to the information.
In the prior art, the de-signature of the AI signal and the EAI signal at the mobile terminal side is usually a relatively complex operation process, and the adulteration of the AI signal affects the de-signature of the EAI signal, thereby affecting the final decision and configuration result.
Disclosure of Invention
According to the problems in the prior art, the technical scheme of the capture indication detection method and the mobile terminal is provided, and aims to reduce the interference during capture indication detection, increase the calculation speed of signature decoding and reduce the detection misjudgment rate;
the technical scheme specifically comprises the following steps:
a capture indication detection method is suitable for a mobile terminal; the mobile terminal sends an access prefix to a base station and receives a corresponding multipath transmission signal sent by the base station, wherein the transmission signal comprises a corresponding acquisition indication signal;
the capture indication detection method specifically comprises the following steps:
step S1, receiving the transmission signal, and performing a de-signature on the capture indication signal to output a corresponding first de-signature value;
step S2, determining whether the first de-signature value is smaller than a first threshold value;
if the first de-signature value is smaller than the first threshold value, go to step S6;
step S3, performing a de-signature on the extended acquisition indicator signal corresponding to the acquisition indicator signal to output a corresponding second de-signature value;
step S4, determining whether the sum of the second de-signature value and the corresponding first de-signature value is smaller than a second threshold;
if the sum of the first de-signature value and the second de-signature value is smaller than the second threshold value, the process goes to step S6;
step S5, calculating the channel resource configured to the mobile terminal according to the extended acquisition indication signal, and then quitting;
step S6, deciding the acquisition indication signal as indicating discontinuous reception, and then exiting.
Preferably, the acquisition indication detecting method, wherein the transmission signal received by the mobile terminal is represented by the following formula:
wherein,
rp,j,crepresenting said transmitted signal received on the p-th path at the c-th chip corresponding to the j-th complex symbol;
hp,jcomplex channel coefficients representing a jth symbol received on a pth path;
Ccrepresenting the corresponding spreading code on the c chip;
Sj,crepresents a random number on the c-th chip corresponding to the j-th symbol;
earepresenting a transmit power of an acquisition indicator signal;
AIarepresenting information carried on an a-th signature sequence of the acquisition indicator signal;
ba,2jrepresents the 2j element on the a signature sequence;
ba,2j+1represents the 2j +1 th element on the a signature sequence;
ωp,j,cinterference noise representing a transmission signal on a c-th chip of a j-th symbol received on a p-th path;
in step S1, the capture indication signal is de-signed according to the following formula:
wherein,
u1 represents the first de-signed value resulting from de-signing the acquisition indicator signal;
l represents the total number of paths of the received multipath signal;
the results of (a) follow a normal distribution.
Preferably, in the capture indication detection method, in step S3, the extended capture indication signal is de-signed according to the following formula:
wherein,
u2arepresenting a decision statistic obtained by de-signing the extended acquisition indication signal;
and judging the position of the second de-signature value on the signature sequence of the extended acquisition signal according to a plurality of judgment statistics obtained by de-signature by the following formula:
wherein,
argmax represents the maximum comparison operation;
and taking the judgment statistic obtained through maximum value comparison operation as the finally output second de-signature value.
Preferably, in the capture indication detection method, in step S3, the first de-signature value output by de-signature is removed from the transmission signal.
Preferably, in the capture indication detecting method, in step S1, if the first de-signature value is greater than the first threshold value, before step S3, the following steps are first performed:
step S21, determining the sign corresponding to the first de-signed value:
if the sign corresponding to the first de-signature value is positive, judging that positive confirmation is indicated, and exiting;
if the sign corresponding to the first de-signature value is negative, go to step S22;
step S22, determining whether the access prefix corresponding to the transmission signal corresponds to a physical random access channel;
if the access prefix corresponds to the physical random access channel, go to step S24;
step S23, determining whether the extended acquisition indicator signal corresponding to the acquisition indicator signal is configured in the transmission signal;
if the extended acquisition indicator corresponding to the acquisition indicator is configured in the transmission signal, go to step S3;
step S24, deciding the acquisition indicator signal as indicating negative acknowledgement, and then exiting.
Preferably, in the capture instruction detection method, the step S3 specifically includes:
step S31, de-signing the extended acquisition indicator signal to output a corresponding plurality of decision statistics;
step S32, judging the position of the second de-signature value on the signature sequence of the extended capture indication signal according to the judgment statistic;
step S33, outputting the finally obtained second de-signed value, and then proceeding to the step S4.
Preferably, in the capture instruction detection method, in step S32, a maximum value of absolute values of a plurality of the decision statistics is found, and the decision statistic corresponding to the maximum value is output as the second de-signature value.
Preferably, in the acquisition indication detection method, in step S31, the sign of each decision statistic is calculated while the extended acquisition indication signal is being de-signed;
in step S5, the polarity of the extended acquisition indicator signal is set according to the symbol of the decision statistic corresponding to the second de-signature value, and the channel resource of the mobile terminal is calculated according to the signature index of the extended acquisition indicator signal and the corresponding polarity.
Preferably, in the acquisition indication detecting method, in step S1, a rake receiver is used to receive the transmission signal, so as to obtain the acquisition indication signal and the spread acquisition indication signal included in the transmission signal.
Preferably, in the capture indication detecting method, in step S1, a rake receiver is used to receive the transmission signal issued by the base station through the space-time transmit diversity technique, and perform corresponding space-time transmit diversity decoding on the received transmission signal, so as to obtain the transmission signal subjected to decoding processing.
Preferably, the acquisition indication detection method is applied to a WCDMA communication system.
A mobile terminal adopts the capture indication detection method.
The beneficial effects of the above technical scheme are:
1) before de-signing the extended acquisition indication signal, removing the acquisition indication signal in the transmission signal to reduce the interference generated to de-signing;
2) the signature decoding process is completed through a solidified fast algorithm, the calculation speed is accelerated, and the calculation efficiency is improved;
3) when the extended capture indicating signal is detected, judgment is carried out by combining the capture indicating signal, and the misjudgment rate of detection is reduced.
Drawings
FIGS. 1-3 are schematic flow charts of a capture indication detection method according to a preferred embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating a structure of a mobile terminal receiving signals according to a preferred embodiment of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
In the prior art, when a mobile terminal side de-signs an AI signal or an EAI signal corresponding to an access prefix returned to the mobile terminal by a base station, the computation process of de-signing the AI signal and the EAI signal is complex, and meanwhile, an AI reconstruction signal is prone to cause inaccurate de-signing results of the EAI signal, so that the misjudgment rate of de-signing is increased.
In view of the above problems, in a preferred embodiment of the present invention, a method for detecting an acquisition indicator is provided, and a general flow of the method is shown in fig. 1, which specifically includes:
step S1, receiving the transmission signal, and performing a de-signature on the capture indication signal to output a corresponding first de-signature value;
in the preferred embodiment of the present invention, before step S1, the mobile terminal first sends an access prefix to the base station to request access to a certain channel. In a preferred embodiment of the present invention, the Access prefix sent by the mobile terminal to the base station may correspond to a request for accessing a Physical Random Access Channel (PRACH), or correspond to a request for accessing an Enhanced Dedicated Channel (E-DCH).
In a preferred embodiment of the present invention, after receiving the access prefix, the base station allocates corresponding network resources according to the signature carried by the access prefix, and returns a corresponding acquisition indicator signal (AI signal) and an extended acquisition indicator signal (EAI signal) to the mobile terminal.
In a preferred embodiment of the present invention, the AI signal is carried in the transmission signal received by the mobile terminal, and in some cases, the AI signal and the corresponding EAI signal are carried in the transmission signal received by the mobile terminal. The mobile terminal may obtain a corresponding decision result by de-signing the AI signal (or the AI signal and the EAI signal), and configure the network resource of the access channel according to the decision result.
In the preferred embodiment of the present invention, in step S1, the corresponding AI signal is obtained from the transmission signal received by the mobile terminal, and then the AI signal is determined.
In the preferred embodiment of the present invention, there is usually multipath transmission between the base station and the mobile terminal, so the transmission signal returned from the base station to the mobile terminal can be a multipath signal. In particular, in a preferred embodiment of the present invention, the mobile terminal receives a multipath transmission signal returned by the base station using a Rake receiver. The so-called rake receiver is a final receiver that can separate multipath signals and efficiently combine the multipath signal energies.
Therefore, in the preferred embodiment of the present invention, the multipath transmission signal returned by the base station and received by the mobile terminal using the rake receiver can be represented by the following formula:
wherein,
rp,j,crepresenting a transmission signal on a c chip corresponding to a j complex symbol received on a p path;
hp,jcomplex channel coefficients representing a jth symbol received on a pth path;
Ccrepresenting the corresponding spreading code on the c chip;
Sj,crepresents a random number on the c-th chip corresponding to the j-th symbol;
earepresenting a transmit power of an acquisition indicator signal;
AIarepresenting the information carried on the a-th signature sequence of the AI signal;
ba,2jrepresents the 2j element on the a signature sequence;
ba,2j+1represents the 2j +1 th element on the a signature sequence;
ωp,j,crepresenting the interference noise of the transmitted signal on the c-th chip of the jth symbol received on the p-th path. In a preferred embodiment of the present invention, the interference noise of the transmission signal generally includes inter-path interference, inter-user interference, and background noise, and the interference noise described in the above formula (1) is actually a noise value obtained by integrating all the above noise conditions.
In a preferred embodiment of the present invention, the de-signature for the AI signal in the multipath transmission signal can be performed according to the following formula:
wherein,
u1 denotes a first de-signed value, i.e. AI, obtained by de-signing the acquisition indicator signalaA corresponding first de-signed value.
In a preferred embodiment of the present invention, for convenience of the following description, equation (2) is modified to be expressed as follows:
u1=k*AIa+ω' (3)
wherein,
then ω' ∈ N (0, δ)2) I.e. ω' follows a normal distribution;
in other words,the results of (a) follow a normal distribution.
In the preferred embodiment of the present invention, the system can explicitly inform the mobile terminal that the AI signal is carried on the fourth signature sequence when the AI signal is issued, i.e. explicitly inform the mobile terminal of the location of the AI signal. Therefore, in the de-signing process, the signature sequence carrying the corresponding AI signal information is de-signed, and a corresponding first de-signed value is obtained and output
In a preferred embodiment of the present invention, if the base station applies a space-time transmit diversity technique when sending a transmission signal to the mobile terminal through an Acquisition Indicator Channel (AICH), that is, when sending the transmission signal, the mobile terminal performs corresponding space-time transmit diversity coding, and when receiving the transmission signal, the mobile terminal needs to perform corresponding space-time transmit diversity decoding on the transmission signal. The specific signal receiving structure is shown in fig. 4: the mobile terminal receives the multipath transmission signal by using the rake receiver a1, combines the multipath energy and sends the combined multipath energy to the space-time transmit diversity decoding unit a 2. The space-time transmit diversity decoding unit a2 decodes the transmission signal, and then performs the subsequent de-signature and decision process a 3.
Therefore, in the preferred embodiment of the present invention, when the space-time transmit diversity technique is used to realize signal transmission, only one space-time transmit diversity decoding process needs to be added on the mobile terminal side, and other processes are the same as those when the non-space-time transmit diversity technique is used to transmit signals in the present invention.
In the preferred embodiment of the present invention, the prior art may include various technical solutions for implementing space-time diversity transmit coding and transmitting on a transmission signal and implementing corresponding space-time transmit diversity decoding on the transmission signal, and the important point in the technical solution of the present invention is not how to perform space-time transmit diversity transmission and how to perform corresponding space-time transmit diversity decoding on the transmission signal, so the above-mentioned processes are not described in detail, and the implementation manner of the above-mentioned processes is not limited in the present invention.
Step S2, determining whether the first de-signature value is smaller than a first threshold value;
if the first de-signature value is smaller than the first threshold value, go to step S6;
in the preferred embodiment of the present invention, the AI signal is first de-signed and a decision is made:
if the first de-signature value u1 obtained by de-signing the AI signal is smaller than a preset first threshold value, the current AI signal is directly determined to indicate Discontinuous reception (DTX), as shown in step S6. At this time, the mobile terminal waits for the next transmission signal returned from the base station regardless of the currently received transmission signal.
If the first de-signature value u1 obtained by de-signing the AI signal is not less than the preset first threshold value, go to step S3 and make a subsequent decision.
Step S3, performing a de-signature on the extended acquisition indicator signal corresponding to the acquisition indicator signal to output a corresponding second de-signature value;
in the preferred embodiment of the present invention, before executing step S3, as shown in fig. 2, the following steps are first executed:
step S21, determining the sign of the first de-signed value:
if the sign of the first de-signature value is positive, judging that positive confirmation is indicated, and exiting;
if the sign of the first de-signed value is negative, go to step S22;
in a preferred embodiment of the present invention, before the step S3 is executed, i.e. before the EAI signal is de-signed and determined, the sign of the first de-signed value u1 obtained by de-signing the AI signal is determined;
in the preferred embodiment of the present invention, if the u1 symbol is positive, the AI signal is determined as positive acknowledgement, at this time, the mobile terminal considers that the base station allows the mobile terminal to access the channel, and the default configuration is adopted to set the channel resource, so as to access the configured channel.
In the preferred embodiment of the present invention, if the sign of u1 is negative, go to step S22 to make the following determination.
Step S22, judging whether the access prefix corresponding to the transmission signal corresponds to the physical random access channel;
if the access prefix corresponds to the physical random access channel, go to step S24;
in the preferred embodiment of the invention, the mobile terminal firstly judges whether the access prefix sent to the base station by the mobile terminal corresponds to the PRACH channel;
in the preferred embodiment of the present invention, if the access prefix corresponds to the PRACH channel, go directly to the following step S24;
if the access prefix does not correspond to the PRACH channel (possibly, the access prefix corresponds to the E-DCH channel), the following determination of step S23 is performed.
Step S23, determining whether an extended acquisition indicator signal corresponding to the acquisition indicator signal is configured in the transmission signal;
if the transmission signal is configured with a corresponding extended acquisition indication signal, go to step S3;
in a preferred embodiment of the present invention, if the access prefix (i.e. the access prefix corresponding to the AI signal returned by the base station) sent by the mobile terminal to the base station does not correspond to the PRACH channel, then a further determination is made: judging whether an EAI signal corresponding to the AI signal is configured in a transmission signal returned by the base station;
in a preferred embodiment of the present invention, if the returned transmission signal is configured with a corresponding EAI signal, the EAI signal is extracted and de-signed. In the preferred embodiment of the present invention, the process of de-signing the EAI signal is similar to the process of de-signing the AI signal, as described in detail below.
Step S24, deciding the acquisition indicator signal as indicating negative acknowledgement, and then exiting.
In a preferred embodiment of the present invention, when the access prefix corresponds to a PRACH channel or a transmission signal is not configured with a corresponding EAI signal (i.e., one of the two conditions is satisfied), the AI signal is determined as a negative acknowledgement. At this time, the mobile terminal considers that the base station does not allow the base station to access the corresponding channel, and the access channel request fails.
In a preferred embodiment of the present invention, in the step S3, before the EAI signal is de-signed and the second de-signed value obtained by de-signing is determined, the AI reconstruction signal is removed first, that is, the first de-signed value u1 output after de-signing the AI signal is removed from the transmission signal, so as to prevent the AI reconstruction signal from affecting the determination of the next EAI signal.
In a preferred embodiment of the present invention, as shown in fig. 3, the process of de-signing the EAI signal includes:
step S31, de-signing the extended capture indication signal to output a plurality of corresponding decision statistics;
in a preferred embodiment of the present invention, the EAI signal is first de-signed using equation (3), i.e.:
u2a=k*AIa+ω' (6)
similarly, ω' ∈ N (0, δ)2) I.e. ω' follows a normal distribution.
Wherein,
u2arepresenting the decision statistic; in the preferred embodiment of the present invention, since the EAI signal carries 16 signature sequences (0-15), there are 16 decision statistics obtained by de-signing.
In the preferred embodiment of the present invention, since the signature of the EAI signal is only transmitted one and unknown, the de-signing of the EAI signal requires two unknowns to be detected, one of which is to obtain a plurality of second de-signed values u2 by the calculation of formula (6), and in the preferred embodiment of the present invention, 16 u2 can be obtained by calculationa(0-15)。
In the preferred embodiment of the present invention, in step S31, the sign corresponding to each decision statistic can be obtained at the same time as obtaining each decision statistic, i.e. the polarity corresponding to each decision statistic is known.
Step S32, judging the position of the second de-signature value on the signature sequence of the extended capture indication signal according to the judgment statistic;
in the preferred embodiment of the present invention, since only one EAI signature is transmitted, as described above, it is necessary to determine which signature sequence of the extended acquisition indicator signal carries the corresponding information according to the following formula, i.e., EAIsOn which signature sequence of the extended acquisition indicator signal:
wherein,
argmax is used to compute a number of decision statistics u2aMaximum of absolute values of (a ∈ 0 … 15) i.e. for u2aAnd carrying out maximum comparison operation.
In the preferred embodiment of the present invention, after the maximum value of the decision statistics is obtained by the maximum value comparison operation, the maximum value u2 is addedaAs a final outputThe second de-signed value, i.e. the corresponding a-th signature sequence of the EAI signal obtained by comparison, carries the corresponding information (EAI)a) Then u2 is correspondedaThe corresponding second de-signed value is finally output.
In step S33, the finally obtained second de-signed value is output, and then the process goes to step S4.
Step S4, determining whether the sum of the second de-signature value and the corresponding first de-signature value is less than a second threshold;
if the sum of the first de-signature value and the second de-signature value is smaller than the second threshold value, the process goes to step S6;
in the preferred embodiment of the present invention, the object determined in step S4 is actually the sum of the first de-signed value u1 and the second de-signed value u2, that is:
u=u1+u2a (8)
wherein,
u is the decision object in step S4.
Step S5, calculating the channel resource allocated to the mobile terminal according to the extended acquisition indication signal, and then quitting;
in the preferred embodiment of the present invention, if the first de-signed value u1 and the second de-signed value u2 are both equalaAnd if the sum u is not less than a preset second threshold value, calculating the channel resource allocation of the access channel according to the EAI signal, and correspondingly allocating the channel according to the calculated channel resource.
Further, in the preferred embodiment of the present invention, when the first de-signature value u1 and the second de-signature value u2 are determinedaWhen the added sum u is not less than a preset second threshold value, the EAI signal (namely EAI) is considereds) Is reliable, and the EAI is determined according to the symbol of the decision statistic corresponding to the second de-signature valuesPolarity (+1 or-1).
In the preferred embodiment of the present invention, the EAI signal (EAI) is based ons) And calculating the carried information and the corresponding polarity to obtain the channel resources for channel configuration.
In the preferred embodiment of the present invention, if the first de-signed value u1 and the second de-signed value u2 are both equalaIf the sum u is smaller than the second threshold, the process goes directly to step S6, where the AI signal is also determined to indicate discontinuous reception, and the next reception is awaited regardless of the transmission signal received this time.
Step S6, deciding the acquisition indicator signal as indicating discontinuous reception, and then exiting.
In summary, the present invention aims to: firstly, the AI signal is judged according to the transmission signal: if the first de-signature value of the AI signal is smaller than the first threshold value, judging the AI signal as indicating DTX, namely waiting for next receiving;
if the first de-signature value of the AI signal is not less than the first threshold, further determining the symbol polarity of the AI signal: if the symbol of the AI signal is positive, judging the AI signal as indicating positive confirmation, namely accessing the channel according to default configuration;
if the AI signal is negative, determining whether the corresponding access prefix corresponds to the PRACH channel or is configured with a corresponding EAI signal: if the access prefix corresponds to the PRACH or the transmission signal is not configured with a corresponding EAI signal, judging the AI signal as indicating negative confirmation, namely, the access channel fails;
if the access prefix does not correspond to the PRACH channel and the corresponding EAI signal is configured in the transmission signal at the same time, the EAI signal is de-signed and judged (before the judgment, the AI reconstruction signal is removed from the transmission signal, namely the first de-signature value u1 is removed, if the EAI signal is de-signed, the second de-signature value u2 is obtainedaIf the sum u added with the first de-signature value u1 is not less than a preset second threshold value, the EAI signal is judged to be reliable, and at the moment, the channel resource allocation is calculated according to the EAI signal and the polarity thereof and is combinedAn access channel should be configured;
a second de-signed value u2 if the EAI signal is de-signedaIf the sum u added to the first de-signature value u1 is less than a preset second threshold, the AI signal is also determined to be DTX.
The capture indication detection method simultaneously detects the AI signal and the EAI signal, and removes the AI reconstruction signal from the integral estimation signal before judging the EAI signal so as to reduce the interference of judging the EAI signal; meanwhile, the de-signature of the EAI signal can be completed through a solidified fast algorithm; when the EAI signal is judged, the de-signature value of the AI signal and the EAI signal can be combined for judgment, and the misjudgment rate is reduced.
In a preferred embodiment of the present invention, the above acquisition indication detection method is applicable to a WCDMA communication system.
In a preferred embodiment of the present invention, a mobile terminal is further provided, wherein the above capture indication detection method is adopted.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.