Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. 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.
First, terms of art mentioned in the present application will be explained.
The RNTI is a technical identifier introduced by the LTE standard for dynamic scheduling, and is mainly classified into the following categories:
C-RNTI: terminal wireless network temporary identifier, range: 61 to 65533;
SI-RNTI: system information radio network temporary identifier, 65535;
P-RNTI: a paging wireless network temporary identifier, which is mainly used for paging a terminal, 65534;
RA-RNTI: random access (response) radio network temporary identity, range: 1 to 60.
In LTE, the smallest single PDCCH transmission unit is defined as a Control Channel Element (CCE), where one CCE is equal to 9 Resource Element Groups (REGs) and one REG is equal to 4 Resource Elements (REs).
RE is the minimum resource unit after LTE data (including control data and user data) modulation. For DCI, the resource unit after modulation of the control data. 1cce =9reg =36re. The RE after single DCI coding and modulation is mapped to REG and then mapped to CCE, and the CCE occupied by the single DCI after mapping.
The number of CCEs occupied by a single DCI is in Aggregation Level (AL) 1, 2, 4 or 8, and the DCI is continuously distributed in the available total CCEs of the entire subframe, where the Aggregation Level is 1 for a good communication condition, the Aggregation Level is 8 for a bad communication condition, and the Aggregation Level is 4 or 4 for a moderate communication condition, for example, the Aggregation Level 4 or 8 is generally used for scheduling and control information DCI at a system Cell (Cell) Level.
Because the base station in the LTE system dynamically allocates the RNTI to each UE, and the positioning management and control device does not know the RNTI of the target terminal, most of the prior art searches and captures all RNTIs in a traversal manner based on an unknown RNTI, which results in large calculation amount and time consumption, and false detection and missed detection, thereby reducing the success rate of capturing and positioning.
Fig. 1 is a schematic flow diagram of a passive positioning method according to an embodiment of the present invention, and referring to fig. 1, the passive positioning method according to the embodiment of the present invention may include:
step 101, checking decoding information of CCE groups based on SI-RNTI, and determining system information block information; the CCE group is determined based on OFDM symbols occupied by PDCCH in the current subframe;
step 102, determining a target RA-RNTI based on the system information block information;
103, checking the decoding information of the CCE group based on the target RA-RNTI to determine random access response information;
104, determining a target C-RNTI queue based on the random access response information;
and 105, positioning the target terminal based on the target C-RNTI queue.
It should be noted that an execution subject of the passive positioning method provided in the embodiment of the present invention may be a positioning management and control device of an LTE system.
Instep 101, the decoding information of the CCE group is checked based on the SI-RNTI, and system information block information is determined.
Alternatively, beforestep 101, a CCE space may be determined based on OFDM symbols occupied by the PDCCH in the current subframe, and CCE groups may be extracted from the CCE space.
Optionally, fig. 2 is a schematic structural diagram of a system frame in the prior art, as shown in fig. 2:
1 systematic frame =10 sub-frames =10ms,
1 subframe =20 slots =14 Orthogonal Frequency Division Multiplexing (OFDM) symbols =1ms.
The PDCCHs may be distributed in OFDM symbols 0 to 3, a plurality of PDCCHs may exist in 1 subframe, each PDCCH carries one piece of DCI information, and CRC check of the DCI information is scrambled using RNTI.
The Physical Downlink Shared CHannel (PDSCH) is distributed in the remaining OFDM symbols, and the decoded PDSCH user information can be extracted according to the blind-detected DCI of the current subframe.
The base station schedules PDSCH (time frequency resource, carrying system message or service data) through PDCCH (carrying DCI), and the PDCCH and the PDSCH are in the same subframe.
According to the OFDM symbols occupied by the PDCCH in the current subframe, a CCE space is determined, the CCE space can comprise a plurality of CCEs, and the number of the CCEs is determined by the bandwidth required by transmitting the current subframe and other parameters of the system.
The starting position in the CCE group may be determined according to the aggregation level AL, and the CCE group may be extracted from the CCE space. The values of AL include 8, 4, 2, and 1,cce group starting positions that are integer multiples of AL.
For example, when the number of CCEs in the CCE space is 80 (CCE sequence numbers are 0 to 79 in order):
when AL =8, then the starting positions in the CCE groups may be 0, 8, 16, 24, 32, 48, 56, 64, and 72, that is, 8 CCE groups may be extracted from the CCE space, where the number of CCEs in each CCE group is 8 and consecutive. The CCE within the first CCE group have a rank of 0 to 7 and the CCE within the second CCE group have a rank of 8 to 15.
When AL =4, the starting positions in the CCE groups may be 0, 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, and 72, 20 CCE groups may be extracted from the CCE space, and the number of CCEs in each CCE group is 4 and consecutive. The CCE within the first CCE group have a rank of 0 to 3, and the CCE within the second CCE group have a rank of 4 to 7.
And after the CCE group is determined, checking the decoding information of the CCE group based on the SI-RNTI, and determining the system information block information.
Optionally, fig. 3 is a schematic flow chart of a search method based on a known RNTI according to an embodiment of the present invention, and referring to fig. 3, after a CCE group is determined, viterbi decoding is performed on the CCE group, and after a decoded sequence is obtained, CRC check may be performed on the sequence.
And generating a local check bit according to the CRC check generating polynomial, comparing the check bit with a known RNTI value, judging that the received DCI information is the information of the UE if the check bit is the same as the known RNTI value, and extracting the DCI information, otherwise, not extracting the DCI information.
Based on the known SI-RNTI =65535, performing CRC check on the decoding information of the CCE group, and if the check is passed, considering that the DCI information of the SIB, that is, the first DCI information, is searched in the current subframe.
And then extracting corresponding data in the PDSCH region of the current subframe according to the first DCI Information and decoding to obtain System Information Block (SIB) Information.
Instep 102, a target RA-RNTI is determined based on the system information block information.
The SIB information includes t _ id information and f _ id information required for calculating RA-RNTI, t _ id is an uplink subframe number (t _ id < 10) of a Physical Random Access Channel (PRACH) for sending a preamble (preamble), and f _ id is an index (f _ id < 6) of the PRACH for sending the preamble in the subframe in a frequency domain.
According to the t _ id and f _ id information, the RA-RNTI value possibly existing in the current subframe can be calculated, and the RA-RNTI calculation formula is as follows:
RA_RNTI=1+t_id+10*f_id
wherein, t _ id is the uplink subframe number of the PRACH sending the Preable (t _ id is more than or equal to 0 and less than 10); f _ id is the index of PRACH for transmitting preamble in the subframe on the frequency domain (0 ≦ f _ id < 6).
For Frequency Division multiplexing (FDD) mode, each subframe has only one PRACH resource, so f _ id is fixed to 0, RA-RNTI value of one system frame in FDD mode is no more than 10, and one subframe is no more than 1.
The RA-RNTI value of one system frame is not more than 60 and one subframe is not more than 6 in Time Division Duplex (TDD) mode.
Therefore, blind detection is carried out according to the known SI-RNTI =65535, SIB information is obtained, t _ id and f _ id information are obtained, a known value of the target RA-RNTI can be obtained through calculation, and blind detection is carried out according to the target RA-RNTI, so that the number of blind detection times is greatly reduced.
Instep 103, the decoding information of the CCE group is checked based on the target RA-RNTI, and random access response information is determined.
And performing blind detection according to the calculated known target RA-RNTI, performing CRC (cyclic redundancy check) on decoding information of the CCE group, if the decoding information passes the check, successfully capturing an RA-RNTI, determining second DCI information corresponding to the RA-RNTI, utilizing the second DCI information to indicate that corresponding data is extracted in a PDSCH (physical downlink shared channel) region, and decoding to obtain Random Access Response (RAR) information.
Instep 104, a target C-RNTI queue is determined based on the random access response information.
The RAR information may include a plurality of C-RNTI values, and a target C-RNTI queue may be formed based on the C-RNTI values included in the RAR information.
Optionally, in this embodiment of the present application, the number of C-RNTIs in the target C-RNTI queue is 16.
Instep 105, a target terminal is located based on the target C-RNTI queue.
And similarly, performing blind detection according to the known C-RNTI in the target C-RNTI queue, performing CRC on the decoding information of the CCE group, and successfully capturing one C-RNTI if the CRC passes.
According to the embodiment of the application, blind detection is carried out based on the known C-RNTI, the range of the blind detection is reduced, and the success rate of the blind detection is increased.
And determining third DCI information corresponding to the C-RNTI according to the captured C-RNTI, extracting corresponding data in a PDSCH region by using the indication of the third DCI information, and decoding to obtain downlink service information so as to identify the target terminal according to the downlink service information.
The downlink service information can be service information of a terminal, such as a short message, a picture or a video, and whether the downlink service information is a target terminal is judged by screening and judging whether the downlink service information conforms to the characteristics of the target terminal.
And after the target terminal is identified, extracting the uplink data of the target terminal in a corresponding PUSCH region according to the indication of the third DCI information, and decoding to obtain the uplink data information so as to position the target terminal.
The uplink data information may be interaction information between the target terminal and the base station before service transmission, and may be, for example, time information of signal transmission from the target terminal to the base station, location information of transmission resources, and the like.
And determining the transmitting power of the target terminal according to the time information of the signal transmitted to the base station by the target terminal and the position information of the transmitting resource, thereby positioning the target terminal according to the transmitting power.
According to the passive positioning method provided by the embodiment of the invention, unknown RNTI searching is converted into local known RNTI searching, the searching range of RNTI is narrowed step by step in a classified manner, the capturing success rate of the C-RNTI of the target terminal is finally improved, and the success rate of positioning the target terminal is further improved.
In some embodiments, the SI-RNTI checks coding information of a CCE group to determine system information block information, including:
checking the decoding information of the CCE group based on the SI-RNTI;
under the condition that the verification is passed, determining first DCI information corresponding to the SI-RNTI;
determining the system information block information from the PDSCH of a current subframe based on the first DCI information.
Optionally, based on the known SI-RNTI =65535, the decoding information of the CCE group is subjected to CRC check sequentially through each aggregation level, and if the CRC check passes, it is considered that the DCI information of the SIB, that is, the first DCI information, is searched in the PDCCH of the current subframe.
And then extracting corresponding data in the PDSCH region of the current subframe according to the indication of the first DCI Information according to the first DCI Information, and decoding to obtain System Information Block (SIB) Information.
The SIB information comprises t _ id information and f _ id information required for calculating RA-RNTI, wherein t _ id is an uplink subframe number (t _ id is more than or equal to 0 and less than 10) of a PRACH for sending a preamble, and f _ id is an index (f _ id is more than or equal to 0 and less than 6) of the PRACH for sending the preamble in the subframe on a frequency domain.
In some embodiments, the checking coding information of the CCE group based on the target RA-RNTI and determining random access response information includes:
checking the decoding information of the CCE group based on the target RA-RNTI;
determining second DCI information corresponding to the target RA-RNTI under the condition that the verification is passed;
determining the random access response information from the PDSCH of the current subframe based on the second DCI information.
Optionally, according to the t _ id and f _ id information, an RA-RNTI value that may exist in the current subframe may be calculated, where the RA-RNTI calculation formula is:
RA_RNTI=1+t_id+10*f_id
wherein, t _ id is the uplink subframe number of the PRACH sending the Preable (t _ id is more than or equal to 0 and less than 10); f _ id is the index of PRACH for transmitting preamble in the subframe on the frequency domain (0 ≦ f _ id < 6).
And traversing each aggregation level according to the calculated known RA-RNTI, sequentially carrying out CRC (cyclic redundancy check) on the decoding information of the CCE group, if the CRC passes, successfully capturing one RA-RNTI, determining second DCI (downlink control information) corresponding to the RA-RNTI, utilizing the second DCI to indicate to extract corresponding data in a PDSCH (physical downlink shared channel) region, and decoding to obtain RAR (radio-relative-radio-temporary-identifier) information.
The RAR information may include a plurality of C-RNTI values.
In some embodiments, said locating the target terminal based on the target C-RNTI queue includes:
in a target time period, respectively checking the decoding information of the CCE group based on all C-RNTIs in the target C-RNTI queue;
determining third DCI information corresponding to the C-RNTI under the condition that the verification is passed;
and positioning the target terminal based on the third DCI information.
Optionally, in a specific time period, performing blind check according to the known C-RNTI in the target C-RNTI queue, traversing each aggregation level, sequentially performing CRC check on the decoding information of the CCE group, and if the check is passed, successfully capturing one C-RNTI.
The captured C-RNTI is a specific C-RNTI for mutual communication between the terminal and the base station, and third DCI information which is issued to a target terminal by the base station can be captured by using the C-RNTI.
And then, the PDSCH message indicated by the C-RNTI is solved through the indication information of the third DCI information, and whether the PDSCH message conforms to the characteristics of the target user is screened and judged, so that the target terminal is identified and positioned.
Further, the positioning the target terminal based on the third DCI information includes:
determining downlink traffic information from the PDSCH of the current subframe based on the third DCI information;
identifying the target terminal based on the downlink service information;
determining uplink data information from a PUSCH corresponding to the current subframe based on the third DCI information;
and positioning the target terminal based on the uplink data information.
Optionally, corresponding data is extracted in the PDSCH region according to the indication of the third DCI information, and downlink service information is obtained through decoding, so that the target terminal is identified according to the downlink service information.
The downlink service information may be service information such as a short message, a picture, or a video of the terminal, and whether the downlink service information meets the characteristics of the target terminal is determined by screening and determining, for example, whether the downlink service information is the target terminal may be determined according to the length of the decoded information, the time within the receiving window, or the correct receiving times.
And after the target terminal is identified, extracting the uplink data of the target terminal in a corresponding PUSCH region according to the indication of the third DCI information, and decoding to obtain the uplink data information so as to position the target terminal.
The uplink data information may be interaction information between the target terminal and the base station before service transmission.
Further, the uplink data information may include:
and the target terminal transmits the time information of the signal and the position information of the transmitting resource.
Therefore, the positioning control equipment can obtain uplink data information according to the decoding, namely the time information of the signal transmitted to the base station by the target terminal and the position information of the transmitting resource, and determine the transmitting power of the target terminal, so that the target terminal is positioned according to the transmitting power.
According to the passive positioning method provided by the embodiment of the invention, unknown RNTI searching is converted into local known RNTI searching, the searching range of RNTI is narrowed step by step in a classified manner, the capturing success rate of the C-RNTI of the target terminal is finally improved, and the success rate of positioning the target terminal is further improved.
Fig. 4 is a second schematic flowchart of the passive positioning method according to the embodiment of the present invention, and referring to fig. 4, the passive positioning method according to the embodiment of the present invention may include:
s1, searching and maintaining system parameters of a cell:
s1.1, primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) search, cell ID and time frame structure are obtained, and Synchronization is carried out in time domain and frequency domain.
S1.2, decoding a Physical Broadcast Channel (PBCH) Channel, and acquiring Management Information Block (MIB) Information, namely Information such as a cell LTE working mode (TDD/FDD) and a working bandwidth.
S1.3, further using the known SI-RNTI =65535, searches for SI-RNTI from the PDCCH channel, and if there is a Viterbi-decoded decoding information sequence CRC check passed, then it is considered that the DCI of the SIB information has been searched.
And then extracting corresponding data in the PDSCH region of the current subframe according to the DCI indication, and decoding to obtain SIB information. The SIB message contains the t _ id and f _ id information needed by the RA-RNTI to be calculated next.
S1.4, repeating the steps S1.1 to S1.3 every 5 seconds or so, and maintaining the synchronization with the cell and corresponding system parameters.
S2, searching C-RNTI of a target user:
s2.1, calculating the possible RA-RNTI value of the current subframe according to the t _ id and f _ id information in the SIB information, and then searching for the known RNTI by using the calculated RA-RNTI value.
The formula for calculating RA _ RNTI is as follows:
RA_RNTI=1+t_id+10*f_id
wherein, t _ id is the uplink subframe number of the PRACH sending the Preable (t _ id is more than or equal to 0 and less than 10); f _ id is the index of PRACH for transmitting preamble in the subframe on the frequency domain (0 ≦ f _ id < 6).
For the FDD mode, each subframe has only one PRACH resource, so f _ id is fixed to 0, RA-RNTI value of one system frame in FDD mode is no more than 10, and one subframe is no more than 1.
In TDD mode, the RA-RNTI value of a system frame is not more than 60, and one subframe is not more than 6.
S2.2, searching by using the known RA-RNTI, and if the Viterbi decoding information sequence CRC passes, successfully capturing an RA-RNTI.
And then, corresponding data is extracted in a PDSCH region by using the DCI instruction, RAR is obtained by decoding, and C-RNTI values (possibly a plurality of values) are extracted from the RAR.
And S2.3, updating the C-RNTI queue, enabling the new C-RNTI value to enter the queue, withdrawing the old C-RNTI value, and always maintaining 16C-RNTIs in the queue (no C-RNTI is in the initial queue).
S3, searching and positioning by a target user:
s3.1, searching PDSCH service information of a target user by using the known C-RNTI in the queue, and also performing blind detection by using the known C-RNTI, wherein if the Viterbi decoding CRC passes, the DCI information of the C-RNTI user is successfully found.
And then extracting corresponding data in the PDSCH region by using the DCI indication, and decoding to obtain downlink user information.
And S3.2, if the DCI indicates the uplink data of the C-RNTI user, extracting the uplink data of the user in a corresponding PUSCH region, and decoding to obtain uplink user information.
And S3.3, capturing the transmitting power of the uplink signal of the target terminal according to the DCI, and positioning the target terminal according to the transmitting power.
And S3.4, when the secondary passive positioning process is finished, repeating the steps S2.1 to S3.4 again in order to position a new target user and implement a continuous positioning and tracking period for an old target user.
According to the passive positioning method provided by the embodiment of the invention, unknown RNTI searching is converted into local known RNTI searching, the searching range of RNTI is narrowed step by step in a classified manner, the capturing success rate of the C-RNTI of the target terminal is finally improved, and the success rate of positioning the target terminal is further improved.
The passive positioning device provided by the present invention is described below, and the passive positioning device described below and the passive positioning method described above may be referred to correspondingly.
Fig. 5 is a schematic structural diagram of a passive positioning device according to an embodiment of the present invention, and referring to fig. 5, the passive positioning device according to the embodiment of the present invention includes:
afirst checking module 510, configured to check decoding information of the CCE group based on the SI-RNTI, and determine system information block information; the CCE group is determined based on OFDM symbols occupied by PDCCH in the current subframe;
a first determiningmodule 520, configured to determine a target RA-RNTI based on the system information block information;
asecond checking module 530, configured to check the decoding information of the CCE group based on the RA-RNTI, and determine random access response information;
a second determiningmodule 540, configured to determine a target C-RNTI queue based on the random access response information;
and apositioning module 550, configured to position the target terminal based on the target C-RNTI queue.
According to the passive positioning device provided by the embodiment of the invention, unknown RNTI searching is converted into local known RNTI searching, the searching range of RNTI is narrowed step by step in a classified manner, the capturing success rate of the C-RNTI of the target terminal is finally improved, and the success rate of positioning the target terminal is further improved.
Optionally, thefirst checking module 510 is specifically configured to:
checking the decoding information of the CCE group based on the SI-RNTI;
under the condition that the verification is passed, determining first DCI information corresponding to the SI-RNTI;
determining the system information block information from the PDSCH of a current subframe based on the first DCI information.
Optionally, thesecond checking module 520 is specifically configured to:
checking the decoding information of the CCE group based on the target RA-RNTI;
determining second DCI information corresponding to the target RA-RNTI under the condition that the verification is passed;
determining the random access response information from the PDSCH of the current subframe based on the second DCI information.
Optionally, thepositioning module 550 is specifically configured to:
in a target time period, respectively checking the decoding information of the CCE group based on all C-RNTIs in the target C-RNTI queue;
determining third DCI information corresponding to the C-RNTI under the condition that the verification is passed;
and positioning the target terminal based on the third DCI information.
Optionally, thepositioning module 550 is further configured to:
determining downlink traffic information from the PDSCH of the current subframe based on the third DCI information;
identifying the target terminal based on the downlink service information;
determining uplink data information from a PUSCH corresponding to the current subframe based on the third DCI information;
and positioning the target terminal based on the uplink data information.
Optionally, the uplink data information includes:
and the target terminal transmits the time information of the signal and the position information of the transmitting resource.
Optionally, thepositioning module 550 is further configured to:
determining the transmitting power of the target terminal based on the time information and the position information;
and positioning the target terminal based on the transmitting power.
Fig. 6 illustrates a physical structure diagram of an electronic device, which may include, as shown in fig. 6: a processor (processor) 610, a communication Interface (Communications Interface) 620, a memory (memory) 630 and acommunication bus 640, wherein theprocessor 610, thecommunication Interface 620 and thememory 630 communicate with each other via thecommunication bus 640. Theprocessor 610 may invoke logic instructions in thememory 630 to perform a passive positioning method comprising:
checking the decoding information of the CCE group based on the SI-RNTI to determine system information block information; the CCE group is determined based on OFDM symbols occupied by PDCCH in the current subframe;
determining a target RA-RNTI based on the system information block information;
checking the decoding information of the CCE group based on the target RA-RNTI to determine random access response information;
determining a target C-RNTI queue based on the random access response information;
and positioning the target terminal based on the target C-RNTI queue.
In addition, the logic instructions in thememory 630 may be implemented in software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product, the computer program product including a computer program, the computer program being stored on a non-transitory computer-readable storage medium, wherein when the computer program is executed by a processor, a computer is capable of executing the passive positioning method provided by the above methods, and the method includes:
checking the decoding information of the CCE group based on the SI-RNTI to determine system information block information; the CCE group is determined based on OFDM symbols occupied by PDCCH in the current subframe;
determining a target RA-RNTI based on the system information block information;
checking the decoding information of the CCE group based on the target RA-RNTI, and determining random access response information;
determining a target C-RNTI queue based on the random access response information;
and positioning the target terminal based on the target C-RNTI queue.
In yet another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored, the computer program, when being executed by a processor, implementing a passive positioning method provided by the above methods, the method including:
checking the decoding information of the CCE group based on the SI-RNTI to determine system information block information; the CCE group is determined based on OFDM symbols occupied by PDCCH in the current subframe;
determining a target RA-RNTI based on the system information block information;
checking the decoding information of the CCE group based on the target RA-RNTI to determine random access response information;
determining a target C-RNTI queue based on the random access response information;
and positioning the target terminal based on the target C-RNTI queue.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment may be implemented by software plus a necessary general hardware platform, and may also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.