Background
In the LTE system, the application of HARQ (hybrid automatic repeat request) technology improves the reliability of communication. It decides whether to retransmit old data through ACK/NACK (acknowledged/not acknowledged) information fed back. For downlink HARQ, ACK/NACK is fed back on an Uplink PUSCH (Physical Uplink Shared Channel) or PUCCH (Physical Uplink Control Channel).
For a TDD (Time Division duplex) system, a frame structure of the system is shown in fig. 1, asymmetry of uplink and downlink subframes determines that one uplink subframe may need to feed back ACK/NACK conditions of several downlink subframes, and a specific subframe configuration is shown in fig. 2. For example, when one UE is configured as TDD uplink and downlink subframe configuration 1, when uplink subframe n is 2, it is necessary to feed back ACK information or NACK information of the UE demodulation results of the first two downlink subframes n-7 and n-6, and the feedback relationship is shown in fig. 3. For the bundling feedback mode, the protocol specifies that the 2-bit ack/NACK generated by two downlink subframes is logically anded to obtain a 1-bit result, and then the uplink subframe n is fed back to 2. If the double stream obtains 2bit result, the logical AND method is shown in figure 4.
The 1bit or 2bit information generated by the UE needs to be fed back to the base station, and the base station determines whether old data needs to be retransmitted or not. When there is no PUSCH scheduling in the uplink, this information needs to be sent to the base station through PUCCH, which is sent on PUCCH format 1a or 1 b. For the bundling feedback mode, the calculation of the PUCCH logical resource index for sending ACK/NACK information is specified in the current protocol as follows:
<math><mrow><msubsup><mi>n</mi><mi>PUCCH</mi><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msubsup><mo>=</mo><mrow><mo>(</mo><mi>M</mi><mo>-</mo><mi>m</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>×</mo><msub><mi>N</mi><mi>p</mi></msub><mo>+</mo><mi>m</mi><mo>×</mo><msub><mi>N</mi><mrow><mi>p</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>+</mo><msub><mi>n</mi><mi>CCE</mi></msub><mo>+</mo><msubsup><mi>N</mi><mi>PUCCH</mi><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msubsup><mtext>;</mtext></mrow></math>
wherein Np is the total number of CCEs of p symbols in the PDCCH, and Np +1 is the total number of CCEs of p +1 symbols in the PDCCH; m is the index of the smallest k value; the index value of the control channel element CCE occupying the beginning of the PDCCH by the downlink subframe corresponding to the minimum k value is nCCE;The base station reserves PUCCH logical resources for SR (Scheduling Request information) and semi-static ACK/NACK, and the PUCCH logical resources are configured and obtained by an RRC (Radio Resource Control protocol) layer of the base station; m is the maximum number of downlink sub-frames ACK/NACK needing to be fed back by the uplink sub-frame; in addition, the base station notifies the UE of the uplink and downlink configuration by broadcasting.
Fig. 5 takes TDD uplink-
downlink configuration 3 as an example, and obtains a mapping map of PUCCH logical resource indexes according to the above formula (M is 3).
Determines the size of physical resource (RB resource block) occupied by PUCCH,
the larger the value, the more RBs occupied by PUCCH.
The goal of the system design is therefore to make
The value is as small as possible, and then determined
The key point of the size lies in a value method of m, the value of m is specified in a protocol to be the m value which enables km (km epsilon to K) to be minimum, and the UE detects the PDCCH in a downlink subframe n-km, wherein the definition of a set K is shown in figure 6. In the uplink/
downlink ratio 3 in fig. 6, the set K of the
uplink subframe 2 is { K }
0=7,k
1=6,k
211, the UE detects PDCCH in all three downlink subframes, and finds the minimum km in the set K, which is 6, and obtains the index m of km, which is 1. In FIG. 5
Represents the (n-7) th subframe logical resource (m ═ 0),
denotes an n-6 th subframe logical resource (m ═ 1),
denotes the N-11 th subframe logical resource (m 2), N
CCE,pRepresenting the number of CCEs when the PCFICH value is p, the black square is the position of PUCCH logical resource for feeding back ACK/NACK, and the corresponding
And calculating the obtained PUCCH logical resource index.
Obviously, obtained by calculation according to the current protocol
This is not the optimal method, since there are also smaller values of m, whether it be seen from the figure or from the formula, which can be made when m is 0
And is smaller.
Similarly, for the TDD in fig. 6, if other uplink and downlink matching modes have the same problem as matching 3, a resource map similar to that in fig. 5 can be obtained, and it can be seen that the m value obtained by the m value selection method specified by the existing protocol is not the minimum m value, so that the obtained m value is not the minimum m value
Nor necessarily at a minimum. The applicant therefore intends to provide a method of making
Smaller, thereby making PUCCH occupy smaller RBs.
In addition, the RI (Rank Indication) reflects the Rank of the spatial channel Matrix, and the UE feeds back the measured RI/PMI (Precoding Matrix Indicator) value to the base station, so that the base station can select an optimal downlink Precoding Matrix according to the value, thereby effectively eliminating the correlation of channels and ensuring the stability of the MIMO (Multiple-Input Multiple-output-Out-Multiple-Input Multiple-output) system in each environment.
The RI may be fed back on the PUSCH or PUCCH, and when there is no PUSCH scheduling, the RI is transmitted on the PUCCH.
In the current implementation, when RI and ACK/NACK coexist, the joint coding is performed and then transmitted in PUCCH format 2a or 2 b. Firstly, RI information is coded by (20, A) to obtain 20bit information, and after scrambling, QPSK (Quadrature Phase Shift Keying) modulation is carried out to obtain 10 symbols; 1/2 bits of the ACK/NACK are individually BPSK (Binary Phase shifting keying) or QPSK modulated to obtain 1 symbol, and finally, 11 symbols are mapped to the PUCCH for transmission.
Obviously, the above implementation is somewhat resource-wasting. When RI and ACK/NACK exist simultaneously, the transmission in PUCCH format 2a/2b can be optimized again, because RI only has 1bit or 2bit information.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a method and a terminal for sending feedback RI information by using an uplink subframe, which optimize the utilization of PUCCH resources in the prior art and save physical resources occupied by PUCCH.
In order to solve the above technical problem, the present invention provides a method for feeding back Rank Indication (RI) information by using an uplink subframe, comprising:
the terminal UE obtains a set K containing a plurality of K values according to the current uplink and downlink proportion, and detects the downlink subframe n-KmWhether a Physical Downlink Control Channel (PDCCH) is occupied and the polymerization degree of CCE occupying the PDCCH is occupied, wherein m is an index of a set K; acquiring a logical resource index implied by a Physical Uplink Control Channel (PUCCH) according to a downlink subframe occupying the PDCCH and the polymerization degree of the CCE;
and when the polymerization degree is greater than 1, the UE selects a physical resource corresponding to the logical resource index implied by the PUCCH to send RI information to the base station through the PUCCH on an uplink subframe n.
Further, the present invention also includes: the UE selects a downlink subframe with the minimum m value from detected downlink subframes occupying the PDCCH, and acquires a PUCCH logical resource index and an implicit logical resource index according to the minimum m value, an index value of a Control Channel Element (CCE) at the beginning of the PDCCH occupied by the downlink subframe with the minimum m value and a polymerization degree of the CCE of the PDCCH.
Further, the present invention also includes: the UE selects a symbol index value p of PDCCH from the set {0, 1, 2, 3} according to the index value of the starting CCE.
Further, the present invention also includes: the index value of the initial CCE is more than or equal to the total number Np of the p symbols of the CCE in the PDCCH and less than the total number Np +1 of the p +1 symbols of the CCE in the PDCCH.
Further, the present invention also includes:
the PUCCH logical resources reserved for scheduling request information and semi-static ACK/NACK by the base station are obtained by the configuration of a wireless resource control protocol layer of the base station; m is the number of elements in the set K.
Further, the present invention also includes: the UE according to the M with the minimum value, the index value of the initial CCE, the total number of the CCEs with p symbols in the PDCCH, the total number of the CCEs with p +1 symbols in the PDCCH, and the sum of M
And acquiring the PUCCH logical resource index.
In order to solve the above technical problem, the present invention further provides a terminal for feeding back rank indication RI information by using an uplink subframe, including: the system comprises an information organization module, a parameter detection module, a resource acquisition module and a sending module;
the information organization module is used forObtaining a plurality of K value sets K according to the current uplink and downlink proportion, and determining a downlink subframe n-KmInforming the parameter detection module, wherein m is an index of k values; the parameter detection module is also used for triggering and informing the sending module of the RI information;
the parameter detection module is used for detecting the downlink subframe n-kmAcquiring the polymerization degree of CCE of the PDCCH from a downlink subframe occupying the PDCCH according to the occupation condition of the PDCCH, and transmitting the polymerization degree to the resource acquisition module; when the polymerization degree is detected to be larger than 1, triggering the information organization module and the sending module;
the resource acquisition module is used for acquiring a logical resource index implied by a Physical Uplink Control Channel (PUCCH) according to a downlink subframe occupying the PDCCH and the polymerization degree and notifying the sending module;
and the sending module is triggered by the parameter detection module and is used for sending RI information to the base station through the PUCCH on the uplink subframe n by selecting the physical resource corresponding to the logical resource index implied by any PUCCH provided by the resource acquisition module.
Further, the parameter detection module is further configured to acquire, from the downlink subframe occupying the PDCCH, an index value of a control channel element CCE that a downlink subframe occupying the PDCCH and whose value m is the smallest occupies the beginning of the PDCCH, and the index value and the value m are the smallest, and send the index value and the value m to the resource acquisition module;
the resource obtaining module is further configured to obtain a logical resource index implied by the PUCCH according to the m with the smallest value, the index value, and the polymerization degree, and notify the sending module.
Further, when detecting that the polymerization degree is not greater than 1, the parameter detection module also notifies the information organization module;
the information organization module is used for carrying out joint coding on the ACK/NACK information and the RI information and informing the sending module;
and the sending module sends the information obtained after the joint coding to the base station on a PUCCH format 2a/2 b.
The invention has the beneficial technical effects that:
the invention fully utilizes the resources implied by the PUCCH format 1/1a/1b to send RI, thereby saving the physical resources of the PUCCH format 2/2a/2 b; in addition, a relatively small PUCCH logical resource index is obtained by selecting the downlink subframe with the minimum value of m and the minimum value of m, so that physical resources used by the PUCCH format 1/1a/1b are saved; in addition, the method for transmitting information on PUCCH format 2a/2b in the prior art can be compatible.
Detailed Description
The core of the invention is that: the UE selects the downlink subframe with the minimum value of m and obtains a relatively small PUCCH logical resource index with the minimum value of m, so that physical resources used by the PUCCH format 1/1a/1b are saved; in addition, the RI is transmitted by fully utilizing the resources implied by the PUCCH format 1/1a/1b, thereby saving the physical resources of the PUCCH format 2/2a/2 b.
FIG. 7 shows a flowchart of the method of the present invention:
step 100, the UE obtains a set K { K) of the current uplink subframe n according to the uplink and downlink proportion1,k2...kmM is an index of the set K and is less than or equal to M-1; referring to fig. 6, a relationship between an uplink-downlink ratio and a set K can be obtained, where M is the number of elements in the set K, and a physical meaning is the maximum number of ACK/NACK information generated by the uplink subframe that needs to be fed back to the downlink subframe; the base station informs the UE of the uplink and downlink ratio through broadcasting;
at the moment, the UE obtains a plurality of downlink subframes n-k corresponding to the uplink subframe nmDetecting whether the DOWNLINK sub-frames occupy a PDCCH (PHYSICAL DOWNLINK CONTROL CHANNEL), and then executing step 200;
step 200, for all detected downlink subframes occupying PDCCH, UE selects the downlink subframe with the minimum value m from the downlink subframes, and obtains an index value n of a CCE (Control Channel Element) occupying the beginning of PDCCH by the downlink subframe with the minimum value mCCEAnd m, where the value is smallest;
the UE also obtains the CCE polymerization degree L of the PDCCH occupied by the downlink subframe according to the condition that the PDCCH is occupied by the downlink subframe;
obviously, the choice of the value of m is a very significant difference between the present invention and the prior art, and the effect can be seen by the following step 400;
step 300, UE according to n obtained in step 200CCESelecting a symbol index value p for the PDCCH from the set {0, 1, 2, 3 };
p is selected to satisfy the following conditions: n isCCEThe total number Np of CCEs of p symbols in the PDCCH is more than or equal to the total number Np of CCEs of p +1 symbols in the PDCCH and is less than the total number Np +1 of CCEs of p +1 symbols in the PDCCH;
the position of the CCE in the PDCCH in the control symbol region may be determined in step 300;
step 400, the UE obtains m with the minimum value according to step 100 and n according to step 200
CCEAnd Np +1 obtained in step 300, obtaining the PUCCH logical resource index
In practical application, the formula for calculating the PUCCH logical resource index for transmitting ACK/NACK information specified in the protocol can be used:
<math><mrow><msubsup><mi>n</mi><mi>PUCCH</mi><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msubsup><mo>=</mo><mrow><mo>(</mo><mi>M</mi><mo>-</mo><mi>m</mi><mo>-</mo><mn>1</mn><mo>)</mo></mrow><mo>×</mo><msub><mi>N</mi><mi>p</mi></msub><mo>+</mo><mi>m</mi><mo>×</mo><msub><mi>N</mi><mrow><mi>p</mi><mo>+</mo><mn>1</mn></mrow></msub><mo>+</mo><msub><mi>n</mi><mi>CCE</mi></msub><mo>+</mo><msubsup><mi>N</mi><mi>PUCCH</mi><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></msubsup></mrow></math>
wherein,
the base station reserves PUCCH logical resources for SR and semi-static ACK/NACK, and the PUCCH logical resources are obtained by the configuration of an RRC layer of the base station; m is the number of elements in the middle set K, and the physical meaning is the maximum number of downlink sub-frames ACK/NACK needing to be fed back by the uplink sub-frame;
meanwhile, step 400 may also obtain other available logical resources implied by the UE:
in this case, the method of the present invention obtains a resource index in comparison with the method prescribed by the existing protocol
The method according to the invention is described below as an application example, which is clearly smaller.
Taking the
above downlink ratio 3 as an example, a logical resource map of the
PUCCH format 1/1a/1b is drawn according to the CCE index occupied by the downlink PDCCH in combination with the values of the elements in the formula, see fig. 8,
represents the (n-7) th subframe logical resource (m ═ 0),
denotes an n-6 th subframe logical resource (m ═ 1),
denotes the N-11 th subframe logical resource (m 2), N
CCE,pRepresents the number of CCEs when the PCFICH value is p.
Calculated to obtain
The closer to the rear, the more RB resources are occupied; for the uplink subframe n, assuming that the PDCCH is detected in the downlink subframes n-7, n-6, n-11, according to the method of the current protocol, the resource index of the feedback ACK/NACK can be obtained
According to the method of the invention, a resource index can be obtained
The specific location is identified in fig. 8. It is obvious that the method results in
Smaller than the values obtained by the existing protocols, closer to the left in fig. 8, there are fewer RB resources to be dynamically allocated to the
PUCCH format 1/1a/1 b. Therefore, the m-value selection method of the present disclosure can reduce the use of RB resources by PUCCH.
Step 500, detecting whether RI information and ACK/NACK information exist at the same time and are fed back in an uplink subframe n; if only ACK/NACK information exists, performing step 600; if the RI information and the ACK/NACK information exist at the same time, step 700 is performed;
step 600, when only ACK/NACK information is fed back in the uplink subframe n, the UE selects the ACK/NACK information determined in step 400
Corresponding physical resources are used for feeding back ACK/NACK information generated by a downlink subframe occupying the PDCCH to the base station on an uplink subframe n through the PUCCH, and the process is ended;
step 700, detecting whether the CCE polymerization degree L of the PDCCH occupied by the downlink subframe with the minimum m value is greater than 1; if not, go to step 800; if greater than 1, go to step 900;
step 800, performing joint coding on ACK/NACK and RI, and sending the ACK/NACK and the RI on PUCCH format 2a/2 b;
step 900, when the CCE polymerization degree L of the PDCCH is more than 1, the UE selects the CCE polymerization degree L
The corresponding physical resource sends ACK/NACK information generated by a downlink subframe occupying a PDCCH to a base station, and selects any physical resource corresponding to the implicit logical resource index to send RI information to the base station;
in service implementation, when the CCE polymerization degree L of the PDCCH is greater than 1, calculating
N in the formula
CCE(CCE starting position) is not continuous, so calculated
The logical resources of L PUCCH formats 1a/1b are implied;
UE selects the same
Corresponding physical resources send ACK/NACK information generated by a downlink subframe occupying PDCCH to a base station, and at the moment, a lot of PUCCH format 1a/1b logical indexes are not used, so that the residual utilization can be considered
A logical resource to transmit the RI;
specific logical resources for sending RI can be specified, so that the receiving end can demodulate according to the logical resources of RI, and achieve transmission of RI information between UE and base station:
1) on a logical resource
Sending ACK/NACK occupying a downlink subframe of the PDCCH;
2) in that
Arbitrarily selecting one of the logical resources to transmit the RI:
if in a logical resource
Transmitting RI at the base station
The RI is received.
If in a logical resource
Transmitting RI at the base station
The RI is received.
......
If in a logical resource
Transmitting RI at the base station
The RI is received.
It can be seen that, compared with the prior art describing the prior RI information transmission method, the present invention effectively utilizes the resources of the implicit PUCCH format 1/1a/1b to transmit RI, and saves the resources of the PUCCH format 2/2a/2 b.
It should be noted that the obtaining manner of the implicit resource used in the RI information sending method of the present invention is not limited to the obtaining manner using the minimum value of m.
In another embodiment, resources are obtained by using the m value specified in the existing protocol to minimize km (km ∈ K).
As shown in fig. 9, the terminal for feeding back ACK/NACK information using an uplink subframe according to the present invention includes: the system comprises an information organization module 10, a parameter detection module 20, a resource acquisition module 30 and a sending module 40;
the information organization module 10 is configured to obtain a plurality of k values according to the current uplink and downlink ratio, and determine a downlink subframe n-kmInforming the parameter detection module 20, where m is an index of k values; receiving the occupation situation of the downlink subframe to the PDCCH notified by the parameter detection module 20, the AC generated by the downlink subframe occupying the PDCCHThe K/NACK information informs the sending module 40; the parameter detection module 20 is further configured to notify the sending module 40 of RI information;
the parameter detecting module 20 is configured to detect the downlink subframe n-kmNotifying the information organization module 10 of the occupation situation of the physical downlink control channel PDCCH; and obtaining the index value n of the initial control channel element CCE of the PDCCH occupied by the downlink subframe with the minimum m value from the downlink subframes occupying the PDCCHCCEThe polymerization degree L of the CCE of the PDCCH and the m with the minimum value are sent to the resource obtaining module 30; when detecting that L is larger than 1, triggering the information organization module 10 and the sending module 40;
the resource obtaining module 30 is configured to obtain the index value n from the parameter detecting module 20
CCEAnd obtaining the physical uplink control channel PUCCH logical resource index for sending the ACK/NACK information by taking the minimum value m
Indexing the PUCCH logical resources
Notifying the sending module 40; and is further configured to use the index value n of the control channel element CCE that occupies the beginning of the PDCCH according to the minimum value m sent by the parameter detection module 20 and the minimum value m of the downlink subframe
CCEAnd acquiring the implicit logical resource index of the PUCCH by occupying the polymerization degree L of the CCE of the PDCCH
And notifies the sending module 40;
the sending module 40 selects the above
Corresponding physical resources are used for feeding back ACK/NACK information generated by a downlink subframe occupying a PDCCH to a base station on an uplink subframe n through the PUCCH; and also for accommodationsThe parameter detection module 20 triggers to select any implicit logical resource index provided by the resource acquisition module 30
And the corresponding physical resource sends RI information to the base station.
The specific operation and function of the terminal also include the
information organization module 10, which is also used for organizing the information according to n
CCESelecting a symbol index value p, n for PDCCH from the set {0, 1, 2, 3}
CCEGreater than or equal to Np and less than Np + 1; and Np, Np +1 and M,
Sending to the resource obtaining module 30; the resource obtaining module 30 obtains the minimum m and n according to the value
CCEAnd M,
And the Np and Np +1 are used for acquiring the PUCCH logical resource index
In addition, the parameter detection module further notifies the information organization module when detecting that the polymerization degree is not greater than 1; the information organization module is used for carrying out joint coding on the ACK/NACK information and the RI information and informing the sending module; and the sending module sends the information obtained after the joint coding to the base station on a PUCCH format 2a/2 b.
The method corresponds to the operation flow of the method, and reference is made to the description of the method for the deficiency, which is not repeated herein.
It should be noted that the obtaining method of the implicit resource used by the RI information sending apparatus of the present invention is not limited to the obtaining method using the minimum value of m.
In another embodiment, resources are obtained by using the m value specified in the existing protocol to minimize km (km ∈ K).
While the foregoing description shows and describes a preferred embodiment of the invention, it is to be understood, as noted above, that the invention is not limited to the form disclosed herein, but is not intended to be exhaustive or to exclude other embodiments and may be used in various other combinations, modifications, and environments and may be modified within the scope of the inventive concept described herein by the above teachings or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.