Embodiment
Embodiment of the present invention receiver is according to the channel condition information of i subband, from the leaf node set, select i the leaf node that subband is corresponding, wherein the leaf node set is that code word that i-1 subband is corresponding is as root node, and the set of the leaf node composition definite according to this root node, i is the positive integer greater than 2; Receiver is determined the positional information of quantized channel information in code book of i subband according to the code word in the leaf node of selecting, and sends positional information to transmitter.Due to the Nested property of utilizing tree-like sub-codebook structure, guarantee in the channel information quantized value word selection of i subband a plurality of code words relevant to the channel status of i-1 subband, when system bandwidth is larger, can make code word and the channel matched of receiver feedback, thereby can improve systematic function in the lower expense of maintenance.
Wherein, the embodiment of the present invention changes the multi-stage codebooks in the background technology of Fig. 1, form a plurality of tree type sub-codebooks, each tree type sub-codebook comprises a root node and a plurality of leaf node, and have nest relation between tree type sub-codebook, each tree type sub-codebook can store into respectively in transmitter and receiver; Also can store in other entities, call for transmitter and receiver.
Specifically can two tree type sub-codebooks be arranged in Fig. 3 referring to Fig. 3, wherein the code word in a leaf node of the code word in the root node of second tree type sub-codebook and first tree-like sub-codebook is identical.
That is to say that each leaf node of first tree type sub-codebook all as other root node, is then determined leaf node under this root node according to the code word in root node.
Concrete, the tree code book with Nested property can produce in the following manner:
With the tree root of each code word in the single-stage code book as a tree, to each root vertex, choose self and have with it a group code word of minimum range as its leaf node.
Because subband has correlation, thus according in this nest relation of tree-like sub-codebook, determine the code word of each subband, thus can make code word and the channel matched of receiver feedback.
A code word in the embodiment of the present invention is exactly a pre-coding matrix, and positional information is exactly quantized channel information value of feedback.
In specific implementation process, the content in root node and leaf node can be code word, also can be with code word as root node and leaf node.
Unless specified otherwise otherwise positional information in the embodiment of the present invention is all the positional information of quantized channel information in code book.
Below in conjunction with Figure of description, the embodiment of the present invention is described in further detail.
As shown in Figure 2, the embodiment of the present invention determines that the system of code word comprises: receiver 10 and transmitter 20.
Receiver 10, be used for the channel condition information according to i subband, select i the leaf node that subband is corresponding from the leaf node set of tree-like sub-codebook, and according to the code word in the leaf node of selecting, determine the positional information of quantized channel information in code book of i subband, and send positional information to transmitter.
Wherein, the leaf node set be code word that i-1 subband is corresponding as root node, and the set that forms according to the leaf node that this root node is determined; Positional information is i the position of quantized channel information in the tree-like sub-codebook of correspondence that subband is corresponding of indication; I is the positive integer greater than 2.
Indicate the position of quantized channel information in code book of first subband for the positional information of first subband.
Transmitter 20 is used for determining i the code word that subband is corresponding according to the positional information from receiver 10 of receiving.
Wherein, system bandwidth is divided into several subbands, and receiver 10 and transmitter 20 are determined the order of each subband according to the sortord of setting.
Store into respectively after sortord can artificially be set in receiver 10 and transmitter 20, determine after also can being consulted by receiver 10 and transmitter 20.
Concrete sortord includes but not limited to a kind of in following order:
Frequency location according to subband sorts from big to small;
Frequency location according to subband sorts from small to large.
Receiver 10 sequentially is the subband sequence according to the subband of determining, then sequentially send the positional information of quantized channel information in code book corresponding to subband according to this, wherein can determine all to send in order again after the positional information (PMI that comprises first subband) of all subbands, also can determine just to send one after a positional information;
Accordingly, transmitter 20 just can be determined corresponding which subband of this positional information according to the order of the positional information of receiving.
Also have a kind of mode can be each allocation of subbands sign, then add the sign of corresponding subband in positional information;
Accordingly, transmitter 20 just can be known corresponding which subband of the positional information of this quantized channel information in code book according to sign.
In specific implementation process, receiver 10 is for first subband, need to be according to the channel condition information of first subband, and select the code word of a root node as code word corresponding to first subband from the code word of the root node of all tree-like sub-codebooks.
Select the mode of code word to have according to channel condition information a variety of, for example according to maximum channel capacity criterion, selected code word can make the equivalent channel after precoding have maximum channel capacity.
After receiver 10 has been determined the code word of first subband, determine the PMI that this code word is corresponding.
Receiver 10 according to the channel condition information of second subband, selects the code word of a leaf node as code word corresponding to first subband after the code word of having determined first subband the code word of all leaf nodes under the root node of selecting; Then according to the code word of second subband and the position relationship (be the position relationship of root node and the leaf node chosen) of code word in tree-like sub-codebook of first subband, determine the quantized channel information of second subband.
Receiver 10 is according to the code word of second subband, look for a root node identical with the code word of second subband from tree-like sub-codebook, then according to the channel condition information of the 3rd subband, select a leaf node all leaf nodes under this root node, and with the code word of the code word in the leaf node of selecting as the 3rd subband.
Accordingly, the code word of the 4th subband be from the root node identical with the code word of the 3rd subband select remaining leaf node, the like, do not repeat them here.
That is to say, as content root node, and select a leaf node in the leaf node of determining according to this root node from code word corresponding to i-1 subband, and with the code word of the code word in the leaf node of selecting as i subband.
As shown in Figure 3, the code word of first subband is A, selects B as the code word of second subband from all leaf nodes of A, then selects C as the code word of the 3rd subband from all leaf nodes of determining take B as root node, the like.
This method embodiment can be according to the variation of channel, and the code word during with quantification expands in all code words goes.In Fig. 3 after the channel information quantized result of known previous subband, the channel information quantized value of current subband will with on choose in a maximally related secondary codebook subset of sub-band channel information quantization value.This feedback method has been considered the correlation of channel between subband, except feeding back B to first subband
0Outside bit, remaining subband all only needs feedback to be used for characterizing l bit of certain subtree leaf node, and feedback quantity altogether is (N-1) l+B
1, wherein N is that number of sub-bands, 1 is the bit number that the needed bit number of positional information, B1 need to feed back for first subband.
Utilize the Nested property of codebook structure, the channel information quantized value of subband i is chosen from the most relevant to the channel status of subband i-1 2
lAmong individual code word, rather than within quantitative information being limited to a subtree centered by the quantized value of subband 1 as the differential feedback method of introducing in background technology, thereby can travel through whole code book, and due to correlation being arranged between filial generation, the code word of a rear subband is to select the leaf node of determining as root node from the code word of last height band, thereby can guarantee that the code word of feeding back can be good at mating with channel.
In the tree-like sub-codebook of introducing in the above, the code word in the root node of arbitrary tree-like sub-codebook must be subordinated to the leaf node set of other tree-like sub-codebook; Arbitrary leaf node must be the root node of the tree-like sub-codebook of another one.
For code word and the channel that further makes feedback can be good at coupling, can also make arbitrary root node is also a leaf node of this tree-like sub-codebook self.
That is to say, the code word in the root node under the code word of a leaf node in the leaf node set and this leaf node set is identical.
In Fig. 3, in the tree-like sub-codebook of A as root node, there is the code word in leaf node identical with code word A in all leaf nodes.
The benefit of doing like this is, if the correlation of two subbands is very strong, the code word that two subbands can occur is all identical, like this can be better and channel matched.
Code word for next subband can continue to select the leaf node below A.
Transmitter 20 can first be received PMI according to the reception order, then determines the code word of first subband according to PMI.
Because certain code word in PMI and code book is corresponding one by one, so transmitter can uniquely according to the PMI of feedback be determined code word corresponding to this PMI.
After the code word of having determined first subband, search the root node identical with this code word, and according to the positional information of first quantized channel information in code book of receiving, determine a leaf node leaf node under the root node that finds, and with the code word of the code word in the leaf node of determining as second subband;
The mode of follow-up definite other subband code words is similar with the mode of the code word of determining second subband, does not repeat them here.
Wherein, the receiver of the embodiment of the present invention can be user terminal, can be also other equipment of user's side; The transmitter of the embodiment of the present invention can be the base station, can be also other equipment of network side.
As shown in Figure 4, embodiment of the present invention receiver comprises: select module 100 and sending module 110.
Select module 100, be used for the channel condition information according to i subband, select i the leaf node that subband is corresponding from the leaf node set of tree-like sub-codebook, and according to the code word in the leaf node of selecting, determine the positional information of quantized channel information in code book of i subband, wherein the leaf node set be code word that i-1 subband is corresponding as root node, and the set that forms according to the leaf node that this root node is determined;
Sending module 110 is used for sending the quantification channel information in the positional information of code book to transmitter, is used to indicate transmitter and determines i the code word that subband is corresponding according to positional information;
Wherein, positional information is i the position of quantized channel information in the tree-like sub-codebook of correspondence that subband is corresponding of indication; I is the positive integer greater than 2.
Wherein, the receiver of the embodiment of the present invention can further include: order module 120.
Order module 120 is used for selecting before module 100 selects leaf node corresponding to subbands, according to the frequency location of subband by height on earth or order from low to high all subbands are sorted.
Sortord in embodiment of the present invention receiver and the embodiment of the present invention determine that the sortord in the system of code word is similar, do not repeat them here.
Wherein, sending module 110 sends positional information corresponding to subband according to the order after sorting, wherein can select module 100 to determine all to send in order again after the positional information (PMI that comprises first subband) of quantized channel information in code book of all subbands, also can select module 100 to determine just to send one after a positional information.
Also having a kind of mode is order module 120 each allocation of subbands sign (specifically corresponding which sign of which subband can artificially be stipulated or be consulted to determine with transmitter 20), then selects module 100 to add the sign of corresponding subband in positional information.
In specific implementation process, select module 100 for first subband, need to be according to the channel condition information of first subband, select the code word of a root node as code word corresponding to first subband from the code word of the root node of all tree-like sub-codebooks; After having determined the code word of first subband, select module 100 to determine PMI corresponding to this code word; After the code word of having determined first subband, select module 100 according to the channel condition information of second subband, select the code word of a leaf node as code word corresponding to first subband the code word of all leaf nodes under the root node of selecting; Then according to the code word of second subband and the position relationship (be the position relationship of root node and the leaf node chosen) of code word in tree-like sub-codebook of first subband, determine the label corresponding to quantized channel information of second subband; Code word according to second subband, look for a root node identical with the code word of second subband from tree-like sub-codebook, then according to the channel condition information of the 3rd subband, select a leaf node all leaf nodes under this root node, and with the code word of the code word in the leaf node of selecting as the 3rd subband.
The code word of the 4th subband be from the root node identical with the code word of the 3rd subband select remaining leaf node, the like, do not repeat them here.
In the tree-like sub-codebook of introducing in the above, the code word in the root node of arbitrary tree-like sub-codebook must be subordinated to the leaf node set of other tree-like sub-codebook; Arbitrary leaf node must be the root node of the tree-like sub-codebook of another one.
For code word and the channel that further makes feedback can be good at coupling, can also make arbitrary root node is also a leaf node of this tree-like sub-codebook self.
That is to say, the code word in the root node under the code word of a leaf node in the leaf node set and this leaf node set is identical.
As shown in Figure 5, embodiment of the present invention transmitter comprises: receiver module 200 and determination module 210.
Receiver module 200 is used for receiving the positional information from receiver.
Determination module 210 is used for according to the code word of i-1 subband and positional information corresponding to quantized channel information corresponding to i subband of receiving, determines i the code word that subband is corresponding from tree-like sub-codebook,
Wherein, positional information is i the position of quantized channel information in the tree-like sub-codebook of correspondence that subband is corresponding of indication, and i is the positive integer greater than 2.
Receiver module 200 can first be received PMI according to the reception order, and then receiver module 200 is determined the code word of first subband according to PMI; After the code word of having determined first subband, receiver module 200 is searched the root node identical with this code word, and according to first positional information of receiving, determine a leaf node leaf node under the root node that finds, and with the code word of the code word in the leaf node of determining as second subband.
The mode of follow-up definite other subband code words is similar with the mode of the code word of determining second subband, does not repeat them here.
As shown in Figure 6, embodiment of the present invention the first determines that the method for code word comprises:
step 601, receiver is according to the channel condition information of i subband, select i the leaf node that subband is corresponding from the leaf node set of tree-like sub-codebook, and receiver is according to the code word in the leaf node of selecting, determine the positional information of quantized channel information in code book of i subband, wherein the leaf node set is that code word that i-1 subband is corresponding is as root node, and the set of the leaf node composition definite according to this root node, positional information is i the position of quantized channel information in the tree-like sub-codebook of correspondence that subband is corresponding of indication, i is the positive integer greater than 2.
Indicate the position of quantized channel information in code book of first subband for the positional information of first subband.
Step 602, receiver send the positional information of determining to transmitter, be used to indicate transmitter and determine i the code word that subband is corresponding according to positional information.
Wherein, can further include before step 601:
Step 600, receiver according to the frequency location of subband by height on earth or order from low to high all subbands are sorted.
In specific implementation process, system bandwidth is divided into several subbands, and Receiver And Transmitter is determined the order of each subband according to the sortord of setting.
Store into respectively in Receiver And Transmitter after sortord can artificially be set, determine after also can being consulted by Receiver And Transmitter.
Concrete sortord includes but not limited to a kind of in following order:
Frequency location according to subband sorts from big to small;
Frequency location according to subband sorts from small to large.
In step 600, receiver sequentially is the subband sequence according to the subband of determining, then receiver sequentially sends positional information corresponding to subband according to this, wherein receiver can be determined all to send in order after the positional information (PMI that comprises first subband) of all subbands again, also can determine just to send one after a positional information;
Accordingly, transmitter just can be determined corresponding which subband of this positional information according to the order of the positional information of receiving.
Also have a kind of mode receiver can be each allocation of subbands sign, then add the sign of corresponding subband in positional information;
Accordingly, transmitter just can be known corresponding which subband of this positional information according to sign.
In step 601, receiver is for first subband, need to be according to the channel condition information of first subband, and select the code word of a root node as code word corresponding to first subband from the code word of the root node of all tree-like sub-codebooks.
Select the mode of code word to have according to channel condition information a variety of, for example according to maximum channel capacity criterion, selected code word can make the equivalent channel after precoding have maximum channel capacity.
After receiver has been determined the code word of first subband, determine the PMI that this code word is corresponding.
Receiver according to the channel condition information of second subband, selects the code word of a leaf node as code word corresponding to first subband after the code word of having determined first subband the code word of all leaf nodes under the root node of selecting; Then according to the code word of second subband and the position relationship (be the position relationship of root node and the leaf node chosen) of code word in tree-like sub-codebook of first subband, determine the quantized channel information of second subband.
Receiver is according to the code word of second subband, look for a root node identical with the code word of second subband from tree-like sub-codebook, then according to the channel condition information of the 3rd subband, select a leaf node all leaf nodes under this root node, and with the code word of the code word in the leaf node of selecting as the 3rd subband.
Accordingly, the code word of the 4th subband be from the root node identical with the code word of the 3rd subband select remaining leaf node, the like, do not repeat them here.
That is to say, as content root node, and select a leaf node in the leaf node of determining according to this root node from code word corresponding to i-1 subband, and with the code word of the code word in the leaf node of selecting as i subband.
In the tree-like sub-codebook of introducing in the above, the code word in the root node of arbitrary tree-like sub-codebook must be subordinated to the leaf node set of other tree-like sub-codebook; Arbitrary leaf node must be the root node of the tree-like sub-codebook of another one.
For code word and the channel that further makes feedback can be good at coupling, can also make arbitrary root node is also a leaf node of this tree-like sub-codebook self.
That is to say, the code word in the root node under the code word of a leaf node in the leaf node set and this leaf node set is identical.
In Fig. 3, in the tree-like sub-codebook of A as root node, there is a code word in leaf node identical with code word in A in all leaf nodes.
The benefit of doing like this is exactly, if the correlation of two subbands is very strong, the code word that two subbands can occur is all identical, like this can be better and channel matched.
Code word for next subband can continue to select the leaf node below A.
Wherein, can further include after step 602:
Step 603, transmitter are determined i the code word that subband is corresponding according to the code word of i-1 subband and i the positional information that subband is corresponding of receiving from tree-like sub-codebook.
Concrete, transmitter can first be received PMI according to the reception order, then determines the code word of first subband according to PMI.
After the code word of having determined first subband, search the root node identical with this code word, and according to first positional information of receiving, determine a leaf node the leaf node under the root node that finds, and with the code word of the code word in the leaf node of determining as second subband;
The mode of follow-up definite other subband code words is similar with the mode of the code word of determining second subband, does not repeat them here.
Wherein, the receiver of the embodiment of the present invention can be user terminal, can be also other equipment of user's side; The transmitter of the embodiment of the present invention can be the base station, can be also other equipment of network side.
The supposing the system bandwidth is 10MHz, takies 50 RB, and the subband size is 6RB, uses the 6bit code book:
According to the feedback system that this method embodiment proposes, suppose that the leaf node of each subtree represents with 3bit, the channel information of initial subband quantizes with 6bit.Required feedback quantity is also altogether
Within but this feedback system was not limited to some subtrees with the quantized value that feeds back, along with the variation of channel, adjacent sub-bands can use different subtrees that channel information is quantized.
As shown in Figure 7, embodiment of the present invention the second determines in the method for code word, and receiver is according to obtaining channel information to measurement or other modes of pilot tone, and adopts differential mode to report the channel information of quantification.
Be fed back to example with frequency domain differential demodulation, receiver calculates the feedback of channel information amount of each subband one by one from certain subband.
Initial condition i=1, i.e. first subband.
Step 700, for initial subband SB
1, use the one-level code book to quantize to obtain feedback quantity to its channel information
Wherein
Expression is with CB
1Quantization operation for code book.
Step 701, i increase by 1, i.e. next subband.
Step 702, check whether i is not more than N, if not, jump out the present embodiment; Otherwise, execution in step 702, wherein, N is the quantity of subband.
Step 703, for second subband, use with FB
1For a subset in the corresponding secondary code book of the subtree leaf node of tree root quantizes to obtain to it
Γ (FB wherein
1) represent with FB
1Then code book for the subtree leaf node of tree root consists of returns to step 701.
The code book that uses due to the invention process has the nest relation of root node and leaf node, FB
2Must be the tree root of certain subtree, therefore for the 3rd subband, will use with FB
2The code book that consists of for the subtree leaf node of subtree root is to SB
3Channel information quantize, obtain the quantized channel information value of feedback of the 3rd subband:
Then, except first subband, other arbitrary subbands are all take the quantized channel information of last subband feedback as the subtree root, and seek the quantized channel information of current subband in the leaf node of this subtree.
Can find out from above-described embodiment: the embodiment of the present invention is according to the channel condition information of i subband, select i the leaf node that subband is corresponding from the leaf node set of tree-like sub-codebook, wherein said leaf node set be code word that i-1 subband is corresponding as root node, and the set that forms according to the leaf node that this root node is determined; Receiver is determined the positional information of quantized channel information in code book of i subband according to the code word in the leaf node of selecting, and sends positional information to transmitter, is used to indicate transmitter and determines i the code word that subband is corresponding according to positional information; Wherein positional information is i the position of quantized channel information in the tree-like sub-codebook of correspondence that subband is corresponding of indication; I is the positive integer greater than 2.
Due to the Nested property of utilizing tree-like sub-codebook structure, guarantee in the channel information quantized value word selection of i subband a plurality of code words relevant to the channel status of i-1 subband, when system bandwidth is larger, can make code word and the channel matched of receiver feedback, thereby can improve systematic function in the lower expense of maintenance;
Further, the embodiment of the present invention can also travel through whole code book when guaranteeing than low-feedback, thereby can well simplify the based on feedback link design according to the variation of channel, and the impact that resource is distributed.
Obviously, those skilled in the art can carry out various changes and modification and not break away from the spirit and scope of the present invention the present invention.Like this, if within of the present invention these are revised and modification belongs to the scope of claim of the present invention and equivalent technologies thereof, the present invention also is intended to comprise these changes and modification interior.