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`US 20130163687Al
`
`c19) United States
`c12) Patent Application Publication
`Jing et al.
`
`c10) Pub. No.: US 2013/0163687 Al
`Jun. 27, 2013
`(43) Pub. Date:
`
`(54) METHOD AND DEVICE FOR PROCESSING
`CODEBOOK SUBSET RESTRICTION
`
`(75)
`
`Inventors: Meifang Jing, Beijing (CN); Qiubin
`Gao, Beijing (CN); Ranran Zhang,
`Beijing (CN); Shaohui Sun, Beijing
`(CN); Guojun Xiao, Beijing (CN);
`Rakesh Tamrakar, Beijing (CN)
`
`(73) Assignee: China Academy of
`Telecommunications Technology,
`Beijing (CN)
`
`(21)
`
`Appl. No.:
`
`13/701,276
`
`(22)
`
`PCT Filed:
`
`Sep.16,2011
`
`(86)
`
`PCT No.:
`
`PCT/CN2011/079711
`
`§ 371 (c)(l),
`(2), ( 4) Date:
`
`Feb.8,2013
`
`(30)
`
`Foreign Application Priority Data
`
`Sep. 16, 2010
`
`(CN) ............................ 201010285420
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`H04B 7104
`(52) U.S. Cl.
`CPC .................................... H04B 710456 (2013.01)
`USPC .......................................................... 375/267
`
`(2006.01)
`
`(57)
`
`ABSTRACT
`
`The present invention discloses a method and device for
`processing codebook subset restriction, which includes: the
`codebooks for every rank of N antenna ports are grouped,
`wherein N is a natural number; after grouping, the status of
`each group is identified as restricted or unrestricted by using
`one bit. The present invention can reduce the signaling over(cid:173)
`head needed for codebook subset restriction.
`
`Group precoding matrixes in codebooks
`at respective ranks with N antenna ports
`respectively, where N is a natural number
`
`101
`
`J
`
`, '
`Identify the state of each group as restricted J
`
`or unrestricted by one bit after grouping
`
`102
`
`~'
`Set, information to identify the respective groups J
`
`in the codebooks at the respective ranks as
`restricted or unrestricted, into a codebook subset
`restriction option of higher-layer signalling
`
`103
`
`, '
`Transmit the higher-layer signalling to a UE to J
`
`instrnct the UE to report a PMI(s) and/or an
`RI(s) according to the codebook subset restriction
`option in the higher-layer signalling
`
`104
`
`Samsung Ex. 1011
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`

`

`Patent Application Publication
`
`Jun. 27, 2013 Sheet 1 of 2
`
`US 2013/0163687 Al
`
`Group precoding matrixes in codebooks
`at respective ranks with N antenna ports
`respectively, where N is a natural number
`
`Identify the state of each group as restricted
`or unrestricted by one bit after grouping
`
`Set, information to identify the respective groups
`in the codebooks at the respective ranks as
`restricted or unrestricted, into a codebook subset
`restriction option of higher-layer signalling
`
`Transmit the higher-layer signalling to a UE to
`instrnct the UE to report a PMI(s) and/or an
`RI(s) according to the codebook subset restriction
`option in the higher-layer signalling
`
`Fig. 1
`
`101
`
`102
`
`103
`
`104
`
`Receive higher-layer signalling
`
`Report a PMI(s) and/or an RI(s) aeeording
`to a codebook subset restriction option in
`the higher-layer signalling
`
`201
`
`202
`
`Fig. 2
`
`Samsung Ex. 1011
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`

`

`Patent Application Publication
`
`Jun. 27, 2013 Sheet 2 of 2
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`US 2013/0163687 Al
`
`r 301
`
`r 302
`
`Storing module
`
`Identifying module
`
`/304
`
`/303
`
`Transmitting
`module
`
`Setting module
`
`Fig. 3
`
`r
`Higher-layer signalling
`(Co debook subset restriction) - Receiving module
`
`401
`
`~
`
`/402
`
`PMI and/ or RI
`
`~
`
`~
`
`Reporting module
`
`Fig. 4
`
`Samsung Ex. 1011
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`

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`US 2013/0163687 Al
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`Jun. 27, 2013
`
`METHOD AND DEVICE FOR PROCESSING
`CODEBOOK SUBSET RESTRICTION
`
`[0001] This application claims the benefit of Chinese
`Patent Application No. 201010285420.0, filed with the Chi(cid:173)
`nese Patent Office on Sep. 16, 2010 and entitled "Method and
`device for processing codebook subset restriction", which is
`hereby incorporated by reference in its entirety.
`
`FIELD
`
`[0002] The present invention relates to the field of wireless
`communication and particularly to a method and device for
`processing a codebook subset restriction.
`
`BACKGROUND
`
`[0003] A Multiple Input Multiple Output (MIMO) system
`adopts a plurality of transmit and receive antennas and uti(cid:173)
`lizes joint processing of a signal in the space, time and fre(cid:173)
`quency domains for velocity, diversity and array gains. In the
`MIMO system, if a transmitter can know channel information
`somehow, then it can optimize a transmission signal accord(cid:173)
`ing to a channel characteristic to improve the quality of recep(cid:173)
`tion and to lower a requirement on the complexity of a
`receiver. In general, a Time Division Duplex (TDD) system
`can obtain channel information due to channel reciprocity,
`but a Frequency Division Duplex (FDD), or the TDD system
`in some special cases, has to require channel information to
`be fed back from a receiver. Quantified channel information is
`typically fed back in a real system to lower a feedback over(cid:173)
`head and a feedback delay. Channel information can be quan(cid:173)
`tified for a channel matrix and a statistic thereof or for a
`preprocessing parameter recommended by the receiver. The
`quantified channel information is mapped into a set consti(cid:173)
`tuted of a limited number of elements, which is referred to as
`a codebook.
`In order to stabilize mutual interference between
`[0004]
`cells for the sake of improving the accuracy of a Channel
`Quality Indicator (CQI) reporting by a User Equipment (UE),
`a method for restricting a codebook subset by higher-layer
`signalling to signal a codebook subset restriction has been
`defined in the Release 8 (Rel-8), and the signalling is referred
`to as codebookSubsetRestriction in the Rel-8. Specifically a
`Precoding Matrix Indicator(s) (PMI) and/or a Rank Indicator
`(s) (RI) reported from the UE are/is restricted by codebook(cid:173)
`SubsetRestriction configured in higher-layer signalling. For a
`specific precoding codebook and a relevant transmission
`mode, whether respective precoding matrixes in all the code(cid:173)
`books are available is specified in a bitmap approach to
`thereby indicate a codebook subset available to the UE. A
`codebook subset restriction may be applied to open loop and
`closed loop multiplexing, multi-user MIMO and precoding of
`a closed loop with an RI=l. A specific correspondence rela(cid:173)
`tionship is as depicted in Table 1.
`
`TABLE 1
`
`The number of bits of codebook subset restriction for different
`transmission modes
`
`Number of bits A
`
`2 antenna ports
`
`4 antenna ports
`
`Transmission mode 3
`Transmission mode 4
`
`4
`64
`
`TABLE I-continued
`
`The number of bits of codebook subset restriction for different
`transmission modes
`
`Number of bits A
`
`2 antenna ports
`
`4 antenna ports
`
`Transmission mode 5
`Transmission mode 6
`Transmission mode 8
`
`4
`4
`
`16
`16
`32
`
`Where Ac represents the number of bits included in code(cid:173)
`bookSubsetRestriction and corresponds to the number of all
`the available precoding matrixes in a corresponding transmis(cid:173)
`sion mode.
`[0005] A new transmission mode is added to the Rel-10 as
`a transmission mode 9. In the case that a PMI feedback is
`configured, a channel is measured and fed back based upon a
`Channel-State Information Reference Signal (CSI-RS) and a
`signal is demodulated based upon a VE-specific Reference
`Signal (UE-RS) in the transmission mode 9. Channel mea(cid:173)
`surement and feedback via at most 8 CSI-RS ports is sup(cid:173)
`ported. A restriction of a codebook subset will also be sup(cid:173)
`ported in the Rel-10, and the number of bits of a codebook
`subset restriction corresponding to 8 antenna ports has not yet
`been defined so far.
`[0006] Codebook subset restrictions in the existing Long
`Term Evolution-Advanced (LTE) Rel-8/9 are defined for 2
`and 4 antenna ports, and the size of a codebook is not vary
`large with 2 and 4 antenna ports. With 4 antenna ports, for
`example, the size of a codebook at each rank is 4 bits, and then
`64 bits in total are required for a codebook subset at 4 ranks.
`However a dual-codebook feedback mechanism including a
`codebook Cl reflecting bandwidth/long-term information
`and a codebook C2 reflecting frequency selectivity/short(cid:173)
`term information is adopted in the Rel-10, where the Cl and
`the C2 are finally integrated into a codebook C. The currently
`accepted sizes of codebooks with 8 antenna ports are as
`depicted in Table 2:
`
`TABLE2
`
`The sizes of Cl and C2 and integrated codebook C with 8 antenna
`ports (the number ofprecoding matrixes)
`
`Rank!
`Rank2
`Rank3
`Rank4
`Rank5
`Rank6
`Rank7
`Rank8
`
`Total
`
`Cl
`
`16
`16
`4
`4
`4
`4
`4
`
`53
`
`C2
`
`16
`16
`16
`
`C
`
`16x16-256
`16x16-256
`4x 16-64
`4 X 8 - 32
`4xl-4
`4xl-4
`4xl-4
`) X 1-)
`
`60
`
`621
`
`[0007] Specifically an 8-antenna port codebook in the Rel(cid:173)
`l O is represented as a two-dimension table where a row index
`i1 corresponds to an index in the codebook Cl and is repre(cid:173)
`sented as a first PMI in a feedback and a column index i2
`corresponds to an index in the codebook C2 and is repre(cid:173)
`sented as a second PMI in a feedback
`[0008] A drawback of the prior art lies in that if each pre(cid:173)
`coding matrix is mapped to 1-bit information as in the bitmap
`approach in the Rel-8, then 621 bits are required for the
`
`Samsung Ex. 1011
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`

`

`US 2013/0163687 Al
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`Jun. 27, 2013
`
`2
`
`signalling codebookSubsetRestriction, thus resulting in a
`considerable signalling overhead.
`
`SUMMARY
`
`[0009] An aspect of the invention is to provide a method
`and device for processing a codebook subset restriction so as
`to address the related problem(s) of restricting a codebook
`subset in the case of multiple antenna ports.
`[0010] There is a method for processing a codebook subset
`restriction in an embodiment of the invention, which includes
`the operations of:
`[0011] grouping precoding matrixes in codebooks at
`respective ranks with N antenna ports respectively, where N is
`a natural number; and
`[0012]
`identifying the state of each group as restricted or
`unrestricted by one bit after grouping.
`[0013] Preferably grouping the precoding matrixes in the
`codebooks at respective ranks respectively includes any one
`of:
`[0014] grouping per row to take each row of precoding
`matrixes in the codebooks as a group;
`[0015] grouping per colunm to take each colunm of precod(cid:173)
`ing matrixes in the codebooks as a group;
`[0016] grouping respectively per row and column to take
`each row of precoding matrixes and each colunm of precod(cid:173)
`ing matrixes in the codebooks respectively as groups and to
`identify a precoding matrix as restricted if a row or colunm, to
`which the precoding matrix belongs, is restricted after group(cid:173)
`ing;
`[0017] grouping per identical precoding matrix to take
`identical precoding matrixes in the codebooks as a group;
`[0018] grouping per same beam direction to take precoding
`matrixes in the same beam direction in the codebooks as a
`group; and
`[0019] grouping per precoding matrix element to take pre(cid:173)
`coding matrixes with identical precoding matrix elements in
`the codebooks as a group.
`[0020] Particularly the codebooks at different ranks can be
`grouped in the same or different ways.
`[0021] Preferably the method further includes:
`[0022]
`setting,
`information to
`identify the respective
`groups in the codebooks as restricted or unrestricted, into a
`codebook subset restriction option of higher-layer signalling.
`[0023] Preferably the method further includes:
`[0024]
`transmitting the higher-layer signalling to a UE to
`instruct the UE to report a Precoding Matrix Indicator(s),
`PMI, and/or a Rank Indicator, RI(s), according to the code(cid:173)
`book subset restriction option in the higher-layer signalling.
`[0025] There is a method for reporting channel information
`in an embodiment of the invention, which includes the opera(cid:173)
`tions of:
`[0026]
`receiving higher-layer signalling; and
`[0027]
`reporting a PMI(s) and/or an RI(s) according to a
`codebook subset restriction option in the higher-layer signal(cid:173)
`ling.
`[0028] There is a device for processing a codebook subset
`restriction in an embodiment of the invention, which
`includes:
`[0029]
`a storing module configured to store a grouping rule
`under which precoding matrixes in codebooks at respective
`ranks are grouped; and
`[0030]
`an identifying module configured to identify the
`state of each group as restricted or unrestricted by one bit after
`the precoding matrixes in the codebooks at the respective
`
`ranks withN antenna ports are grouped respectively under the
`grouping rule, where N is a natural number.
`[0031] Preferably the storing module includes any one or
`combination of the following units:
`[0032]
`a row grouping unit configured to store the grouping
`rule under which each row of precoding matrixes in the code(cid:173)
`books is taken as a group;
`[0033]
`a colunm grouping unit configured to store the
`grouping rule under which each colunm of precoding
`matrixes in the codebooks is taken as a group;
`[0034]
`a row and colunm grouping unit configured to store
`the grouping rule under which each row of precoding
`matrixes and each colunm of precoding matrixes in the code(cid:173)
`books are taken respectively as groups and to identify a pre(cid:173)
`coding matrix as restricted if it is both restricted and unre(cid:173)
`stricted after grouping;
`[0035]
`a precoding matrix grouping unit configured to store
`the grouping rule under which identical precoding matrixes in
`the codebooks are taken as a group;
`[0036]
`a beam grouping unit configured to store the group(cid:173)
`ing rule under which precoding matrixes in the same beam
`direction in the codebooks are taken as a group; and
`[0037]
`an element grouping unit configured to store the
`grouping rule under which precoding matrixes with identical
`precoding matrix elements in the codebooks are taken as a
`group.
`[0038] Particularly the codebooks at the respective ranks
`can have the same or different grouping rules.
`[0039] Preferably the device further includes:
`[0040]
`a setting module configured to set, information to
`identify the respective groups in the codebooks at the respec(cid:173)
`tive ranks as restricted or unrestricted, into a codebook subset
`restriction option of higher-layer signalling.
`[0041] Preferably the device further includes:
`[0042]
`a transmitting module configured to transmit the
`higher-layer signalling to a UE to instruct the UE to report a
`PMI(s) and/or an RI(s) according to the codebook subset
`restriction option in the higher-layer signalling.
`[0043] There is a device for reporting channel information
`in an embodiment of the invention, which includes:
`[0044]
`a receiving module configured to receive higher(cid:173)
`layer signalling; and
`[0045]
`a reporting module configured to report a PMI(s)
`and/or an RI(s) according to a codebook subset restriction
`option in the higher-layer signalling.
`[0046] An advantageous effect of the invention are as fol(cid:173)
`lows:
`[0047]
`In the technical solution according to the embodi(cid:173)
`ments of the invention, an overhead of signalling required for
`a codebook subset restriction can be reduced as a result of
`firstly grouping and then performing a restriction process on
`codebooks.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0048] FIG. 1 is a schematic diagram of a method for pro(cid:173)
`cessing a codebook subset restriction according to an
`embodiment of the invention;
`[0049] FIG. 2 is a schematic diagram of a method for
`reporting channel information according to an embodiment
`of the invention;
`[0050] FIG. 3 is a schematic structural diagram of a device
`for processing a codebook subset restriction according to an
`embodiment of the invention; and
`
`Samsung Ex. 1011
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`US 2013/0163687 Al
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`Jun. 27, 2013
`
`3
`
`[0051] FIG. 4 is a schematic structural diagram of a device
`for reporting channel information according to an embodi(cid:173)
`ment of the invention.
`
`DETAILED DESCRIPTION OF THE
`EMBODIMENTS
`
`[ 0052]
`In a multi-antenna system based upon linear precod(cid:173)
`ing, a receiver selects an appropriate precoding matrix ( or
`vector) index from a linear precoding codebook according to
`channel information and feeds the index back to a transmitter
`so that the transmitter can perform appropriate preprocessing
`on a transmission signal to improve the efficiency and/or
`reliability of information transmission. A method for restrict(cid:173)
`ing a codebook subset by higher-layer signalling to reduce the
`number of beams in a codebook has been defined in the Rel-8
`so as to stabilize mutual interference between cells for the
`sake of improving the accuracy of a CQI reporting by a UE.
`This function will also be supported in the Rel-10, but if each
`precoding matrix in a codebook is mapped to 1-bit informa(cid:173)
`tion as in the bitmap approach in the Rel-8, then a consider(cid:173)
`able signalling overhead will be necessary due to the large
`size of an 8-antenna ports codebook in the Rel-10. In view of
`this, there is a new solution in embodiments of the invention
`to restrict codebook subset for the possibility of a lowered
`overhead ofhigh-layer signalling. Embodiments of the inven(cid:173)
`tion will be described below with reference to the drawings.
`[0053] FIG. 1 is a schematic diagram of a method for pro(cid:173)
`cessing a codebook subset restriction, and as illustrated, the
`restricting process may include the following operations:
`[0054] An operation 101 is to group precoding matrixes in
`codebooks at respective ranks with N antenna ports respec(cid:173)
`tively, where N is a natural number;
`[0055] An operation 102 is to identify by one bit the state of
`each group as restricted or unrestricted, that is, whether the
`group of precoding matrixes is available, after grouping.
`[0056]
`In an implementation, the parameter with a name of
`codebookSubsetRestriction, which is merely a parameter
`defined in the LTE, is described, but the parameter may have
`another variable name in a future system or another system,
`therefore the technical solution according to the embodi(cid:173)
`ments of the invention is not intended to be applicable only to
`an option of signalling as referred to the specific variable
`name codebookSubsetRestriction in the LTE although the
`following description will be given in connection with such a
`name.
`[0057]
`In the following implementations, a description
`with N=S and the accepted 8 antenna ports codebooks in
`Rel-10 will be given as an example, but those skilled in the art
`will readily appreciate that this technical idea of grouping can
`also be applicable to an implementation with a larger number
`of antenna ports but will not be limited to only an implemen(cid:173)
`tation with 8 antenna ports; and codebooks at the respective
`ranks will be described taking the generally accepted code(cid:173)
`books as an example, and with a newly added or modified
`codebook, this technical idea of grouping can simply be
`applied to the new codebook but will not be limited to the
`codebooks listed in the following embodiments which also
`can be apparent to those skilled in the art.
`[0058]
`In an implementation and taking 8 antenna ports as
`an example, the codebooks at the respective ranks with 8
`antenna ports can be grouped and each group can be identified
`by one bit as restricted or unrestricted so as to reduce an
`overhead of the higher-layer signalling codebookSubsetRe(cid:173)
`striction. Table 3 depicts a schematic table of codebooks at the
`
`rank 1, where i1 and i2 correspond respectively to precoding
`matrix indexes of codebooks Cl and C2. Of course, those
`skilled in the art will readily appreciate that the row and
`column locations of the indexes i1 and i2 can be interchanged
`without influencing precoding matrixes of the entire resultant
`codebook. A process on codebooks at the rank 1 will be
`described in an implementation below as an example.
`
`TABLE3
`
`Schematic diagram of codebooks at the rank 1
`
`13
`
`14
`
`15
`
`13
`14
`15
`
`[0059] For better understanding of codebooks grouping, a
`process on codebooks at the rank 1 will be described below as
`an example in which codebooks at the respective ranks are
`grouped in the same way. Of course the codebooks at the
`respective ranks can alternatively be grouped in different
`ways in practice; and the codebooks at the respective ranks
`are grouped for the purpose of a reduced overhead of the
`higher-layer signalling codebookSubsetRestriction, so the
`codebooks at the respective ranks can be grouped in the same
`or different ways which will not be correlated necessarily so
`long as this purpose can be satisfied. Thus the codebooks at
`the respective ranks can be grouped under the same or differ(cid:173)
`ent rules also as be readily apparent to those skilled in the art.
`[0060] The codebooks at the rank may be grouped in any
`one of the following ways:
`
`First Embodiment
`
`[0061]
`In this embodiment, the codebooks are grouped per
`row, where each row of precoding matrixes in the codebooks
`is taken as a group.
`[0062] Specifically the codebooks at the respective ranks
`are grouped per row, for example, each row of precoding
`matrixes in Table 3 is taken as a group, and then only 16 bits
`are required for a codebook subset restriction at the rank 1,
`and 53 bits are required for a total overhead of a codebook
`subset restriction according to the sizes of the codebooks Cl
`corresponding to i1 at the respective ranks in Table 2, so each
`of information bits aA _1 , . . . , a3 , a2 , ai, a0 , where, Ac=53, of
`the higher-layer sign;lling codebookSubsetRestriction indi(cid:173)
`cates a restriction condition of a row of precoding matrixes in
`codebooks, for example, a0 indicates the first row of the rank
`1 codebook, a 15 indicates the 16th row of the rank 1 codebook
`, a 16 indicates the first row of the rank 2 codebook, and aA _1
`indicates the last row of the rank 8 codebook.
`"
`
`Second Embodiment
`
`[0063]
`In this embodiment, the codebooks are grouped per
`column, where each colunm of precoding matrixes in the
`codebooks is taken as a group.
`
`Samsung Ex. 1011
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`US 2013/0163687 Al
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`Jun. 27, 2013
`
`4
`
`[0064] Specifically the codebooks at the respective ranks
`are grouped per column, for example, each column of pre(cid:173)
`coding matrixes in Table 3 is taken as a group, and then only
`16 bits are required for a codebook subset restriction at the
`rank 1, and 60 bits are required for a total overhead of a
`codebook subset restriction according to the sizes of the code(cid:173)
`books C2 corresponding to i2 at the respective ranks in Table
`2, so each of information bits aA _1 , . . . , a3 , a2 , ai, a0 , where,
`Ac 60, of the higher-layer signall"ing codebookSubsetRestric(cid:173)
`tion indicates a restriction condition of a column of precoding
`matrixes in a codebook.
`
`Third Embodiment
`
`In this embodiment, the codebooks are grouped
`[0065]
`respectively per row and column, where each row of precod(cid:173)
`ing matrixes and each column of precoding matrixes in the
`codebooks are taken respectively as groups, and a precoding
`matrix will be identified as restricted if a row or column, to
`which the precoding matrix belongs, is restricted after group(cid:173)
`ing.
`In an implementation, the codebooks at the respec(cid:173)
`[0066]
`tive ranks are grouped respectively per row and column, for
`example, each column of precoding matrixes and each row of
`precoding matrixes in Table 3 is taken respectively as groups
`and then 32 bits are required for a codebook subset restriction
`at the rank 1, and 109 to 113 bits are required for a total
`codebook subset restriction according to the sizes of the code(cid:173)
`books Cl and C2 corresponding to i 1 and i2 at the respective
`ranks in Table 2 (particularly since only one column is
`included in the codebook at each of the ranks 5 to 8, no
`corresponding bit is required to indicate the group corre(cid:173)
`sponding to the column, and at this time there are 109 bits of
`the codebook subset restriction). Given 109 bits of the code(cid:173)
`book subset restriction, each ofinformation bits aA _1 , ... , a3 ,
`a2 , a1 , a0 , where, Ac=109, corresponding to the higher-layer
`signalling codebookSubsetRestriction indicates a restriction
`condition of a column of precoding matrixes or a row of
`precoding matrixes in a codebook. The codebooks can be
`grouped firstly per row and then per column or firstly per
`column and then per row. It shall be noted that one precoding
`matrix correspond to one row indicating bit and one column
`indicating bit when the codebooks are grouped per both row
`and column, and at this time the precoding matrix will be
`restricted and can not be used so long as either of indicating
`bits corresponding to the row and the column is 0.
`
`Fourth Embodiment
`
`In this embodiment, the codebooks are grouped
`[0067]
`according to whether precoding matrixes are identical, where
`identical precoding matrixes in the codebooks are taken as a
`group.
`In an implementation, identical precoding matrixes
`[0068]
`at the respective ranks are taken as a group, there are a large
`number of pairs of identical precoding matrixes in the result(cid:173)
`ant codebooks from the currently generally accepted 8-an(cid:173)
`tenna port codebooks, and the identical precoding matrixes
`being taken as a group can reduce an overhead of bits required
`for a codebook subset restriction. Taking the rank 1 as an
`example, the first precoding matrix in the first row is taken as
`the first group, and the precoding matrixes are grouped per
`row, where the second precoding matrix in the first row is
`taken into the first group if it is identical to the first precoding
`matrix or into the second group if it is different, and so on, and
`
`thus the number of resultant groups at each rank can be
`determined, and the total number of the groups at the respec(cid:173)
`tive ranks is determined as the number of bits required for a
`codebook subset restriction. Of course the precoding
`matrixes can alternatively be grouped per column without
`influencing the effect of grouping. This way, among the cur(cid:173)
`rently generally accepted codebooks, 128 groups can result at
`the rank 1, 192 groups can result at the rank 2, and there are no
`identical precoding matrixes at each of the rank 3 to the rank
`8 so that there is a single precoding matrix in a group and 109
`groups in total result, thus resulting in 429 groups in total, and
`then there are information bits aA -1' . . . , a3 , a2 , ai, a0 , where,
`Ac=429, corresponding to the higher-layer signalling code(cid:173)
`bookSubsetRestriction.
`
`Fifth Embodiment
`
`In this embodiment, the codebooks are grouped
`[0069]
`according to whether beam directions are identical, where
`precoding matrixes in the same beam direction in the code(cid:173)
`books are taken as a group.
`In an implementation, precoding matrixes in the
`[0070]
`same beam direction at the respective ranks are taken as a
`group, where the resultant precoding matrix corresponding to
`the rank r with 8 antenna ports is of 8xr dimensions, and the
`beam direction of this precoding matrix is determined by the
`first half part of the precoding matrix, i.e., the 4xr part, and
`those precoding matrixes, among all the precoding matrixes
`at the rank r, with the same first half part, are taken as a group.
`Taking the rank 1 as an example, the first precoding matrix in
`the first row is taken as the first group, and the precoding
`matrixes are grouped per row, where the second precoding
`matrix in the first row is taken into the first group if the first
`half part of the second precoding matrix is identical to the first
`half part of the first precoding matrix or into the second group
`if the first half part of the second precoding matrix is different
`from the first half part of the first precoding matrix, and so on,
`and thus the number of resultant groups at each rank can be
`determined, and the total number of the groups at the respec(cid:173)
`tive ranks is determined as the number of bits required for a
`codebook subset restriction. Of course the precoding
`matrixes can alternatively be grouped per column without
`influencing the effect of grouping. This way, among the cur(cid:173)
`rently generally accepted codebooks, 32 groups can result at
`the rank 1, 96 groups can result at the rank 2, 16 groups can
`result at the rank 4, and there are no precoding matrixes in the
`same direction at each of the rank 3 and the rank 5 to the rank
`8 so that there is a single precoding matrix in a group and 77
`groups in total result, thus resulting in 221 groups in total, and
`then there are information bits aA _1 , . . . , a3 , a2 , a 1 , a0 , with
`Ac=221, corresponding to the higher-layer signalling code(cid:173)
`bookSubsetRestriction.
`
`Sixth Embodiment
`
`In this embodiment, the codebooks are grouped per
`[0071]
`precoding matrix element, where precoding matrixes with
`identical precoding matrix elements in the codebooks are
`taken as a group.
`In an implementation, the codebooks at the respec(cid:173)
`[0072]
`tive ranks are grouped per precoding matrix element, for
`example, precoding matrixes, at the rank 1, constituted of
`Quadrature Phase Shift Keying (QPSK) elements are taken as
`a group, precoding matrixes constituted of8PSK (Phase Shift
`Keying) elements other than the precoding matrixes consti-
`
`Samsung Ex. 1011
`
`

`

`US 2013/0163687 Al
`
`Jun. 27, 2013
`
`5
`
`tuted of QPSK elements are taken as a group, precoding
`matrixes constituted of 16PSK elements other than the pre(cid:173)
`coding matrixes constituted of SPSK elements are taken as a
`group, and precoding matrixes constituted of 32PSK ele(cid:173)
`ments other than the precoding matrixes constituted of
`16PSK elements are taken as a group, and thus 4 groups in
`total result; 4 groups in total result also at the rank 2 like the
`rank 1 ; and precoding matrixes at each of the rank 3 to the
`rank 8 are constituted of 16PSK elements, and thus 3 groups
`result at each of the ranks, thus resulting in 26 groups in total,
`and then there are information bits aA _1 , . . . , a3 , a2 , a1 , a0 ,
`with Ac=26, corresponding to the higher-layer signalling
`codebookSubsetRestriction.
`[0073] The flow of processing a codebook subset restric(cid:173)
`tion may further include:
`[0074] An operation 103 is to set, information to identify
`the respective groups in the codebooks at the respective ranks
`as restricted or unrestricted, into a codebook subset restriction
`option of higher-layer signalling.
`[0075] After setting the higher-layer signalling, the process
`may further include:
`[0076] An operation 104 is to transmit the higher-layer
`signalling to a UE to instruct the UE to report a Precoding
`Matrix Indicator(s) (PMI) and/or a Rank Indicator(s) (RI)
`according to the codebook subset restriction option in the
`higher-layer signalling.
`[0077] Correspondingly an embodiment of the invention
`further provides a method for reporting channel information,
`which will be described below.
`[0078] FIG. 2 is a schematic flow chart of performing a
`method for reporting channel information, and as illustrated,
`the reporting process may include the following operations:
`[0079] An operation 201 is to receive higher-layer signal(cid:173)
`ling.
`[0080]
`In an implementation, the higher-layer signalling is
`used to instruct a UE to report a Precoding Matrix Indicator( s)
`(PMI) and/or a Rank Indicator(s) (RI) according to a code(cid:173)
`book subset restriction option in the higher-layer signalling,
`and reference can be made to the foregoing embodiments for
`setting of the codebook subset restriction option.
`[0081] An operation 202 is to report a PMI(s) and/or an
`RI(s) according to a codebook subset restriction option in the
`higher-layer signalling.
`[0082] Based upon the same inventive idea, embodiments
`of the invention further provide a device for processing a
`codebook subset restriction and a device for reporting chan(cid:173)
`nel information, and since these devices address the problem
`under a similar principle to the method for processing a code(cid:173)
`book subset restriction and the method for reporting channel
`information, reference can be made to the implementations of
`the methods for implementations of these devices, and a
`repeated description thereof will be omitted here.
`[0083] FIG. 3 is a schematic structural diagram of a device
`for processing a codebook subset restriction, and as illus(cid:173)
`trated, the device includes:
`[0084]
`a storing module 301 configured to store the group(cid:173)
`ing rule under which precoding matrixes in codebooks at
`respectiv