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~DL~?N~mod2?1~,N?0andn?Nandn?n?N?PRBnullVRBVRBnullVRBrow~DL?n~??N?N/2,N?0andn~?N~mod2?0andn?PRBrownullnullVRBVRB?NnullVRB~, nPRB(ns)??~~DL~~???Nnull/2,Nnull?0andnVRB?NVRB?NnullandnVRBmod4?2?nPRB~????nPRB, otherwise~DL~DL~??2N??n~mod2??n~/2?Nwhere n?n/N?VRB?VRBVRBVRB, PRBrowVRB~DL~DL~???N??n~mod4??n~/4?Nand n?n/N??PRBrowVRBVRBVRBVRBVRB,
~DL~?nmodNwhere nVRBVRBVRB and nVRB is obtained from the downlink scheduling assignment as described in [4].
????For odd slot number ns;
~DL~DL~DL~DL~(n)?n~(n?1)?Nn/2modN?N?n/NPRBsPRBsVRBVRBVRB?VRBVRB?
??Then, for all ns;
~DL~(n)~n,?n(n)?NPRBsPRBsVRB/2. nPRB(ns)??~~DL~DL~n(n)?N?N/2,nPRB(ns)?NVRB/2gapVRB?PRBs
6.2.4 资源单元组
资源单元组用于定义控制信道到资源单元的映射。
A resource-element group is represented by the index pair (k?,l?) of the resource element with the lowest index k in
the group with all resource elements in the group having the same value of l. The set of resource elements (k,l) in a resource-element group depends on the number of cell-specific reference signals configured as described below with
RBDL, 0?nPRB?NRB. k0?nPRB?Nsc- In the first OFDM symbol of the first slot in a subframe the two resource-element groups in physical resource
block nPRB consist of resource elements (k,l?0) with k?k0?0, k0?1,..., k0?5 and k?k0?6, k0?7,..., k0?11, respectively. - In the second OFDM symbol of the first slot in a subframe in case of one or two cell-specific reference signals configured, the three resource-element groups in physical resource block nPRB consist of resource elements (k,l?1) with k?k0?0, k0?1,..., k0?3, k?k0?4, k0?5,..., k0?7 and k?k0?8, k0?9,..., k0?11, respectively. - In the second OFDM symbol of the first slot in a subframe in case of four cell-specific reference signals configured, the two resource-element groups in physical resource block nPRB consist of resource elements (k,l?1) with k?k0?0, k0?1,..., k0?5 and k?k0?6, k0?7,..., k0?11, respectively. - In the third OFDM symbol of the first slot in a subframe, the three resource-element groups in physical resource block nPRB consist of resource elements (k,l?2) with k?k0?0, k0?1,..., k0?3, k?k0?4, k0?5,..., k0?7 and k?k0?8, k0?9,..., k0?11, respectively. - In the fourth OFDM symbol of the first slot in a subframe in case of normal cyclic prefix, the three resource-element groups in physical resource block nPRB consist of resource elements (k,l?3) with
k?k0?0, k0?1,..., k0?3, k?k0?4, k0?5,..., k0?7 and k?k0?8, k0?9,..., k0?11, respectively.
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Release 8 42 3GPP TS 36.211 V8.5.0 (2008-12)
- In the fourth OFDM symbol of the first slot in a subframe in case of extended cyclic prefix, the two resource-element groups in physical resource block nPRB consist of resource elements (k,l?3) with
k?k0?0, k0?1,..., k0?5 and k?k0?6, k0?7,..., k0?11, respectively. Mapping of a symbol-quadruplet z(i),z(i?1),z(i?2),z(i?3) onto a resource-element group represented by resource-element (k?,l?) is defined such that elements z(i) are mapped to resource elements (k,l) of the resource-element
group not used for cell-specific reference signals in increasing order of i and k. In case a single cell-specific reference signal is configured, cell-specific reference signals shall be assumed to be present on antenna ports 0 and 1 for the purpose of mapping a symbol-quadruplet to a resource-element group, otherwise the number of cell-specific reference signals shall be assumed equal to the actual number of antenna ports used for cell-specific reference signals. The UE shall not make any assumptions about resource elements assumed to be reserved for reference signals but not used for transmission of a reference signal.
6.2.5 半双工FDD操作的保护周期
For half-duplex FDD operation, a guard period is created by the UE by not receiving the last part of a downlink subframe immediately preceding an uplink subframe from the same UE.
6.2.6 TDD 操作保护周期
For frame structure type 2, the GP field in Figure 4.2-1 serves as a guard period.
6.3 下行物理信道一般性结构
This section describes a general structure, applicable to more than one physical channel.
The baseband signal representing a downlink physical channel is defined in terms of the following steps: - 对将要在物理信道上传输的每个码字中已编码比特进行加扰。 - 对加扰比特进行调制，生成复值调制符号。
- 映射复值调制符号到一个或若干个传输层 （transmission layers）
- 对每传输层上的复值调制符号进行预编码，以便在天线端口（可以是多个端口）上传输。 - 映射每个天线端口上的复值调制符号到资源单元（每个单元就是一个符号占用的时频资源）。 - 每个天线端口上生成复值时域OFDM信号。
code wordslayersantenna portsScramblingModulation mapperLayermapperPrecodingResource element mapperOFDM signal generationScramblingModulation mapperResource element mapperOFDM signal generation
Figure 6.3-1: Overview of physical channel processing.
6.3.1
加扰
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6.3.2 调制
Table 6.3.2-1: Modulation schemes
Physical channel Modulation schemes PDSCH QPSK, 16QAM, 64QAM PMCH QPSK, 16QAM, 64QAM
6.3.3 层映射
The complex-valued modulation symbols for each of the code words to be transmitted are mapped onto one or several (q)layers. 复值调制符号d(q)(0),...,d(q)(Msymb?1) for code word q shall be mapped onto the
layerlayerlayersx(i)?x(0)(i)...x(??1)(i), i?0,1,...,Msymb is the number of ?1 where ? is the number of layers and Msymb??Tmodulation symbols per layer.
6.3.3.1 单天线端口传输层映射
单天线端口传输采用单层，即??1，映射定义如下
layer(0). x(0)(i)?d(0)(i)，Msymb?Msymb6.3.3.2 空分复用层映射
对于空分复用，应根据表6.3.3.2-1执行层映射，层数量?应少于或等于物理信道传输使用的天线端口数量P。
The case of a single codeword mapped to two layers is only applicable when the number of antenna ports is 4.
Table 6.3.3.2-1: Codeword-to-layer mapping for spatial multiplexing
层数 1 2 22 13 2CW 1CW 2PrecoderCW 1CW 2码字个数 （数据流个数） 1 PrecoderCodeword-to-layer mapping layeri?0,1,...,Msymb?1 x(0)(i)?d(0)(i) x(0)(i)?d(0)(i) Precoderlayer(0) Msymb?Msymblayer(0)(1) Msymb?Msymb?Msymbx(i)?d(i) x(0)(i)?d(0)(2i) x(1)(i)?d(0)(2i?1)(1)(1)CW 1 layer(0)Msymb?Msymb2 x(0)(i)?d(0)(i) x(1)(i)?d(1)(2i) (2)(1)x(i)?d(2i?1)x(0)(i)?d(0)(2i) (1)(0)x(i)?d(2i?1)layer(0)(1)Msymb?Msymb?Msymb2 4 2CW 1CW 2Precoder x(2)(i)?d(1)(2i) (3)(1)x(i)?d(2i?1)layer(0)(1)Msymb?Msymb2?Msymb2
6.3.3.3 发射分集层映射
对于发射分集，应根据表 6.3.3.3-1完成层映射，这里仅支持一个码字，且层数?等于天线端口数P。
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表6.3.3.3-1: 发射分集码字-层映射
Number of layers Number of code words Codeword-to-layer mapping layeri?0,1,...,Msymb?1 x(0)(i)?d(0)(2i)2 1 x(i)?d (1)(0)(2i?1) layer(0)Msymb?Msymb2 x(0)(i)?d(0)(4i)x(1)(i)?d(0)(4i?1)4 1 M layersymbx(2)(i)?d(0)(4i?2)x (3)(0)(0)?Msymb4if Msymbmod4?0? ??(0)(0)??Msymb?24 if Msymbmod4?0??(i)?d(0)(4i?3)If Msymb(0)mod4?0 two null symbols shall be (0)(0)(Msymb?1) appended to d
6.3.4 预编码
layer预编码器将输入向量块x(i)?x(0)(i)...x(??1)(i), i?0,1,...,Msymb?1转化生成新的向量块
ap?1 以映射到每个天线端口资源，这里y(p)(i)表示天线端口p上符号。 y(i)?...y(p)(i)..., i?0,1,...,Msymb??T??T6.3.4.1 单天线端口传输预编码
单天线端口上的传输预编码定义为：
y(p)(i)?x(0)(i)
apaplayer这里p??0,4,5?是物理信道传输使用的单天线端口编号，i?0,1,...,Msymb. ?Msymb?1, Msymb6.3.4.2 空分复用预编码
空分复用预编码仅和6.3.3.2节中描述的空分复用的层映射联合应用。空分复用支持2个或4个天线端口，即p??0,1?或p??0,1,2,3?。
6.3.4.2.1 不带 CDD的预编码
无循环延迟分集 (CDD)的空分复用预编码定义为
?y(0)(i)??x(0)(i)?????????W(i)??? ?y(P?1)(i)??x(??1)(i)?????apaplayer这里预编码矩阵W(i)大小为P??，i?0,1,...,Msymb。 ?Msymb?1，Msymb对于空分复用, W(i)通过选择码本中的预编码矩阵得到，码本由表6.3.4.2.3-1或表6.3.4.2.3-2给出。
6.3.4.2.2 大时延 CDD预编码
对于大时延CDD，空分复用预编码定义为
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?y(0)(i)??x(0)(i)?????????W(i)D(i)U??? ?y(P?1)(i)??x(??1)(i)?????apaplayer其中预编码W(i)大小为P??，i?0,1,...,Msymb。???对角阵D(i)和???矩阵U由表?Msymb?1,Msymb6.3.4.2.2-1给出。
表6.3.4.2.2-1: 大时延循环时延分集
层数? 2 U 1?1?1??j2?2? 2?1e?11??11?1e?j2?3e?j4?3??? 3??j4?3e?j8?3??1e?111??1??j2?4e?j4?4e?j6?4?1?1e??j4?4?j8?4?j12?4 ?ee2?1e??j6?4?j12?4?j18?4?1eee??D(i) 0??1?0e?j2?i2? ??3 4 ?1?0e?j2?i4??00?0?000??1?0e?j2?i30??? ?0e?j4?i3??0?0000e?j4?i40?0?? 0??e?j6?i4?W(i)从表6.3.4.2.3-1或表6.3.4.2.3-2中选择：
? ?
2天线端口，W(i)?C1，C1对应表6.3.4.2.3-1中码字索引0对应的码字。
4天线端口，W(i)?Ck，k??????mod4???1，k=1,2,3,4，C1,C2,C3,C4为表6.3.4.2.3-2中码字
??i??????索引12~15对应的码字。
6.3.4.2.3 预编码码本
对于在两个天线端口上的传输，p??0,1?，预编码矩阵W(i)应从表 6.3.4.2.3-1中或其子集中选择。对于文献[4]中所定义的闭环空分复用传输模式，码本序号0在层数??2的情况下禁用。
Table 6.3.4.2.3-1: 天线端口?0,1?上的传输预编码码本
码字索引 0 1 2 3 层数? 1 2 1?1??? 2?1?1?1??? 2??1?1?1??? 2?j?1?1???j? 2??1?10??? 2?01?1?11??? 2?1?1?1?11??? 2?j?j?-
{s}对于四个天线端口p??0,1,2,3?上的传输，预编码矩阵W应从表 6.3.4.2.3-2 或其子集中选择。Wn表示由 HHWn?I?2unununun矩阵的{s}列向量构成的矩阵，这里I 是 4?4单位矩阵，un由表6.3.4.2.3-2给出。
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