网站没被收录,公司做网站有用吗,企业做网站有什么好处,网站入股云建站5G中引入了频率栅格的概念#xff0c;也就是小区中心频点和SSB的频域位置不能随意配置#xff0c;必须满足一定规律#xff0c;主要目的是为了UE能快速的搜索小区#xff1b;其中三个最重要的概念是Channel raster 、synchronization raster和pointA。
1、Channel raster …5G中引入了频率栅格的概念也就是小区中心频点和SSB的频域位置不能随意配置必须满足一定规律主要目的是为了UE能快速的搜索小区其中三个最重要的概念是Channel raster 、synchronization raster和pointA。
1、Channel raster
可以理解为载波的中心频点的可选位置 一般频点值都以NR-ARFCNNR绝对射频频率信道编号数值间接表示即下面表格中的Nref一般在RRC消息中传递的都是这个信道编号如果需要知道具体代表的频率值 参考下面公式中的频率Fref 的计算
ΔFGlobal全局频率栅格间隔(granularity of the global frequency raster)不同频率范围取值见下表。
Fref RF reference frequencies也即具体频率值
NR-ARFCNNR Absolute Radio Frequency Channel Number绝对信道号取值范围FR1为0…2016666FR2为2016667 – 3279165与RF reference frequency Fref的关系见下式。
FREF FREF-Offs ΔFGlobal (NREF – NREF-Offs) channel raster 是RF reference frequencies的子集对每个band来说中心频点不能随意选需要按照一定起点和步长选取具体可用的见下表。
ΔFRaster为间隔粒度大于等于ΔFGlobal。 比如对n41如果步长是3换算出对应的频率的步长是3Fglobal3×515Khz如果步长是6换算出对应的频率的步长是6Fglobal6×530Khz这里有两种ΔFRaster根据 I 确定。未找到 I 如何确定。
Table 5.4.2.3-1: Applicable NR-ARFCN per operating band NR operating band ΔFRaster (kHz) Uplink Range of NREF (First – Step size – Last) Downlink Range of NREF (First – Step size – Last) n1 100 384000 – 20 – 396000 422000 – 20 – 434000 n28 100 140600 – 20 – 149600 151600 – 20 – 160600 n41 15 499200 – 3 – 537999 499200 – 3 – 537999 30 499200 – 6 – 537996 499200 – 6 – 537996 n77 15 620000 – 1 – 680000 620000 – 1 – 680000 30 620000 – 2 – 680000 620000 – 2 – 680000 n78 15 620000 – 1 – 653333 620000 – 1 – 653333 30 620000 – 2 – 653332 620000 – 2 – 653332 n79 15 693334 – 1 – 733333 693334 – 1 – 733333 30 693334 – 2 – 733332 693334 – 2 – 733332
整个载波的中心频率channel raster 位置和RB总数有关系在RB数量为偶数时表示Nprb的子载波0当RB数量为基数时表示Nprb的子载波6。也即比小区频率的绝对中心向上偏移了半个子载波。 2、synchronization raster
synchronization raster可以理解为SSB块的中心频点可选位置也是为了让UE更快速的找到SSB5G里面SSB的中心和载波的中心不需要重合 参见下面表格SSB的中心频率即下表中的SSref也是按照一定规律步进的 SSB的中心频率一般也是通过GSCN的编号值间接表示的方便消息传递
GSCN Global Synchronization Channel Number即全球同步信道号是用于标记SSB的信道号。
每一个GSCN对应一个SSB的频域位置SSREFSSB的RB10的第0个子载波的起始频率GSCN按照频域增序进行编号。
Table 5.4.3.1-1: GSCN parameters for the global frequency raster Frequency range SS Block frequency position SSREF GSCN Range of GSCN 0 – 3000 MHz N * 1200kHz M * 50 kHz, N1:2499, M ϵ {1,3,5} (Note 1) 3N (M-3)/2 2 – 7498 3000 – 24250 MHz 3000 MHz N * 1.44 MHz N 0:14756 7499 N 7499 – 22255 NOTE 1: The default value for operating bands with which only support SCS spaced channel raster(s) is M3. Table 5.4.3.1-1: GSCN parameters for the global frequency raster Frequency range SS block frequency position SSREF GSCN Range of GSCN 24250 – 100000 MHz 24250.08 MHz N * 17.28 MHz, N 0:4383 22256 N 22256 – 26639
Synchronization raster也不是SSB块的绝对的中心1/2处SSB块是20个RB共计20*12240个子载波absoluteFrequencySSB对应于第10个RB从0编号的第0号子载波的中心也就是和绝对的中心向上偏了半个子载波
Table 5.4.3.2-1: Synchronization raster to SS block resource element mapping Resource element index k 0 Physical resource block number nPRB of the SS block nPRB 10
3、PointA
根据公共参考点absoluteFrequencyPointA的定义这个参考点是第0个RBRB0的第0个子载波的中心点注意不是边沿edge很多网上文章都理解为edge
Absolute frequency position of the reference resource block (Common RB 0). Its lowest subcarrier is also known as Point A. Note that the lower edge of the actual carrier is not defined by this field but rather in the scs-SpecificCarrierList. Corresponds to L1 parameter offset-ref-low-scs-ref-PRB (see 38.211, section FFS_Section)参见38.211 定义
absoluteFrequencyPointA for all other cases where absoluteFrequencyPointA represents the frequency-location of point A expressed as in ARFCNThe center中心 of subcarrier 0 of common resource block 0 for subcarrier spacing configuration μ coincides with ‘point A’. 4、各参数的关系
offsetToPointA 表示SSB最低RB的最低子载波与point A 之间的频域偏移单位为RB注意这里频域偏移计算时不是以真实的子载波间隔来计算的而是对于FR1假设子载波间隔为15kHz对于FR2假设子载波间隔为60kHz。
offsetToPointA for a PCell downlink where offsetToPointA represents the frequency offset between point A and the lowest subcarrier of the lowest resource block, which has the subcarrier spacing provided by the higher-layer parameter subCarrierSpacingCommon and overlaps with the SS/PBCH block used by the UE for initial cell selection, expressed in units of resource blocks assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier spacing for FR2;
Kssbpoin A 和 SSB的0号RB0号子载波相差的RB数量不一定正好差整数个RB可能还会差出几个子载波Kssb就表示还差出几个子载波这里也是假设子载波间隔为固定值FR1为15kHzFR2为60kHz。Kssb的低4比特由高层参数ssb-SubcarrierOffset给出。对于SS/PBCH block type Bμ∈{3,4} 来说kSSB∈{0,1,2,...,11} 4比特就足够了而SS/PBCH block type Aμ∈{0,1} 的kSSB∈{0,1,2,...,23} 需要5比特表示。
所以poin A 和 SSB的RB0的0号子载波相差的频率等于offsetToPointA*15*12Kssb*15
而absoluteFrequencySSB和SSB的RB0的0号子载波相差的频率等于10×12×subCarrierSpacingCommonSSB的RB数量为20
offsetToCarrierPoint ACRB0最低子载波与最低可用子载波之间的频域偏移单位为PRB。
Offset in frequency domain between Point A (lowest subcarrier of common RB 0) and the lowest usable subcarrier on this carrier in number of PRBs (using the subcarrierSpacing defined for this carrier). The maximum value corresponds to 275*8-1. Corresponds to L1 parameter offset-pointA-low-scs (see 38.211, section 4.4.2)
对于3GHz以下
ΔFGlobal 5
absoluteFrequencyPointA × ΔFGlobal offsetToPointA×15×12Kssb×15 SSREF - 10×12×subCarrierSpacingCommon SSREF absoluteFrequencySSB * ΔFGlobal absoluteFrequencySSB × 5
也即
absoluteFrequencyPointA offsetToPointA×15×12/5 Kssb ×15/5 absoluteFrequencySSB - 10×12×subCarrierSpacingCommon/5
载波中心NR-ARFCN
NREF 载波中心NR-ARFCN absoluteFrequencyPointA N_CRB×12/2× subcarrierSpacing/5 offsetToCarrier × 12 × subcarrierSpacing/5 5、NSA配置
NSA里基站会通过RRC重配置消息通知UE关于频点的信息帮助UE快速搜索到目标小区 NRband 41是小于3Ghz的band可以套用上面表格5.4.2.1-1对应的第一列的参数
carrierBandwidth273代表载波里面是273个RB273RB * 12 * 30Khz 98.280Mhz并没有完全占满100Mhz带宽因为两边需要留出保护带宽guard band。 subcarrierSpacing代表子载波间隔是30Khz每个RB有12个子载波
absoluteFrequencyPointA503172代表公共参考点A503172 *5Khz 2515860Khz
absoluteFrequencySSB 504990 代表SSB块的中心频点504990*5Khz 2524950Khz也就是SSB中心位于2524950Khz
offsetToCarrier 0
NREF 载波中心ARFCN absoluteFrequencyPointA N_CRB×12/2× subcarrierSpacing/5 offsetToCarrier × 12 × subcarrierSpacing/5
载波中心NR-ARFCN 503172 273*12/2* subcarrierSpacing / 5 0 503172 9828 513000
频率为513000 ×5 2565000kHz
absoluteFrequencyPointA offsetToPointA×15×12/5 Kssb ×15/5 absoluteFrequencySSB - 10×12×subCarrierSpacingCommon/5
503172 offsetToPointA×15×12/5 Kssb ×15/5 504990 - 10 ×12 × 30 / 5
offsetToPointA × 36 Kssb ×3 1098
得出offsetToPointA 30Kssb 6
SSB GSCN 6312N 2104M 3
各变量的关系如下图所示 6、SA配置
可以看到MIB中配置的sb-SubcarrierOffset 6,offsetToPointA 30offsetToCarrier 0。 7、限制条件
1、最小保护间隔
最小保护间隔在38.101中定义
Table 5.3.3-1: Minimum guardband for each UE channel bandwidth and SCS (kHz) SCS (kHz) 5 MHz 10 MHz 15 MHz 20 MHz 25 MHz 30 MHz 40 MHz 50 MHz 60 MHz 70 MHz 80 MHz 90 MHz 100 MHz 15 242.5 312.5 382.5 452.5 522.5 592.5 552.5 692.5 N/A N/A N/A N/A N/A 30 505 665 645 805 785 945 905 1045 825 965 925 885 845 60 N/A 1010 990 1330 1310 1290 1610 1570 1530 1490 1450 1410 1370 Table 5.3.3-1: Minimum guardband for each UE channel bandwidth and SCS (kHz) SCS (kHz) 50 MHz 100 MHz 200 MHz 400 MHz 60 1210 2450 4930 N. A 120 1900 2420 4900 9860
NOTE: The minimum guardbands have been calculated using the following equation: (BWChannel x 1000 (kHz) - NRB x SCS x 12) / 2 - SCS/2, where NRB are from Table 5.3.2-1.
The number of RBs configured in any channel bandwidth shall ensure that the minimum guardband specified in this clause is met. Figure 5.3.3-2: UE PRB utilization
2、UE在不同频段支持的带宽
Table 5.3.5-1 Channel bandwidths for each NR band NR band / SCS / UE Channel bandwidth NR Band SCS kHz 5 MHz 101,2 MHz 152 MHz 202 MHz 252 MHz 30 MHz 40 MHz 50 MHz 60 MHz 70 MHz 80 MHz 90 MHz 100 MHz n1 15 Yes Yes Yes Yes 30 Yes Yes Yes 60 Yes Yes Yes n28 15 Yes Yes Yes Yes7 30 Yes Yes Yes7 60 n41 15 Yes Yes Yes Yes Yes Yes 30 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 60 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes n77 15 Yes Yes Yes Yes Yes Yes Yes 30 Yes Yes Yes Yes Yes Yes Yes Yes Yes4 Yes Yes4 Yes 60 Yes Yes Yes Yes Yes Yes Yes Yes Yes4 Yes Yes4 Yes n78 15 Yes Yes Yes Yes Yes Yes Yes 30 Yes Yes Yes Yes Yes Yes Yes Yes Yes4 Yes Yes Yes 60 Yes Yes Yes Yes Yes Yes Yes Yes Yes4 Yes Yes Yes n79 15 Yes Yes 30 Yes Yes Yes Yes Yes 60 Yes Yes Yes Yes Yes
