NB-IOT物理层原理及测试

NB-IOT原理及测试
ıNB-IOT技术背景
ıNB-IOT标准化过程
ıNB-IOT布网模式及双工方式
ıNB-IOT无线帧结构和下行物理信道
ıNB-IOT无线帧结构和上行物理信道
ıNB-IOT应对物联网海量接入和低功耗机制ıNB-IOT测试
ıNB-IOT技术背景
ıNB-IOT标准化过程
ıNB-IOT布网模式及双工方式
ıNB-IOT无线帧结构和下行物理信道
ıNB-IOT无线帧结构和上行物理信道
ıNB-IOT应对物联网海量接入和低功耗机制ıNB-IOT测试
IOT市场趋势
IOT主要无线技术
NB-IOT需求背景
CIOT市场
NB-IOT技术优势
NB-IOT技术优点
内容
ıNB-IOT技术背景
ıNB-IOT标准化过程
ıNB-IOT布网模式及双工方式
ıNB-IOT无线帧结构和下行物理信道
ıNB-IOT无线帧结构和上行物理信道
ıNB-IOT应对物联网海量接入和低功耗机制ıNB-IOT测试
3GPP主要IOT技术参数对比
NB-IOT vs. eMTC
ıeMTC can only be deployed within LTE system, while NB-IoT has more flexibility as it can be deployed in-band, guard band and standalone.
ıNB-IoT can support up to 200k devices per cell per 200kHz
ıNB-IoT uplink transmission (3.75kHz, 15kHz) is much more efficient than eMTC wideband uplink transmission
ıNB-IoT has about 6.3dB better coverage than eMTC
内容
ıNB-IOT技术背景
ıNB-IOT标准化过程
ıNB-IOT布网模式及双工方式
ıNB-IOT无线帧结构和下行物理信道
ıNB-IOT无线帧结构和上行物理信道
ıNB-IOT应对物联网海量接入和低功耗机制ıNB-IOT测试
NB-IOT系统带宽
NB-IOT部署模式
NB-IOT多载波模式
NB-IOT 100kHz raster offset for in-band
例如对于10MHz带宽的LTE，NB-IOT既不能占用同步和广播信道所在的PRB，又要满足100kHz raster要求，因此其带内NB-IOT只能位于4, 9, 14, 19, 30, 35, 40, 45号PRB，而且要做2.5kHz offset
NB-IOT raster offset indicated by NB-MIB PRB indexing for NB-IoT in-band operation
ıPRB indexing offset is from the middle of the LTE system ı5 bits are used to indicate the index as given in the table
NB-IOT双工模式
ı只支持half-duplex FDD type B
NB-IOT双工方式的优点ı降低了终端成本和功耗
内容
ıNB-IOT技术背景
ıNB-IOT标准化过程
ıNB-IOT布网模式及双工方式
ıNB-IOT无线帧结构和下行物理信道
ıNB-IOT无线帧结构和上行物理信道
ıNB-IOT应对物联网海量接入和低功耗机制ıNB-IOT测试
NB-IOT Downlink OFDM参数ı下行基于OFDMA
ıFF点数=128
ı基带采样速率1.92MHz
ı子载波间距15kHz
ı有效带宽180kHz=1PRB
ıCP length=10/9 samples
NB-IOT时隙结构和RE资源ı只支持kHz
∆f
15
=
NB-IOT Downlink 基带信号
()()
⎣⎦
⎡⎤∑-
-=-∆+⋅
=-1
2/2/)2/1(2)(,)(RB sc RB sc s ,CP )(N N k T N t f k j p l k p l l e a t s π()()⎣⎦()⎡⎤∑∑=-∆--=-∆⋅+⋅=
+-2/12)(,12/2)(,)
(RB sc DL RB s ,CP )(RB sc DL RB s ,CP )(N N k T N t f k j p l k N N k T N t f k j p l k p l l l e
a
e a t s ππNB-IOT Downlink 基带信号：
LTE Downlink 基带信号：
NB-IOT 和LTE 基带信号差别：NB-IOT 下行基带使用了DC 载波并且具有频域具有半载波频移以降低射频链路直流泄露的影响，与LTE 的上行基带处理方式类似
NB-IOT物理信道
NB-IOT下行物理信道和物理信号
NB-IoT: Broadcasting of System Information
ıMaster information broadcast and system information broadcast are supported for NB-IoT ıOperations:
-In-Band : SIB for resource management required (coexistence with LTE Band)
-Standalone / Guard Mode : No need for resource management (static scheduling)
ıIt contains information required to acquire SIB1
ı(TBS, repetitions, like eMTC schedulingInfoSIB1-NB)
ı1 bit for indicating access barring (AB) activation/deactivation
ıAdded systemInfoValueTag(indicates changes of SIB1 or SI messages,
ı24hrs after last successful validation, system information is declared invalid)ıThe 4 most significant bits of NB-IoT SFN are indicated in NB-MIB
ı4 bits are used to indicate NB-SIB1 scheduling information in NB-MIB
ıThe number of NB-RS ports (1 or 2) is indicated by NB-PBCH CRC masking ı(all 0’s for 1 port, and all 1’s for 2 ports, as in the current spec for LTE CRS)ıThe number of LTE CRS ports is indicated by NB-MIB
ıRaster offset
ıThe deployment mode is indicated by NB-MIB: 2 bits indicating:
00: In-band mode when the same PCI indicator is true
01: In-band mode when the same PCI indicator is false
10: Guard band mode
11: Stand-alone mode
LTE PBCH TTI为40ms，频域占用中心72个子载波，时域为Slot1的前4个符号
NB-IoT: System Information Block Type 1
ıSIB1-NB
Cell access/selection, other SIB scheduling
Control region size (no PCFICH) for in-band case (guard band and standalone =0)
NPDCCH
ıA narrowband physical control channel is transmitted on an aggregation of one or two consecutive narrowband control channel elements (NCCEs), where a narrowband control channel element corresponds to 6 consecutive subcarriers in a subframe where NCCE 0 occupies subcarriers 0 through 5 and NCCE 1 occupies subcarriers 6 through 11. The NPDCCH supports multiple formats as listed in Table 10.2.5.1-1. For NPDCCH format 1, both NCCEs belong to the same subframe.
ıOne or two NPDCCHs can be transmitted in a subframe.
ıIn LTE 1*CCE=9*REG=36*RE
NB-IOT NPDSCH
ıThere are two NB-IoT downlink transmission schemes defined in all operation modes:• Single antenna port (port 0)
• Two antenna ports (ports 0 and 1), using transmit diversity, i.e. SFBC
ıSame transmission scheme is applied to NPDCCH, NPBCH, and NPDSCH
NB-IoT: NPSS
()()
()
10
,...,
1,0
,
11
1
=
⋅
=
+
-
n
e
l
S
n d
n un j
l π
()()13
,...,
3S
S
NB-IoT: NSSS
NRS
NB-IOT Downlink物理信道配置
内容
ıNB-IOT技术背景
ıNB-IOT标准化过程
ıNB-IOT布网模式及双工方式
ıNB-IOT无线帧结构和下行物理信道
ıNB-IOT无线帧结构和上行物理信道
ıNB-IOT应对物联网海量接入和低功耗机制ıNB-IOT测试
NB-IOT Uplink
NB-IOT uplink support Single-Tone and Multi-Tone and UE must report its ability
ıSingle-Tone
•Include 3.75kHz and 15kHz bandwidth
•A cyclic prefix is inserted
•Frequency domain Sinc pulse shaping in the physical layer description
•Better coverage 、coverage and power consumption
•Enables extreme low cost IoT terminals to compete with non-cellular devices
•Enable faster time to market.
•Not only cellular industry, low cost chip vendors are interested in building ST only chips.
ıMulti-Tone
•SC-FDMA
•Higher peak rate
•Additional mechanisms for PAPR reduction FFS
•Based on SC-FDMA with the same 15 kHz subcarrier spacing, 0.5 ms slot, and 1 ms subframe as LTE
NB-IOT Single-Tone
Within ST Flexible bandwidth of 3.75kHz and 15kHz adaptive to different scenarios ı3.75kHz:
•provides better coverage with relaxed timing requirements due to longer CP length •better capacity for large cell PRACH and PUSCH links
•lower power consumption
ı15kHz:
•better coexist with legacy LTE links
NB-IOT uplink Slot structure and physical resources
SC-FDMA symbols
One uplink slot
s
u
b
c
a
r
r
i
e
r
s
Resource element kHz
15
=
∆f
{}19
,...,
1,0
s
∈
n
kHz
75
.3
=
∆f
{}4
,...,
1,0
s
∈
n
A single antenna port is used for all uplink transmissions.
NB-IOT uplink Resource unit
ıResource units are used to describe the mapping of the NPUSCH to resource elements.ıNPUSCH can be mapped to one or more than one resource units
ıThe narrowband physical uplink shared channel supports two formats: NPUSCH format 1, used to carry the UL-SCH
NPUSCH format 2, used to carry uplink control information
NB-IOT uplink 物理信道
NB-IOT Demodulation reference signal
NB-IOT 下行基带信号生成
()()()
⎣
⎦
2
RB sc
)
(212,,s ,CP ,)(N k k
e
e a t s T N t
f k j j l k l k l l
k +
=⋅⋅=--∆+-πϕ1
RU sc
=N 1
RU sc
>N ()()()
⎣
⎦
⎡
⎤
∑
--=-∆+⋅=
-1
2/2
/212)
(,)(RB sc UL RB RB sc UL RB s ,CP )(N N N N k T N t f k j p l
k p l
l e
a t s π。