LTE NB-IOT协议介绍

NB-IOT protocol collection

1. NB-IOT基本概念

Improved indoor coverage, support for massive number of low throughput devices,

low delay sensitivity, ultra low device cast, low device power consumption

NB-IOT should support 3 different modes of operation ：

‘ Stand-alone operation ’ utilizing for example the spectrum currently being used by GERAN

systems as a replacement of one or more GSM carriers, as well as scattered spectrum for potential

IoT deployment.

‘ Guard band operation ’ utilizing the unused resource blocks within a LTE carrier ’ s guard-band

仅支持 type-B half-duplex FDD operation (type-B 定义参考 3GPP 36.211 R13 chapter6.2.5)

NB-IOT vs eMTC vs legacy LTE

LTE R9 NB-IoT

系统带宽 1.4M/3M/5M/10M/15M/20M 200kHz

工作模式 full duplex FDD/TDD half-duplex FDD

最大传输速率

DL: 150Mbps; UL 50Mbps DL/UL: < 200kbps

频带部署方式 LTE授权频 段 带内，带外，保护带三种部署方 式

覆盖范围 (MCL)

~145dB 164dB

NPSS/NSSS，构造以及相对间隔都与

随机接入

Preamble/RAR/MSG3/MSG4 NPRACH/NPDSCH

解调信号 DL: CRS UL: DMRS DL: NRS UL: NDMRS

上下行信道探测

下行 CSI，上行 SRS 没有 CSI，没有 SRS

下行数据信道

PDSCH NPDSCH

QPSK, 16QAM, 64QAMP QPSK

1/3 turbo coding 1/3 Tail biting convolutional coding

单子帧传输一个传输块

EPDCCH

DCI Format 0/1/1A/2/2A/3/3A … DCI Format N0/N1/N2

上行数据信道

PUSCH NPUSCH

15kHz sub-carrier spacing 15kHz or 3.75kHz sub-carrier spacing

1/3 turbo coding 1/3 turbo coding

单子帧传输一个传输块

以 Resource Unit(可以跨多个子帧 )作

为传输块的传输单 位

UL-SCH和 UCI 在同一个子帧发送

wideband uplink transmission

NB-IoT has about 6.3dB better coverage than eMTC

In-Band 操作的一些特殊处理？？？

Symbols and abbreviations

UL

The following narrowband physical channels are defined:

slot

T

1.

Table 10.1.2.1-1: NB-IoT parameters.

UL

sc

A single antenna port

is used for all uplink transmissions.

Comment: 上行有两种时隙结构，一种是针对子载波间隔 15kHz 的，和 legacy LTE的时隙结

构相同；一种是针对子载波间隔 3.75kHz 的，一个 RB内包含的子载波数是 48，是 legacy

LTE的 4 倍。同时时隙长度是 2ms，是 legacy LTE的 4 倍。一个无线帧只包含 5 个 Slots。

所以一个无线帧仍然是 10ms。

NB-IOT上行总是使用 p=0 的单天线发送。

2.1.2.1 Uplink resource unit(10.1.2.3)

Resource units are used to describe the mapping of the NPUSCH to resource elements. A resource unit is

defined as

NN consecutive SC-FDMA symbols in the time domain and

N consecutive

Table 10.1.2.3-1: Supported combinations of

UL

symb

N .

RU

sc

UL

slots

N

UL

symb

N

Comment:NPUSCH资源分配的基本单位称之为 Resource Unit。一个 Resource Unit 定义为

NN

sc

N 个连续子载波。

Scrambling shall be done according to clause 5.3.1. The scrambling sequence generator shall be initialised

with

Ncell

ID

9

s

RNTIinit

f

where

n

is the first slot of the transmission

of the codeword. In case of NPUSCH repetitions, the scrambling sequence reinitialised according to the

above formula after every

identical

f

n

set to the first

slot and the frame, respectively, used for the transmission of the repetition. The quantity

NPUSCH

M is

given by clause 10.1.3.6.

2.1.3.3 NPUSCH layer mapping and precoding

3GPP TS 36.213 [4], each of which shall be transmitted

kHz75.31