Nb iot presentation

Narrow Band Internet Of Things (NB IoT)
Copyright @ Nex-G | Skills, NESPL 1

Table Of Content
Contents
IoT Introduction
NB IoT Introduction
RRC Layer
PDCP Layer
RLC Layer
Mac Layer
Physical Layer

IOT INTRODUCTION
 It Is a network of devices embedded with sensors and network connectivity that
enables them to collect and exchange data.
 The IOT allows objects to be sensed and controlled remotely across existing network
infrastructure creating opportunities for direct integration between the physical and
digital world resulting in improved efficiency, accuracy and economic benefits.
 “Things” in IOT refers to the objects in physical world that could be connected to the
internet by sensors.
 These devices collect useful data with the help of various existing technologies and
then autonomously flow the data between other devices.
 IOT is an evolution of mobiles, homes and embedded applications connected to the
internet integrating greater capabilities and using data analytics to extract
meaningful information.

ELEMENTS OF IOT

SENSORS
Sensors Function
 Measures value
 Sends raw data
 Low power

LOCAL PROCESSING AND STORAGE
 Get data from sensors
 Process the data
 Send some data to cloud for
fog computing
 Store data locally if
debugging needed

NETWORK AND INTERNET
 IoT Gateway
 Gathers processed data Iot gateway
 Protocols
 CoAP
 MQTT
 HTTP
 XMPP

CLOUD STORAGE
 Aggregate Data
 Storage
 Interferences

Categories of IOT
IOT
NON-CELLULAR IOT CELLULAR IOT

 3GPP has been working on 3 different IoT standard solutions-
 LTE-M based on LTE evolutions, Cat0(rel 12) and cat-1(rel 13)
 EC-GSM – A narrowband solution based on GSM evolution,
 NB-LTE- A narrowband cellular IoT solution, also known as
clean state solutions, Cat200KHz.
 Later, EC-GSM and NB-LTE, were combined for standardization
as a single NB-IoT technology.
NB-IOT STANDARDS DEVELOPMENT

NB-IoT Introduction
 Narrowband IoT (also known as NB-IoT or LTE-M2) is a proposed
LPWAN technology.
 NBIoT is a Low Power Wide Area Network (LPWAN) radio technology
standard that has been developed to enable a wide range of devices and
services to be connected using cellular telecommunications bands.
 NB-IoT technology can be deployed “in-Band, Guard-Band, Standalone.
 It is also suitable for the re-farming of GSM spectrum
 NB-IoT focuses specifically on indoor coverage, low cost, long battery life,
and enabling a large number of connected devices.
 Other 3GPP IoT technologies include eMTC (enhanced Machine-Type
Communication) and EC-GSM-IoT.

Objectives

Features of NB IoT
 Low device cost/complexity: <$5 per module
 Extended coverage: 164 dB MCL, 20 dB better compared to GPRS
 Long battery life: >10 years
 Capacity: 40 devices per household, ~55k devices per cell
 Uplink report latency : <10 seconds

Foreseeing NB-IoT Applications
NB-IoT applications can cross many service categories. These include:
 Smart metering (electricity, gas and water)
 Facility management services
 Intruder and fire alarms for homes & commercial properties
 Connected personal appliances measuring health parameters
 Tracking of persons, animals or objects
 Smart city infrastructure such as street lamps or dustbins
 Connected industrial appliances such as welding machines or air
compressors.

Major market potential for NBIoT services:

The NB-IOT deployment scenarios
 Standalone
 Guard Band
 In Band

NB-IOT Operation Modes

NB-IoT Architecture

Transmission bandwidth configuration

Channel Bandwidth and Transmission Bandwidth Configuration for one
NB-IoT carrier
Bandwidth Configuration

Channel Bandwidth for LTE and NB-IoT Channel Bandwidth for NB-
IoT in band operation

Channel Bandwidth for LTE and NB-IoT Channel Bandwidth for NB-
IoT in guard band operation

 200 kHz UE RF bandwidth for both downlink and uplink
Downlink:
 OFDMA
 15 kHz sub-carrier spacing for all the modes of operation (with
normal or extended CP).
uplink:
 SC-FDMA
 Single tone transmissions. : 3.75 KHz sub-carrier spacing for all the
modes of operation (with normal or extended CP).
 Multi-tone transmissions: 15 kHz. sub-carrier spacing for all the
modes of operation (with normal or extended CP).

Network deployment

NB IoT Characteristics
 Highest modulation scheme QPSK
 ISM bands vs licensed bands
– NB-IoT currently works on licensed bands only
– Narrowband operation (180 kHz bandwidth)
 in-band (LTE), guard band (LTE) or standalone operation mode (e.g. refarm
the GSM carrier at 850/900 MHz)
 Half Duplex FDD operation mode with 60 kbps peak rate in uplink and 30
kbps peak rate in downlink
 Maximum size of PDCP SDU and PDCP control PDU is 1600 bytes
 Multicast capabilities work in progress for 3GPP Release-14

Fixed reference channel (FRC) parameters for dynamic range for NB-IoT
Reference channel A13-2 A13-1
Sub carrier spacing (kHz) 3.75 15
Number of tone 1 1
Modulation π/4 QPSK π/4 QPSK
IMCS / ITBS 7 / 7 7 / 7
Payload size (bits) 104 104
Allocated resource units 1 1
Transport block CRC (bits) 24 24
Coding rate (target) 2/3 2/3
Coding Rate 0.67 0.67
Code block CRC size (bits) 0 0
Number of code blocks – C 1 1
Total symbols per resource unit 96 96
Total number of bits per resource unit 192 192
Tx time (ms) 32 8

Reference channel A12-2 A12-1
Sub carrier spacing (kHz) 3.75 15
Number of tone 1 1
Modulation π/2 BPSK π/2 BPSK
IMCS / ITBS 0 / 0 0 / 0
Payload size (bits) 32 32
Allocated resource units 2 2
Transport block CRC (bits) 24 24
Coding rate (target) 1/3 1/3
Coding Rate 0.29 0.29
Code block CRC size (bits) 0 0
Number of code blocks – C 1 1
Total symbols per resource unit 96 96
Total number of bits per resource unit 96 96
Tx time (ms) 64 16
Required SNR (dB) -2.0 -2.1
FRC parameters and simulation results for BS reference sensitivity

 RAN1 to specify the physical layer aspects, covering:
 Physical channel and mapping of transport channels
 Channel coding and physical channel mapping
 Physical layer procedures
 Physical layer measurements
 UE physical layer capabilities
 RAN2 to specify the following radio protocol aspects:
 The radio interface protocol architecture
 MAC, RLC, PDCP, and RRC protocols
 UE capabilities
Objectives of WG RAN

 RAN3 to specify changes to existing S1 interface.
 RAN4 to specify core requirements (when needed) to allow
for “standalone” , “in guard band operation” and “in-band
operation” in specific bands (depending on operator input) as
follows:
 UE radio transmission and reception
 Base Station radio transmission and reception
 UE and Base Station Requirements for support of Radio
Resource management.
Continue…..

 For the stand-alone operation, specify RF requirements to meet
(a) GSM mask relevant for NB-IoT or (b) MSR spectral mask
depending on the BS operational configuration.
 For the guard band operation, specify RF requirements for
adjacent / non-adjacent co-existence with LTE in the guard band.
 For the in-band operation, specify RF requirements for adjacent
channel coexistence with another LTE carrier and specify RF
requirements for in-band co-existence with LTE.

Bands with high priority defining any RAN4

Summary for NB-IoT

RRC:
Radio Resource Control

NB-IoT PROTOCOL Stack

 RRC layer specification is defined in TS 36.331 , and for NB-IoT, the
RRC layer specifications are slightly different from that of LTE.
 UE must make the transition to RRC Connected mode before
transferring any application data, or completing any signaling
procedures.
 RRC connection establishment is a 3-way handshake between UE and
eNodeB, which is used to make the transition of UE from RRC Idle
mode to RRC Connected mode.
 RRC connection establishment procedure has mainly 3 steps. RRC
connection request message sent by UE, RRC connection setup sent by
eNodeB, RRC setup complete messages send by UE.
NB-IoT RRC

 The RRC connection establishment procedure is always initiated by the
UE but can be triggered by either the UE or the network.
For example, the UE triggers RRC connection establishment if the
end-user starts an application to browse the internet, or to send an
email.
 The UE triggers RRC connection establishment if the UE moves into a
new Tracking Area and has to complete the Tracking Area Update
signaling procedure.
 The network triggers the RRC connection establishment procedure by
sending a Paging message. This could be used to allow the delivery of
an incoming SMS or notification of an incoming voice call.
NB-IoT RRC

 The initial Non-Access Stratum (NAS) message is transferred as part
of the RRC connection establishment procedure to reduce connection
establishment delay
 RRC connection establishment configures Signaling Radio Bearer
(SRB) 1 and (SRB1 bis) allows subsequent signaling to use the
Dedicated Control Channel (DCCH) rather than the Common
Control Channel (CCCH) used by SRB 0
 some of the functions of normal LTE function are not supported in
LTE-NB.
NB-IoT RRC

 Functionality that are supported in normal LTE but not in LTE-NB.
These are based on 36.331 4.4 Functions.
 ETWS Notification, CMAS Notification
 Inter RAT Mobility including e.g. security activation transfer of
RRC context information
 Measurement Configuration and Reporting
 Self-configuration and Self-optimization
 Measurement logging and reporting for network performance
optimization
NB-IoT RRC

System Information Block

 UEs exclusively use these SIBs and ignore those from LTE, even in the case of in-
band operation.
 It is always mandatory for a UE to have a valid version of MIB-NB, SIB1-NB and
SIB2- NB through SIB5-NB. The other ones have to be valid if their functionality is
required for operation. For instance, if access barring (AB) is indicated in MIB-NB,
the UE needs to have a valid SIB14-NB.
 System information acquisition and change procedure is only applied in the
RRC_IDLE state. The UE is not expected to read SIB information while being in the
RRC_CONNECTED state.
 If a change occurs, the UE is informed either by paging or direct indication. The
eNodeB may also release the UE to the RRC_IDLE state for the purpose of acquiring
modified system information.
System Information Block

NB-IoT RRC States
There are Two states in NB IoT
 No transitions to the associated UTRA and GSM states
 No handover to LTE

RRC Connection Establishment
The RRC Connection Establishment has the same message flow as for
the LTE system.

RRC Connection Resume request accepted by the eNodeB
RRC Connection Resume request accepted

RRC Connection Resume request not accepted by the eNB
RRC Connection Resume request not accepted

RRC connection release, always triggered by the eNodeB
RRC connection release

 UE Capability Transfer message is usually considerably smaller
than the corresponding LTE message, because all LTE features
which are not supported in NB-IoT, like further access
technologies or carrier aggregation, are left out.
UE Capability Transfer

PDCP:
PACKET DATA CONVERGENCE
PROTOCOL

PDCP
PACKET DATA CONVERGENCE PROTOCOL
 In terms of basic operation, what PDCP does seems very
simple. Just "adding the PDCP header to the incoming data
and forward to RLC in downlink", or "removing the PDCP
header from the incoming packet and forward it to IP layer in
case of uplink" is all that it does.

PDCP Functions

PDCP Functions (Contd..)
 Transfer of Data (C-Plane and U-Plane) between RLC and Higher U-Plane interface
 Maintenance of PDCP SN(Sequence Number)
 Transfer of SN Status (for use Upon Handover)
 ROHC (Robust Header Compression)
 In-Sequence delivery of Upper Layer PDUs at re-establishment of lower layer
 Elimination of duplicate of lower layer SDUs at re-establishment of lower layer for
RLC AM
 Ciphering and Deciphering of C-Plane and U-Plane data
 Integrity Protection and Integrity verification of C-Plane Data
 Timer based Discard
 Duplicate Discard
 For split and LWA bearers, routing and reordering.

PDCP Functional Diagram

Changes in PDCP layer w.r.t to Nb-IoT
Changes in NB IoT PDCP layer with respect to LTE PDCP Layer.
 The maximum supported size of a PDCP SDU is 8188 Octets, except
in NB-IoT for which the maximum supported size of a SDU is 1600
Octets.
 PDCP status report receive operation is not applicable in NB-IoT.
 In PDCP, PDU carrying data from DRBs mapped on RLC UM but in
case of NB-IoT DRBs are mapped on RLC AM.
 Length: 5,7,12,16 or 18 bits are used in PDCP SN for DRB but in NB-
IoT only 7 bit PDCP SN is used for DRB.

RLC
Radio Link Control

RLC Sub Layer Function
 Transfer of upper layer PDUs;
 Error correction through ARQ (only for AM
data transfer)
 Concatenation, segmentation and reassembly
of RLC SDUs (UM and AM)
 Re-segmentation of RLC data PDUs (AM)
 Reordering of RLC data PDUs (UM and
AM);
 Duplicate detection (UM and AM);
 RLC SDU discard (UM and AM)
 Protocol error detection and recovery.

LTE RLC Sub Layer

RLC Modes

Acknowledged Mode Transmit Overview
 Receives upper layer SDU from PDCP or RRC.
 Add the SDU to the transmit buffer.
 Segment the SDU into RLC PDUs when the
MAC scheduler permits transmission.
 Make a copy of the transmit buffer for possible
retransmissions.
 Add the RLC header to the RLC PDUs.
 Pass the RLC PDUs to MAC for transmission
over the air.
 For NB-IoT, RLC UM is only supported for
SC-MCCH and SC-MTCH.

Acknowledged Mode Receive Overview
 The MAC layer passes the received RLC PDU to
the RLC layer.
 The RLC layer removes the RLC header.
 The RLC PDU is received correctly, so mark the
block for positive acknowledgement.
– Acknowledgements are sent periodically to the
remote peer.
 The RLC layer assembles an upper layer
SDUs if receipt of an RLC PDU completes the
assembly of the SDU.
 Pass the assembled SDUs to the PDCP or RRC
layers.
 For NB-IoT: - The receiving side of an RLC
entity shall behave such that the timer values of t-
Reordering and t-StatusProhibit are 0, if not
configured.

Acknowledged Mode: Rec. Positive Ack
 A positive acknowledgement is received
from the remote end.
 Access the retransmission queue and
remove the buffer as it has been
acknowledged.
 Update the received sequence numbers to
advance the sliding window.

Ack Mode: Received -ve Acknowledgement
 A negative acknowledgement is received
from the remote end.
 Access the retransmission queue and extract
the buffer for retransmission.
 Retransmit the buffer
– If MAC does not support the original
transmission rate, re-segment the RLC
block into the smaller available block size

Ack Mode: Received Retransmission
 A retransmission for a previously
negatively acknowledged RLC PDU
is received.
 Update the received data buffer
– The received buffer may fill a hole
in the previously received data.
 Assemble all the in sequence
received data into SDUs– Pass the
received SDUs to the RRC or PDCP
layers.

 When a RLC data PDU is received from lower layer, where the RLC data
PDU contains byte segment numbers y to z of an AMD PDU with SN = x,
the receiving side of an AM RLC entity shall:
 if x falls outside of the receiving window; or
 if byte segment numbers y to z of the AMD PDU with SN = x have been
received before: discard the received RLC data PDU;
else:
 place the received RLC data PDU in the reception buffer;
 if some byte segments of the AMD PDU contained in the RLC data PDU
have been received before:
-
RLC data PDU is received from lower layer

MAC:
Media Access Control

CELLACESS

 It first searches a cell on an appropriate frequency,
 Reads the associated SIB information, and
 Starts the random access procedure to establish an RRC
connection.
 With this connection it registers with the core network via the NAS
layer, if not already done.
 After the UE has returned to the RRC_IDLE state, it may either
use again the random access procedure if it has mobile originated
data to send, or waits until it gets paged.
CELLACCESS

 Mapping of logical channels onto transport channels.
 Multiplexing of MAC SDU’s from one or different logical channels
onto transport blocks to be delivered to physical layer on UE side.
 Error correction through HARQ retransmission.
 Priority handling between UE’s by means of dynamic scheduling.
 Logical channel prioritization.
 Transport format selection and TB size selection.
MAC LAYER FUNCTION

 Initial access from RRC idle state.
 RRC connection re-establishment procedure.
 Achieving UL synchronization from UE to eNodeB.
 When UE’s UL synchronization is lost or “non-synchronized”.
 When UE has msg3 data to be send.
Why RACH procedure

RACH PROCEDURE
 The RACH procedure has the same message flow
as for LTE, however, with different parameters
 For NB-IoT the RACH procedure is always
contention based and starts with the transmission
of a preamble
 After the associated response from the eNodeB, a
scheduled message, msg3, is transmitted in order
to start the contention resolution process.
 The associated contention resolution message is
finally transmitted to the UE in order to indicate
the successful completion of the RACH procedure.

RANDOM ACCESS PREAMBLE
The preamble is based on symbol groups on a single subcarrier. Each symbol
group has a cyclic prefix (CP) followed by 5 symbols.

Contention based RACH procedure

HARQ RETRANSMITTION PROCESS

 Extended Connected mode DRx Cycles of 5.12s and 10.24s are supported
 Extended Idle mode DRx Cycles upto 3hr supported
Enhanced DRx Cycle

PHY:
PHYSICAL LAYER

Physical Layers Function
 Enables exchange of data & control info between eNodeB and UE and also
transport of data to and from higher layers
 Functions performed include error detection, FEC, antenna processing,
synchronization, etc.
It consists of Physical Signals and Physical Channels
 Physical Signals are used for system synchronization, cell identification and
channel estimation.
 Physical Channels for transporting control, scheduling and user payload
from the higher layers
 OFDMA in the DL, SC-FDMA in the UL
 NB-IoT supports FDD and TDD modes of operation

Physical Channels
 Physical channels
 A downlink narrowband physical channel corresponds to a set of resource
elements carrying information originating from higher layers.
 The following downlink physical channels are defined:
 Narrowband Physical Downlink Shared Channel, NPDSCH
 Narrowband Physical Broadcast Channel, NPBCH
 Narrowband Physical Downlink Control Channel, NPDCCH

Physical Channels
The following figure illustrates the connection between the transport channels and
the physical channels:

Physical Channels
 Downlink
For the DL, three physical channels
 NPBCH, the narrowband physical broadcast channel
 NPDCCH, the narrowband physical downlink control channel
 NPDSCH, the narrowband physical downlink shared channel and two
physical signals
 NRS, Narrowband Reference Signal
 NPSS and NSSS, Primary and Secondary Synchronization Signals are
defined. These are less channels than for LTE.
 The physical multicast channel PMCH is not included, because there is
no MBMS service for NB-IoT.,

Frame and Slot Structure
Frame and Slot Structure
These slots are summed up into subframes and radio frames in the same way as
for LTE:
Frame structure for NB-IoT for DL and UL with 15kHz subcarrier spacing-

Physical Resource Block
In the DL, OFDM is applied using a 15 kHz subcarrier spacing with normal cyclic
prefix (CP). Each of the OFDM symbols consists of 12 subcarrier occupying this
way the bandwidth of 180 kHz. Seven OFDMA symbols are bundled into one slot,
so that the slot has the following resource grid.
Resource grid for one slot. There are 12 subcarriers for the 180 kHz bandwidth

Physical Channels
 This is the same resource grid as for LTE in normal CP length for one
resource block, which is important for the in-band operation mode. A
resource element is defined as one subcarrier in one OFDMA symbol
and is indicated in above Figure by one square.
 Each of these resource elements carries a complex value with values
according to the modulation scheme.
 There are 1024 cyclically repeated radio frames, each of 10ms duration.
A radio frame is partitioned into 10 SFs, each one composed of two slots.
 In addition to the system frames, also the concept of hyper frames is
defined, which counts the number of system frame periods, i.e. it is
incremented each time the system frame number wraps.
.

Narrowband Reference Signal
 Narrowband Reference Signal
 The narrowband reference signal (NRS) is transmitted in all SFs which
may be used for broadcast or dedicated DL transmission, no matter if data
is actually transmitted or not.
 Depending on the transmission scheme, NRS is either transmitted on one
antenna port or on two. Its values are created like the CRS in LTE, with
the NCellID taken for the PCI.
 The NRS mapping shown in below figure is additionally cyclically shifted
by NCellID mod6 in the frequency range. When NRSs are transmitted on
two APs, then on every resource element used for NRS on AP0, the same
resource element on AP1 is set to zero and vice versa.

Reference Signal Mapping sequence
The mapping sequence is shown in the following figure:
.

Synchronization Signals
Synchronization Signals
 For a first synchronization in frame and subframe and in order to determine the
NCellID, the LTE concept of Primary Synchronization Signal (PSS) and Secondary
Synchronization Signal (SSS) is reused. With these signals, also timing and frequency
estimation may be refined in the UE receiver.
 In order to distinguish these signals from their LTE counterparts, they are denoted as
NPSS and NSSS, respectively.
 The first 3 OFDM symbols are left out, because they may carry the PDCCH in LTE
when NB-IoT is operated in the in-band mode. Note that during the time when the UE
synchronizes to the NPSS and NSSS, it may not know the operation mode,
consequently this guard time applies to all modes. In addition, both synchronization
signals are punctured by the LTE's CRS.

PSS and SSS
Primary and secondary synchronization signals indicated in light blue and
green, respectively. In violet, LTE CRS locations are shown. NRS are not
transmitted in the NPSS and NSSS sub-frames.
.

Narrowband Phy Broadcast Channel
Narrowband Physical Broadcast Channel.
 NPBCH is a special channel to carry MIB and has following characteristics:
It carries only the MIB.
It is using QPSK.
 Overall channel coding process is almost same as legacy LTE (the differences
are input/output bit length of each channel coding process) and of course
resource element mapping and transmission cycle/sub-frame will be
drastically different from legacy LTE.

Dedicated Channels
 The principle of control and shared channel also applies for NB-IoT,
defining the Narrowband Physical Downlink Control Channel (NPDCCH)
and the Narrowband Physical Downlink Shared Channel (NPDSCH).
 Not all SFs may be used for transmission of the dedicated DL channels
For the case that a SF is not indicated as valid, dedicated DL channel
transmission is postponed until the next valid SF..
 The NPDCCH indicates for which UE there is data in the NPDSCH, where
to find them and how often they are repeated. Also, the UL grants are
provided therein, showing the resources the UE shall use for data
transmission in the UL. Finally, additional information like paging or system
information update is contained in the NPDCCH as well.

 NB-IoT is the 3GPP radio-access technology designed to meet the connectivity
requirements for massive MTC applications.
 In contrast to other MTC standards, NB-IoT enjoys all the benefits of licensed
spectrum, the feature richness of EPC and the overall ecosystem spread of 3GPP .
 It is optimized to small and infrequent data packets this way UE can be kept in a cost
efficient way and needs only a small amount of battery power.
 In the ongoing discussions in 3GPP surrounding 5G , LTE will continue to be an
integral part of radio networks beyond 2020, and so, NB-IoT 's resemblance to LTE
safeguards the technology from diverging evolution paths.
 With Release 14, the development of NB-IoT will continue . According to the current
plans, NB-IoT will be extended to include positioning methods, multicast services
required.
CONCLUSION

TS 36.331-Radio Resource Control (RRC); Protocol specification
TS 36.323- Packet Data Convergence Protocol (PDCP) specification
TS 36.322- Radio Link Control (RLC) protocol specification
TS 36.321-Medium Access Control (MAC) protocol specification
TS 36.211-Physical channels(PHY) and modulation
http://www.huawei.com/minisite/iot/img/nb_iot_whitepaper_en.pdf
https://en.wikipedia.org/wiki/NarrowBand_IOT
https://www.u-blox.com/en/narrowband-iot-nb-ioT
https://resources.nokia.com/asset/200178
https://www.link-labs.com/blog/overview-of-narrowband-iot
https://www.pages.arm.com/NB-IoT-White-Paper.htm
https://www.literature.cdn.keysight.com/litweb/pdf/5992-1734EN.pdf?id=2775285
https://www.3gpp.org/news-events/3gpp-news/1785-nb_iot_complete
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