3GPP NB-IoT發展現況...Complexity/cost Reductions for LTE-M and NB-IoT Evolution 5 Source:“LTE evolution for IoT connectivity” whitepaper, Nokia, July 2016 • Target for a

3GPP NB-IoT發展現況

資策會

汪海瀚工程師

IoT Use Cases

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Source:“LTE evolution for IoT connectivity” whitepaper, Nokia, July 2016

Technologies Addressing Different IoT

Segments

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Source:“Cellular networks for massive IoT” whitepaper, Ericsson, January 2016

Comparison of LPWA IoT solutions

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2863

Complexity/cost Reductions for LTE-M and NB-

IoT Evolution

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• Target for a NB-IoT module that costs less than 5 USD

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3GPP Evolution Steps for Massive IoT

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Source:“Cellular networks for massive IoT” whitepaper, Ericsson, January 2016

Rel-12Rel-8

Rel-12Rel-13

Rel-13

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History of 3GPP MTC (1/2)

• TSG Radio Access Network (TSG RAN) Work Items:

– Release 10: RAN mechanisms to avoid CN overload due to Machine-Type

Communications (NIMTC-RAN_overload, WID: RP-101026)

– Release 11: RAN overload control for Machine-Type Communications (SIMTC-RAN_OC,

WID: RP-111373)

• Introduced Extended Access Barring (EAB)

– Release 12:

• Low cost & enhanced coverage MTC UE for LTE (LC_MTC_LTE, WID: RP-130848)

– DL/UL category 0, downlink and uplink maximum TBS size of 1000 bits, Type B half-duplex FDD

operation.

• RAN enhancements for Machine-Type and other mobile data applications

Communications (MTCe-RAN, WID: RP-140752)

– Power Saving Mode (PSM)

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History of 3GPP MTC (2/2)

– Release 13:

• Further LTE Physical Layer Enhancements for MTC (LTE_MTCe2_L1 (often referred

as eMTC), WID: RP-141660)

– DL/UL category M1, bandwidth reduced to 1.4MHz, repetitions of PHY signal, cross-subframe

scheduling, asynchronous UL HARQ, 23/20dBm maximum output power,downlink and uplink

maximum TBS size of 1000 bits, Type B half-duplex FDD operation.

• RAN enhancements for extended DRX in LTE (LTE_extDRX, WID: RP-150493)

– Introduced extended DRX (eDRX)

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New Categories Introduced for MTC

• DL/UL category 0, DL/UL category M1 (TS36.306)

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Origin of NB-IoT (1/4)

• GERAN Study Item “Cellular System Support for Ultra Low Complexity and Low Throughput Internet of Things” (FS_IoT_LC) completed in GERAN GERAN#67 meeting.– The aim was to study both the possibility of evolving current GERAN system and

the design of a new access system “clean slate” towards low complexity and low throughput radio access technology to address the requirements of cellular internet of things.

– Technical Report: TR45.820

– The following is the outcome of the study:• EC-GSM concluded and shown compliance to all objectives.

• NB-CIoT concluded and shown compliance to all objectives.

• NB-LTE, NB-M2M, NB-OFDMA, N-GSM, C-UNB are partially described.

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Reference:RP-151148


• EC-GSM

– Re-using existing design

– Backwards compatibility and co-existence with GSM

– Achieving extended coverage

– Release 13 Work Item “Extended Coverage GSM (EC-GSM) for support of Cellular

Internet of Things” (CIoT_EC_GSM (often referred as EC-GSM-IoT), WID: GP-151039)

started from GERAN #67 meeting

– Release 14 Work Item “Radio Interface Enhancements for Extended Coverage GSM for

support of Cellular Internet of Things” (CIoT_EC_GSM_radio_enh, WID: RP-161806)

started from RAN #73 meeting

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• NB-CIoT– Not backward compatible with LTE

– DL: OFDMA, 48 subcarriers with subcarrier spacing=3.75kHz, 10kHz guard band at each end.

– UL: FDMA with single carrier GMSK modulation, 36 subcarriers with subcarrier spacing=5kHz, 10kHz guard band at each end.

• NB-LTE– Backward compatible with LTE. NB-LTE aims to reuse the higher layer user

plane designs of LTE to a very large extent.

– DL: OFDMA, same numerology as LTE (subcarrier spacing=15kHz)

– UL: SC-FDMA, 72 subcarriers with subcarrier spacing=2.5kHz

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• Release 13 Work Item “Narrowband IOT (NB_IOT, WID:

RP-151621)” was approved in RAN #69 meeting to

address the so called "Clean Slate" part of the GERAN SI

and the low end of the IOT market.

– Also to address some operators’ interests to have CIoT solution

deployable in-band LTE.

– Only one Work Item: Followed strong request from some

operators for a unified solution.

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Release 13 NB-IoT (1/6)

• Work Item completed in RAN# 72, June 2016.

• NB-IoT supports 3 operation modes– Inband:

• Use one (or more) PRB(s) of a LTE carrier.

• Mapping of symbols avoids LTE PDCCH, CRS in DL.

• Physical layer operations, i.e., IFFT, CP insertion, I/Q modulation, RF up-conversion,…etc., can be done together with LTE signal, ensuring orthogonality between subcarriers.

– Guardband:• Utilize one (or more) 200kHz carrier(s) within LTE carrier guardband

– Can also be used together with inband carrier(s)

• Physical layer operations can be done together with LTE signal as described above.

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– Standalone:

• Utilize one (or more) 200kHz carrier(s) outside LTE system bandwidth

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• DL– OFDMA, 12 subcarriers with subcarrier spacing=15kHz

– Use TBCC instead of turbo code for data channel

– Redesigned synchronization channel, broadcast channel, control channel to fit in a carrier.

• UL– SC-FDMA, support 2 numerologies

• 12 subcarriers with subcarrier spacing=15kHz

• 48 subcarriers with subcarrier spacing=3.75kHz– NPRACH always uses single tone with 3.75kHz subcarrier spacing

• Modulation: 𝜋

2BPSK,

𝜋

4QPSK

– Support single tone transmission

– Asynchronous HARQ

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17

1 symbol

1 slot, 2ms

3.75kHz 15kHz

1 slot 1 slot 1 slot 1 slot

UL Resource Grid


• New UE category: Cat. NB1

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• Main radio protocol features

– Single HARQ process

– Only RLC AM mode with simplified status reporting

– Two PDCP options:• Option1, used for control plane solution. SRB 0 and 1bis only. No AS security

(only NAS security). PDCP operating in transparent mode.

• Option2, used for user plane solution. SRB 0, 1 and at most two DRB. AS security, which is cached upon RRC connection release.

– For PDCP option 2, RRC connection suspend/resume procedures to maintain AS security context.

– Significantly reduced broadcast system information

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Source:“3GPP Standards for the Internet-of-Things”, Smart Summit Singapore November 2016

Summary for eMTC, NB-IOT and EC-GSM-IoT

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Special Feature Introduced for NB-IoT (1/2)

• User plane solution supports RRC suspend/resume

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Special Feature Introduced for NB-IoT (2/2)

• Support inter-eNB UE Context Resume:

– Retrieval of UE context for a UE which attempts to resume its RRC

connection in an eNB different from where the RRC connection was

suspended.

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NB-IoT Design Objectives

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164dB MCL

Source: “NB-IoT-Enabling New Business Opportunities”, Huawei 2015

Release 14 eMTC• WI: Further enhanced MTC for LTE (LTE_feMTC (often referred as FeMTC),

WID: RP-161321)

• Main feature enhancements

– Support for positioning (E-CID and OTDOA)

– Support for Multicast (SC-PTM)

– Mobility for inter-frequency measurements

– Higher data rates

• Specify HARQ-ACK bundling in CE mode A in HD-FDD

• Larger maximum TBS

• Larger max. PDSCH/PUSCH channel bandwidth (5MHz for BL UE) in connected mode at least

in CE mode A in order to enhance support e.g. voice and audio streaming or other applications

and scenarios

• Up to 10 DL HARQ processes in CE mode A in FD-FDD

– Support for VoLTE (reduce DL repetitions, new repetition factors, and adjusted

scheduling delays)

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Release 14 NB-IoT

• WI: Enhancements of NB-IoT (NB_IOTenh (often referred as eNB-IoT), WID: RP-161324) approved at RAN #72.

• Objectives:

– Positioning: for tracking applications, fault location/fast repair, smart parking, medical wearable,…etc.

– Multicast: for firmware or software updates, group message delivery.

– Non-anchor carrier enhancements: more number of supportable devices.

– Mobility and service continuity enhancements: connected mode mobility

– New power class: lower maximum transmission power (14dBm)

– Power consumption and latency reduction (added at RAN #73): for higher throughput

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Positioning for eNB-IoT

• Support OTDOA (Observed Time Difference of Arrival)

and E-CID (Enhanced Cell ID).

• Reuse LPP (LTE Positioning Protocal)

• Introduce Narrowband Positioning Reference Signal

(NPRS)

• Support measurement in IDLE mode

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Narrowband Positioning Reference Signal

• Resource Element pattern

– Reuse Rel-9 PRS RE pattern for inband case

– Add more REs on top of Rel-9 PRS RE pattern for guardband,

standalone case

Figure 2: Mapping of NPRS (normal cyclic prefix) for

guardband and standalone scenario

R1-1613294, WF on NPRS pattern for NB-IoT OTDOA

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NPRS subframe configuration

• NPRS is configured per NB-IoT carrier transmitting NPRS– Each NB-IoT carrier can have different configuration parameter

– Part A:A bitmap for NPRS subframe indication in one NPRS occasion• bitmap length is the same as valid subframe configuration, i.e. 10 bits or 40 bits

– For Part-B NB-IoT specific assistance information:• Number of subframes of NPRS in one occasion is NPRS {10, 20, 40, 80, 160, 320, 640, 1280}

• Periodicity of NPRS occasion TPRS: 160ms, 320ms, 640ms, 1280ms.

• Valid configurations are those satisfying NPRS <= TPRS

• For a given periodicity of NPRS occasion, the starting subframe offset of NPRS occasion

=𝛼𝑇𝑃𝑅𝑆, 𝛼𝜖 0,1

8,2

8,3

8,4

8,5

8,6

8,7

8

– If part A and part B are both configured then a subframe contains NPRS if both configurations indicate it contains NPRS

– If NPRS subframe configuration is part B only, NPRS is punctured in OFDM symbols 5 and 6 in each slot

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SC-PTM for eNB-IoT

• SC-MCCH and SC-MTCH are dynamically scheduled by DCI (same as in

LTE)

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Source:R1-166178

Maximum TBS for SC-PTM

• Allow to use the even larger TBS agreed in RAN1 #87

• Maximum TBS value for NPDSCH carrying SC-MCCH or SC-MTCH is 2536 bits

–Cat NB-1 UE does not need to receive the NPDSCH if the DCI indicates a TBS larger than 680 bits

• Using larger TBS can reduce the number of TBs needed for each UDP/IP packet

• Increase the probability of successfully receiving a UDP/IP packet

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Non-Anchor Carrier Enhancements• For paging:

– Up to 15 non-anchor carrier can be used as paging carrier.

– For a Rel-14 NB-IoT UE, both anchor and non-anchor carrier can be selected as the paging carrier• A Rel-14 UE chooses the carrier based on UE_ID and weights of each paging carrier

• Paging message on NPDSCH is scheduled by NPDCCH on the same carrier.

• For random access:– Up to 15 non-anchor carrier can be used for random access.

– UE selects NPRACH resource (including selection of carrier) based on random draw.

– Use different carrier selection probability for anchor and non-anchor carriers.

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Mobility Enhancements

• Mobility is triggered by RLF (Radio Link Failure)

• RLF triggers RRC Connection Re-establishment

• No additional mechanism is introduced to avoid NAS

recovery for the CIOT UP solution

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2 HARQ Processes(1/2)

There is a new NB-IoT UE category with max UL and max DL TBS of 2536 bits

Introduce the {1 HARQ + 2536 bits UL/DL TBS} TBS tables in R1-1613508

Introduce the {2 HARQ + [1352] bits DL TBS, [1800] bits UL TBS and no change to any Rel-13

specification for NPUSCH}

o After receiving one DL grant, Rel-14 UE is required to continue monitoring any NPDCCH search spaces

containing candidates ending at least 2 ms (i.e., x1 ≥ 2 ms) before the start of the first NPDSCH.

o The gap between NPUSCH to any DL reception is ≥ 1ms.

o Reuse Rel-13 timing relationship and scheduling delay values for each of the 2 HARQ processes

o HARQ process ID is indicated DL grant DCI with one bit

Monitored only in USS

o FFS TBS table details.

Soft buffer size is FFS until next RAN1#88

The support of 2 HARQ by UE is an optional capability, signalling is left to RAN2

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RAN1 Chairman’s Notes, RAN1 #87

2 HARQ Processes(2/2)

•

Source:R1-1611865

Source:R1-1611866

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5G mMTC

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164dB MCL

15 Yrs 1M devices/km2

• At RAN #74

– 3GPP’s IMT-2020 self-evaluations towards mMTC requirements will

assess NB-IoT and/or LTE eMTC

Rel-15 NB-IoT

• Companies (Ericsson, Huawei) proposed to support NB-

IoT in unlicensed spectrum

– Offload lower priority traffic to unlicensed carrier

– Standalone (Ericsson)

– Licensed-Downlink Assisted (Huawei)

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Documents

3GPP NB-IoT發展現況...Complexity/cost Reductions for LTE-M and NB-IoT Evolution 5 Source:“LTE evolution for IoT connectivity” whitepaper, Nokia, July 2016 • Target for a