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TS 36.201
E-UTRA — LTE Physical Layer –
General Description

V17.0.0 (PDF)  2022/03  17 p.
V16.0.0  2020/06  17 p.
V15.3.0  2020/03  17 p.
V14.1.0  2017/03  17 p.
V13.3.0  2017/03  16 p.
V12.2.0  2015/03  16 p.
V11.1.0  2012/12  15 p.
V10.0.0  2010/12  15 p.
V9.1.0  2010/03  15 p.
V8.3.0  2009/03  15 p.
Rapporteur:
Mr. Baker, Matthew
Alcatel-Lucent

Content for  TS 36.201  Word version:  16.0.0

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1  ScopeWord‑p. 5

The present document describes a general description of the physical layer of the E-UTRA radio interface. The present document also describes the document structure of the 3GPP physical layer specifications, i.e. TS 36.200 series. The TS 36.200 series specifies the Uu and Un points for the 3G LTE mobile system, and defines the minimum level of specifications required for basic connections in terms of mutual connectivity and compatibility.

2  ReferencesWord‑p. 5

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
  • References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
  • For a specific reference, subsequent revisions do not apply.
  • For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1]
TR 21.905: "Vocabulary for 3GPP Specifications".
[2]
TS 36.211: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation".
[3]
TS 36.212: "Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding".
[4]
TS 36.213: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures".
[5]
TS 36.214: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer - Measurements".
[6]
TS 36.216: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer for relaying operation".
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3  Definitions, symbols and abbreviationsWord‑p. 5

3.1  DefinitionsWord‑p. 5

For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905.
none

3.2  SymbolsWord‑p. 5

For the purposes of the present document, the following symbols apply:
none

3.3  AbbreviationsWord‑p. 6

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.
BPSK
Binary Phase Shift Keying
CoMP
Coordinated Multi-Point
CP
Cyclic Prefix
CQI
Channel Quality Indicator
CRC
Cyclic Redundancy Check
CSI
Channel State Information
eNode-B
Evolved Node B
EPDCCH
Enhanced Physical Downlink Control Channel
E-UTRA
Evolved Universal Terrestrial Radio Access
FDD
Frequency Division Duplex
HARQ
Hybrid Automatic Repeat Request
LAA
Licensed-Assisted Access
LTE
Long Term Evolution
MAC
Medium Access Control
MBMS
Multimedia Broadcast and Multicast Service
MBSFN
Multicast/Broadcast over Single Frequency Network
MIMO
Multiple Input Multiple Output
MPDCCH
MTC Physical Downlink Control Channel
MTC
Machine Type Communications
NPBCH
Narrowband Physical Broadcast Channel
NPDCCH
Narrowband Physical Downlink Control Channel
NPDSCH
Narrowband Physical Downlink Shared Channel
NPRACH
Narrowband Physical Random Access Channel
NPUSCH
Narrowband Physical Uplink Shared Channel
OFDM
Orthogonal Frequency Division Multiplexing
PBCH
Physical Broadcast Channel
PCFICH
Physical Control Format Indicator Channel
PDSCH
Physical Downlink Shared Channel
PDCCH
Physical Downlink Control Channel
PHICH
Physical Hybrid ARQ Indicator Channel
PMCH
Physical Multicast Channel
PRACH
Physical Random Access Channel
ProSe
Proximity Services
PSBCH
Physical Sidelink Broadcast Channel
PSCCH
Physical Sidelink Control Channel
PSDCH
Physical Sidelink Discovery Channel
PSSCH
Physical Sidelink Shared Channel
PUCCH
Physical Uplink Control Channel
PUSCH
Physical Uplink Shared Channel
QAM
Quadrature Amplitude Modulation
QPP
Quadratic Permutation Polynomial
QPSK
Quadrature Phase Shift Keying
RLC
Radio Link Control
RN
Relay Node
R-PDCCH
Relay Physical Downlink Control Channel
RRC
Radio Resource Control
RSSI
Received Signal Strength Indicator
RSRP
Reference Signal Received Power
RSRQ
Reference Signal Received Quality
SAP
Service Access Point
SC-FDMA
Single-Carrier Frequency Division Multiple Access
SPDCCH
Short Physical Downlink Control Channel
SPUCCH
Short Physical Uplink Control Channel
TDD
Time Division Duplex
TX Diversity
Transmit Diversity
UE
User Equipment
V2X
Vehicle-to-Everything
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4  General description of LTE Layer 1Word‑p. 7

4.1  Relation to other layersWord‑p. 7

4.1.1  General protocol architectureWord‑p. 7

The radio interface described in this specification covers the interface between the User Equipment (UE) and the network, and sidelink transmissions between UEs. The radio interface is composed of the Layer 1, 2 and 3. The TS 36.200 series describes the Layer 1 (Physical Layer) specifications. Layers 2 and 3 are described in the 36.300 series.
Copy of original 3GPP image for 3GPP TS 36.201, Fig. 1: Radio interface protocol architecture around the physical layer
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Figure 1 shows the E-UTRA radio interface protocol architecture around the physical layer (Layer 1). The physical layer interfaces the Medium Access Control (MAC) sub-layer of Layer 2 and the Radio Resource Control (RRC) Layer of Layer 3. The circles between different layer/sub-layers indicate Service Access Points (SAPs). The physical layer offers a transport channel to MAC. The transport channel is characterized by how the information is transferred over the radio interface. MAC offers different logical channels to the Radio Link Control (RLC) sub-layer of Layer 2. A logical channel is characterized by the type of information transferred.
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4.1.2  Service provided to higher layersWord‑p. 7

The physical layer offers data transport services to higher layers. The access to these services is through the use of a transport channel via the MAC sub-layer. The physical layer is expected to perform the following functions in order to provide the data transport service:
  • Error detection on the transport channel and indication to higher layers
  • FEC encoding/decoding of the transport channel
  • Hybrid ARQ soft-combining
  • Rate matching of the coded transport channel to physical channels
  • Mapping of the coded transport channel onto physical channels
  • Power weighting of physical channels
  • Modulation and demodulation of physical channels
  • Frequency and time synchronisation
  • Radio characteristics measurements and indication to higher layers
  • Multiple Input Multiple Output (MIMO) antenna processing
  • Transmit Diversity (TX diversity)
  • Beamforming
  • RF processing. (Note: RF processing aspects are specified in the TS 36.100 series)
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4.2  General description of Layer 1Word‑p. 8

4.2.1  Multiple accessWord‑p. 8

The multiple access scheme for the LTE physical layer is based on Orthogonal Frequency Division Multiplexing (OFDM) with a cyclic prefix (CP) in the downlink, and on Single-Carrier Frequency Division Multiple Access (SC-FDMA) with a cyclic prefix in the uplink and sidelink. To support transmission in paired and unpaired spectrum, two duplex modes are supported: Frequency Division Duplex (FDD), supporting full duplex and half duplex operation, and Time Division Duplex (TDD).
The Layer 1 is defined in a bandwidth agnostic way based on resource blocks, allowing the LTE Layer 1 to adapt to various spectrum allocations. A resource block spans either 12 sub-carriers with a sub-carrier bandwidth of 15kHz or 24 sub-carriers with a sub-carrier bandwidth of 7.5kHz or 72 sub-carriers with a sub-carrier bandwidth of 2.5kHz, each over a slot duration of 0.5ms, or 144 sub-carriers with a sub-carrier bandwidth of 1.25kHz over a slot duration of 1ms, or 486 sub-carriers with a sub-carrier bandwidth of approximately 0.37kHz over a slot duration of 3ms. Narrowband operation is also defined, whereby certain UEs may operate using a maximum transmission and reception bandwidth of 6 contiguous resource blocks within the total system bandwidth; for narrowband operation, sub-resource-block operation may also be used in the uplink, using 2, 3 or 6 sub-carriers.
For Narrowband Internet of Things (NB-IoT) operation, a UE operates in the downlink using 12 sub-carriers with a sub-carrier bandwidth of 15kHz, and in the uplink using a single sub-carrier with a sub-carrier bandwidth of either 3.75kHz or 15kHz or alternatively 3, 6 or 12 sub-carriers with a sub-carrier bandwidth of 15kHz.
The radio frame structure type 1 is only applicable to FDD (for both full duplex and half duplex operation) and, for sub-carrier bandwidths other than 1.25kHz and approximately 0.37kHz, has a duration of 10ms and consists of 20 slots with a slot duration of 0.5ms. Two adjacent slots form one sub-frame of length 1ms, except when the sub-carrier bandwidth is 1.25kHz or approximately 0.37kHz, in which cases one slot forms one sub-frame or has a time duration of 3ms, respectively. When the sub-carrier bandwidth is 15kHz, a slot can be further subdivided into three subslots of length 2 or 3 OFDM or SC-FDMA symbols for reduced latency operation.
The radio frame structure type 2 is only applicable to TDD and consists of two half-frames with a duration of 5ms each and containing each either 10 slots of length 0.5ms, or 8 slots of length 0.5ms and three special fields (DwPTS, GP and UpPTS) which have configurable individual lengths and a total length of 1ms. A subframe consists of two adjacent slots, except for subframes which consist of DwPTS, GP and UpPTS, namely subframe 1 and, in some configurations, subframe 6. Both 5ms and 10ms downlink-to-uplink switch-point periodicity are supported. Further details on the LTE frame structure are specified in [2]. Adaptation of the uplink-downlink subframe configuration via Layer 1 signalling is supported.
The radio frame structure type 3 is only applicable to LAA secondary cell operation. It has a duration of 10ms and consists of 20 slots with a slot duration of 0.5ms. Two adjacent slots form one subframe of length 1ms. Any subframe may be available for downlink or uplink transmission. For downlink transmission, the eNB shall perform the channel access procedures as specified in [4] prior to transmitting. A downlink or uplink transmission may start at the subframe boundary or later, and may end at the subframe boundary or earlier. For uplink transmission, the UE shall perform the channel access procedures as specified in [4] prior to transmitting.
To support a Multimedia Broadcast and Multicast Service (MBMS), LTE offers the possibility to transmit Multicast/Broadcast over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. MBSFN transmission enables highly efficient MBMS, allowing for over-the-air combining of multi-cell transmissions in the UE, where the cyclic prefix is utilized to cover the difference in the propagation delays, which makes the MBSFN transmission appear to the UE as a transmission from a single large cell. Transmission on a dedicated carrier for MBSFN is supported, as well as transmission of MBSFN on a mixed carrier with both MBMS transmissions and point-to-point transmissions using time division multiplexing. In addition to the 15kHz sub-carrier bandwidth, the sub-carrier bandwidth of 7.5kHz with a longer CP, the sub-carrier bandwidth of 2.5kHz with a long CP (100μs), the sub-carrier bandwidth of 1.25kHz with a very long CP (200μs), and the sub-carrier bandwidth of approximately 0.37kHz with a very long CP (300μs) are all supported on both dedicated and mixed MBSFN carriers. Transmission of PDSCH also in MBSFN subframes that are not used for MCH is supported on mixed MBSFN carriers.
Transmission with multiple input and multiple output antennas (MIMO) are supported with configurations in the downlink with up to 32 transmit antenna ports and eight receive antennas, which allow for multi-layer downlink transmissions with up to eight streams and beamforming in both horizontal and vertical dimensions. Multi-layer uplink transmissions with up to four streams are supported with configurations in the uplink with up to four transmit antenna ports and four receive antennas. Multi-user MIMO, i.e. allocation of different streams to different users is supported in both UL and DL.
Coordinated Multi-Point (CoMP) transmission and reception are supported, including the possibility to configure a UE with multiple Channel State Information (CSI) feedback processes.
Aggregation of multiple cells is supported in the uplink and downlink with up to 32 serving cells, where each serving cell can use a transmission bandwidth of up to 110 resource blocks and can operate with either frame structure type 1 or frame structure type 2. Dual connectivity to groups of serving cells that belong to two different eNode-Bs is also supported.
Sidelink transmissions are defined for ProSe Direct Discovery and ProSe Direct Communication between UEs. The sidelink transmissions use the same frame structure as uplink and downlink when the UEs are in network coverage; however, the sidelink transmissions are restricted to a sub-set of the uplink resources. V2X communication between UEs is supported via sidelink transmissions or via the eNB.
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4.2.2  Physical channels and modulationWord‑p. 9

The physical channels defined in the downlink are:
  • the Physical Downlink Shared Channel (PDSCH),
  • the Physical Multicast Channel (PMCH),
  • the Physical Downlink Control Channel (PDCCH),
  • the Enhanced Physical Downlink Control Channel (EPDCCH),
  • the MTC Physical Downlink Control Channel (MPDCCH),
  • the Relay Physical Downlink Control Channel (R-PDCCH),
  • the Short Physical Downlink Control Channel (SPDCCH),
  • the Physical Broadcast Channel (PBCH),
  • the Physical Control Format Indicator Channel (PCFICH),
  • the Physical Hybrid ARQ Indicator Channel (PHICH),
  • the Narrowband Physical Broadcast Channel (NPBCH),
  • the Narrowband Physical Downlink Control Channel (NPDCCH),
  • and the Narrowband Physical Downlink Shared Channel (NPDSCH).
The physical channels defined in the uplink are:
  • the Physical Random Access Channel (PRACH),
  • the Physical Uplink Shared Channel (PUSCH),
  • the Physical Uplink Control Channel (PUCCH),
  • the Short Physical Uplink Control Channel (SPUCCH),
  • the Narrowband Physical Random Access Channel (NPRACH),
  • and the Narrowband Physical Uplink Shared Channel (NPUSCH).
The physical channels defined in the sidelink are:
  • the Physical Sidelink Broadcast Channel (PSBCH),
  • the Physical Sidelink Control Channel (PSCCH),
  • the Physical Sidelink Discovery Channel (PSDCH),
  • and the Physical Sidelink Shared Channel (PSSCH).
In addition, signals are defined as reference signals, primary and secondary synchronization signals, resynchronization signals, wake-up signals, and discovery signals.
The modulation schemes supported are:
  • in the uplink, depending on the type of operation, π/2 BPSK, π/4 QPSK, QPSK, 16QAM, 64QAM and 256QAM,
  • in the downlink, QPSK, 16QAM, 64QAM, 256QAM and 1024QAM,
  • in the sidelink, QPSK, 16QAM and 64QAM.
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4.2.3  Channel coding and interleavingWord‑p. 10

The channel coding scheme for transport blocks in LTE is Turbo Coding with a coding rate of R=1/3, two 8-state constituent encoders and a contention-free quadratic permutation polynomial (QPP) turbo code internal interleaver (except for downlink transport blocks in NB-IoT operation). Trellis termination is used for the turbo coding. Before the turbo coding, transport blocks are segmented into byte aligned segments with a maximum information block size of 6144 bits. Error detection is supported by the use of 24 bit CRC. Further channel coding schemes for BCH, control information and downlink transport blocks in NB-IoT operation are specified in [3].
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4.2.4  Physical layer proceduresWord‑p. 10

There are several Physical layer procedures involved with LTE operation. Such procedures covered by the physical layer are;
  • Cell search,
  • Power control,
  • Uplink synchronisation and Uplink timing control,
  • Random access related procedures,
  • HARQ related procedures,
  • Relay related procedures,
  • Sidelink related procedures,
  • Channel Access procedures.
Through the control of physical layer resources in the frequency domain as well as in the time and power domains, implicit support of interference coordination is provided in LTE.
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4.2.5  Physical layer measurementsWord‑p. 10

Radio characteristics are measured by the UE and the eNode-B and reported to higher layers in the network. These include, e.g. measurements for intra- and inter-frequency handover, inter RAT handover, timing measurements and measurements for RRM and in support for positioning.
Measurements for inter-RAT handover are defined in support of handover to GSM, UTRA FDD, UTRA TDD, NR, CDMA2000 1x RTT, CDMA2000 HRPD and IEEE 802.11.

5  Document structure of LTE physical layer specificationWord‑p. 11

5.1  OverviewWord‑p. 11

The physical layer specification consists of a general document (TS 36.201), and five documents (TSs 36.211, 36.212, 36.213, 36.214 and 36.216). The relation between the physical layer specifications in the context of the higher layers is shown in Figure 2; TS 36.216 is the physical layer specification for transmissions between an eNode-B and an RN.
Copy of original 3GPP image for 3GPP TS 36.201, Fig. 2: Relation between Physical Layer specifications
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5.2  TS 36.201: Physical layer - General descriptionWord‑p. 11

The scope is to describe:
  • The contents of the Layer 1 documents (TS 36.200 series);
  • Where to find information;
  • A general description of LTE Layer 1.

5.3  TS 36.211: Physical channels and modulationWord‑p. 11

The scope of this specification is to establish the characteristics of the Layer-1 physical channels, generation of physical layer signals and modulation, and to specify:
  • Definition of the uplink, downlink and sidelink physical channels;
  • The structure of the physical channels, frame format, physical resource elements, etc.;
  • Modulation mapping (BPSK, QPSK, etc);
  • Physical shared channel in uplink, downlink and sidelink;
  • Reference signals in uplink, downlink and sidelink;
  • Random access channel;
  • Primary and secondary synchronization signals;
  • Resynchronization signal;
  • Primary and secondary sidelink synchronization signals;
  • Wake-up signals;
  • OFDM signal generation in downlink;
  • SC-FDMA signal generation in uplink and sidelink;
  • Scrambling, modulation and up conversion;
  • Uplink-downlink and sidelink timing relations;
  • Layer mapping and precoding in downlink, uplink and sidelink.
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5.4  TS 36.212: Multiplexing and channel codingWord‑p. 12

The scope of this specification is to describe the transport channel and control channel data processing, including multiplexing, channel coding and interleaving, and to specify:
  • Channel coding schemes;
  • Coding of Layer 1 / Layer 2 control information;
  • Interleaving;
  • Rate matching.

5.5  TS 36.213: Physical layer proceduresWord‑p. 12

The scope of this specification is to establish the characteristics of the physical layer procedures, and to specify:
  • Synchronisation procedures, including cell search procedure and timing synchronisation;
  • Power control procedure;
  • Random access procedure;
  • Physical downlink shared channel related procedures, including CSI feedback reporting;
  • Physical uplink shared channel related procedures, including UE sounding and HARQ ACK/NACK detection;
  • Physical shared control channel procedures, including assignment of shared control channels;
  • Physical multicast channel related procedures;
  • Sidelink related procedures;
  • Channel access procedures.
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5.6  TS 36.214: Physical layer - MeasurementsWord‑p. 12

The scope of this specification is to establish the characteristics of the physical layer measurements, and to specify:
  • Measurements to be performed by Layer 1 in UE and E-UTRAN;
  • Reporting of measurement results to higher layers and the network;
  • Handover measurements, idle-mode measurements, etc.

5.7  TS 36.216: Physical layer for relaying operation |R10|Word‑p. 12

The scope of this specification is to establish the characteristics of eNB - RN transmissions, and to specify relay-specific advancements in relation to:
  • Physical Channels and Modulation;
  • Multiplexing and channel coding;
  • Relay Node procedures.

A  Preferred mathematical notationsWord‑p. 14

The following table contains the preferred mathematical notations used in L1 documentation.
item notation
multiply product
matrix product
scalar product (product of a matrix by a scalar)
matrix dimensioning
Kronecker product
bracketing of sets (all elements of same type, not ordered elements)
bracketing of lists (all elements not necessary of same type, ordered elements)
bracketing of sequences (all elements of same type, ordered elements)
bracketing of function argument
bracketing of array index
bracketing of matrix or vector
Separation of indexes
use of italic for symbols
bracketing of arithmetic expression to force precedence of operations
necessity of bracketing arithmetic expressions
number type
binary xor and and
matrix or vector transpose
1×1 matrices
vector dot product
complex conjugate
matrix or vector Hermitian transpose
real part and imaginary part of complex numbers
Modulo operation (including negative value)
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$  Change HistoryWord‑p. 15


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