Part 3 - WiMAX Air Interface
Transcript of Part 3 - WiMAX Air Interface
-
8/11/2019 Part 3 - WiMAX Air Interface
1/38
WiMAX Air Interface
2007 Rohde & Schwarz
1
WiMAX Air Interface
Heinz MELLEIN, R&S
Technology Management Systems & Projects
-
8/11/2019 Part 3 - WiMAX Air Interface
2/38
WiMAX Air Interface
2007 Rohde & Schwarz
2
List of content
WiMAX TDD Reference Signal Maps
OFDMA key parameters
Permutation zones
Map information
PHY
MAC
MIMO
-
8/11/2019 Part 3 - WiMAX Air Interface
3/38
WiMAX Air Interface
2007 Rohde & Schwarz
3
c+9
c+8
c+7
c+6
c+5
c+4
c+2
c+1
c
k+8k+7k+6k+5k+4k+3k+2k+1k
OFDM(A) signal description
Number
of subchannels
Number of OFDM
symbols
Dataregion
Burst
symbol
offset
sub channeloffset
DL PUSC SLOT:
Minimum possible data unit:
2 symbols x 1 subchannel
= 48 symbols
= 96 Bits (QPSK)
= 192 Bits (16QAM)= 288 Bits (64QAM)
symbol
index
subchannel index
Reminder: 1 subchannel = 24 not necessarily adjacent frequency carriers
-
8/11/2019 Part 3 - WiMAX Air Interface
4/38
WiMAX Air Interface
2007 Rohde & Schwarz
4
OFDMA frequency domain sub channelisation
f
ffc
Sub
channel
-
8/11/2019 Part 3 - WiMAX Air Interface
5/38
WiMAX Air Interface
2007 Rohde & Schwarz
5
MRCT default Frame structure: normal MAP
-
8/11/2019 Part 3 - WiMAX Air Interface
6/38
WiMAX Air Interface
2007 Rohde & Schwarz
6
OFDM key parameters BW = Nominal channel bandwidth
Nused= No of used sub-carriers
NFFT= Smallest power of 2 greater than Nused
Sampling frequency Fs
Sub-carrier spacing = Fs/NFFT (frequency bin)
Useful symbol time Tb= 1/
CP time Tg= G
@
Tb
OFDMA symbol time Ts= Tb+ Tg= (1+G) @Tb
Sampling time Tb/NFFT
-
8/11/2019 Part 3 - WiMAX Air Interface
7/38
WiMAX Air Interface
2007 Rohde & Schwarz
7
Multiple permutation zones
1 TDD frame
-
8/11/2019 Part 3 - WiMAX Air Interface
8/38
WiMAX Air Interface
2007 Rohde & Schwarz
8
OFDMA sub carrier allocation modes for PHY layer
scalability
AdjacentAdjacentsubsubcarriercarrierpermutationpermutation
ForForfixedfixed((ororlowlowmobilitymobility))channelschannels
DistributedDistributedsubsubcarriercarrierpermutationpermutation
For mobile (For mobile (multipathmultipath))channelschannels
DistributedDistributedsubsubcarriercarrierpermutationspermutations FUSC (FUSC (FullyFullyUsedUsedSubSubchannelisationchannelisation) (DL) (DLonlyonly))
AllAllsubsubchannelschannelsavailableavailable
SubSubcarrierscarriersdistributeddistributedtotosubsubchannelschannelsbybypermutationpermutationmechanismmechanism
MinimiseMinimisethetheprobabiliyprobabiliyofofsubsubcarriercarrierclashesclashes
MaximiseMaximisefrequencyfrequencydiversitydiversitytotominimiseminimisefadingfadingimpactimpact
PUSC (PUSC (PartiallyPartiallyUsedUsedSubSubchannelisationchannelisation))
-
8/11/2019 Part 3 - WiMAX Air Interface
9/38
WiMAX Air Interface
2007 Rohde & Schwarz
9
Partially Used Subchannelisation (PUSC) Distributed permutation type
First divide available subcarriers into subchannels
Allocate pilots within each subchannel
Each subchannel contains ist own set of pilots
Pilot permutation is designed to
minimise the risk of physical subcarrier hits between adjacent cells/sectors
maximise frequency diversity to minimise degradation due to fading
DL PUSC
Cluster structure (14 adjacent subcarriers per cluster incl. 2 pilots) Subchannels are assigned to 3 segments(e.g. representing 3 sectors of the same cell)
UL PUSC
Tile structure (3 symbols x 4 subcarriers incl. 4 pilots)
-
8/11/2019 Part 3 - WiMAX Air Interface
10/38
WiMAX Air Interface
2007 Rohde & Schwarz
10
Downlink PUSC symbol structure
6 (3)30 (15)60 (30)120 (60)No of clusters Ncluster(subchannels)
723607201440No of data subcarriers Ndata
Scalable OFDMA (Rel. 16e)Rel. 2004
642565121024DC subcarrier index
1260120240No of pilot subcarriers Npilot
844208401680No of used subcarriers Nused (excl. DC)
22/2146/4592/91184/183Guard subcarriers (Left/Right)
128 FFT(1.25 MHz)
512 FFT(5 MHz)
1024 FFT(10 MHz)
2048 FFT(20 MHz)
DL PUSC slot = 1 subchannel x 2 OFDMA symbols
Cluster structure: 14 adjacent subcarriers incl. 2 pilots
k k+1
Pilot
Data
Symbol
index
Subcarrier
index
-
8/11/2019 Part 3 - WiMAX Air Interface
11/38
WiMAX Air Interface
2007 Rohde & Schwarz
11
Uplink PUSC symbol structure
Scalable OFDMA (Rel. 16e)Rel. 2004
642565121024DC subcarrier index
24102210420No of tiles Ntiles
4173570No of subchannels Nsubchannels
964088401680No of used subcarriers Nused (excl. DC)
16/1552/5192/91184/183Guard subcarriers (Left/Right)
128 FFT(1.25 MHz)
512 FFT(5 MHz)
1024 FFT(10 MHz)
2048 FFT(20 MHz)
Tile structure:
(3 OFDM symbols) x (4 subcarriers)
No of tiles per subchannel: 6
Pilot
Data
1 slot = 1 subchannel x 3 OFDMA symbolsSymbol
index
Subcarrier
index
-
8/11/2019 Part 3 - WiMAX Air Interface
12/38
WiMAX Air Interface
2007 Rohde & Schwarz
12
Subchannel group allocation
N/A526 .. 295
2420 .. 254N/A316 .. 193
1210 .. 152
N/A16 .. 91
001280 .. 501024N/A552 .. 595
10 .. 14440 .. 514
N/A332 .. 393
5 .. 9220 .. 312
N/A112 .. 191
0 .. 405120 .. 1102048
Subchannel
range
Subchannel
groupFFT size
Subchannel
range
Subchannel
groupFFT size
Profile 1A
-
8/11/2019 Part 3 - WiMAX Air Interface
13/38
WiMAX Air Interface
2007 Rohde & Schwarz
13
WiMAX PHY signal processing chain
Randomisation
(energy dispersal) FEC
Interleaving
Symbol mapping
Space Time Coding
Beam Forming
MIMO encoding
Data from
MAC
Subchannelisation
Pilot Insertion IFFT CP
RF
frontend
SubchannelisationPilot Insertion
IFFT CPRF
frontend
SISOOuter
Coding
Inter
leaving
Inner
Coding
CP = Cyclic Prefix
-
8/11/2019 Part 3 - WiMAX Air Interface
14/38
WiMAX Air Interface
2007 Rohde & Schwarz
14
Mobile WiMAX FEC channel coding schemes
HARQ Incremental Redundancy
OPTIONAL
CTC:
Convolutional Turbo CodeHARQ chase combining
OPTIONAL
CRC:
Cyclic Redundancy Check (Block code)
OPTIONALLDPC:
Low Density Parity Check Code
OPTIONALBTC:
Block Turbo Code
Coding rates: , 2/3, , 5/6
MANDATORY
RS-CC / CC:
Concatenated Reed-Solomon convolutional code
Mobile WiMAX Application
-
8/11/2019 Part 3 - WiMAX Air Interface
15/38
WiMAX Air Interface
2007 Rohde & Schwarz
15
ARQ and HARQ
-
8/11/2019 Part 3 - WiMAX Air Interface
16/38
WiMAX Air Interface
2007 Rohde & Schwarz
16
Example: DL Frame Prefix Processing
24 Bits of Data containing DL Frame Prefix Information Elements
Duplicate to 48 Bits (minimum FEC block length)
CC 1:2 coding results in 96 Bits
Repetition Factor 4 results in 384 Bits
QPSK Modulation creates 192 Modulation OFDM Symbols
Map onto FCH that spreads over 4 DL PUSC slots
(1 slot = 2 OFDM Symbols x 1 subchannel a 24 physical channels)
2 OFDM symbols x 4 x 24 subcarriers = 192 OFDM Symbols
-
8/11/2019 Part 3 - WiMAX Air Interface
17/38
WiMAX Air Interface
2007 Rohde & Schwarz
17
OFDMA DLFP Format and FCH mapping
Segment 0
Segment 1
OFDM symbol index
Segment 2
FCH
FCH
FCH
SubchannelIndex
(1
subchannel=
24
subcarriers
)
DL subframe
FEC Input Block (48 Bits)
Convolutional Coder
Bit Interleaver
96 Bit block
4 X Repeater
96 Bit block
QPSK Modulator
384 Bit Sequence
24 Bit DLFP 24 Bit DLFP
Slot 0
Slot 1
Slot 2
Slot 3
48 Symbols
per slot
DL_Frame_Prefix_Format (IEEE 802.16e-2005)
Used subchannel bitmapBit#0 enables subchannel group #0
Bit#5 enables subchannel group #5
RESERVED
Repetition Coding Indication for DL-MAP{ 0, 2, 4, 6 }
Coding Indication for DL-MAP{ CC, BTC, CTC, ZTCC, LDPC }
DL-MAP length(max. 255)
RESERVED
6
Bits
8Bits
3Bits
2
1
4
-
8/11/2019 Part 3 - WiMAX Air Interface
18/38
WiMAX Air Interface
2007 Rohde & Schwarz
18
OFDMA FCH: DL frame prefix (FP) (excerpt)
Indicates length of DL map message in terms
of slots
8 bitsDL MAP length
000b = CC encoding used on DL-MAP
001b = BTC encoding
010b = CTC encoding
011b = ZT CC encoding
100b = CC encoding with interleaver
101b = LDPC encoding
3 bitsCoding indication
Flag indicating change of ranging regions1 bitRanging change indication
Bit #0: subchannel group 0
Bit #1: subchannel group 1
Bit #2: subchannel group 2
Bit #3: subchannel group 3
Bit #4: subchannel group 4
Bit #5: subchannel group 5
6 bitsUsed subchannel bitmap
RemarksSize/RangeParameter
CC = Convolutional Code
BTC = Block Turbo Coding
CTC = Convolutional Turbo Coding
ZT = Zero Tailing
LDPC = Low Density Parity Check
-
8/11/2019 Part 3 - WiMAX Air Interface
19/38
WiMAX Air Interface
2007 Rohde & Schwarz
19
DL-MAP management message
DL_MAP MAC Management
Management
Message Type
OFDMA PHY SYNC field
Frame duration codeFrame Number ( mod 224)
DCD count
Base Station Identifier
Number of OFDMA symbols inthe dowlink subframe
DL-MAP_IE #1
describes burst #1
DL-MAP_IE #n
DL_MAP_IE
DIUCDownlink Interval Usage Code
CID(MAC) Connection Identifier
OFDMA Symbol Offset
Subchannel Offset
Boosting
Number of OFDMA symbols
Number of subchannels
Repetition Coding Indication
SymbolOffset
Subchannelindex
0
Subchannel
Offset
Number
of symbols
Numbero
f
subchanne
ls
OFDMA symbol index
-
8/11/2019 Part 3 - WiMAX Air Interface
20/38
WiMAX Air Interface
2007 Rohde & Schwarz
20
OFDMA DL-MAP Format and mapping
SubchannelIndex
(1
subchannel=
24
subcarrier
s)
DL subframe
Min FEC block size
Padding
FEC (rate r)(as indicated in FCH)
j Bit block
Bit Interleaver
j / r Bit block
Repeater (R)(as indicated in FCH)
j / r Bit block
2N-QAM Modulator
R x j / r Bit sequence
i Bits DL_MAP message
Slot 4
Slot 5
...Slot n
R x j / r / N symbols:
48 symbols per slot
Number of required DL-MAP slots:
n = R x j / r / N / 48
DL_MAP MAC Management
Management
Message Type
OFDMA PHY SYNC fieldFrame duration code
Frame Number ( mod 224)
DCD count
Base Station Identifier
Number of OFDMA symbols in
the dowlink subframe
DL-MAP_IE #1
describes burst #1
DL-MAP_IE #n
-
8/11/2019 Part 3 - WiMAX Air Interface
21/38
WiMAX Air Interface
2007 Rohde & Schwarz
21
UL-MAP management message
Reserved Bits; Set to 0
UL_MAP MAC Management
Management
Message Type
UCD count
UL allocation start time
[physical slots 4/Fs]
Number of OFDMA symbols in
the uplink subframe
UL-MAP_IE #1describes burst #1
UL-MAP_IE #n
UL_MAP_IE: Ranging zone
UIUC = 12Uplink Interval Usage Code
CID(MAC) Connection Identifier
OFDMA Symbol Offset
Subchannel Offset
Number of OFDMA symbols
Number of subchannels
Ranging method
(initial, periodic)
UL_MAP_IE: Burst allocation
UIUC = 1..10Uplink Interval Usage Code
CID(MAC) Connection Identifier
Duration
(number of slots!)
Repetition coding
(0,2,4,6)
-
8/11/2019 Part 3 - WiMAX Air Interface
22/38
WiMAX Air Interface
2007 Rohde & Schwarz
22
MRCT default Frame structure: normal MAP
Data
-
8/11/2019 Part 3 - WiMAX Air Interface
23/38
WiMAX Air Interface
2007 Rohde & Schwarz
23
Downlink Preamble structure
36143284568No of pilot subcarriers per set
(size of modulating PN series)
10/1042/4186/86172/172Guard subcarriers (Left/Right)
128 FFT512 FFT1024 FFT2048 FFT
3 sets of preamble carriers are defined, i.e. 1 set per segment.
PreambleCarrierSet(n) = n + 3k ; n = {0,1,2}; k = {0 .. 567} Note: DC carrier not used (n=0)
0xADBC1B844
Map 1B -1 and 0B +1
1234
PN series (e.g. FFT-128)Segment 0 .. 2IDcell 0.. 31Index 0 .. 113
0 3 6 9 1695 1698 1701
38 PN series per segment.
-
8/11/2019 Part 3 - WiMAX Air Interface
24/38
WiMAX Air Interface
2007 Rohde & Schwarz
24
Cell searchSpectral power detection
C
Signal Bandwidth
(Carrier spacing: FFT size)
C
Position estimate of pilots(3 optionsB Segment number, FCH position)
C
Preamble set search(38 possible PN series)
CPN series correlation process
(Knowledge: BPSK)
C
IDCellDefines subcarrier permutation for first PUSC zone:
Used as DL_PermBase
Segment 1
Preamble set 1
PN index 36
IDCell 4
Segment 2
Preamble set 2
PN index 76
IDCell 12
Segment 0
Preamble set 0
PN 9
IDCell 9
-
8/11/2019 Part 3 - WiMAX Air Interface
25/38
WiMAX Air Interface
2007 Rohde & Schwarz
25
WIMAX Protocol Architecture
PHY
MAC-CSConvergence Sublayer*:ATM and packet
MAC-CPSCommon Part Sublayer
MAC-SSSecurity Sublayer
MAC SAP
PHY SAP
CS SAP
Higher layers:
ATMIEEE 802.3 (Ethernet)
ISO/IEC 8802-3 (CSMA/CD)
*Vendor specific MAC-CS applicable to
support vendor specific higher layers
SAP = Service Access Point
Classification of higher layer data (e.g. for QoS purposes)
Payload header suppression (PHS) 16 Bit CID assignment (output of classification procedure)
Layer for IP connection
Defines multiple access: PtP, multicast, broadcast
Duplexing: FDD, TDD Framing, fragementation, packing, etc.
Issue/Analyse MAC management messages
Hyphering
-
8/11/2019 Part 3 - WiMAX Air Interface
26/38
WiMAX Air Interface
2007 Rohde & Schwarz
26
WiMAX MAC features
MAC provides intelligence to PHY
Designed for point-to-multipoint communication
Supporting continuous and bursty traffic
Connection oriented: 16 Bit CID (connection identifier)
Independant handling of downlink and uplink CIDs
Dynamic bandwidth allocation
48 Bit MAC address = Equipment identifier
-
8/11/2019 Part 3 - WiMAX Air Interface
27/38
WiMAX Air Interface
2007 Rohde & Schwarz
27
WiMAX PMP connection overview
MandatoryMandatorymanagementmanagementconnectionsconnectionsat SSat SSinitialisationinitialisation
3 different3 differentlevelslevelsofofQoSQoSforfor managementmanagementtraffictrafficPMP = Point to Multipoint
-
8/11/2019 Part 3 - WiMAX Air Interface
28/38
WiMAX Air Interface
2007 Rohde & Schwarz
28
MAC connection types
Basic CID: 0x0001 m
Primary Management CID: m+1 2m
BSBase
Station
SS
(MS)Subscriber
(Mobile)
Station
unique
MAC
address48 bit
unique
MAC
address48 bit
according to
IEEE 802-2001
according to
IEEE 802-2001
Transport CID: 2m+1 0xFEFE
Initial ranging CID: 0x0000
AAS initial Ranging CID: 0xFEFF
Multicast Polling CID: 0xFF00 0xFFFC
Broadcast CID: 0xFFFF
Padding CID: 0xFFFE
Fragmentable Broadcast CID: 0xFFFD
Secondary Management CID: 2m+1 0xFEFE
-
8/11/2019 Part 3 - WiMAX Air Interface
29/38
WiMAX Air Interface
2007 Rohde & Schwarz
29
INITIAL SS REGISTERING
BROADCAST: FP, UCD, DCD, DL-MAP, UL-MAP
RNG-REQRNG-RSP
REG-REQPKM-REQ
REG-RESP
PKM-RSP
BASIC MANAGEMENT
PRIMARY MANAGEMENT
Description of downlink and uplink
Ranging to determine power and burst profile changes
Registration and Privacy management
Own CID
for eachconnection!
REG = Registry
PKM = Private Key Management aquivalent to SIM cards
-
8/11/2019 Part 3 - WiMAX Air Interface
30/38
WiMAX Air Interface
2007 Rohde & Schwarz
30
SERVICE FLOW HANDLING
CREATE SERVICE FLOW: DSA-REQ : DSA-RSP : DSA-ACK
CHANGE SERVICE FLOW: DSC-REQ : DSC-RSP : DSC-ACK
DELETE SERVICE FLOW: DSD-REQ : DSD-RSP
BASIC MANAGEMENTRNG-RSP RNG-REQ
BROADCAST: FP, UCD, DCD, DL-MAP, UL-MAP
DSA = Dedicated Service Access
-
8/11/2019 Part 3 - WiMAX Air Interface
31/38
WiMAX Air Interface
2007 Rohde & Schwarz
31
Default Service flow setup
BS DDD DCD (Downlink Channel Descriptor, CID 0xFFFF) DDDDE SS
BS DDD UCD (Uplink Channel Descriptor, CID 0xFFFF) DDDDDDE SS
BS FDDDDDDD RNG-REQ (Ranging Request, CID 0x0000) DDDDDDD SSBS DDDDDDDD RNG-RSP (Ranging Response, CID 0x0000) DDDDDDDE SS
BS FDDDDDDDDD SBC-REQ (SS Basic Capability Request) DDDDDD SS
BS DDDDDDDDDD SBC-RSP (SS Basic Capability Response) DDDDDE SS
BS FDDDDDDDDDD REG-REQ (Registration Request) DDDDDDDDDDD SS
BS DDDDDDDDDDD REG-RSP (Registration Response) DDDDDDDDDDE SSBS DDDDD DSA-REQ (Dynamic Service Addition Request) DDDDDE SS
BS FDDDD DSA-RSP (Dynamic Service Addition Response) DDDDDD SS
BS D DSA-ACK (Dynamic Service Addition Acknowledgement) DE SS
BS DDD REP-REQ (Channel Measurement Report Request) DDDDDE SS
BS FDDDD REP-RSP (Channel Measurement Report Response) DDDD SS
-
8/11/2019 Part 3 - WiMAX Air Interface
32/38
WiMAX Air Interface
2007 Rohde & Schwarz
32
MAC Formats: Generic MAC Header(GMH)
Generic
MAC header
PAYLOAD
(optional)
CRC
(optional)
HT EC Type (6)
LEN LSB (8)
CID LSB (8)
CID MSB (8)
HCS (8)
CI Rsv LEN MSB
EK
S
(2)
CI CRC Indicator
CID Connection Identifier (16 Bits)
EC Encryption Control
EKS Encryption Key Sequence
HCS Header Check Sequence
(for header protection)HT Header Type
LEN Length (bytes) of PDU
Type subheader, payload indicator
ESF Extended subheader field (16e)
Rsv ReservedCRC Cyclic Redundancy Check
(for payload protection)
ESF
16e
16e: Additional subheader types introduced (extended subheaders) incl. appropriate indicator bit ESF
MAC PDU (Protocol Data Unit) of length LEN bytes
Rsv
-
8/11/2019 Part 3 - WiMAX Air Interface
33/38
WiMAX Air Interface
2007 Rohde & Schwarz
33
MIMO and friends
SISO
SIMO1xMM
ISO
Nx1
Single/MultipleOutput
Transm
itter
1
N Single/MultipleOutput
Recei
ver
1
M
MIMONxM
-
8/11/2019 Part 3 - WiMAX Air Interface
34/38
WiMAX Air Interface
2007 Rohde & Schwarz
34
WiMAX types of MIMO
STBC Space Time Block Coding Referred to as Matrix A in IEEE 802.16e-2005
Same data is space-time coded and transmitted through different antennas
Impoving downlink SNR and increasing coverage areas
Invented by Mr. Alamouti
SM Spatial Multiplexing Referred to as Matrix B in IEEE 802.16e-2005 Delivers parallel data streams on different antennas
Increases downlink throughput
Uplink collaborative MIMO link Two MS transmit collaboratively on the same uplink subchannel
Increasing uplink throughput without need for mulitple power PA in MS devices
-
8/11/2019 Part 3 - WiMAX Air Interface
35/38
WiMAX Air Interface
2007 Rohde & Schwarz
35
MISO: STBC according to Alamouti(increase performance, i.e. coverage)
TX
Ant 1
TX
Ant 2
Time
RX
Ant
h1
h2
n
r2*
r1
HH
de2
de1
Estimates
Space
Time
Space
-d2
*
d1
*
d1
d2
de
Space-Time-Block
LO
( ) ' 21 nIhhnHdHHrHd HHHe rr
r
r
r
++=+==
( )( )
2221
*
211
*
22
1121*
221*
11
'
'
ndhhrhrhd
ndhhrhrhd
e
e
++=+=
+
+=
+
=
-
8/11/2019 Part 3 - WiMAX Air Interface
36/38
WiMAX Air Interface
2007 Rohde & Schwarz
36
True MIMO: Spatial Multiplex(increase throughput or coverage)
-
8/11/2019 Part 3 - WiMAX Air Interface
37/38
WiMAX Air Interface
2007 Rohde & Schwarz
37
WiMAX MIMO DL PUSC profile
Open-Loop 2 transmit MIMO at BS
Matrix A or Matrix B mode
Vertical* STBC transmit matrix A (Alamouti)
Vertical* spacial multiplexing of transmit of matrix B
Multiple receive antennas at MS
Maximum ratio combining techniques
2 receive antennas mandatory
4 receive antennas as applicable (e.g. in notebooks)
Increasing SNR and thus coverage area, primarily
*Vertical Encoding: Single FEC encoded stream over multiple antennas
Matrix
A or B
Pilot
-
8/11/2019 Part 3 - WiMAX Air Interface
38/38
WiMAX Air Interface
2007 Rohde & Schwarz
38
WiMAX MIMO UL PUSC profile
Open-loop collaborative MIMO
2 MS transmit on the same subchannel
Horizontal** spatial multiplexing transmit on
matrix B BS to perform Maximum Likelihood detection
Increasing the uplink capacity (throughput)
Conventional single PA at MS
OFDM symbol
Subcarriers
Pilot
Data
MS #1 MS #2
Uplink PUSC tile structure
**Horizontal Encoding:
Multiple separately FEC encoded streams over multiple antennas
Matrix
B