Common Public Radio Interface
eCPRI IWF presentation
eCPRI introduction
eCPRI/CPRI Inter-Working Function (IWF)
eCPRI V2.0’s main motivation and aim is the reuse of existing
REs and/or RECs in a system including eCPRI transport
network by introducing and defining new functionality:
Interworking Function (IWF) types 0, 1 and 2.
IWF is a function providing a bridge
between eCPRI and CPRI nodes.
PTP
GM
eREC
REC
eRE
eREC
element
local network
IWF
type 1
Transport
The protocol for both eCPRI and CPRI is
terminated within the IWF and bridged
to/from each other.
eREC
eREC
eREC
element element
Network
IWF
IWF
type 0
type 2
eRE
local network
eCPRI link
Local eCPRI
CPRI link
RE
RE
eRE
eRE
element element
eRE
element
eCPRI introduction
eCPRI/CPRI Inter-Working Function (IWF) types
Three types of IWF are defined:
-Type 0, connected to an eREC and RE:
Used in a “eREC Fronthaul  IWF type 0  RE” configuration
-Type 1, connected to a REC:
Used in a “REC  IWF type 1  Fronthaul  IWF type 2  RE” configuration
-Type 2, connected to an RE:
Used in a “REC  IWF type 1  Fronthaul  IWF type 2  RE” configuration
eCPRI introduction
eCPRI/CPRI Inter-Working Function (IWF) configurations
Two Interworking Function(IWF) configurations are introduced:
- Configuration with IWF type 0:
The Interworking Function type 0 is located between the eCPRI transport network and
one/several CPRI RE node(s).
- Configuration with IWF type 1 and 2:
The Interworking Functions of type 1 and 2 are located between the respective CPRI
nodes and the transport network.
eCPRI introduction
Configuration with IWF type 0
looks as an
REC
looks as an
eRE
eREC
type 0
CPRI link
eCPRI/CPRI Interworking Function type 0
CPRI Radio Equipment Control (eREC)
Sync
C&M
SAPU
SAPS
SAPCM
User Plane Sync
SAPU
eCPRI
specific
Standard
Protocols
Transport Network Layer
Transport
Network
SAPS
C&M
SAPCM
Standard
Protocols
Transport Network Layer
User Plane Sync
SAPIQ
SAPS
RE
CPRI Radio Equipment (RE)
IWF
User
Plane
eCPRI
specific
IWF
eCPRI transport network
Antenna
User
Plane
Sync
C&M
SAPIQ
SAPS
SAPCM
C&M
SAPCM
Layer 2
Layer 2
Layer 1
Layer 1
The SAPs in the IWF shall be terminated at both eCPRI and CPRI ends and bridged to each
other via vendor specific functionality
eCPRI introduction
Configuration with IWF type 1 and 2
looks like an RE
REC
CPRI link
looks like an REC
IWF type 1
eCPRI transport network
IWF type 2 CPRI link
CPRI Radio Equipment Control (REC)
User Plane
SAPIQ
Sync
C&M
SAPS
SAPCM
CPRI Radio Equipment (RE)
Layer 2
Layer 1
RE
User Plane
Sync
C&M
SAPIQ
SAPS
SAPCM
Layer 2
IWF
type 1
Transport Network
IWF
type 2
Layer 1
The Interworking Functions bridge the CPRI link over the Fronthaul Transport Network
eCPRI User Plane messages
eCPRI Message types for IWF type 1 and 2
Message Types #8-#11 are introduced for IWF types 1 and 2.
Message Type #
8
9
10
11
12 – 63
64 – 255
Name
IWF Start-Up
IWF Operation
IWF Mapping
IWF Delay Control
Reserved
Vendor Specific
eCPRI User Plane messages
eCPRI Message types for data transfer: #8, #9 , #10 and #11
Message Type #8: IWF Start-up
Used during the start-up sequence to transfer CPRI control words between CPRI nodes (REC and RE).
Typically, this message is used during line bitrate negotiation.
This message also instructs the IWFs when to start the CPRI frame structure compared to the IWFs local clocks.
Message Type #9: IWF Operation
To transfer CPRI basic frames or part of CPRI basic frames between CPRI nodes (REC and RE) after CPRI startup.
Message Type #10: IWF Mapping
To negotiate the mapping configuration between two IWFs by defining sub-part locations within the IQ data
block area of a CPRI basic frame.
Message Type #11: IWF Delay Control
To retrieve delay values from a remote device. A typical use is to assist in the delay management of IWFs type
1 and type 2 in an eCPRI-CPRI interworking scenario. The use of this message type is though not limited to this
case.
eCPRI User Plane messages
Message Type #8: IWF Start-Up message format
Byte
0
PC_ID
1
2
#Z
3
#X
4
5
Timestamp
6
7
8
F
r
Line Rate
Data transferred (first byte)
L bytes
9
S
Data transferred (last byte)
8+L
0
7
MSB
LSB
eCPRI User Plane messages
MessageByteType #9: IWF Operation format
1st
Sub-part
...
...
...
...
...
...
8th
Sub-part
...
...
...
8xNth
Sub-part
0
N bytes
PC_ID
...
1
2
#Z0
3
#X0
...
...
...
...
0
7
MSB
LSB
Chunk0 (first byte)
Byte
S0 bytes
...
S0+3
Chunk0 (last byte)
0
CWMain CWExt DB
E
M
r
BFF
N
1
N+1 bytes1
k-1
S Si+2x(1+k)
N-byte Bitmask
#Zk
i=0-k
#Xk
Sk bytes
k
S Si+2x(1+k)+1
i=0-k
0
MSB
Chunkk (first byte)
Data transferred (first byte)
...
...
Chunkk (last byte)
Data transferred (last byte)
7
LSB
1
0
7
MSB
LSB
: These N+1 bytes are present if M=1.
eCPRI User Plane messages
Message Type #9: eCPRI chunk example M=1, N=1 and 1-byte bitmask = 0xC0
Byte
0
W = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Y=0
BYTE #Z.X.0
B=0: A
B=1: B
…
Y=1
BitOffset=46
B=14: G
B=15: H
BYTE #Z.X.1
B=7: H
B=8: A
…
control word
E
1
1
23
IQ
M=1
r
00b
1
2 bytes
1 chip = 1/3.84MHz
BitOffset=16
CWMain CWExt DB=
=0
=0
1
0
0
0
0
0
0
1
1
0
0
0
16
31
24
39
32
time
Data block
47
8 bytes
46
45
44
43
42
41
40
55
48
63
56
BitOffset=106
15 * 16 bits
BitOffset=76
71
1
1
1
0
0
0
64
0
0
0
0
75
74
73
72
0
7
MSB
LSB
Bytes
transmitted
from top
to bottom
eCPRI User Plane messages
Message Type #9: eCPRI chunk example M=1, N=1 and 1-byte bitmask = 0x90
Byte
0
BYTE #Z.X.0
Y=0
Y=1
BitOffset=46
B=14: G
B=15: H
BYTE #Z.X.1
B=7: H
B=8: A
…
control word
IQ
time
Data block
BitOffset=106
15 * 16 bits
BitOffset=76
r
0
0
00b
0
0
1
0
0
23
16
31
24
39
32
107
8 bytes
M=1
1
1
1 chip = 1/3.84MHz
B=0: A
B=1: B
…
E
2 bytes
W = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
BitOffset=16
CWMain CWExt DB=
=0
1
=0
106
45
44
43
42
41
40
115
108
123
116
131
124
0
0
0
0
135
134
133
132
0
7
MSB
LSB
Bytes
transmitted
from top
to bottom
eCPRI User Plane messages
Byte
0
Message Type #9: eCPRI chunk example M=0
1 chip = 1/3.84MHz
Y=0
BYTE #Z.X.0
B=0: A
B=1: B
…
Y=1
BitOffset=46
B=14: G
B=15: H
BYTE #Z.X.1
B=7: H
B=8: A
…
control word
IQ
time
BitOffset=106
15 * 16 bits
BitOffset=76
M=0
r
00b
16
31
24
39
32
46
45
44
43
42
41
40
55
48
63
56
71
64
79
Data block
E
23
47
W = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
BitOffset=16
CW Main CWExt DB=
=0
=0
1
78
77
76
75
74
73
72
15 bytes
87
80
95
88
103
96
111
110
109
108
107
106
105
104
119
112
127
120
135
128
0
7
MSB
LSB
Bytes
transmitted
from top
to bottom
eCPRI User Plane messages
Message Type #9: IWF Operation sequence diagram example
IWF1
IWF 2
eCPRI User Plane messages
Message Type #10: IWF Mapping format
Byte
0
PC_ID
1
2
Mapping_Config_ID
3
Action Type
Action Types
4
StartOffset1
Bytes
transmitted
from top
to bottom
4xL
bytes
Length1
StartOffsetL
LengthL
3+4xL
0
7
MSB
LSB
Request/Response
SetRxConfigRequest
SetRxConfigResponseAccept
SetRxConfigResponseReject
SetRxConfigResponsePropose
eCPRI User Plane messages
Message Type #10: IWF Mapping sequence diagram examples
IWF1
IWF2
eCPRI User Plane messages
Message Type #11: IWF Delay Control format
Byte
0
PC_ID
1
2
Delay Control ID
3
Action Type
Action Types
4
Bytes
transmitted
from top
to bottom
5
Delay A
6
7
8
9
Delay B
10
11
0
7
MSB
LSB
Request/Response
Request get delays
Response get delays
eCPRI User Plane messages
Message Type #11: IWF Delay Control sequence diagram example
IWF type 1
IWF type 2
Networking with eCPRI-CPRI IWF type 0
eREC
Interworking function type 0
SAPU SAPCM SAPS
SAPU SAPCM SAPS
SAPIQ SAPCM SAPS
Networking
eCPRI
eCPRI
Logical
connection
SAPIQ SAPCM SAPS
SAPIQ SAPCM SAPS
Networking
CPRI
Master Port
Transport network
(fronthaul network)
RE
Networking RE
SAPIQ SAPCM SAPS
CPRI
Slave Port
CPRI
Master Port
CPRI
Slave Port
Networking with eCPRI-CPRI IWF type 1 and type 2
REC
SAPIQ SAPCM SAPS
Interworking function type 1
SAPIQ SAPCM SAPS
Interworking function type 2
SAPU SAPCM SAPS
SAPU SAPCM SAPS
Networking
CPRI
Master Port
CPRI
SAPIQ SAPCM SAPS
Networking
eCPRI
IWF Slave Port
eCPRI
CPRI
IWF Master Port
Transport Network
Logical
connections
SAPIQ SAPCM SAPS
RE
CPRI
Slave Port
Networking with eCPRI-CPRI IWF type 1 and type 2
Protocol stack of Interworking Function type 1 or type 2
IWF type 1 or type 2
IWF
C&M
CPRI link
Sync info
Management
Processing
Processing
User
Data
Control
Words
MUX
CPRI TDM
8B/10B or 64B/66B
8B/10B scrambler
64B/66B FEC, sync
64B/66B scrambler
PMD
PTP,
SCTP,
UDP/IP
UDP/IP
etc.
Ethernet MAC
Ethernet PHY
Media
Media
eCPRI
layer
eCPRI link