By Peled Nir, APLP Validation team.
®
Intel Communications Group – Cellular and Handheld Group
The Problem and The solution
• The problem:
– Simulating a close to real environment
using a PC.
– Tracking the MSR state in every
scenario.
L1
• The solution:
MSR
L2/
L3
TM
MS
TCC…
– The PC as simulator of the APLP clock.
– Working synchronously in each
scenario.
– Simulating a nun synchronous
environment using frame simulation.
The project’s purpose is to build a system that will check the MSR
module in the new Intel Corporation Hermon WCDMA chip, integrated
with existing system for checking the whole L1 and APLP stand alone
systems. My goal is to design a simple and understandable testing
machine capable of checking all of the physical states of the system
and all of its possible tasks
General Protocol Architecture
Layer 3
Layer 1
Control / Measurements
Layer 2
Radio Resource Control (RRC)
Logical channels
Medium Access Control (MAC)
Transport channels
Physical layer
The APLP modules
RRC
RL Setup &
Configuration Manager
Measurements Manager
ABC
Cell
Measure
ments
Overall
Signal
Measure
ments
Measure
ment
Database
A
P
I

Phy Channel
Maintenance

Channel Switch
Algorithm
Power Control
Synthesizer / RF
Status
Data Request
Data Indication
Physical Access
Request/Confirm
In/Out of Sync Indication
Physical Status Indication
TrCH Maintain Confirm
TrCH Maintain Request
Setup/
Config
Channel
Channel Manager
& Configuration
Control



APL Package
Manager
Data Flow API
In/Out of Sync Indication
Notifications
DRX/Modem Sleep
Status
Setup/
Config
Channel
TX Control
Compress Mode
MAC
Channel Manager &
Configuration Control
API
Radio Link Setup &
Configuration API
Rake Finger Control
Results
Measureme
nt Target
Measurements API
RL Maintain Confirm
RL Maintain Request
Measurements Request
Measurements Indications
RLC
Open
Close
Configure
Channel
Quality
Monitoring
Dravers
Measurements Manager
PHY Channel Control
Tr Channel Control
Data
APLP
Control
Control
Control
Control & Data
PLP ACP Interface Manager Package
Data
Control
Modem Manager
The Testing machine
Simulate L2/L3
Simulate PLP
General Description MSR
Measurements Request
Measurements Indication
RRC
Results
Measureme
nt Target
Measurements API
Measurements Manager
Cell
Measure
ments
manager
Measure
ment
Datab ase
Overall
signal
measure
ments
manager
A
P
I
Measurements Manager
Control
PLP ACP Interface
Manager
According to the 3GPP specification, UE measurements can be
divided in to few basic types as the following:
1. Intra-frequency measurements: Ec/Io and SFN-CFN
observed time difference (PLP searcher relates
services) measurements on the ‘active’ cells set and
neighboring cells.
2. Inter-frequency measurements: Ec/Io and SFN-CFN
observed time difference measurements on WCDMA
neighboring cells at different frequencies. Same as above
with added complexity of transient frequencies switching.
3. Inter-System measurement: Measurements of GSM cells,
not supported in our system.
4. LCS (location services) measurement: not supported in our
system.
5. Traffic Volume measurement: not in scope of L1.
6. Quality measurement: this feature is not well defined in the
standard. These are measurements of the quality of data
transfer at TrCh (BLER, CRC).
7. UE internal measurement: Tx level and Tx-Rx difference.
How the APLP works ?!
• General procedure:
–
–
L2 \ L3
–
–
Get Requests
Return Replies
It receives requests from RRC for the
above types 1, 2, 6, and 7
Accordingly commands the PLP for
measurement activity.
Receives results, processes them
And then distributes them to any interested
item. Certainly, a main receiver of results
of measurements is the RRC entity.
• In general terms, measurement module
Process Results
APLP
Process Request
Send Commands
Receives Replies
PLP
•
•
activities can be divided to the following
two types:
Cell measurement maintenance:
Handling of measurements that associate
with specific cell (Ec/Io and SFN-CFN
observed time difference).
Overall signal measurement
maintenance: Handling of measurements
that associated with the overall received
and transmitted signal (SIR, RSSI and Tx
power).
“Finding” a cell…
•
L2 \ L3
Request
Indication
•
BSS Group
•
MPS Group
APLP
Cell search reply
•
PLP
BSS
BackGround
&
ForeGround
Cpich reply
MPS Group
BSS Group
Did pass BSS
•
MPS
BSS – Base Station Search to find cells
timing from a list of SC (scrambling Codes)
MPS – Multi Pass Search to collect energy
from all cells paths and to perform
measurement on the cell (for Tracker
Maintenance).
PERIODIC MEASUREMENT
After the APLP send a
PERIODIC_GROUP_CELL_SEARCH to PLP,
the PLP start the periodic BSS. From this
point the PLP will send every 100 mSec’ all
the CELL_SEARCH_REPLY s back to APLP
with the cells frame boundary if was found.
After the APLP send a
PERIODIC_GROUP_CPICH_SEARCH to PLP,
the PLP start the periodic MPS. From this
point the PLP will send every 50 mSec’ all
the CPICH_SEARCH_REPLY s back to APLP.
These replies contains up to 6 strongest path
that where found in the search window of
the MPS. A path is specified by its power
(Ec/Io) and its accurate location in time
(scrambling time offset in1/8 chip).
If there was a change in one of the Groups
(Cell or CPICH), a new
PERIODIC_GROUP_CELL/CPICH_SEARCH
command is sent to PLP with the new Group
members. The replies for the new Group
Search are departing from the old Group
Search By their ID.
Building the Measurement request
0
Scrambling Code
Client Bit Map
Active
Monitor
SFN Action Type
SFN Detected By L1
Modified
+ + +
Modified
Modified
Scrambling Code
Client Bit Map
Active
Monitor
SFN Action Type
SFN Detected By L1
Modified
...
-
-
- -
-
-
29 30 31
1 2 3 4
0 0
+ - -
+
+
...
- + + - 0
Scrambling Code
Client Bit Map
Active
Monitor
SFN Action Type
SFN Detected By L1
+
+
- - - - -
0
Scrambling Code
Client Bit Map
Active
Monitor
SFN Action Type
SFN Detected By L1
29 30 31
1 2 3 4
29 30 31
1 2 3 4
+ - - + +
+
...
+ +
- + + + -
+ +
0
29 30 31
1 2 3 4
+ - - + +
+ +
+
- + + + -
...
-
+ +
+ +
-
The measurement request is the way for the RRC
to ask L1 to monitor cells. When L1
receive this API function, it should perform
measurement searching on the given cells
and send back indication on them back to
the RRC
The RRC can ask L1 to monitor total of 32 intra
cells. It’s the RRC responsibility to have no
more then 32 intra cells monitored in
every given moment
The request for SFN_SFN measuring can only be
sent in the FACH mode and it is always
commit BCH establishing on the monitored
cell.
The request for CFN_SFN measuring can only be
sent in the DCH mode and it is not always
committed for BCH establishing on the
monitored cell.
Step 1 – Copy Global DB to Local DB
Step 2 – Set Removed Cell in Request.
Random number from 0 to number
of monitored cells.
Step 3 – Set Added Cell in Request.
Random number from 0 to (32monitored cell)
Step 4 – Set SFN Measurement. Random
number from 0 to number of
monitored cells.
Step 5 – Set the Measurement Request.
Insert the “modified” cells to the
request structure.
Step 6 – Send Request and Set Global DB.
In the same order the cells are in the
request structure.
The Base Station Search Group
(Cell Group)
•
•
The BSS group (Cell Group) is a part of the testing machine Data Base. It holds up to 32
(max) Scrambling Codes (an array). The SC in this group stands for unknown cells.
The cells in this group are being searched periodically after APLP sent the
PERIODIC_GROUP_CELL_SEARCH command with all of these cells (SC).
A new SC is added to the array in the last place available.
After removing a cell from the Group, the last cell in the Group array will be set in the
removed cell place (in the array).
There are two reasons for removing a SC from the Cell Group
•
There are two reasons to add new SC to the Cell Group
•
•
•
–
–
–
–
Request from RRC for stop monitoring this cell.
If the PLP found strong path from this cell, it passes the BSS and will be moved from the Cell Group to
the CPICH Group.
Request from RRC for monitoring an unknown cell.
Removed cell from the CPICH group (Long Fade).
• The testing machine holds two structures of this kind, static and dynamic.
•Pointer
•Modified
•Need abort
•Last group ID
•Cell Search Array
•Scrambling Code
•Measured
0
1
2
3
…
30 31
Cell Search Reply (BSS results)
CellSearchReply
CellSearchReply
CellSearchReply
APLP
PLP
• After the PLP receive periodic group cell search
•
•
•
•
command from APLP it starts the BSS on all the cells in
the group list that where in the command. As results
CellSearchReplies are send back to the APLP. These
replies will all be sent in the next coming 100 mSec
(maximum, worst case).
When a CellSearchReply has a ScramblingTimeOffset
value that means that this cell pass the BSS (and now
MPS need to be perform on it).
We define 2 periods, the first time it enter this function
(when System_SFN mod 5 == 0), and the second time
it enter this function (when System_SFN mod 10 ==
0).
In the first period, two things happen, the dynamic
BSS group is being copied to the static BSS group,
and the number of CellSearchReplies in this period is
set to be a random number from 0 to number of cells
in group.
In the second period, the number of CellSearchReplies
is all the remaining cells.
Cell Search Reply (BSS results) cont
DPCH
Offset
New Cell
DPCH Offset
Tx window
Active Cell
New Cell
• Mechanism for CellSearchReply sending to
Frame in
1/8 chip
•
APLP:
– Randomly chooses a cell from the static
BSS group that haven’t been measured
yet
– Decide if the replay should be a
successful one (33% if visible cell)
– If the cell passes the BSS successfully,
then it should be moved from the
dynamic BSS group to the MPS
group. Because of the change in both
groups, the
PERIODIC_GROUP_CELL_SEARCH and
PERIODIC_GROUP_CPICH_SEARCH
should be sent to PLP.
CellSearchReply parameters setting:
– DPCH offset is determine.
– Setting the scrambling time offset by
finding the Tx window and reducing the
cells DPCH offset (that was just defined).
The Multi-Path Group (CPICH Group)
•
•
•
•
•
•
The MPS Group (CPICH group) is part of the testing machine Data Base. It holds up to 10(max)
scrambling codes (in an array). The SC in this group stands for cells that passed the BSS and are
in the MPS Group.
The active cells should all be in this group and the known neighbor cells.
The cells in this group are being search periodically after the APLP send the
PERIODIC_GROUP_CPICH_SEARCH command with all of these cells.
Adding and removing a cell to/from the group is done same as in the BSS Group.
A cell is added to MPS group if it passes the BSS.
There are two reasons to remove a SC from the MPS Group
–
–
Request from RRC to stop monitoring this cell and this cell is not an Active cell. Then it’ll be removed
from all DB (not pass to Cell Group).
After the cell didn’t receive paths in the last 5 Sec’ (Long Fade procedure), then it will be removed from
CPICH Group and added back to the BSS Group
•Pointer
•Modified
•Last group ID
•Cpich cells Array
•Scrambling Code
•Search ID
0
•Don’t get paths
•Last count with path
1
2
3
…
8
9
Cpich Search Reply (MPS results)
• CpichSearchReplies on all the cells in the Cpich
APLP
CpichSearchReply
CpichSearchReply
CpichSearchReply
•
•
Group it received in the first coming 50 mSec’.
But in order to simulate the un_synchronization
between the PLP and the APLP we set the
number of replies to be 50-150% from the MPS
group size.
The order of the replies is not known to APLP,
therefore the testing machine sends the replies
in a random order.
• CpichSearchReply parameters and functionality:
–
–
PLP
Power in EcIo
–
“time” in 1/8 chip
Search Window
A cell can receive up to 6 strong path.
The power is indicated in linear, but in order to
simulate logarithmic changes the testing
machine randomize the power value in a
logarithmic scale and convert it to linear scale.
All the paths scrambling time offset are in the
search window and be at list ½ chips apart.
Cpich Search Reply (MPS results)
cont’
• All paths in the system (all paths
and trackers including those of
other cells) with there DPCH offset
should be in the Tx window of 512
chips.
• After sending the reply:
148 chip
148 chip
– The earliest path found in this
CpichSearchReply is set to be the
cells scrambling time offset
– The trackers statuses are modified.
– The cells power is added to the
power filter in DB.
– Long Fade procedure
– Adding the cell to the next
indication structure.
Measurement Indication
• This is the API that the APLP uses for
Indication
On cell
CpichSearchReply
A
Indication
On cell
D
L2 \ L3
PLP
Indication
On cell
B
Send As Indication
Cell A
•
•
•
sending the indication back to RRC on
the cells the it requested.
The APLP “gather” information on
the monitored cells according to the
RRC request and send Indication back
to RRC periodically.
The Indication structure can hold up
to 32 cells.
The indication is built based on the
CpichSearchReply sent by the PLP
–
• Power indication contain:
–
–
–
APLP
For every CpichSearchReply on a
monitored cell, the APLP add this cell
to the indication structure.
RSSI, the energy at the antenna.
EcIo, the average of last 4 paths
power found on this cell.
RSCP, EcIo + RSSI.
Example
L3/L2
MS
Track M
Meas
TrCH
PLP
MSR handles X_1, X_2, X_3 cells in the MP and Y_1, Y_2, Y_3 cells in the BS data bases.
plwCphyIntraFreqCellMeasurementReq
(Add new Y_4 cells remove X_1, Y_1 cells)
PERIODIC_GROUP_CPICH_SEARCH (X_2, X_3)
PERIODIC_GROUP_CELL_SEARCH
(Y_2, Y_3, Y_4)
CELL_SEARCH_REPLY (Y_2, Fail)
CELL_SEARCH_REPLY (Y_3, Success)
PERIODIC_GROUP_CELL_SEARCH
(Y_2, Y_4)
CELL_SEARCH_REPLY (Y_4, Success)
PERIODIC_GROUP_CPICH_SEARCH
(X_2, X_3, Y_3)
PERIODIC_GROUP_CELL_SEARCH
(Y_2)
PERIODIC_GROUP_CPICH_SEARCH
(X_2, X_3, Y_3, Y_4)
CELL_SEARCH_REPLY (Y_2, Success)
SEARCH_ABORT (Base Station Foreground)
PERIODIC_GROUP_CPICH_SEARCH
(X_2, X_3, Y_3, Y_4)
CPICH_SEARCH_REPLY (X_2)
CPICH_SEARCH_REPLY (Y_4)
plwCphyIntraFreqCellMeasurementInd (X_2, Y_4)
L3/L2
MS
Track M
Meas
TrCH
PLP
Example cont’
L3/L2
MS
Track M
Meas
TrCH
PLP
CPICH_SEARCH_REPLY (X_2)
CPICH_SEARCH_REPLY (Y_4)
CPICH_SEARCH_REPLY (X_3)
CPICH_SEARCH_REPLY (Y_3)
plwCphyIntraFreqCellMeasurementInd (X_2, X_3, Y_3,Y_4)
CPICH_SEARCH_REPLY (X_2)
CPICH_SEARCH_REPLY (Y_4)
CPICH_SEARCH_REPLY (X_3)
CPICH_SEARCH_REPLY (Y_3)
CPICH_SEARCH_REPLY (X_2)
plwCphyIntraFreqCellMeasurementInd (X_2, X_3, Y_3,Y_4, X_2)
CPICH_SEARCH_REPLY (Y_4)
CPICH_SEARCH_REPLY (X_3)
CPICH_SEARCH_REPLY (Y_3)
plwCphyIntraFreqCellMeasurementInd (X_3, Y_3, Y_4)
CPICH_SEARCH_REPLY (X_2)
CPICH_SEARCH_REPLY (Y_4)
CPICH_SEARCH_REPLY (X_3)
CPICH_SEARCH_REPLY (Y_3)
plwCphyIntraFreqCellMeasurementInd (X_2, X_3, Y_3, Y_4)
L3/L2
MS
Track M
Meas
TrCH
PLP
SFN_SFN measurement
•
•
•
The SFN_SFN measurement can occur during FACH mode.
In SFN_SFN measuring, L1 should establish PCCPCH to read the cells SFN (the RRC should ask it to do so).
In the SFN_SFN measurement we can distinguish two cases:
•
Steps:
–
–
The serving cell scrambling time offset smaller then the neighbor.
The serving cell scrambling time offset bigger then the neighbor.
–
–
–
–
–
Establishing BCH to read neighbor SFN.
Maintaining the SFN.
Calculating the chip offset from the earliest path received from this cell.
Check for frame migration.
Report it in the next coming indication to RRC.
Serving >
Set BCH_SFN in Ind
As BCH_SFN
10
11
12
13
14
15
Serving <
Set BCH_SFN in Ind
As BCH_SFN-1
10
11
12
13
14
15
Neighbor
SFN
0
1
2
Sent Ind’ to RRC
3
4
5
SFN_SFN measurement cont’
• The BCH_DATA_RX has TTI = 2 frames, therefore the PLP need two frames
•
to receive this data.
In the BCH_DATA_RX the cells SFN is in the first two words, when the APLP
receive this data, the SFN it reads from it is relevant to the time the
neighbor cell started to transmit the BCH_DATA_RX, two frames ago.
> Serving
Set SFN in data
As SYS_SFN-2
10
11
< Serving
12
13
14
Set SFN in data
As SYS_SFN-1
10
11
12
15
Indication sent to RRC
13
14
15
Neighbor
SFN
0
Set SFN in
BCH_DATA_RX
1
Receive
BCH_DATA_RX
2
3
4
5
The BCH_SFN when Indication sent
SFN_SFN measurement cont’ frame
migration.
• The signals received from a cell move in the frame. It is possible that this signal will
•
•
move and migrate to the next frame.
In this case the SFN of the neighbor cell change relevant to the migration direction.
difference of more the half a frame size between the last Tm found and the current
Tm indicate a migration.
Tm #1
chips37900
Frame 1 size
38400 chips
Frame 2 size
38400 chips
Tm #2
chips38100
Frame 1 size
38400 chips
Frame 1 size
38400 chips
chips200
Frame 2 size
38400 chips
Tm #3
chips20
Frame 2 size
38400 chips
chips37080
THE END