1. GPRS Radio Resource Management
Traffic Model
The definition of a GPRS session in our model:
Packet 1
Packet 2
Packet 3
Packet Call1
Packet Call 2
Packet Call 3
Session1
Session2
Session3
Time[ s]
Time[ m]
Time[ h]
Group 896
GPRS Radio Resource Management

2. GPRS Radio Resource Management
Traffics:
Mixture of GSM Voice calls and GPRS Data sessions
Each session/call was randomly assigned to a Mobile Station(MS), where each MS only represent a propagation condition(C/I) corresponding to a certain distance from the BTS.
Group 896
GPRS Radio Resource Management

3. GPRS Radio Resource Management
Traffic Generation Method
Group 896
GPRS Radio Resource Management

4. GPRS Radio Resource Management
Model Assumptions
1 session assigned to 1MS corresponding to a certain radio condition
1MS can have multiple sessions based on radio condition
All the sessions are in the BSS to be transmitted
No Handover
Based on one Cell Configuration
No uplink simulation
Higher layers(TCP/IP, LLC) is not considered
ARQ for uplink is not considered
Group 896
GPRS Radio Resource Management

5. GPRS Radio Resource Management
Parameters List
Parameters
Stochastic Process
Parameter
Values
GSM
Arrival Time
Exponential
Holding Time
GPRS
Session Size
Geometrical
P=0.5
Object Size = 50 Kbytes
Mean Session Size=100Kbytes
In traffic generator while calculating the mean GPRS holding time:
We use average data speed: 25kbps.
Which comes from some simulation output on different traffic load.
Traffic Load = 5 ~ 29 Erlang
GSM Voice: Traffic_Load*70%
GPRS Data: Traffic_Load*30%
Group 896
GPRS Radio Resource Management

6. Mapping GPRS session to RLC blocks
Session size (bits)
GPRS SESSION
time
CS-x
RLC blocks
arrival time
Mapping to block
We map a GPRS session( a number of bits) only into RLC blocks and simplify the upper layers.
Because in simulation the transmission was working on RLC block level.
Group 896
GPRS Radio Resource Management