GSM/GPRS/EGPRS throughput
Throughput is basically measure of performance of the wired/wireless system. Here it is a basically a measure of rate at which data can be sent through the GSM/GPRS /EGPRS network. It is specified in bits per second per time slot. It is also referred as data rate. As the internet is accessed through the GPRS in GSM network we will be covering throughput based on GPRS coding schemes.
Following table mentions theoretical maximum throughput achievable in GPRS network for coding schemes such as CS1, CS2, CS3 and CS4 when data is allocated in one time slot case. The lower end in the range is applicable for 100 active users and the upper end limit is applicable for 1 active user in the cell. In case of multiple time slots multiply following values by that multiplication factor will give the throughput for occupied multiple slots. The throughput will vary for GPRS in acknowledged and unacknowledged mode of transmissions.
| GPRS Coding Scheme | Info. Bits |
Parity. Bits |
Pre-code USF |
Tail Bits | CE o/p | Punctured bits | code rate | No.slots | Max. throughput |
|---|---|---|---|---|---|---|---|---|---|
| CS1 | 184 | 40 | 3 | 4 | 456 | 0 | 1/2 | 1 | 9.2 kbit/s |
| CS2 | 271 | 16 | 6 | 4 | 588 | 132 | 2/3 | 1 | 13.55 kbit/s |
| CS3 | 315 | 16 | 6 | 4 | 676 | 220 | 3/4 | 1 | 15.75 kbit/s |
| CS4 | 431 | 16 | 12 | 0 | 456 | 0 | 1 | 1 | 21.55 kbit/s |
Normalized throughput = Total data received correctly / Total Data Transmitted
The normalized throughput is usually higher in un-acknowledged transmission mode compare to acknowledged transmission mode. This is as expected because in unacknowledged transmission mode, incorrect frame is discarded while in the case of acknowledged transmission mode the incorrect frame is re-transmitted. This result into increase in the total data transmitted and hence normalized throughput decreases.
To improve the throughput in acknowledgement mode of transmission,retransmissions need to be avoided wherever possible.
The following table covers throughput for EGPRS/EDGE modulation coding schemes viz. MCS1,MCS2,MCS3,MCS4,MCS5,MCS6,MCS7,MCS8 and MCS9.
EGPRS/EDGE max. throughput
| EGPRS modulation coding Scheme | code rate | RLC block/radio block | Max. throughput |
|---|---|---|---|
| MCS1 | 0.37 | 1 | 8.8 |
| MCS2 | 0.49 | 1 | 11.2 |
| MCS3 | 0.53 | 1 | 14.8 |
| MCS4 | 0.66 | 1 | 17.6 |
| MCS5 | 0.76 | 1 | 22.4 |
| MCS6 | 0.85 | 1 | 29.6 |
| MCS7 | 0.92 | 2 | 44.8 |
| MCS8 | 1 | 2 | 54.4 |
| MCS9 | 1 | 2 | 59.2 |
GSM RELATED LINKS
GSM Channels
GSM Logical Channels
traffic channel processing
control Channel processing
GSM SDCCH
GSM SACCH
GSM RACH
GSM PCH
GSM FACCH
GSM BCCH
GSM AGCH
GSM SCH
GSM FCCH
GSM TCH
GSM CCCH
GSM Noncombined
GSM Combined