| 1. What is GPRS |
GPRS is the short form for General Packet Radio Service, which is an add-on service based on GSM network. Unlike regular circuit switched telephony service, GPRS is based on packet switched technology to provide high-speed mobile communication.
Using GPRS service to transmit information, the data is divided into small packets sent over the shared network; unlike circuit switched service needs to take up an exact circuit to transmit data. Therefore, transmission rate is highly enhanced under the limited bandwidth. GPRS enabled networks offer 'always-on', higher capacity, Internet-based content and packet-based data services. This enables services such as color Internet browsing, e-mail on the move, powerful visual communications, multimedia messages and location-based services. |
| GPRS service type the following three: |
| Service Type |
Description |
| CLASS A |
Support GPRS and GSM Network; two services can be used simultaneously. |
| CLASS B |
Support GPRS and GSM Network. Two services cannot be used at a time, but they can be switched automatically. |
| CLASS B |
Either GPRS or GSM service is supported. Need to switch manually between services. |
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| 2. GPRS Transmission Rate |
| The transmission speed and reliability are decided by timeslot, there are four following categories: |
| Timeslot |
Transmission speed in each slot (K bit/sec) |
Maximum speed
(K bit/sec) at 8 slots |
Reliability |
| CS-1 |
9.05 |
9.05*8 =72.4 |
High |
| CS-2 |
13.4 |
13.4*8 =107.2 |
Med. High |
| CS-3 |
15.6 |
15.6*8 =124.8 |
Med. Low |
| CS-4 |
21.4 |
21.4*8 =171.2 |
Low |
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| There are 29 categories of multi-slot transmission. For example, Class 8 has 4 downlink channels and 1 uplink channel. The speed of each timeslot is specified as follows: |
| Timeslot |
Downlink Channel |
Uplink Channel |
| CS-1 |
9.05*4=36.2 |
9.05*1=9.05 |
| CS-2 |
13.4*4=53.6 |
13.4*1=13.4 |
| CS-3 |
15.6*4=62.4 |
15.6*1=15.6 |
| CS-4 |
21.4*4=85.6 |
21.4*1=21.4 |
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| 29 multi-slot classes are stated as follows: |
| 類型CLASS |
下載槽數 |
上傳槽數 |
| 1 |
1 |
1 |
| 2 |
2 |
1 |
| 3 |
2 |
2 |
| 4 |
3 |
1 |
| 5 |
2 |
2 |
| 6 |
3 |
2 |
| 7 |
3 |
3 |
| 8 |
4 |
1 |
| 9 |
3 |
2 |
| 10 |
4 |
2 |
| 11 |
4 |
3 |
| 12 |
4 |
4 |
| 13 |
3 |
3 |
| 14 |
4 |
4 |
| 15 |
5 |
5 |
| 16 |
6 |
6 |
| 17 |
7 |
7 |
| 18 |
8 |
8 |
| 19 |
6 |
2 |
| 20 |
6 |
3 |
| 21 |
6 |
4 |
| 22 |
6 |
4 |
| 23 |
6 |
6 |
| 24 |
8 |
2 |
| 25 |
8 |
3 |
| 26 |
8 |
4 |
| 27 |
8 |
4 |
| 28 |
8 |
6 |
| 29 |
8 |
8 |
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