Solution To Test: "Ericsson WCDMA System Overiew"
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Bassem AbouamerSolution To Test: "Ericsson WCDMA System Overiew"
Uploaded by
Bassem AbouamerSolution to Test
“Ericsson WCDMA System
Overiew”
Ericsson WCDMA Systems Overview
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Ericsson WCDMA Systems Overview
Table of Contents
Topic Page
SOLUTION TO TEST.............................................................................1
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SOLUTION TO TEST
1. Which Technology introduces packet switching into the GSM network?
GPRS introduces packet switching into the GSM network.
GPRS: General packet radio service
2. Which new nodes have to be introduced?
SGSN: Serving GPRS support node
GGSN: Gateway GPRS support node
3. Which other HW needs to be introduced and why?
PCU: Packet control unit
Module for the BSC to handle the packet data traffic.
4. Which new technology is introduced in the GSM radio network for better
utilization of the air link?
Enhanced data rate for GSM evolution
5. Which modulation scheme does this technology use?
The new modulation scheme is 8-PSK.
6. What is IMT-2000, 3GPP, and 3GPP2?
- IMT-2000: International Mobile Telecommunication 2000
The ITU term for 3G standardization
- 3GPP: 3rd Genertion Partnership Project
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The organization for working out the 3G technical spcifications in
Europe/Japan
- 3GPP2: 3rd Genertion Partnership Project 2
The organization for working out the 3G technical spcifications in
USA/South Korea
7. Name the layers of the layered core network!
Application layer
Control layer
Connectivity layer
8. What is the purpose of each of those layers?
Application layer:
This layer forms the service network. All services reside in this layer.
Control layer:
This layer provides the control of the call, session and signaling.
Connectivity layer:
All data traffic is transported (routed/swithced) in this layer.
9. What is ATM?
- what does the abbreviation stand for?
ATM is the Asynchronous Transfer Mode, a technology that is used in WCDMA
Systems networks.
10. What is an Adaptation Layer in ATM?
The Adaptation Layer in ATM “adapts” the information to be conveyed according
to its nature, so that the transport via ATM can be most efficient.
11. On which layer(s) of the OSI model does ATM operate?
ATM operates at least on Layer 2 – but it could operate on all layers.
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12. On which layer of the OSI model happens the switching in ATM? On wich one in
TCP/IP?
The switching in ATM occurs on Layer 2, in TCP/IP on Layer 3
13. What is the Cello Packet Platform?
Cello is a platform product from which it is possible to develop a switching
network node, such as a small- to medium-sized asynchronous transfer mode
(ATM) switch, a radio base station, or a radio network control node.
14. What cell size does an ATM cell have and what advantages offer fixed length
packets?
A cell is a 53-byte packet with 5 bytes of header / descriptor and 48 bytes of
payload, for user traffic as voice, data or video. Because of the fixed length delays
become predictable.
15. What is a Media Gateway (MGW)?
A Media GateWay (MGW) is a node, which provides bearer adaptation for the
user plane from the PLMN core network to external networks like PSTN, ATM or
the Internet. The MGW will also provide the bearer adaptation/conversion for the
signaling plane.
16. Which network elements belong to the Radio Access Network (RAN), and which
of them controls the Node B in a WCDMA/UMTS network?
- RAN: Node B, RNC
- Radio Network Controller (RNC) controlles the Node B.
17. What is the difference of CDMA compared to FDMA and TDMA?
- FDMA (Frequency Division Multiple Access) devides different channels by
using different frequencies
- TDMA (Time Division Multiple Access) devides different channels by using
timeslots
- CDMA (Code Division Multiple Access) devides different channels by using
different codes.
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18. What is the spreading factor (SF) and how is it defined?
- The spreading factor denotes to the number of chips per data symbol.
SF = chiprate / symbolrate
19. What does OVSF-code mean and what is it used for?
- Orthogonal Variable Spreading Factor code. This code is used to preserve
separation of the physical channels transmitted by one transmitter.
20. How many channels could be distinguished in WCDMA technology theoretically?
An infinite number of channels could be supported theoretically. The possible
number in practice depends on the Signal over Noise strength.
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