05-03-2013, 12:53 PM
WIDEBAND CODE DIVISION MULTIPLE ACCESS
[attachment=52638]
ABSTRACT
W-CDMA seems to be the BIG rage nowadays!
The Third Generation Mobile System is the future mobile communication technology that carries existing and future services on a unified platform. W-CDMA is a prominent step in this direction. Killer Wireless Application or not, W-CDMA is being adopted in more and more countries and is becoming one of the leading Wireless Standards in the World.
Wideband Code division Multiple Access (W-CDMA) is a "spread spectrum" technology, which means that it spreads the information contained in a particular signal of interest over a much greater bandwidth than the original signal. WCDMA makes very efficient use of the available radio spectrum. No frequency planning is needed, since one-cell re-use is applied.
WHY W-CDMA?
The power of information is limitless. The way to tap into this source of great power is through effective communication -- in business as well as in the more personal dimension of our lives. However, the world of today is a place where we can no longer afford to remain stationary in order to provide or obtain information. We must constantly be "in touch", no matter where we may be. We are witnessing the dawning of a new age – the age of mobile multimedia.
BCABACCAB
The following figure shows the comparison between the present day radio cell structure compared to the radio cells that will be used in the W-CDMA system. Uplink and downlink capacity can be adjusted according to needs.
GSM and similar ABC
F1 F2 Each cell corresponds to ABC
The W-CDMA systems employs transmission power control, diversity reception and an error control scheme capable of following the time variations in the radio propagation circuit in order to maintain high speech quality in poor radio propagation circuits and adopts a noise robust voice coding methods. To achieve high system capacity, a spectrum spreading modulation/demodulation method which is robust to interference noise and an efficient interference cancellation system are adopted.
ARCHITECTURE OF THE RADIO-INTERFACE:
In the standard, the mobile device is referred to as “User Equipment” (UE), which means a mobile device and multimedia terminal that takes care of voice (basically like a mobile phone) as well as transferring pictures and video.
On the terminal side, the UE is a mobile device that could contain a variety of functions – and not necessarily an ordinary mobile phone. On the infrastructure side, the UE is communicating with the Node B – the base station. In the next instance, Node Bs are communicating with the Radio Network Controller (RNC). The Mobile Switching Center is shared among all connected networks.
Broadcast Multicast Control
The requirements to get point-to-multipoint services for the protocol are fulfilled with the BMC Layer. Data is sent unacknowledged and delivery of information is not guaranteed.
Radio Resource Control
By far, the most complex and the largest layer in the radio interface protocol is RRC because of wide range of functions delivered and provided. The main tasks are to establish, maintain, and release a connection. However, the RRC also controls several other essential SAP functions. The other functions taken care of by the RRC includes establishing and maintaining required QoS for a connection. This implies the controlling of the other layers and accomplishes right decisions out of reported/collected connection statistics and measurements.
A WCDMA COMMUNICATION SYSTEM
W-CDMA uses a data stream of 1024Mbps and is passed through an encoder and interleaver. The interleaver provides error-protection by shifting bit positions so that the effects of interference bursts are distributed throughout the data stream and can be corrected once the signal is deinterleaved at the receiver. The resultant data stream is now multiplied by the chip sequence (12.288Mbps). This processing is equivalent to performing an X-OR operation between the data and the spreading code (also known as chipping). A band pass filter limits the
[attachment=52638]
ABSTRACT
W-CDMA seems to be the BIG rage nowadays!
The Third Generation Mobile System is the future mobile communication technology that carries existing and future services on a unified platform. W-CDMA is a prominent step in this direction. Killer Wireless Application or not, W-CDMA is being adopted in more and more countries and is becoming one of the leading Wireless Standards in the World.
Wideband Code division Multiple Access (W-CDMA) is a "spread spectrum" technology, which means that it spreads the information contained in a particular signal of interest over a much greater bandwidth than the original signal. WCDMA makes very efficient use of the available radio spectrum. No frequency planning is needed, since one-cell re-use is applied.
WHY W-CDMA?
The power of information is limitless. The way to tap into this source of great power is through effective communication -- in business as well as in the more personal dimension of our lives. However, the world of today is a place where we can no longer afford to remain stationary in order to provide or obtain information. We must constantly be "in touch", no matter where we may be. We are witnessing the dawning of a new age – the age of mobile multimedia.
BCABACCAB
The following figure shows the comparison between the present day radio cell structure compared to the radio cells that will be used in the W-CDMA system. Uplink and downlink capacity can be adjusted according to needs.
GSM and similar ABC
F1 F2 Each cell corresponds to ABC
The W-CDMA systems employs transmission power control, diversity reception and an error control scheme capable of following the time variations in the radio propagation circuit in order to maintain high speech quality in poor radio propagation circuits and adopts a noise robust voice coding methods. To achieve high system capacity, a spectrum spreading modulation/demodulation method which is robust to interference noise and an efficient interference cancellation system are adopted.
ARCHITECTURE OF THE RADIO-INTERFACE:
In the standard, the mobile device is referred to as “User Equipment” (UE), which means a mobile device and multimedia terminal that takes care of voice (basically like a mobile phone) as well as transferring pictures and video.
On the terminal side, the UE is a mobile device that could contain a variety of functions – and not necessarily an ordinary mobile phone. On the infrastructure side, the UE is communicating with the Node B – the base station. In the next instance, Node Bs are communicating with the Radio Network Controller (RNC). The Mobile Switching Center is shared among all connected networks.
Broadcast Multicast Control
The requirements to get point-to-multipoint services for the protocol are fulfilled with the BMC Layer. Data is sent unacknowledged and delivery of information is not guaranteed.
Radio Resource Control
By far, the most complex and the largest layer in the radio interface protocol is RRC because of wide range of functions delivered and provided. The main tasks are to establish, maintain, and release a connection. However, the RRC also controls several other essential SAP functions. The other functions taken care of by the RRC includes establishing and maintaining required QoS for a connection. This implies the controlling of the other layers and accomplishes right decisions out of reported/collected connection statistics and measurements.
A WCDMA COMMUNICATION SYSTEM
W-CDMA uses a data stream of 1024Mbps and is passed through an encoder and interleaver. The interleaver provides error-protection by shifting bit positions so that the effects of interference bursts are distributed throughout the data stream and can be corrected once the signal is deinterleaved at the receiver. The resultant data stream is now multiplied by the chip sequence (12.288Mbps). This processing is equivalent to performing an X-OR operation between the data and the spreading code (also known as chipping). A band pass filter limits the