ETSI WIDEBAND CDMA STANDARD FOR THE UTRA FDD AIR
INTERFACE by
Nicky Jee-Ngai Yuen
Electrical Engineering 563
Wireless Personal Telecommunications Systems ETSI WIDEBAND CDMA STANDARD FOR THE UTRA FDD AIR
INTERFACE Submitted to
Dr. P. Takis Mathiopoulos
The University of British Columbia


iii
LIST OF ILLUSTRATIONS

Table 1. Key Parameters of W-CDMA..............................................................................4
Table 2. Physical Channel Format.....................................................................................9

Figure 1. ITU Spectrum Allocation ...................................................................................3
Figure 2. Hierarchical Cell Structure for Smooth Handovers...............................................6
Figure 3. Physical Channel Structure.................................................................................9
Figure 4. Uplink DPDCH/DPCCH Structures..................................................................10
Figure 5. Uplink DPCH Spreading/Modulation................................................................11
Figure 6. Random Access Scheme ..................................................................................12
Figure 7. Uplink PRACH Structure.................................................................................12
Figure 8. Data Part of PRACH........................................................................................13
Figure 9. Downlink Spreading/Modulation......................................................................14
Figure 10. Downlink DPCH...........................................................................................15
Figure 11. Primary and Secondary CCPCHs....................................................................16
Figure 12. Synchronization Channel................................................................................17
Figure 13. Test Route.....................................................................................................18
Figure 14. Average BER Performance with Variable Chip Rate........................................20 iv
LIST OF ABBREVIATIONS

BCCH.................................................................................... Broadcast Control Channel
BER.............................................................................................................Bit Error Rate
BPSK....................................................................................... Binary Phase Shift Keying
BTS.............................................................................................Base Transceiver Station

W-CDMA..........................................................Wideband Code Division Multiple Access

v
TABLE OF CONTENTS

ABSTRACT....................................................................................................................ii
LIST OF ILLUSTRATIONS............................................................................................iii
LIST OF ABBREVIATIONS...........................................................................................iv
1.0 INTRODUCTION.....................................................................................................1
2.0 UMTS TERRESTRIAL RADIO ACCESS..................................................................3
2.1 Significant Features of W-CDMA...........................................................................3
2.2 Performance Capabilities........................................................................................5
2.2.1 Capacity.........................................................................................................5
2.2.2 Coverage and Link Budget..............................................................................5
2.2.3 Asynchronous BTS Operation..........................................................................6
2.2.4 Handovers......................................................................................................6
2.2.5 Adaptive Antenna Arrays ................................................................................7
2.2.6 Spreading and Scrambling Codes.....................................................................7
2.2.7 Packet Access.................................................................................................8
3.0 PHYSICAL CHANNEL STRUCTURES ....................................................................9
3.1 Physical Channel Format........................................................................................9
3.2 Uplink .................................................................................................................10
3.2.1 DPCH..........................................................................................................10
3.2.2 CPCH..........................................................................................................11
3.3 Downlink.............................................................................................................13
3.3.1 DPCH..........................................................................................................14
3.3.2 CPCH..........................................................................................................15
4.0 EXPERIMENT ON VARIABLE SPREADING BANDWIDTH .................................18
5.0 CONCLUSION........................................................................................................21
REFERENCES...............................................................................................................22

3. limited coverage at up to 2 Mbps in a picocell; fixed,
4. high spectrum efficiency compared to existing systems, and
5. high flexibility to introduce and multiplex new services at different bit rates and
E
b
/N
0
requirements.

ETSI Wideband CDMA Standard for the UTRA FDD Air Interface
2
One of the more popular technologies being developed for IMT-2000 is known as wideband
CDMA. It has two versions: cdma2000 and W-CDMA. Both versions differ in chip rate,
downlink channel structure, and network synchronization, but they both promise wireless
voice at much higher capacity and lower cost then current 2G and 2.5G systems. The latter
version, which is the focus of this paper, was proposed in January 1998 by ETSI, the
European Telecommunications Standards Institute, as their proposal to the ITU for the
Frequency Division Duplex (FDD) spectrum of IMT-2000. ETSI’s proposal is identified as
UTRA, UMTS Terrestrial Radio Access. ETSI Wideband CDMA Standard for the UTRA FDD Air Interface
3
2.0 UMTS TERRESTRIAL RADIO ACCESS

The ETSI UTRA is based on a wideband, 5 MHz, 4.096 Mcps Direct Sequence (DS) CDMA
technology. The UTRA Network, or UTRAN, is connected to an evolved GSM core network
to provide both circuit switched and packet switched services. The chip rate is extendible to
higher rates of 8.192 Mcps and 16.384 Mcps. W-CDMA was selected for FDD (paired
UMTS frequency band) operation, and time-division CDMA (TD/CDMA) was selected for

detection, and interference cancellation,
8) asynchronous base transceiver station (BTS) operation, and
9) fast transmit power control (TPC) in both directions.

The following table lists the key parameters of W-CDMA.
Multiple-access scheme DS-CDMA
Bandwidth 5 / 10 / 20 MHz
Chip rate 4.096 / 8.192 / 16.384 Mcps
Carrier spacing (4.096 Mcps) Flexible in the range 4.4 – 5.2 MHz (200 kHz carrier raster)
Roll-off factor 0.22
Frame length 10 ms (20 ms optional)
Inter-cell synchronization Asynchronous; no synchronization needed (synchronous also
possible)
Spreading modulation QPSK (downlink)
QPSK (uplink)
Data modulation QPSK (downlink)
BPSK (uplink)
Coherent detection User-dedicated time-multiplexed pilot (uplink and downlink),
Common pilot can also be used in downlink
Multirate Variable-spreading and multicode
Spreading factor (ratio of chip
rate over information rate)
4 – 256 (4.096 Mcps)
Channel coding Convolutional coding (R = 1/3 or 1/2, K = 9), Turbo code
Spreading Spreading code and Scrambling code
Spreading code (downlink) Variable-length orthogonal sequences for channel separation,
Gold sequences for cell and user separation
Spreading code (uplink) Variable-length orthogonal sequences for channel separation,
Gold sequence 2
41

Coverage of W-CDMA is determined by the link performance through the link
budget. With W-CDMA, it is possible to reuse GSM1800 cell sites when moving
from the GSM to W-CDMA infrastructure, since the latter uses a similar network
protocol structure. W-CDMA voice service will tolerate a few dB higher path loss
than GSM. This means that W-CDMA gives better voice coverage than GSM when
reusing the same cell sites at the same frequency band.