Page 208 - Antennas for Base Stations in Wireless Communications

Antenna Issues and Technologies for Enhancing System Capacity 181

Figure 5.4 shows the relationship between capacity and half-power
beamwidth (HPBW) in a W-CDMA system for a three-sector or six-sector
7
per cell scheme. Each sector division angle is 120° for a three-sector per
cell scheme or 60° for six-sector per cell scheme. However, Figure 5.4a
shows that peak system capacity in the uplink can be achieved for an
HPBW of 60°–90° for the three-sector per cell scheme and 35°–45° for
the six-sector per cell scheme, respectively. Similarly, from Figure 5.4b,
the peak system capacity in the downlink occurs when the HPBW varies

1.0
Normalized capacity 0.8 6 sectors 3 sectors

0.6

0.4

0.2

0
0 50 100 150
HPBW [degree]
(a) Uplink

1.0

Normalized capacity 0.6 6 sectors 3 sectors
0.8

0.4

0.2

0
0 50 100 150
HPBW [degree]
(b) Downlink
Figure 5.4 Relationship between capacity and HPBW in W-CDMA