Mobile Wireless Design Considerations

Mobile Wireless TDMA Design Considerations

# Number of logical channels (number of time slots in TDMA frame): 8

# Maximum cell radius (R): 35 km

# Frequency: region around 900 MHz

# Maximum vehicle speed (Vm):250 km/hr

# Maximum coding delay: approx. 20 ms

# Maximum delay spread (m): 10 s

# Bandwidth: Not to exceed 200 kHz (25 kHz per channel)


Mobile Wireless CDMA Design Considerations

# Soft Handoff – mobile station temporarily connected to more than one base station simultaneously

# RAKE receiver – when multiple versions of a signal arrive more than one chip interval apart, RAKE receiver attempts to recover signals from multiple paths and combine them

-This method achieves better performance than simply recovering dominant signal and treating remaining signals as noise