Saturday, April 27, 2013

Discontinued Reception

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Discontinued Reception

The DRx (Discontinued Reception) controls the deep-sleep/wakeup cycle of the mobile phones.

Discontinued Reception


Figure 1: Discontinued Reception
DRXn where n = {2, 3, ..., 9}. DRX7 is the most common selected by the service providers. The receiver active ON time is less than 6 milliseconds for GSM and depending on signal processors can be between 1 msec and 20 msec for WCDMA. Smaller DRx cycle reduces standby battery life. Longer DRx cycle results in longer time before cell phone first ring with more ring back cycles to call originator.

During the deep sleep mode the system clock is off.

For GSM
n = DRx cycle = n * (15*8*51)/26 milliseconds

eg.:
DRx2 = 2 * (15*8*51)/26 = 470.769 msec
DRx3 = 706.154 msec
DRx4 = 941.538 msec
DRx5 = 1.176923 seconds (commonly used for GSM systems)
DRx6 = 1.412308 seconds
DRx7 = 1.647.692 seconds
DRx8 = 1.883077 seconds
DRx9 = 2.118462 seconds


For WCDMA k = DRx cycle=>  DRx(k) = 2k * 0.01 seconds
eg.:
K= 2 =
22 * 0.01 = 40 mses
K= 3 = 80 msec
K= 4 = 160 msec
K= 5 = 320 msec
K= 6 = 640 msec
K= 7 = 1.28 seconds (commonly used for WCDMA systems)
K= 8 = 2.56 seconds
K= 9 = 5.12seconds



Reference