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Example: NOM_PWR and INIT_PWR are expressed as a two's complement value in increments or units of 1 dB. In the access parameters message, 4 bits are allocated to NOM_PWR and 5 bits are allocated to INIT_PWR. Suppose that NOM_PWR, a 4-bit two's complement value, equals decimal 3 dB. Then in binary, NOM_PWR equals 0011. If INIT_PWR, a 5-bit two's complement value, equals decimal -3 dB its two's complement is found as follows. First the magnitude equals decimal 3, which using 5 bits equals 00011. The complement of this binary word equals 11100. The negative decimal 3 is represented by the 5-bit word equal to the complement 11100 plus 00001 or 11101. For the decimal values of NOM_PWR and INIT_PWR equal to 3 and -3 dB respectively, the binary words in the access parameters message conveying these values would be 0011 and 11101 respectively. The open loop power control algorithm for terrestrial cellular IS-95 systems is that the initial power in dBm transmitted from a mobile, Pt, equals Pt = -PrTOT -73 + NOM_PWR + INIT_PWR (1) where PrTOT is the total power in the 1.25 MHz physical bandwidth of the mobile measured in dBm. For example, with PrTOT equal to -83 dBm and NOM_PWR and INIT_PWR equal to decimal +3 and -3 dB, the mobile would initially access the system at a transmitted power level of -(-83) -73 or 10 dBm, which equals 10 mW. The open loop power control algorithm for PCS at 1900 MHz is very similar except the initial power in dBm transmitted from a mobile, Pt, equals Pt = -PrTOT -76 + NOM_PWR + INIT_PWR (2) where again PrTOT is the total power in the 1.25 MHz physical bandwidth of the mobile measured in dBm. USE YOUR BROWSER "BACK" BUTTON TO RETURN © 1999 DR. ERNEST SIMO - SPACE2000 |
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