Page 2 of 8 APPLICATION NOTE Power Design Tool for Remote Radio Heads POWER DIMENSIONING FOR REMOTE RADIOS Power dimensioning for remote radio heads (RRH) is an important task for system design engineers. For network roll-outs, upgrades of existing networks or re-use of existing cable infrastructure the following questions arise: What is the maximum allowable RRH power consumption for a given cable configuration? What is the minimum required cable cross section to supply a specific RRH at a given tower height? What is the maximum allowed cable length for a prespecified cable cross section and RRH? E.g., a 500 W remote radio with 6 mm2 power cable. A power unit at the base station supplies the mast-mounted RRHs with a constant DC voltage UBTS. The remote radio has a constant power consumption PRRH at a given minimum operating voltage URRH. The power supply cable causes electrical losses due to the electrical resistance of copper leading to a cable drop voltage U = UBTS URRH. The electrical resistance of the copper cable depends on the cable length L, the copper cross section A, and the electrical conductivity (T) which is influenced by the temperature T RL L , whereas (20°C) = 5.46 107 S/m. (T ) A The resulting drop voltage is U U BTS U RRH 2 I RL 2 I P L L 2 RRH A U RRH A since the power consumption PRRH is the product of the electrical current I and the remote radio voltage URRH. These formulas are used for power dimensioning in the HUBER+SUHNER power design tool. HUBER+SUHNER disclaims any liability resulting from incorrect calculation including any damages resulting from the use of of the power design tool.
Download PDF file
Build your own flipbook