uncalibrated general-purpose SDRs (was Re: Balancing BTS'es for handover)

Hi Gullik, On Sat, Jan 12, 2019 at 08:22:05PM +0100, Gullik Webjorn wrote: What do you mean by "downlink is 35dB"? If you are using a general-purpose SDR hardware you cannot expect that any of the signal levels written anywhere actually meany anything at all. There is no absolute levels reported by SDR hardware anywhere, and there is no calibration of either transmit nor receiver. This means: * there's no general calibration curve for the chip/board * there's no per-unit individual calibration curve for the unit you have This is *very* different from a real GSM base station. Without designing a calibration procedure for the above, as well as some mechanism to apply it in production, I don't think one can expect any of the readings to state anything realistic, nor expect any power control loops to operate. Please don't get me wrong, general-purpose SDRs such as USRPs or LimeSDR are great tools for experiments in the lab. But that's what they are - at least for the time being. There is a *big* difference between a real-world base station and a GP-SDR board. The 16dBm is probably the closest one can get to the 15 dBm you requested: How do you establish this fact? Did you attach a RF power meter to the MS output and masure the output power? -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)