A method for determining threshold signal power for a switching control module of a time-division-duplexing, TDD, switching sub-system comprising: setting a threshold signal power to a first value, wherein the threshold signal power is compared to a measured signal power of a downlink signal of a downlink path of a telecommunication system from a measurement receiver; determining a first downlink signal time using the first value, wherein the first downlink signal time is an amount of time elapsed from when a first downlink signal is first detected to when the first downlink signal is no longer detected, wherein the first downlink signal is detected when its downlink power exceeds the threshold signal power set to the first value; characterized in that the method further comprises: adjusting the threshold signal power to a second value; determining a second downlink signal time using the second value, wherein the second downlink signal time is an amount of time elapsed from when a second downlink signal is first detected to when the second downlink signal is no longer detected, wherein the second downlink signal is detected when its downlink power exceeds the threshold signal power adjusted to the second value; determining a difference between the first downlink signal time and the second downlink signal time; when the difference between the first downlink signal time and the second downlink signal time does not exceed a predetermined threshold time, determining whether the second downlink signal time corresponds to a known valid downlink signal time; when the second downlink signal time corresponds to the known valid downlink signal time, setting a fixed threshold signal power for use during online operation of the switching control module. setting a threshold signal power to a first value, wherein the threshold signal power is compared to a measured signal power of a downlink signal of a downlink path of a telecommunication system from a measurement receiver; determining a first downlink signal time using the first value, wherein the first downlink signal time is an amount of time elapsed from when a first downlink signal is first detected to when the first downlink signal is no longer detected, wherein the first downlink signal is detected when its downlink power exceeds the threshold signal power set to the first value; characterized in that the method further comprises: adjusting the threshold signal power to a second value; determining a second downlink signal time using the second value, wherein the second downlink signal time is an amount of time elapsed from when a second downlink signal is first detected to when the second downlink signal is no longer detected, wherein the second downlink signal is detected when its downlink power exceeds the threshold signal power adjusted to the second value; determining a difference between the first downlink signal time and the second downlink signal time; when the difference between the first downlink signal time and the second downlink signal time does not exceed a predetermined threshold time, determining whether the second downlink signal time corresponds to a known valid downlink signal time; when the second downlink signal time corresponds to the known valid downlink signal time, setting a fixed threshold signal power for use during online operation of the switching control module. adjusting the threshold signal power to a second value; determining a second downlink signal time using the second value, wherein the second downlink signal time is an amount of time elapsed from when a second downlink signal is first detected to when the second downlink signal is no longer detected, wherein the second downlink signal is detected when its downlink power exceeds the threshold signal power adjusted to the second value; determining a difference between the first downlink signal time and the second downlink signal time; when the difference between the first downlink signal time and the second downlink signal time does not exceed a predetermined threshold time, determining whether the second downlink signal time corresponds to a known valid downlink signal time; when the second downlink signal time corresponds to the known valid downlink signal time, setting a fixed threshold signal power for use during online operation of the switching control module.