Sadly srsRAN does not seem to implement TDMA. Ham radio operators have a slice at 2.3 GHz which overlaps Band 40, supported by a good number of phones.
Also band 40 is the only widely supported TDMA in range of the cheaper SDRs.
Even a limesdr mini can speak that, though one may want to get an LTE quartz to keep phase noise in spec (the fraction from the normal quartz has a really big denominator, that makes fractional PLL problematic if you don't sense fractional phase of the reference quartz) with the PLLs on those SDRs.