E1-based BTS¶

OsmoBSC supports a number of E1-based BTS models in addition to IP-based OsmoBTS and nanoBTS. This mode of operation is probably not used very much these days, due to dwindling supply of legacy E1 BTS hardware, but I (falconia) hold the view that in certain aspects of TCH operation (particularly the path from TCH UL Rx to TRAU-UL frame output), some E1-based BTS should be used as a "golden reference" for most correct BTS operation, to be replicated in OsmoBTS.

Themyscira development HQ currently has a Nokia InSite BTS, donated by laforge and manawyrm. This small E1 BTS is connected to an icE1usb with GPS; the latter adapter is in turn driven by a RPi5. OsmoBSC and other Osmocom CNI components for the test network with this BTS run on the RPi5.

The following pages collect tidbits of knowledge obtained with this BTS, and/or note areas where more knowledge-gathering experiments are still needed.

• BFI criteria
• DTXu half-blocks
• HRv1 UL Rx
• InSite UL captures
• No-data output