tranceiver support for osmo-bts

[Andreas Eversberg]

hi,

i would like to start implementing the trx manager interface support to 
osmo-bts. before going to work, i'm writing this mail, because i like to 
read some pros and cons for my approach.

as already stated, thomas a. cooper already implemented an interface 
between sysmo-bts's dsp device and trx manager interface by using code 
from openbts, running in an own process  [1]. i would like to follow a 
different approach by writing a scheduler and adding the udp interface 
for the trx(s). some benefits are in my oppinion:

- not having an extra process running with additional latency and overhead
- smaller code, because only a small multiframe scheduler + udp 
interface for the trx is required (coding scheme and forward error 
correction code can be used from libosmocore.)
- no running after dsp's api changes, (caused by newer firmware of sysmobts)
- trx specific features and limitations can be considered. (vty options 
for setting special features, limitations can affect oml ack/nack 
responses to be considered by bsc)
- no use of multithreading, use of talloc. the code is easier to debug 
and so becomes more stable.
- easy to add initial support for BCCH(+SDCCH4), SDCCH8, TCH/F, TCH/H, 
PDCH (gprs) for a whide range of applications.

comments are welcome.

regards,

andreas


[1] 
http://scholar.lib.vt.edu/theses/available/etd-05082012-141540/unrestricted/Cooper_TA_T_2012.pdf