Providing enhanced emergency services to an IP Telephony-based PBX or similar system, by utilizing aspects of the intelligence of end-user SIP client devices to address challenges and difficulties associated with E-911-like services in LAN-based telephony environments. It is possible to compute the upper bound of the maximum mutual information at least based on the total energy of all resolvable paths in the fading channels. Further such an external input may be excluded from the hints if none of the statements of at least one of the alternative paths following from the conditional statement in which it is used have a data dependency to another statement of the program.