We
all are, painfully, aware of service providers applying fair usage policy,
beyond a certain limit of data usage, by throttling mobile data speeds.
Typically this is done using a PCRF/OCS. With latest revisions of 3GPP (Release
9) we can achieve FUP just by using PCRF. However I want to put forth another
way of doing this. Push the LTE subscribers to UMTS after a data threshold;
similarly push UMTS subscribers to GPRS/EDGE. Don’t kill me; I am just stating
another feature of 3GPP :-).
Few
years back we had GPRS/EDGE widely deployed, with UMTS coming in a new network
was deployed along side of GPRS/EDGE. Also LTE is going to co-exist with
UTRAN/GERAN. As of now most of the devices that do data are 3G capable and are
always hooked on to UMTS/HSPA. The numbers of 3G/4G capable devices are on the
rise leaving the GPRS/EDGE network least used. What if we push the 3G
subscribers to GPRS/EDGE after a certain limit? This way we could still utilize
the GERAN.
I am
not sure of limitations on radio side, but from core network it seems like a
simple feature. HLR/HSS store information about
subscriber and can dictate which Radio Access
Technology (RAT) a UE can connect to. Refer to 3GPP
TS 29.272 and look for “Access Restriction Data”. The AVP has values like
“UTRAN Not Allowed”, “GAN Not Allowed”, “E-UTRAN Not Allowed” etc. Based on
these values MME/SGSN will either allow or block the UE from accessing a
corresponding RAT. Typically blocking a RAT will lead to an “Attach Reject”
with definite “Cause” towards an UE. Assume a UE is blocked from E-UTRAN, so
when that UE tries to gain E-UTRAN access, MME rejects the Attach with Cause “EPS
services not allowed”. This will stop UE from connecting to E-UTRAN, until it
is switched off and switched on. Similarly we can achieve this over UTRAN and
make UE fallback to GERAN.
Downsides
- Identify the subscribers whose data threshold are hit and re-program the HSS/HLR to block access. Once billing cycle is complete re-program the HSS/HLR again to allow access.
- What happens when the coverage for the enforced RAT is not present? Assume the subscriber is pushed to GERAN and he/she is in a location where GERAN is not available.
This
is pretty lousy solution to implement, but achievable. Nice way to
implement is rate limit the subscriber using PCRF. We could still use
this feature to block certain users from accessing a RAT all-together, which is
reasonable.
This
shows the amount of control a mobile network can have over a subscriber!
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