Therefore, our results are slightly optimistic. In the case of low load, we note that the failure probability is very small, since only channel fading effects may cause RLC PDUs being lost.
However, when the number of smart objects is greater than or equal to 70, the
failure probability becomes non-negligible, which suggests that the LTE gateway suffers from intra-node contention among the different CoAP sessions.
On the other hand,with high cell loads (see right side of Fig. 6), the failure
probability becomes non-negligible also with a small number of smart objects, and is very high (and likely unbearable) for many smart objects served by the LTE gateway. Therefore, we argue that isolation mechanism are necessary to protect
M2M communication protocols from both intra-gateway and inter-UE traffic.