  Stationary collectors reading wireless, battery powered smart meters, often
operate in harsh channel conditions to cut network installation cost to a
minimum, challenging the individual link to each meter. The desired performance
measure is reliable reception of at least some data from as many as possible
meters, rather than increasing the fraction of received packets from one meter.
As a first step for improving reliable reception, and motivated by the recent
revision of Wireless M-Bus, we propose the use of a deterministic packet
transmission interval to group packets from the same meter. We derive the
probability of falsely pairing packets from different senders in the simple
case of no channel errors, and show through simulation and data from an
experimental deployment the probability of false pairing with channel errors.
The pairing is an essential step towards recovery of metering data from as many
as possible meters under harsh channel conditions. From the experiment we find
that more than 15% of all conducted pairings are between two erroneous packets,
which sets an upper bound on the number of additional meters that can be
reliably recovered.
