  In this paper, we analyze the impact of different encoding schemes on the age
of information (AoI) performance in a point-to-point system, where a source
generates packets based on the status updates collected from multiple sensors
and transmits the packets to a destination. In this system, we consider two
encoding schemes, namely, the joint encoding scheme and the distributed
encoding scheme. In the joint encoding scheme, the status updates from all the
sensors are jointly encoded into a packet for transmission. In the distributed
encoding scheme, the status update from each sensor is encoded individually and
the sensors' packets are transmitted following the round robin policy. To
ensure the freshness of packets, the zero-wait policy is adopted in both
schemes, where a new packet is immediately generated once the source finishes
the transmission of the current packet. We derive closed-form expressions for
the average AoI achieved by these two encoding schemes and compare their
performances. Simulation results show that the distributed encoding scheme is
more appropriate for systems with a relatively large number of sensors,
compared with the joint encoding scheme.
