  Connected and Automated Vehicles (CAVs) utilize a variety of onboard sensors
to sense their surrounding environment. CAVs can improve their perception
capabilities if vehicles exchange information about what they sense using V2X
communications. This is known as cooperative or collective perception (or
sensing). A frequent transmission of collective perception messages could
improve the perception capabilities of CAVs. However, this improvement can be
compromised if vehicles generate too many messages and saturate the
communications channel. An important aspect is then when vehicles should
generate the perception messages. ETSI has proposed the first set of message
generation rules for collective perception. These rules define when vehicles
should generate collective perception messages and what should be their
content. We show that the current rules generate a high number of collective
perception messages with information about a small number of detected objects.
This results in an inefficient use of the communication channel that reduces
the effectiveness of collective perception. We address this challenge and
propose an improved algorithm that modifies the generation of collective
perception messages. We demonstrate that the proposed solution improves the
reliability of V2X communication and the perception of CAVs.
