Opportunistic multiple access (OMA) for crowdsensing networks with sparse activation

For gathering data in a crowdsensing network, we need to support the connectivity of a massive number of low power devices. In this paper, a new multiple access technique is proposed for such networks with a large number of devices/sensors/users where we have taken advantage of the fact that these devices usually do not become active at the same time, which we refer to as sparse activation property. In this scheme, each device uses a specific spreading code which is changing at symbol level. Symbol‐level change of the spreading code and the random nature of user activation are the two building blocks that provide opportunistic low interference between data transmitted by devices, which are activated in a specific time slot. We also discuss how the proposed scheme can be used in grant free schemes which eliminate the need for heavy signaling before data transmission. The performance of the proposed scheme has been evaluated in different scenarios, and the block error rates are compared with a few other multiple access schemes.