Ubiquitous communication is a key component of Ambient Intelligence, enabling objects to communicate with each-other by means of a wireless ad-hoc network. A presence service allows knowing the availability or responsiveness status of elements in a communication (entities). Traditionally, only human use this service, however all smart devices or objects (with embedded wireless sensor nodes) could interact with each other thus a presence service could also enhance communication among them. To achieve this objective we look into existing protocols to propose the requirements needed to provide presence service on Wireless Sensor Networks (WSN). The main contribution of this paper is the discussion of requirements for presence services on WSN and the new proposed architecture to cope with presence services in WSN.