Joint communication and sensing is emerging as a potential extension to the existing wireless communication systems. In this paper, we present an overview of sensing using a primarily wireless communication network and investigate different design aspects such as hardware implications, spectrum requirements and multiplexing of communication and sensing signals. Also, we present sensing signal design based on the required sensing accuracies for an OFDM-based communication system and show the corresponding detection performance. One interesting finding is the large difference between transmission power of sensing compared to transmission power used for communication. We will discuss how this impacts the design, including duplex direction as well as waveform that is used for sensing. Finally, we discuss some tradeoffs between sensing accuracy and the overhead of sensing signal and solutions to reduce the overhead in a joint communication and sensing system.