1 CDMA The basic idea behind CDMA is to assign each user a signature (also called a code-word), s m (t). Users will use antipodal signaling (i.e., multiplying their signatures by ±1 to send data. Thus, what the receiver sees is (idealistically) r(t) = m b m s m (t) + w(t) where the b m are the users' bits (again, ±). We also generally assume that the system is interference limited so that the n...

This paper addresses the problem of pay-as-you-watch services over unicast and multicast communications. For each communication model, we present two solutions, non-verifiable and verifiable, depending on the existence or non-existence of trust between the source and the receiver(s). In verifiable schemes, the source obtains a proof of correct reception by the receiver(s); in non-verifiable sch...

For true low-power peer-to-peer wireless links for sensing, link symmetry must be maintained unlike in [1,2] where the burden is shifted to the receiver. In addition, the transceiver power dissipation and performance should be adaptive to save power when the link distance is short. We present a 120μW MICS/ISM band receiver with -90dBm sensitivity at a data-rate of 200kb/s with BER<0.1%. The rec...