Telefonaktiebolaget LM Ericsson (publ)
Reliable communication to energy-detection receivers

Abstract:

A method for detecting a data transmission, the method including measuring a signal level for each of a predetermined plurality of distinct time-frequency transmission resources within a first time interval, non-coherently summing the measured signal levels, and comparing the sum to at least a first threshold to determine whether a channel-hardened signal targeted to the wireless receiver is present. A corresponding method for encoding a channel-hardened signal comprises transmitting, in a first time interval and using M antenna ports and T1 time-frequency resources, an array X of M.times.T1 symbols, where each row of the array corresponds to one of the M antenna ports and each column of the array X corresponds to one of the first set of T1 time-frequency resources. X satisfies the expression XX.sup.H=aI, where X.sup.II is the conjugate transpose of X, I is an identity matrix, and .alpha. is a constant.