Exploiting pulse compression to generate an IEEE 802.15.4a-compliant UWB IR pulse with increased energy per bit

Abstract

The radio coverage is limited by the energy per bit transmitted. UWB pulses used in impulse radio are extremely short and, consequently, carry a very little energy per bit that results in an unacceptable short radio coverage. The energy per bit could be increased by enlarging the duration of UWB carrier pulse, however, this solution cannot be used because the correlation of received pulse envelope with a reference pulse defined in IEEE Std. 802.15.4a has to exceed a prescribed value. To solve the problem the pulse compression approach is proposed here where the duration of radiated UWB carrier pulse is enlarged considerably to get enough energy per bit and the duration of received UWB pulse is compressed by a matched filter at the receiver. The increased energy per bit increases the radio coverage and the envelope of compressed UWB pulse satisfies the requirements of IEEE Std. 802.15.4a. The gains in energy per bit are about 18 dB and 22 dB when the UWB pulse durations are set to 100 ns and 300 ns, respectively.