Waveform optimization using trapezoidal pulses for 5G random access with short message support

Abstract

It is well-known that sporadic traffic will be an increasing demand in the 5G market. Obviously, bulky synchronization procedure of the current 4G LTE cellular systems is not a viable option. Transmission of control signaling and payload “in one shot” in physical layer random access channel is an interesting direction. A major challenge is to cope with highly asynchronous access as well as high carrier frequency offsets of low-cost IoT devices. We address this challenge by using a waveform design approach based on a (tail-biting) bi-orthogonal frequency division multiplexing approach (at non-critical density). More specifically, we introduce a 2-parameter trapezoidal pulse family and investigate their properties both by analysis and simulations. In particular, we reveal surprising favorable properties like excellent time domain localization measured in terms of their L1-norm and relate this to “extreme” cases like the triangle pulse and the sinc pulse which appear as special cases of the trapezoidal family.