## The Arrival of 6G

Recently, IEEE Communications Society published an article “What will 6G be?” Some of the important points it highlighted are the following. More spectrum is needed for more bits: As with all new Gs, more spectrum is needed to entertain more bits ðŸ™‚ Sometimes I wonder where exactly we have made a phenomenal progress in delivering orders of magnitude higher data rates. According to Gerhard Fettweis, several bands between 100 and 300 GHz show some promise. Bits/s/$m^3$: Since the success of a company is measured in the revenue generated, and not exactly the bits delivered per second, the real focus is

## Discrete Frequency

An Analog to Digital Converter (ADC) samples a continuous-time signal to produce discrete-time samples. For a digital signal processor, this signal just resides in memory as a sequence of numbers. Consequently, the knowledge of the sample rate $F_S$ is the key to signal manipulation in digital domain. As far as time is concerned, one can easily determine the period or frequency of such a signal stored in the memory. For example, the period $T$ in the sinusoid of Figure below is clearly $10$ samples and sample time $T_S=1/F_S$ can be employed to find its period in seconds. For a sample

## Location Estimation through Differential Phase Difference of Arrival

In an article on carrier phase based ranging, we saw how phase observations were employed to find the range between two wireless devices. Today we explore how phase can also be used for the purpose of location estimation. Background To determine the position of a wireless device, its range needs to be computed from a set of anchor nodes. When these anchors and the device itself are synchronized with each other, the signal propagation time of an electromagnetic wave arriving at these anchors after its emission from a Tx can be employed to calculate the corresponding distances. This is the