<<<All Things Wireless>>>
The basic building blocks.
The basic concept of Kay’s estimator is quite simple. It finds the phase advanced from one sample to the next and this gives us the frequency. Averaging is performed over the time window to get more accurate results. Averaging can be performed using uniform weighting or a weighting function defined by Kay in [1].
Read moreAs discussed in previous posts it is frequently required in communications and signal processing to estimate the frequency of a signal embedded in noise and interference. The problem becomes more complicated when the number of observations (samples) is quite limited. Typically, the resolution in the frequency domain is inversely proportional to the window size in the time domain.
Read moreIn this post we present the simplest method of frequency estimation that is called the Zero Crossing (ZC) method. Since a sine wave crosses the x-axis twice during each cycle, we can simply count the number of crossings and divide it by two and again divide it by the observation window size, giving us the frequency in Hertz.
Read moreConventional battery powered systems can be impractical, expensive, or have negative environmental impacts. Energy harvesting (EH) offers a potential solution to these problems. Through ambient sources such as solar, vibrational, thermal, and RF, self-sustaining IoT devices can be designed. These devices can be easily implemented in wearables, medical implants, and infrastructure. Companies such as TI and ADI have developed power management systems for EH and consumer products already exist. These products continue to increase in efficiency and practicality every year.
Read morePulse Amplitude Modulation (PAM) is a one dimensional or in other words real modulation. Simply put it is an extension of BPSK with M amplitude levels instead of two. This can be a bit confusing because BPSK can be looked at as a phase modulation and its natural extension must be QPSK or 8-PSK modulations. To remove this ambiguity lets call M-PAM an extension of simple amplitude modulation but with M levels. In the discussion below we consider M=4 but then extend it to the general case of M=2k (k=1,2,3…).
Read moreMassive MIMO is no longer a theoretical concept and it is already being adopted in the industry. So we now need to look beyond Massive MIMO or MaMIMO as it is popularly referred to.
Read moreWhen a wireless signal travels from a transmitter (Tx) to a receiver (Rx) it undergoes some changes. In simple terms the signal s(t) is scaled by a factor h(t) and noise n(t) is added at the receiver.
Read more60GHz Millimeter Wave Band is a band spread between 57GHz and 64GHz. This unlicensed band was first released in the US in 2001 but with limited allowance for transmit power (EIRP of 40dBm). Later on, in 2013, this limit was increased (EIRP of 82dBm) to allow for greater transmit power and larger range.
Read moreThe mmWave Channel It is well known that wireless signals at millimeter wave frequencies (mmWave) suffer from high path loss, which limits their range. In particular there are higher diffraction and penetration losses which makes reflected and scattered signals to be all the more important. Typical penetration losses for building materials vary from a few dBs to more than 40 dBs [1]. There is also absorption by the atmosphere which increases with frequency. But there are also some favorable bands where atmospheric losses are low (<1dB/km).
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