Wireless/SDR Archives | Page 17 of 22

Channel hardening implies the channel flutucations due to small-scale fading smooth out

December 3, 2021 Wireless/SDR

On Massive MIMO, Channel Hardening and Favorable Propagation

Imagine an alien race looking at our planet from outside the solar system through a lens of time. They will notice one unmistakable direction. Our pursuit of MORE in everything. This tendency might be ingrained in the fundamental idea of life itself. To live is to grow. While our dreams for faster transportation face mechanical roadblocks from the laws of physics, technologies for faster communication are only bound by the laws of electromagnetics. Ever since we linked digital electronics to information exchange from one point to another without any physical medium, on-demand reception and transmission of data at any place

Blocks of a simple binary communication system

August 21, 2016 Wireless/SDR

A Simple Communication System

"The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point." Claude Shannon – A Mathematical Theory of Communication Our main purpose is to transfer digital information – which is a sequence of bits 0’s and 1’s – from one system to another through a communication channel. Let us return for a moment to the concept behind simple digital logic where logic 0 can be assigned to one voltage level while logic 1 to another. Provided the static discipline is followed, all our system electronics has to do is

Earth lies in the Goldilocks Zone of our solar system

November 4, 2021 Wireless/SDR

Diversity in Wireless Communication Systems

Diversity is one of those few ideas that are extremely dumb and extremely clever at the same time. It can be explained in one sentence as well as in a whole book. The basic idea, nevertheless, is quite simple. What is Diversity? Consider the following two different cases. Many phenomena in the world need a series of outcomes to succeed. For instance, for life to exist in the cold and dark universe, we need a star to provide energy as heat. A planet is also required as a home. Furthermore, this planet must reside in the Goldilocks Zone of that

MSK as a special case of both non-linear and linear modulation schemes

January 25, 2017 Wireless/SDR

Minimum Shift Keying (MSK) – A Tutorial

Minimum Shift Keying (MSK) is one of the most spectrally efficient modulation schemes available. Due to its constant envelope, it is resilient to non-linear distortion and was therefore chosen as the modulation technique for the GSM cell phone standard. MSK is a special case of Continuous-Phase Frequency Shift Keying (CPFSK) which is a special case of a general class of modulation schemes known as Continuous-Phase Modulation (CPM). It is worth noting that CPM (and hence CPFSK) is a non-linear modulation and hence by extension MSK is a non-linear modulation as well. Nevertheless, it can also be cast as a linear

Due to a Sampling Clock Offset (SCO), a fast Rx clock collects extra samples

January 10, 2022 Wireless/SDR

Effect of Sampling Clock Offset on a Single-Carrier Waveform

We have discussed before the distortion caused by a symbol timing offset on the communication waveform. We have also derived a maximum likelihood estimate of the clock phase offset. In this article, we describe the impact of a sampling clock offset in a single-carrier waveform, also commonly known as a clock frequency offset or timing drift. A clock frequency offset is defined as the rate mismatch between the Tx and Rx clocks. Just like a carrier phase and frequency offset, the clock used to sample the incoming continuous-time signal at a rate $T_S=1/F_S$ contains a phase and frequency offset as