Explained

The 802.11ax brings important features, focusing on network capacity, latency and range. High data rates are still in the picture, but rather in the background. Introducing OFDMA and using MU-MIMO allows AP to schedule data for multiple users simultaneously. This way, latency can be greatly decreased. With the new colors of the channels, frequencies can be spatially reused.

Introduction to Wi-Fi Security Distributing data using wireless medium means that anyone can capture the signal. There is no boundary, like in case of cable communication, which prevents unwanted access. This means we must take other security measures. In this blogpost we will review current algorithms providing Wi-Fi security and we will take a sneak […]

Introduction First Wi-Fi networks appeared in late 90s and many of us use them ever since. During these years we could observe significant increase of throughput, but what is important, it is not only due to the ISP providing better link. Wi-Fi standard also evolved to keep up with the higher throughputs. If there will […]

Introduction Communication between devices is often discussed on link level, which means that the focus is on how two end points exchange information: what is the protocol, waveform, timing in sending messages etc. This however, does not take into account that there are other devices wanting to use the medium. Using the same medium by […]

After discussing the main wireless transmission concept (How wireless works?), main channel propagation phenomena (What is pathloss? and What is shadowing?), and antenna configurations (What is MIMO?), let’s now take a look at one of the most commonly used transmission scheme nowadays, namely Orthogonal Frequency Division Multiplexing (OFDM). But, before we explain why do we […]

To explain how does a switch work, let me make an introduction to the subject by explaining background of TCP/IP stack layers, frame and the purpose of switch. This will help you to understand the exact operation of switch which is the main agenda here. To allow communication between billions of computer devices, intermediate network […]

What is wireless? Wireless is a way of transporting signals without any wires or optic fibers. Signals propagate through free space in this case. Often, the term wireless, refers to wireless communication. This is a way of transferring information between devices that are not connected with wires. Where is wireless used? Before learning how wireless […]

Introduction to pathloss A transmitter generally radiates the signal which has a specific power using an antenna. This signal travels in the environment as an electromagnetic wave and suffers from a phenomenon known as pathloss. This wave isn’t aware of the exact route to the receiver and hence once transmitted propagates in the direction where […]

Shadowing happens, when there is a large object such as a hill or a building that obscures the main signal path between the transmitter and the receiver. This is known as shadowing (shadow-fading), or slow-fading, as it makes the signal level slowly changing with the time (as e.g., the building is “always” there).

In MIMO systems, we have multiple antennas at the transmitter, multiple antennas at the receiver and a radio channel in-between. This is where inputs and outputs comes into play – i.e., we have Multiple Inputs (input signals TO the wireless channel) and Multiple Outputs (output signals FROM the wireless channel).