Antennas – RAYmaps

Techrxiv Preprints

A Primer on Ray-Tracing: Shooting and Bouncing Ray Method Ray-tracing is a promising alternative for Radio Frequency Planning particularly in urban areas. There are two fundamental techniques used for ray-tracing namely Shooting and Bouncing Rays and Method of Images. In this paper, we focus on the former and present simulation results for an urban scenario in the city of Helsinki. We also give an insight into how the Shooting and Bouncing Ray method can be implemented using basic linear algebra techniques. We show that ray-tracing can be used to evaluate the performance improvement attained through electromagnetic reflectors. Finally, we close […]

September 28, 2022December 9, 20245G, Antennas, Capacity, Fundamentals

MIMO, SIMO and MISO Capacity in AWGN and Fading Environment

In a previous post we had discussed MIMO capacity in a fading environment and compared it to AWGN capacity. It sometimes feels unintuitive that fading capacity can be higher than AWGN capacity. If a signal is continuously fluctuating how is it possible that we are able to have reliable communication. But this is the remarkable feature of MIMO systems that they are able to achieve blazing speeds over an unreliable channel, at least theoretically.

April 22, 2020June 3, 20226G, Antennas

Reconfigurable Intelligent Surfaces Explained

Transmit or receive beamforming has been around for a long time and it works like magic. But there is a down side to it; antenna arrays require multiple RF chains which can be a power hungry and expensive solution. What if instead of aligning the copies at the transmitter or receiver we do it while the signal is under transmission in the channel; this is achieved through a Reconfigurable Intelligent Surface (RIS).

March 10, 2019June 4, 20225G, Fundamentals

60 GHz Millimeter Wave Band – Seems Like a Free Lunch

60GHz 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.

October 14, 2018December 22, 2018Antennas, BER Performance, Fundamentals, LTE

Massive MIMO Fundamentals and Code

Background Just like different frequency bands and time slots can be used to multiplex users, spatial domain can also be exploited to achieve the same result. It is well known that if there are 4 transmit antennas and 4 receive antennas then four simultaneous data streams can be transmitted over the air. This can be scaled up to 8 x 8 or in the extreme case to 128 x 128. When the number of transmit or receive antennas is greater than 100 we typically call it a Massive MIMO scenario and we need specialized signal processing techniques to handle this […]