Multipath Propagation - Multipath in wireless systems

Multipath Propagation Explained and What Causes Multipath Issues

In an ideal world for wireless communication there would be no object in-between or around the transmitting and receiving antennas. With no objects between the antennas, an ideal line of sight can be achieved with a proper setup. However, in the real world there are trees, buildings, and even the Earth that make a perfect line of sight just about impossible. Wireless signals reflect off these objects on their way from the transmitting antenna to the receiving antenna, creating multiple paths for the signal to travel. This phenomenon is known as multipath Propagation.

The receiving antenna receives the transmitted waves via multiple signals due to reflecting off of objects; therefore the signal is picked up multiple times. In the figure below there are two “signals” being transmitted, one has a direct line of sight and the other is reflected off an object.

Multipath propagation Picture

 

The reflected signal has a longer distance to travel than the direct line of sight, which could cause the signals to arrive at different phases and cause deconstructive interference. When this occurs the radio will see a weaker signal from the receiving antenna or could even cause the signal to drop out completely.

When your cell phone loses all of its available bars or your car radio cuts out completely, your issue may be multipath Propagation. Mostly everyone knows that by moving to a different location the signal will usually improve. With the idea of multipath Propagation, you are moving to a spot where the reflected signals off of everyday objects are coming to a point where the magnitude of the interference between them is lower. Stay tuned for next week’s #TechTuesday where we will discuss how multi-polarized antenna designs mitigate multipath propagation in wireless deployments!

MP Antenna, LTD. (http://www.mpantenna.com) is the exclusive developer and manufacturer of advanced Multi-Polarized antennas that are well-suited for a range of applications including public safety, wireless broadband systems, WiFi, WiMax, video monitoring systems, 3G, CDMA, GSM, PCS and LTE. The company’s product line improves signal penetration and connectivity in obstructed deployments providing increased data throughput, enhanced voice clarity and multi-path mitigation. MP Antenna’s products are protected under numerous US patents with many US and foreign patents pending. MP Antenna is privately held and designs and manufactures its products at their headquarters located near Cleveland, Ohio, USA.