What is the difference between MIMO and SISO?

MIMO and SISO are two antenna technologies used in wireless networks. MIMO stands for Multiple Input Multiple Output, and it is one of the key building blocks of 4G LTE and 5G NR networks. MIMO is also a key feature within modern WiFi networks such as WiFi6. SISO, on the other hand, stands for Single Input Single Output, and it is essentially the most basic antenna technology used by wireless networks to communicate from a transmitter to a receiver.

MIMO (Multiple Input Multiple Output) is a modern antenna technology that employs multiple antenna elements at the transmitter and receiver; SISO (Single Input Single Output) is an older antenna technology that uses one antenna at the transmitter and one at the receiver. 4G and 5G networks use MIMO.

MIMO uses multiple antennas

MIMO – Multiple Input Multiple Output is an antenna system that employs multiple antenna elements at the transmitter and the receiver. In MIMO, the transmitter antenna is made of multiple antenna elements that transmit the signal. Similarly, at the receiving end, the receiver antenna also has multiple antenna elements to pick up the signal sent by the transmitter. MIMO systems use three key capabilities, including spatial multiplexing, spatial diversity, and beamforming, to improve the radio signal quality and the achievable data rates.

SISO uses single antennas

SISO – Single Input Single Output is the most straightforward antenna technology that uses one antenna at the transmitter and one at the receiver. When a radio signal travels in the air, it comes across many obstructions such as buildings, mountains, trees, poles, cables, reflecting surfaces, etc. All of these obstructions have a negative impact on the strength of the radio signal. Radio signals are electromagnetic waves, and when they encounter any obstacles, they undergo a scattering effect. As a result, the radio signal can become very weak or “fade” when it arrives from the transmitter to the receiver. Since SISO systems only have one antenna to receive the signal, the receiver antenna cannot do anything if the signal fades during transmission due to taking multiple paths. When this multipath fading happens, the signal quality drops and errors can get introduced into the signal. One of the options used by mobile operators to deal with multipath fading is spatial diversity, where the cellular base station employs multiple antennas to receive the signal coming from mobile phones.

Conclusion

MIMO and SISO are antenna technologies used by wireless networks. MIMO stands for Multiple Input Multiple Output and uses multiple antenna elements at the transmitter and the receiver. SISO stands for Single Input Single Output, and it uses one antenna at the transmitter and one at the receiver. SISO is an older technology, whereas MIMO is a modern technology used by the latest wireless networks such as 4G LTE, 5G NR and WiFi6.

Here are some helpful downloads

Thank you for reading this post, I hope it helped you in developing a better understanding of cellular networks. Sometimes, we need some extra support, especially when preparing for a new job, studying a new topic, or maybe just buying a new phone. Whatever you are trying to do, here are some downloads that can help you:

Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy, which explains the network nodes, e.g., BTS, MSC, GGSN etc.

Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and the challenges considering how quickly the industry evolves. The bigger picture comes from experience, which is why I’ve carefully put together a few slides to get you started in no time. So if you work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on the product overview and product roadmap.

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