Hello, everyone!
As a supplement to the ONT basic knowledge, I begin to introduce a series of basic Wi-Fi knowledge.
Today, I will share knowledge about MIMO.
Wi-Fi signals are transmitted and received through antennas. What will help if the Wi-Fi is too slow? Add more antennas. This method of using multiple antennas to improve wireless transmission quality is called multiple-input multiple-output (MIMO). It has become an essential element of wireless communication standards including IEEE 802.11n (first Wi-Fi standards that introduced MIMO), substantially increasing the theoretical Wi-Fi rate.
Definition of MIMO
A MIMO antenna system includes m transmit antennas and n receive antennas. Signals are transmitted and received by multiple antennas at the transmit end and the receive end, enhancing communication quality. MIMO multiplies the capacity of a system channel by using multiple transmit antennas and receive antennas under the same spectrum resources and antenna transmit power. With this obvious advantage, MIMO is regarded as the core technology for next-generation mobile communication.
The following table lists the theoretical air interface rates supported by 802.11n/ac with different numbers of spatial streams.
MIMO (m×n) | IEEE 802.11n (64QAM，40MHz)(Mbit/s) | IEEE 802.11ac (256QAM，80MHz)(Mbit/s) |
1×1 | 150 | 433 |
2×2 | 300 | 867 |
3×3 | 450 | 1300 |
4×4 | 600 | 1733 |
MIMO Forms
Based on the numbers of transmit antennas or receive antennas, MIMO can be classified into SISO, SIMO, MISO, and MIMO.
Detailed descriptions are as follows:
Single-input single-output (SISO)
Single-input multiple-output (SIMO)
Multiple-input single-output (MISO)
In a broad sense, SIMO and MISO are MIMO variations.
Based on the number of users, MIMO can be classified into single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO).
More information on SU-MIMO and MU-MIMO will be shared in the next article.
That's all for today's basic knowledge sharing.
Welcome to leave a message at the bottom of the forum.
Thank you!
For more information about ONT basics, click the homepage of the topic.
