MIMO Technology: Advantages and Disadvantages

This page covers the advantages and disadvantages of MIMO (Multiple Input Multiple Output) technology. It highlights the benefits and drawbacks of MIMO and provides links to various topics related to MIMO basics.

What is MIMO?

Introduction:

MIMO is a multiple antenna technology that utilizes more than one antenna at both the transmitter and receiver. This smart antenna technology transmits different sets of data symbols to achieve a higher data rate compared to SISO (Single Input Single Output) systems, which rely on a single antenna. The data received from multiple antennas undergoes processing through mathematical algorithms to recover the original transmitted information without errors. This approach helps in achieving higher data rates or throughput while maintaining a good Bit Error Rate (BER).

Other variations of multiple antenna technology include MISO (Multiple Input Single Output) and SIMO (Single Input Multiple Output). In MIMO, multiple antennas are used at both the transmit and receive ends, as illustrated in the figure-1 depicting a 2x2 MIMO mode. In MISO, multiple antennas are used at the transmit end, while a single antenna is used at the receive end. Conversely, in SIMO, a single antenna is used at the transmit end, and multiple antennas are used at the receive end.

There are numerous MIMO variants based on antenna configurations at the transmit and receive ends, such as 4x4, 8x8, and so on.

Benefits or Advantages of MIMO

Following are the benefits of MIMO:

• Higher Data Rate: Achieved through multiple antennas and Spatial Multiplexing (SM) techniques, resulting in higher downlink and uplink throughput.

• Reduced BER: Advanced signal processing algorithms applied to the received data symbols from multiple antennas help reduce the Bit Error Rate (BER).

• Extended Cell Coverage: Techniques like Space-Time Block Coding (STBC) and Beamforming (BF) extend cell coverage when employed in MIMO systems.

• Minimized Fading Effects: MIMO-based systems minimize fading effects experienced by information traveling between the transmitter and receiver, thanks to various diversity techniques like time, frequency, and space diversity.

• Lower Susceptibility to Tapping: Multiple antennas and algorithms reduce the likelihood of unauthorized interception.

• High QoS: MIMO systems offer high Quality of Service (QoS) with increased spectral efficiency and data rates.

• Wide Coverage & High Subscriber Capacity: The wide coverage supported by MIMO systems facilitates supporting a large number of subscribers per cell.

• Standard Adoption: MIMO is widely adopted in the latest wireless standards, including WLAN (802.11n, 802.11ac etc.), WiMAX (IEEE 802.16e), LTE, and LTE-Advanced.

Drawbacks or Disadvantages of MIMO

The following are the disadvantages of MIMO:

• Higher Resource Requirements & Hardware Complexity: Compared to single antenna systems, MIMO requires more resources and has higher hardware complexity. Each antenna needs individual RF units for radio signal processing. Additionally, advanced DSP chips are needed to run advanced mathematical signal processing algorithms.

• Increased Power Requirements: More hardware resources increase power consumption. Battery drain is faster due to the processing of complex and computationally intensive signal processing algorithms, which reduces battery life.

• Higher Cost: MIMO-based systems are more expensive than single antenna systems due to increased hardware and advanced software requirements.