Performance analysis of commercial multiple-input-multiple-output access point in distributed antenna system.

Area of Science:

• Wireless communication systems
• Radio-over-fiber technology
• Antenna array systems

Background:

• Distributed antenna systems (DAS) are crucial for extending wireless coverage.
• IEEE 802.11n 2x2 multiple-input-multiple-output (MIMO) offers enhanced data rates.
• Radio-over-fiber (RoF) technology enables high-bandwidth signal transmission over long distances.

Purpose of the Study:

• To experimentally evaluate the throughput performance of IEEE 802.11n 2x2 MIMO signals in a RoF-based DAS.
• To investigate the impact of varying fiber lengths and power imbalance on system throughput.
• To compare MIMO performance with spatial diversity in a DAS environment.

Main Methods:

• Experimental setup using a RoF-based DAS with IEEE 802.11n 2x2 MIMO and spatial diversity access points (APs).
• Throughput measurements conducted with wireless users in an office environment at various locations.
• System performance analyzed under different fiber length differences between remote antenna units (RAUs) and varying received power imbalances.

Main Results:

• MIMO signal throughput remains high for fiber length differences under 100m, decreasing significantly thereafter.
• Spatial diversity signals maintain high throughput even with a 150m fiber length difference.
• Throughput performance degrades when received power imbalance exceeds approximately 13 dB, impacting peak bit-rate coverage.

Conclusions:

• Fiber length difference is a critical factor affecting MIMO throughput in RoF-based DAS.
• Spatial diversity offers greater tolerance to fiber length differences compared to MIMO.
• A trade-off exists between the extent of wireless coverage for moderate bit-rates and the area achieving peak bit-rates due to power imbalance.