MIMO overview — spatial multiplexing, diversity, and capacity intuition
Multiple-input multiple-output wireless: diversity vs multiplexing, channel matrix rank, and where MIMO shows up in LTE/NR.
MIMO
Maximum ratio combining (MRC) — receive diversity that maximizes SNR
MRC weights each diversity branch by its channel gain to maximize post-combiner SNR — formula, intuition, and comparison to selection combining.
Selection combining — pick the strongest receive branch
MIMO & Diversity (same on every page in this path) 1. Diversity vs multiplexing → 2. SIMO models → 3. Selection combining (you are here) → 4. MRC → 5. MIMO overview Tools: Diversity & multiplexing demo Lesson 5 of 6. After SIMO models, selection combining is the intuitive baseline. Finish with maximum-ratio combining, which … Read more
SIMO receive-diversity channel models — from one transmit antenna to several receivers
MIMO & Diversity (same on every page in this path) 1. Diversity vs multiplexing → 2. SIMO models (you are here) → 3. Selection combining → 4. MRC → 5. MIMO overview Tools: Diversity & multiplexing demo Lesson 4 of 6. Fading is random — multiple receive antennas give you options. Next: the simplest combiner, … Read more
Model and characterize MIMO channels
MIMO / Capacity Lab path:MIMO overview → Characterize MIMO channels → SISO capacity → Ergodic SISO capacity → MIMO capacityTool: Shannon–Hartley capacity calculator Two flavors of MIMO implementation – spatial multiplexing and spatial diversity – were discussed in the previous article. In that, it was mentioned that the reliability of a MIMO system is governed … Read more
Diversity techniques and spatial multiplexing
MIMO & Diversity Lab path: 1. Diversity & spatial multiplexing (this article) → 2. SIMO models → 3. Selection combining → 4. Maximum ratio combining → 5. MIMO overview Interactive tool: Diversity vs spatial multiplexing demo In one sentence: Extra antennas can be spent in two ways — to make a link more reliable (diversity) … Read more
Introduction to Multiple Antenna Systems
Regarded as a breakthrough in wireless communication system design, multiple antenna systems fuel the ever increasing data rate requirements of advanced technologies like UMTS, LTE, WLAN etc. Multiple antenna systems come in different flavors and are generally referred as Multiple Input Multiple Output systems (MIMO). In a series of articles, I intend to cover various … Read more