Imagine millions of people accessing phones, websites, apps, and more on daily commutes, morning coffee shop trips, and lazy weekend afternoons. The technology collectively making this nonstop high-speed access possible: multiplexing.
This technique lets many signals share bandwidth simultaneously. And evolutions in wireless multiplexing directly enable those leaps from early 3G calls to binge-watching video over 5G today. By allowing ever more data to flow over limited airwaves, it builds the bridges to each next-gen mobile network.
So how do seminal techniques like code division (CDMA) and now orthogonal frequency division (OFDM) actually work their magic? Let‘s explore the multiplexing secrets behind 3G, 4G and 5G – and demystify why OFDM remains the key formula leading the charge to 6G.
Multiplexing Drives Mobile Innovation
Before diving into differences across generations, it‘s helpful to step back and define what multiplexing means in telecommunications.
At the most basic level, multiplexing solves a numbers problem. Networks have finite bandwidth, but almost infinite users with data to send and receive. Whether phone calls, web pages, or streamed videos, that traffic doesn‘t neatly take turns – it competes and collides. Multiplexing allows efficient sharing of bandwidth across all these simultaneous needs.
As mobile demand grew exponentially, new multiplexing techniques emerged better capable of multiplying capacity over constrained cellular spectrum. Compare it to building carpool highway lanes. More vehicles can now use the same concrete real estate, getting to their destinations faster.
Now let‘s explore the two major technologies that powered this evolution over the past twenty-plus years of cellular advancements.
3G Calls upon Code Division (CDMA)
Remember the era of hotspotting primitive mobile phones to pull up black and white web pages on tiny displays? These early 2000s 3G networks, including cdmaOne and CDMA2000, did represent major progress – delivering always-on data alongside voice.
The multiplexing engine that made this possible: Code Division Multiple Access. CDMA allows multiple transmitters to overlay signals across the entire channel bandwidth by giving each one a unique numeric code to identify it. Signals appear noise-like, but receivers decode the right data stream by matching to authorized codes.
While CDMA efficiently packed more simultaneous information flows vs older networks, speed and capacity only stretched so far…
4G LTE Leaps Forward with OFDM
When iPhone and Android smartphones unleashed mobile apps and 24/7 social, people expected faster, more responsive experiences. LTE and 4G standards answered the call by introducing orthogonal frequency division multiplexing (OFDM).
Unlike CDMA‘s single wideband channel, OFDM divides data across many tightly-spaced sub-carrier frequencies transmitting in parallel. This helps combat interference and signal fading since effects vary across frequencies. OFDM‘s orthogonal subcarriers prevent overlap and maximize spectral efficiency.
With more optimized use of available spectrum real estate, OFDM facilitated speedier connections. Peak theoretical LTE rates shot to 300Mpbs down from CDMA‘s 3-4Mpbs peaks. Latency shrunk from hundreds of milliseconds to dozens. Music and movies could now stream smoothly, video calls grew crisp.
And most importantly, all those points of mobile innovation still connected back to the continuing quest to multiply capacity – thanks again to evolving multiplexing mastery.
5G Extends OFDM‘s Winning Model
Early 2020s hype proclaimed 5G the key to self-driving cars, robotic surgery, and more. Ambitious use cases aside, baseline 5G NR further elevated OFDM‘s flexibility to new levels.
Upgrades like scalable sub-carrier spacing cater to everything from Internet of Things sensors to virtual reality headsets. Advanced beamforming and MIMO antennas better separate user signal streams. Collectively, 5G wrings faster speeds out of the same limited frequencies using improved OFDM techniques.
Carriers continue relying on a proven foundation that balances bleeding-edge performance and global feasibility. And with billions of smartphones already packing 4G radios, this incremental 5G evolution helps smooth network transitions through software and hardware compatibility.
OFDM Continues Driving Multiplexing Improvements
Stepping back, it‘s clear OFDM struck communications gold – surging past CDMA once smartphone usage exploded demand for speed and responsiveness. Its balance of resilient performance and practical scalability makes OFDM almost destined to continue leading multiplexing innovations into 6G and beyond.
So what specific advantages coronate OFDM as the future multiplier underpinning orders of magnitude more mobile connectivity?
Adaptable Architecture – Flexibility is built into OFDM‘s structure. Just tweak spacing between subcarriers or symbols and trade off throughput, latency and coverage. This malleability caters optimization across diverse 5G use cases today while sustaining growth trajectories to 6G speeds.
Efficiency at Scale – By dividing spectrum into orthogonal parallel streams, OFDM avoids interference and makes the most of finite bandwidth across massive device densification. More users binge Netflix for less. Share spectrum smarter, not harder.
Resilience by Design – Wireless networks battle signal fading and distortion across distance, weather and congestion. OFDM‘s narrow subcarrier bands mostly dodge those effects so data reliably reaches its destination. Resilience translates into coverage, crucial for global 5G buildouts.
Simply put, no successors on the horizon can match OFDM‘s near-perfect balance of spectral efficiency, resilience and flexibility. Engineers will continue harnessing these properties to sustain orders of magnitude more devices and use cases. The multiplexing quest continues!
