Toward 6G: MIMO Continues to Evolve, Foundational Innovation Unlocks Long-Term Value

When each generation of mobile communication standards begins, people's imagination often starts with "disruption." But when technological complexity and industry investment have accumulated to today's scale, generational evolution ultimately returns to a simple proposition: the balance between technology and business.

This industry-wide consensus is reflected in the 6G standardization process: it is built on top of 5G's key foundational technologies rather than starting from scratch.

Judging from the current state of standardization, a notable feature of 6G is not disruption but continuity.

In June of this year, the 3GPP RAN plenary finalized the Release 21 timeline. Among other things, 5G baseline technologies such as waveform, modulation, frame structure, and channel coding are carried forward. 6G's continuation of 5G is both a pragmatic technical choice and an inevitable commercial path. For industry participants, the long-term accumulation they built around foundational connectivity technologies in the 3G, 4G, and 5G eras is becoming the direct starting point for participating in 6G standard evolution.

Continuity, not disruption: the pragmatic underpinning of 6G

As early as the 3GPP RAN1 meetings in August and October 2025, the industry reached preliminary foundational decisions on waveform, modulation, frame structure, and channel coding, which were further confirmed at the June plenary: retain proven 5G technologies and extend them further only where there are quantifiable gains in dimensions such as spectral efficiency, energy consumption, coverage, and area efficiency.

At the waveform level, CP-OFDM and DFT-s-OFDM continue to be used as the baseline schemes for the uplink and downlink; at the modulation level, the 5G NR constellation structure is retained; at the frame structure and numerology level, the 5G NR slot framework and scalable numerology are reused; at the channel coding level, LDPC continues to be used for data channels and Polar coding for control channels.

These underlying inventive technologies that underpin the definition of 5G NR have been validated globally and together form the core mechanisms of the 6G air interface, including how spectrum is used, how signals are encoded, and how user equipment (such as smartphones or other types of terminals) communicates with the network. This also shows that 5G to 6G itself has strong continuity, and this continuity further reflects the long-term value of foundational technological innovation.

But it must be emphasized that 6G's continuation of 5G does not mean performance gains will stagnate. From the outset, 6G's design took into account co-evolution with AI and distributed computing. For the sustained uplink-intensive traffic scenarios spawned by AI and agents, 6G will extend DFT-s-OFDM from the single-layer capability of the 5G era to support multi-layer transmission, with up to two layers of uplink transmission. These enhancements are important for extended reality (XR), real-time video, sensing, and AI-driven workloads.

In addition, around the new 7GHz band, the network side can support channel bandwidths of up to 400MHz, a significant leap compared with the 100MHz commonly seen in 5G mid-band. These capabilities support the evolution of wireless communication systems toward more dynamic, multi-terminal collaborative, and compute-driven application scenarios without relying on carrier aggregation technology.

Therefore, 6G's continuation of the 5G technology baseline is not a conservative move born of weak innovation, but a rational choice of a mature path validated globally: for terminal and network equipment manufacturers, it reduces the technical and investment uncertainty of generational transition; for companies deeply engaged in underlying technologies, technical assets accumulated over many years can continue to release value in the 6G era.

MIMO: moving toward 6G through continuous evolution

If the overall carryover of 5G foundational technologies outlines the contours of 6G, then MIMO provides another sample for observing technological continuity and evolution.

MIMO has long been a foundational technology spanning multiple generations of cellular communication systems, and it continues to evolve as networks continue to expand capacity, coverage, and performance.

In the 4G era, MIMO antenna schemes greatly improved data rates and reliability; in the 5G era, MIMO schemes evolved toward "massive MIMO" technology, greatly expanding network coverage and improving network performance, data transmission rates, and reliability.

In 6G, MIMO evolves from a highly impactful feature into a system-level design framework spanning all 6G frequency bands. Giga-MIMO leverages denser antenna arrays and higher spatial reuse to extend massive MIMO to the upper mid-band of 6-8 GHz, allowing the system to scale the number of antennas proportionally without increasing panel size, compensating for higher path loss with narrower beams and delivering further improvements in network performance and user experience.

Qualcomm's system evaluations show that adding an upper mid-band layer can achieve about 5x network load expansion and about 3x average user throughput improvement while maintaining overall user performance gains. Conventional 5G multi-user MIMO systems can support up to 16 layers in the downlink, while with better spatial resolution, 6G Giga-MIMO can support up to 32 downlink layers, delivering both network performance and user experience improvements.

The significance of 6G Giga-MIMO lies not only in higher peak capacity, but in combining wider bandwidth, denser antenna arrays, and spatial domain expansion capabilities while taking into account deployable infrastructure constraints, turning upper mid-band spectrum into a practical wide-area capacity layer.

In addition, in 6G, integrated sensing and communication (ISAC) extends MIMO beyond communications, enabling base stations to reuse communication infrastructure, reference signals, and waveforms for detecting, locating, tracking, and classifying passive targets. This brings innovative applications and services including real-time detection and classification of aerial drones and high-fidelity wireless digital twins.

Looking back at this path of continuous MIMO evolution, each step stands on the foundation validated by the previous generation and is gradually formed through sustained research, system-level design, and multi-generational standardization. There is no tearing down and starting over, but layer upon layer of accumulation—this is the direct embodiment of 6G's "continuity rather than disruption."

Foundational innovation releases long-term value

Mobile communications may be one of the industries with the longest return cycles: for a generation of standards, from research to commercialization, the cycle is measured in decades; and the life cycle of each technology that is "carried forward" in a standard is far longer than that. Before being written into specifications, they have gone through years of research, repeated validation, and polishing through multiple generations of standardization.

If 6G's choice to continuously evolve on top of 5G core foundational technologies reflects industry consensus, then behind this consensus is also the industry's long-term sustained investment in and accumulation of foundational technologies. Qualcomm is one of the long-term participants.

Since its founding, Qualcomm has always focused on long-term foundational research. Over the past decade, Qualcomm's investment in R&D has exceeded US$70 billion.

In the 5G New Radio specifications, Qualcomm contributed important foundational technological inventions including scalable OFDM-based air interface, flexible slot-based framework, advanced channel coding, and massive MIMO, becoming important components supporting the "tree of 5G." In 6G MIMO, Qualcomm is shaping the evolution direction of 6G MIMO with Giga-MIMO, energy-efficient system design, and end-to-end prototype validation. Around the three pillars of connectivity, computing, and sensing, Qualcomm is preparing for gradual 6G commercialization starting in 2029, moving from massive MIMO to ultra-massive Giga-MIMO, and advancing frontier directions such as non-terrestrial networks and integrated sensing and communication.

From 3G and 4G to 5G, and now to 6G, whose standardization process is underway, mobile communication technology has always been built on sustained research, validation, and evolution. For Qualcomm, the foundational technology accumulation it has built across multiple generations of mobile communications has also become an important basis for continuing 6G research. As 6G standardization gradually advances, Qualcomm is also continuing to advance key technology research, standard evolution, and exploration of the industry ecosystem.