6G modulation and waveforms will start out looking just like 5G's

Huawei and Apple pushed to scrap the 6G Radio study outright — a proposal that would have stalled early standardization work before it produced a single technical baseline. It failed to gain traction against nearly every other contributing company, but the fact that two major players floated it shows how unsettled the business case for 6G's physical layer still feels, barely past 5G's own rollout.

Modulation is where consensus formed fastest: 6G will launch with the same QAM constellations as 5G — QPSK through 256QAM uplink, up to 1024QAM downlink for CP-OFDM, plus π/2-BPSK for DFT-s-OFDM. Higher-order options like 4096QAM downlink and 1024QAM uplink remain under study, but only if they clear tests on error vector magnitude, interference and fixed wireless access performance. Qualcomm and Apple are among those expected to run the simulations that will decide whether those denser constellations are worth the added receiver complexity.

Coding is heading the same direction, though less firmly. AT&T, Fujitsu, Ericsson, Samsung, Lenovo, LGE, Qualcomm, Intel and Nokia want LDPC carried over from 5G as the baseline, with extensions to hit peak rates Huawei pegs at 281–375 Gbps per base station; Huawei alone insists Polar coding stay on the table for data channels. A separate bloc — Xiaomi, Intel, NTT DOCOMO, CMCC and Ericsson — argues that since 6G's reliability target (1-10^-5 for high-reliability low-latency traffic) matches 5G's, no coding redesign is even necessary yet.

Waveform choices split along similar lines: 18 companies including Google, Nokia, OPPO, Samsung and Ericsson want to restrict 6G to OFDM-based signals and require any new waveform to prove a clear benefit over 5G NR; ZTE, Panasonic, MediaTek, LGE, Huawei and Apple want the door left open to non-OFDM candidates. One concrete idea did advance without much fight — LG Electronics, NEC, Lenovo and IIT Kanpur got support for studying DFT-s-OFDM on the downlink, aimed at stretching coverage for satellite and IoT links.

RAN1#123 is where the energy-efficiency work plan comes due: candidate technologies for network sleep modes and device wake-up signals must be finalized there, after companies agreed such features should be mandatory from 6G's first release rather than optional add-ons as in 5G. Separately, RAN#109's fronthaul proposal — backed by NTT DOCOMO, AT&T, Verizon and 14 others to leave the Radio Unit interface to the O-RAN Alliance — was only endorsed as base architecture text, not adopted as final policy, and will return for further debate.