Phones keep old SRS hopping pattern as chipmakers beat Ericsson and Huawei

Ericsson, Huawei, Xiaomi and NTT DOCOMO wanted a new frequency-hopping pattern for the Sounding Reference Signal (SRS) that lets a base station measure the uplink channel — Ericsson cited simulations showing 'non-negligible gains in throughput.' MediaTek, Qualcomm, Nokia, Samsung, Apple and eight more companies rejected it, arguing a new pattern would make it harder to multiplex with older Release-17 phones on the same cell. The 13-vs-9 split was not resolved this quarter, so networks keep the legacy pseudorandom pattern for now.

One dispute did close: for SRS repetition symbols hopping within a single frequency chunk, 3GPP locked in exact starting-position patterns (for example {0,0,1,1} and {1,1,0,0} when two positions are used) and ruled that the number of repeated symbols must always be a whole multiple of the number of starting positions — CATT, Sony and Huawei pushed this through over Samsung and InterDigital, who called it redundant. Chipset makers now have a fixed recipe instead of an open-ended design question. Whether phones must keep the signal's phase steady across those hops was left to each manufacturer to decide, not mandated in the spec.

For phones just connecting to the network, companies including Samsung, Huawei, Apple, Qualcomm and MediaTek proposed timing early channel measurements 3 milliseconds after the phone's connection acknowledgment, and letting the network dynamically set the delay for antenna-switching SRS, CSI-RS and tracking signals via a MAC command rather than a fixed broadcast setting. Neither proposal was formally adopted, but RAN1 did confirm concrete limits: early channel sounding will support up to 32 antenna ports and up to 2 tracking-signal bursts, and this early signal will be locked to the same beam the phone used to first access the cell.

A separate MIMO feedback fight: Ofinno proposed a 1-bit flag so phones could report when their current beam is already the strongest, avoiding a negative-number problem in the reporting format. Google, Spreadtrum, ZTE, Xiaomi, Samsung, Nokia, Ericsson, Huawei and NTT DOCOMO — nine companies against one — rejected it, saying phones should simply avoid triggering a report in that case rather than adding a new signaling bit. Meanwhile OPPO, Xiaomi and Samsung lost a separate 3-vs-7 vote over when to reset beam-event counters, with Ericsson, Huawei, Nokia and others winning support for resetting counters whenever the network reconfigures measurement resources.

Watch for the cross-slot SRS timing fight to resume: Samsung, ZTE and Ericsson want a 1-bit flag marking which of two slots an SRS resource falls in, Xiaomi wants to stretch an existing offset parameter, and Sony wants the position implied by resource order — none were down-selected this quarter, and the choice will decide how much signaling overhead networks pay every time a phone reports channel quality across a slot boundary.