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Glossary

RACH (Random Access Channel) in 3GPP: meaning and where it is specified

Published 2026-10-16Updated 2026-10-16

At a glance

Term
RACH
Stands for
Random Access Channel
Defined in
3GPP TR 21.905 V19.2.0, clause 4
Used in
TS 25.211, TS 25.212, TS 25.221

In plain words

RACH stands for Random Access Channel, and TS 25.221 describes it as "an up link transport channel that is used to carry control information from mobile station". In plain terms, it carries control information from a mobile station over an uplink transport channel. TS 25.211 uses RACH in a clause heading, while TS 25.212 includes a passage about a RACH CCTrCH.

Source: 3GPP TS 25.221 V17.0.0, clause 4.1.2.4. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.221/25221-h00.zip

Sources

  1. 3GPP TR 21.905 V19.2.0, clause 4. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/21_series/21.905/21905-j20.zip
  2. 3GPP TS 25.221 V17.0.0, clause 4.1.2.4. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.221/25221-h00.zip
  3. 3GPP TS 25.211 V19.0.0, clause 4.1.2.4. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.211/25211-j00.zip
  4. 3GPP TS 25.212 V19.0.0, clause 4.2.13.2. © 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TSDSI, TTA, TTC). Official text: https://www.3gpp.org/ftp/Specs/archive/25_series/25.212/25212-j00.zip

How this page was made

The facts box comes straight from the 3GPP TDoc list and specification archive as indexed by 3GPP Scout. An AI model (GPT-6 Luna) wrote the paragraph and named the source of each sentence. Code checked every quote word for word against the stored source text and every number against the cited source. A second AI model from another company (Claude Opus 5.5) reviewed the paragraph against the same sources. The 3GPP documents themselves govern.