-
Notifications
You must be signed in to change notification settings - Fork 27
WMABS SP 001 System Requirements Specification
TECHNICAL SPECIFICATION
────────────────────────────────────────
WMABS-SP-001
Wi-Fi Mesh Access and Backhaul Subsystem
System Requirements Specification for Standards-Based Wireless Mesh Access and Multi-Hop Backhaul in License-Exempt Spectrum
────────────────────────────────────────
Document ID: WMABS-SP-001
Version: 0.1 (Draft)
Date: 2026-02-09
Classification: Internal / Restricted
Status: DRAFT
CONFIDENTIAL --- FOR AUTHORISED DISTRIBUTION ONLY
Document Control
Revision History
Version Date Author Description
0.1 2026-02-09 H. Martin Initial draft for internal review
Review and Approval
Role Name Date Signature
Systems Architect
RF Engineering
Lead
Regulatory
Compliance
Programme Manager
Conventions
This document uses the keywords SHALL, SHALL NOT, SHOULD, SHOULD NOT, MAY, and MUST as defined in IETF RFC 2119. The use of these keywords indicates a normative requirement or permission level as follows:
Keyword Meaning
SHALL / MUST An absolute requirement of the specification. Non-compliance renders an implementation non-conformant.
SHALL NOT An absolute prohibition. The specified behaviour is explicitly forbidden.
SHOULD A recommended behaviour. Deviation is permitted only with documented technical justification.
MAY An optional capability. Implementations are free to include or omit the feature.
Table of Contents
This document defines the system-level requirements for the Wi-Fi Mesh Access and Backhaul Subsystem (WMABS). WMABS provides a standards-based wireless networking layer that delivers local access connectivity for client devices and multi-hop backhaul between mesh nodes, using exclusively license-exempt radio spectrum.
The specification is intended to serve as the normative reference for hardware selection, firmware development, integration testing, and regulatory certification activities across all deployment jurisdictions.
This specification covers the following functional areas of WMABS:
-
Radio technology selection and PHY/MAC layer requirements based on IEEE 802.11ax (Wi-Fi 6) and optional IEEE 802.11ax extensions in the 6 GHz band (Wi-Fi 6E)
-
Spectrum utilisation constraints, including frequency band selection, maximum EIRP, DFS, TPC, and indoor/outdoor usage classifications
-
Configurable regulatory profiles enabling multi-jurisdiction deployment without hardware modification
-
Operational environment definitions for indoor baseline, outdoor baseline, and extended outdoor (Phase B) deployments
-
Mesh network topology, routing protocol requirements, and multi-hop backhaul architecture
-
Channelisation strategy and performance constraints for throughput, latency, and co-channel coexistence
-
Security architecture including WPA3-Personal (SAE), WPA3-Enterprise (802.1X), and traffic domain separation
-
Normative regulatory boundary conditions governing antenna configurations, EIRP modifications, and deployment classification changes
This specification does not cover application-layer services, captive portal design, network management protocols, or end-user device requirements.
WMABS is designed for deployment in environments where traditional wired backhaul is impractical, cost-prohibitive, or unavailable. Target deployment scenarios include dense urban mesh networks, temporary event infrastructure, rural connectivity extensions, and building-to-building campus links using standard Wi-Fi equipment.
All requirements in this document apply to WMABS node hardware and firmware. Requirements marked as Phase B apply only when the Phase B operational mode is explicitly enabled via a validated regulatory profile.
This specification is intended to be read alongside the following companion documents, where applicable:
-
WMABS-IF-001: Node Management Interface Specification (planned)
-
WMABS-TP-001: Test Plan and Verification Procedures (planned)
-
WMABS-RP-001: Regulatory Profile Registry (planned)
The following documents are referenced normatively within this specification. For dated references, only the cited edition applies. For undated references, the latest edition (including amendments) applies.
Reference Title
IEEE 802.11-2020 IEEE Standard for Information Technology --- Telecommunications and Information Exchange Between Systems --- Local and Metropolitan Area Networks --- Specific Requirements --- Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications
IEEE 802.11ax-2021 IEEE Standard for Information Technology --- Amendment 1: Enhancements for High-Efficiency WLAN (Wi-Fi 6)
IEEE 802.11s-2011 IEEE Standard for Information Technology --- Amendment 10: Mesh Networking
IEEE 802.11w-2009 IEEE Standard for Information Technology --- Amendment 4: Protected Management Frames
IEEE 802.11i-2004 IEEE Standard for Information Technology --- Amendment 6: Medium Access Control (MAC) Security Enhancements
IEEE 802.1X-2020 IEEE Standard for Local and Metropolitan Area Networks --- Port-Based Network Access Control
IETF RFC 2119 Key Words for Use in RFCs to Indicate Requirement Levels (S. Bradner, March 1997)
WPA3 Specification Wi-Fi Alliance: Wi-Fi Protected Access 3 (WPA3) v3.3 Specification, Version 3.3
ETSI EN 301 893 5 GHz RLAN; Harmonised Standard covering the essential requirements of the Radio Equipment Directive
FCC 47 CFR Part 15 United States Federal Communications Commission --- Radio Frequency Devices, Subpart C and E
For the purposes of this document, the following terms and definitions apply.
Access Point (AP): A WMABS node operating in infrastructure mode, providing connectivity to client stations (STAs) via one or more BSSs.
Backhaul Link: A wireless link between two WMABS mesh nodes used to relay traffic toward or away from a gateway node.
Gateway Node: A WMABS node that provides connectivity between the wireless mesh network and an upstream wired or wireless network.
Mesh Node: A WMABS device participating in the mesh topology, capable of relaying traffic on behalf of other nodes.
Mesh Portal: A mesh node that bridges traffic between the mesh network and a non-mesh network (e.g., Ethernet LAN).
Regulatory Profile: A machine-readable configuration dataset that encodes the radio-frequency constraints applicable to a specific country or regulatory domain.
Phase A (Baseline): The default operational mode of WMABS, using internal antennas and standard EIRP levels suitable for general indoor and outdoor deployment.
Phase B (Extended Outdoor): An optional extension to WMABS permitting external antennas, directional antennas, and elevated mounting configurations, subject to per-country regulatory validation.
Abbreviation Definition
AP Access Point
BSS Basic Service Set
DFS Dynamic Frequency Selection
EIRP Equivalent Isotropically Radiated Power
HWMP Hybrid Wireless Mesh Protocol
MAC Medium Access Control
MU-MIMO Multi-User Multiple-Input Multiple-Output
OFDMA Orthogonal Frequency-Division Multiple Access
PHY Physical Layer
PMF Protected Management Frames
RLAN Radio Local Area Network
SAE Simultaneous Authentication of Equals
STA Station (client device)
TPC Transmit Power Control
TWT Target Wake Time
UNII Unlicensed National Information Infrastructure
WPA3 Wi-Fi Protected Access 3
This section defines the radio interface requirements for all WMABS nodes.
[RT-001] WMABS SHALL operate exclusively using IEEE 802.11 Radio Local Area Network (RLAN) standards.
[RT-002] WMABS SHALL implement IEEE 802.11ax (Wi-Fi 6) as the baseline physical layer (PHY) and medium access control (MAC) layer.
[RT-003] All WMABS nodes SHALL support Orthogonal Frequency-Division Multiple Access (OFDMA) for both uplink and downlink transmissions as defined in IEEE 802.11ax.
[RT-004] WMABS nodes SHOULD support Multi-User MIMO (MU-MIMO) for simultaneous multi-client communication where hardware capabilities permit.
[RT-005] WMABS SHALL support dual-band operation in the 2.4 GHz ISM band (2.400--2.4835 GHz) and the 5 GHz UNII bands (5.150--5.850 GHz).
[RT-006] WMABS MAY support operation in the 6 GHz band (5.925--7.125 GHz, Wi-Fi 6E) only in jurisdictions where such operation is explicitly permitted by the applicable regulatory authority.
[RT-007] WMABS SHALL NOT require any form of licensed spectrum allocation under any operating mode, in any deployment configuration.
The following PHY layer capabilities define the performance envelope for WMABS nodes:
[RT-008] WMABS SHALL support BSS Colouring (as defined in IEEE 802.11ax) to improve spatial reuse in dense deployments.
[RT-009] WMABS SHOULD support Target Wake Time (TWT) to enable coordinated sleep scheduling for battery-powered client devices.
[RT-010] WMABS nodes SHALL support a minimum of 2 spatial streams (2x2 MIMO) per radio chain.
[RT-011] WMABS nodes SHOULD support 1024-QAM modulation where link conditions and regulatory constraints permit.
Note: The use of 1024-QAM is dependent on signal-to-noise ratio conditions and is not guaranteed in all deployment environments. This modulation scheme is defined as an optional capability within IEEE 802.11ax.
[SR-001] WMABS SHALL operate solely within license-exempt spectrum as designated by the regulatory authority of the deployment country.
[SR-002] WMABS SHALL NOT transmit outside the frequency ranges permitted for the specific country of deployment.
[SR-003] WMABS SHALL comply with all applicable national and regional regulations governing maximum Equivalent Isotropically Radiated Power (EIRP), channel bandwidth, indoor and outdoor usage constraints, Dynamic Frequency Selection (DFS) where required, and Transmit Power Control (TPC) where required.
Regulatory profiles provide a structured mechanism for encoding jurisdiction-specific radio-frequency constraints into a machine-readable format. This approach enables multi-jurisdiction deployment from a common hardware and firmware platform.
[SR-004] WMABS implementations MUST support configurable regulatory profiles.
[SR-005] A regulatory profile SHALL define, at minimum: allowed frequency bands and sub-bands, maximum EIRP per band, indoor-only or outdoor-permitted operation classification, DFS requirements (including channel availability check time and non-occupancy period), and TPC requirements.
[SR-006] WMABS MUST enforce the active regulatory profile at runtime. No transmission SHALL occur outside the constraints defined by the active profile.
[SR-007] WMABS SHALL support runtime switching of regulatory profiles without requiring a firmware update or hardware modification.
[SR-008] The active regulatory profile SHALL be cryptographically authenticated to prevent tampering or unauthorised modification.
See Annex A for the normative regulatory profile data schema.
Where mandated by the active regulatory profile, WMABS nodes operating in DFS-required sub-bands SHALL implement the following:
[SR-009] WMABS SHALL perform a Channel Availability Check (CAC) of at least 60 seconds before transmitting on a DFS channel, or as specified by the applicable regulation.
[SR-010] WMABS SHALL detect radar signals during operation and vacate the channel within the time period mandated by the applicable regulation (typically 10 seconds for ETSI, 260 ms for FCC).
[SR-011] After radar detection, WMABS SHALL observe a Non-Occupancy Period (NOP) of at least 30 minutes before re-using the vacated channel.
[SR-012] Where TPC is required, WMABS SHALL dynamically adjust transmit power based on link conditions, reducing EIRP to the minimum level necessary for reliable communication.
[OE-001] WMABS SHALL support indoor operation using internal (integrated) antennas.
[OE-002] Indoor operation SHALL be considered the baseline deployment mode for all WMABS nodes.
[OE-003] Indoor operation SHALL be compliant in all jurisdictions that permit standard RLAN devices operating in the 2.4 GHz and 5 GHz bands.
[OE-004] WMABS nodes deployed indoors SHOULD support automatic channel selection to avoid co-channel interference with neighbouring access points.
[OE-005] WMABS SHALL support outdoor operation using internal antennas where permitted by local regulation.
[OE-006] Outdoor operation SHALL enforce all applicable EIRP, DFS, and TPC constraints as defined by the active regulatory profile.
[OE-007] Outdoor nodes SHALL meet the environmental protection requirements defined in the hardware specification (IP rating, operating temperature range, humidity tolerance).
[OE-008] Outdoor operation SHALL be considered part of the Phase A (baseline) system.
Phase B defines an optional extension to the baseline WMABS operational envelope. Phase B configurations are intended for scenarios requiring increased link range or throughput beyond what is achievable with internal antennas.
[OE-009] Phase B SHALL be defined as an optional extension to WMABS.
Phase B configurations MAY include:
-
External antennas (omnidirectional or sectoral)
-
Directional antennas (e.g., panel or parabolic dish)
-
Elevated mounting locations (rooftop, pole-mount, tower)
-
Point-to-point (PtP) or point-to-multipoint (PtMP) link configurations
[OE-010] Phase B SHALL remain within license-exempt spectrum at all times.
[OE-011] Phase B SHALL enforce combined transmitter power and antenna gain limits such that the total EIRP does not exceed the maximum permitted by the active regulatory profile.
[OE-012] Phase B SHALL be disabled by default and SHALL NOT be activated unless explicitly enabled by a validated regulatory profile.
[OE-013] Phase B deployments MUST undergo per-country regulatory validation before operational use. Evidence of this validation SHALL be retained as part of the deployment documentation.
[MR-001] WMABS SHALL support point-to-multipoint connectivity between WMABS nodes and client devices (stations).
[MR-002] WMABS SHALL support multi-hop mesh connectivity between WMABS nodes for backhaul traffic.
[MR-003] A WMABS node MAY simultaneously operate as an access point for client devices and as a mesh relay for upstream or downstream backhaul traffic.
[MR-004] The mesh topology SHALL support a minimum of one gateway node that provides connectivity to an upstream network (e.g., wired Ethernet, fibre, or cellular backhaul).
Mesh routing is the mechanism by which WMABS nodes discover paths, select optimal routes, and relay traffic across the mesh network.
[MR-005] Mesh routing SHALL be implemented using one of the following: (a) IEEE 802.11s Hybrid Wireless Mesh Protocol (HWMP) as defined in IEEE 802.11-2020, or (b) a vendor-specific mesh routing protocol operating above the IEEE 802.11 MAC layer.
[MR-006] Where IEEE 802.11s HWMP is implemented, WMABS SHALL support both on-demand (reactive) and proactive tree-based path selection.
[MR-007] Vendor-specific mesh routing implementations MUST NOT violate IEEE 802.11 RF compliance requirements.
[MR-008] The mesh routing protocol SHALL support path metric computation based on airtime link cost or an equivalent metric that accounts for link data rate, frame error rate, and channel overhead.
[MR-009] The mesh routing protocol SHALL support self-healing: automatic re-routing around failed or degraded links within a convergence time not exceeding 10 seconds under normal operating conditions.
[MR-010] Gateway nodes SHALL support Mesh Portal functionality as defined in IEEE 802.11s, bridging traffic between the mesh network and a non-mesh LAN.
[MR-011] WMABS SHALL support multiple simultaneous gateway nodes for redundancy and load distribution.
[CP-001] WMABS SHOULD default to 20 MHz channel widths to maximise coexistence with other RLAN devices and to ensure broad regulatory compatibility.
[CP-002] WMABS MAY support 40 MHz and 80 MHz channel widths where permitted by the active regulatory profile and where interference conditions allow.
[CP-003] WMABS SHALL NOT use 160 MHz channel widths in Phase A deployments due to limited channel availability and DFS constraints in the 5 GHz band.
[CP-004] WMABS SHOULD limit the mesh hop count to a maximum of four (4) hops between any client-serving node and the nearest gateway node.
Rationale: Each mesh hop approximately halves available throughput due to the shared medium. A four-hop limit provides a practical balance between coverage extension and acceptable end-to-end throughput and latency.
[CP-005] Deployments exceeding four mesh hops SHALL document the expected throughput and latency degradation in the site-specific deployment plan.
[CP-006] WMABS MAY support dedicated radio chains for mesh backhaul where the hardware platform provides three or more independent radio interfaces.
Where a dedicated backhaul radio is available, it SHOULD operate on a different frequency band or channel from the client-access radio to avoid self-interference. This configuration is sometimes referred to as tri-band or dedicated backhaul mode.
The following performance targets are informative guidelines for deployment planning. Actual performance will depend on environmental factors, channel conditions, and client device capabilities.
Parameter Single Hop Four Hops (Max)
Aggregate Throughput > 200 Mbps (typical) > 25 Mbps (estimated) (downlink)
Round-trip Latency < 5 ms < 30 ms
Jitter < 2 ms < 10 ms
Note: These values assume 80 MHz channel width with 2 spatial streams, moderate client density, and no co-channel interference. They are provided for planning purposes and are not normative requirements.
[SE-001] WMABS SHALL support WPA3-Personal (Simultaneous Authentication of Equals, SAE) for public and community access networks.
[SE-002] WMABS SHALL support WPA3-Enterprise (IEEE 802.1X with EAP) for managed, operational, or enterprise networks.
[SE-003] WMABS SHOULD support Opportunistic Wireless Encryption (OWE, IEEE 802.11-2020 section 12.12) for open networks where per-user credentials are not practical, to provide encryption without authentication.
[SE-004] All data frames transmitted over the air interface SHALL be encrypted. Unencrypted (open) SSIDs SHALL NOT be deployed unless OWE is enabled.
[SE-005] Protected Management Frames (PMF) as defined in IEEE 802.11w SHALL be enabled on all BSSs where the client population supports it.
[SE-006] PMF SHALL be set to required mode for WPA3-Personal and WPA3-Enterprise BSSs.
WMABS SHALL provide logical separation between distinct traffic domains to prevent unauthorised cross-domain access.
[SE-007] WMABS SHALL support a minimum of two logically separated traffic domains: (a) public/user traffic and (b) node management and control traffic.
[SE-008] Traffic domain separation SHALL be enforced at the MAC layer using separate BSSs or VLANs.
[SE-009] Management and control traffic SHALL be isolated such that it is not accessible from the public/user traffic domain under any configuration.
[SE-010] Inter-node mesh backhaul links SHALL be authenticated and encrypted using SAE or a mesh-specific key management protocol (e.g., Authenticated Mesh Peering Exchange as defined in IEEE 802.11s).
[SE-011] Mesh link encryption keys SHALL be rotated periodically. The default rotation interval SHALL NOT exceed 24 hours.
WMABS is intentionally constrained to standardised Wi-Fi technologies and license-exempt spectrum to enable multi-jurisdiction deployment with minimal regulatory friction. This section defines the normative boundary conditions that govern how WMABS configurations interact with regulatory requirements.
Any configuration change that alters the RF emissions profile of a WMABS node beyond the baseline (Phase A) parameters is classified as a regulation-dependent configuration. The following changes are explicitly classified as regulation-dependent:
-
Enabling external antennas (omnidirectional, sectoral, or directional)
-
Increasing antenna gain beyond the integrated antenna specification
-
Changing the indoor/outdoor deployment classification of a node
-
Modifying EIRP above the baseline regulatory profile limits
-
Enabling operation in the 6 GHz band
-
Deploying in a jurisdiction not covered by an existing validated regulatory profile
[RB-001] Any regulation-dependent configuration change SHALL require explicit validation against the regulatory framework of the deployment country.
[RB-002] Validation SHALL be documented and retained as part of the deployment record.
[RB-003] WMABS firmware SHALL prevent activation of regulation-dependent configurations unless a corresponding validated regulatory profile is loaded and authenticated.
[RB-004] The system integrator or deploying organisation bears responsibility for ensuring that all regulation-dependent configurations comply with applicable local, national, and regional regulations.
Annex A Regulatory Profile Schema (Normative)
This annex defines the minimum data fields that SHALL be present in a WMABS regulatory profile. Implementations MAY extend this schema with additional fields, provided the minimum fields are preserved.
Field Type Required Description
profile_id String Yes Unique identifier for this regulatory profile.
country_code ISO 3166-1 Yes Two-letter country code alpha-2 identifying the jurisdiction.
regulatory_domain String Yes Regulatory domain identifier (e.g., FCC, ETSI, MIC).
bands[] Array Yes List of permitted frequency bands with sub-band definitions.
bands[].freq_start_mhz Integer Yes Start frequency of the sub-band in MHz.
bands[].freq_end_mhz Integer Yes End frequency of the sub-band in MHz.
bands[].max_eirp_dbm Integer Yes Maximum permitted EIRP in dBm for this sub-band.
bands[].dfs_required Boolean Yes Whether DFS is required in this sub-band.
bands[].tpc_required Boolean Yes Whether TPC is required in this sub-band.
bands[].indoor_only Boolean Yes Whether operation is restricted to indoor environments.
phase_b_permitted Boolean Yes Whether Phase B (extended outdoor) configurations are permitted.
max_antenna_gain_dbi Integer Conditional Maximum permitted external antenna gain in dBi. Required if phase_b_permitted is true.
signature String Yes Cryptographic signature for (Base64) profile authentication.
Annex B Conformance and Requirement Traceability (Informative)
This annex provides a summary index of all normative requirements defined in this specification for traceability and compliance-verification purposes.
Req. Section Level Summary ID
RT-001 4.1 SHALL Operate using IEEE 802.11 RLAN standards only
RT-002 4.1 SHALL Implement IEEE 802.11ax as baseline PHY/MAC
RT-005 4.2 SHALL Support dual-band 2.4 GHz and 5 GHz operation
RT-007 4.2 SHALL NOT Require licensed spectrum under any mode
SR-001 5.1 SHALL Operate solely in license-exempt spectrum
SR-004 5.2 MUST Support configurable regulatory profiles
SR-006 5.2 MUST Enforce active regulatory profile at runtime
MR-001 7.1 SHALL Support point-to-multipoint connectivity
MR-002 7.1 SHALL Support multi-hop mesh connectivity
SE-001 9.1 SHALL Support WPA3-Personal (SAE)
SE-002 9.1 SHALL Support WPA3-Enterprise (802.1X)
RB-001 10.2 SHALL Validate regulation-dependent config changes
Note: This table is a representative subset. The complete requirement register SHALL be maintained in the project requirements management tool.