Interpretations

Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretations for IEEE Std 802.11g™-1999 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 AMENDMENT 4: Further Higher Data Rate Extension in the 2.4 GHz Band

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February 2005

Interpretation Request #1 (1-01/05)
Topic: (Service field content) Relevant Clause: Annex GClassification: Conflicts with Clause 17

Clause 19.3.2.1 states that within the SERVICE field "Bit b2 is used to indicate that the transmit frequency and symbol clocks are derived from the same oscillator. For all ERP systems, the Locked Clock Bit shall be set to 1."

However, clause 15.2.3.4 states "The 8-bit IEEE 802.11SERVICE field shall be reserved for future use. The value of X'00' signifies IEEE 802.11 device compliance."

Is a Clause 19 ERP device non-conformant if it sends a 1 or 2 Mbps frame without the SERVICE field bit B2 set?

Interpretation Response #1
The standard is unambiguous in this case. A PHY implementing Clause 19 shall set bit B2 in the Service field, as required by 19.3.2.1 in all transmissions. A PHY implementing Clause 15 that is dependent upon a particular value in a reserved field for its correct operation is not compliant with the standard. All implementations must ignore values of reserved fields upon reception. The editor of the standard will be instructed to remove the sentence "The value of X'00' signifies IEEE 802.11 device compliance " from 15.2.3.4.