IEEE 802 and 3GPP step up collaboration on LAA

IEEE 802 and 3GPP are working together more on coexistence of Licensed Authorized Access (LAA) and Wi-Fi. Since November, each group has made a presentation to the other. There’s been an exchange of liaison statements, the latest on March 18 when IEEE 802 sent 3GPP two statements containing several requests and recommendations.

LAA is being defined for 3GPP Release 13, due out in early 2016. It’s a subset of unlicensed LTE (LTE-U), which is also supported using protocols in Releases 10, 11, and 12. LTE-U bundles licensed and unlicensed spectrum to increase capacity.

IEEE 802 is concerned that LTE-U can essentially control the band it shares with Wi-Fi. LTE can transmit when it wants. Wi-Fi transmissions are contention based, and will back off back off exponentially after each failed transmission.

3GPP has proposed mechanisms in LAA to provide for “fair” sharing by apportioning transmit time to each technology. Since it’s LAA that does the apportioning, the definition of fairness and details of the medium sharing algorithms concern IEEE 802. Likewise, since the effectiveness of proposed solutions is determined in part by modeling, assumptions used in simulations, such as device density and traffic type (FTP, voice, video, etc.), are relevant. In sum, IEEE 802 wants Wi-Fi and LAA to have equal access to the band regardless of use case — a sort of unlicensed neutrality.

A related concern to some IEEE 802 members is LTE-U operation proposed by some operators this year, using protocols in existing 3GPP specifications (pre-Release 13). The LTE-U Forum, formed last year by Verizon along with several vendors, recently released a coexistence specification and other technical documents for non-LAA LTE-U. Some in IEEE 802 would like more details on these, but 3GPP and LAA is the focus at the moment.

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