Extending Fast Session Transfer Session Setup to Dynamic STA Enablement Scenarios

1. Extending Fast Session Transfer Session Setup to Dynamic STA Enablement Scenarios Authors: Date: 2011-05-05 Bahareh Sadeghi et al, Intel Corp.

2. Abstract • Devices supporting DSE bands (3.65-3.7 GHz, TVWS) radio may also support non-DSE bands (2.4GHz, 5GHz and 60GHz) • Depending on the operating environment there is a need to be able to switch between these bands with little or no impact to higher layer application performance. • Critical when the device is portable • This submission proposes an extension the TGad Fast Session Transfer Setup procedure to be usable in DSE bands • Normative Text corresponding to the proposal is in document 11/0651r1. Bahareh Sadeghi et al, Intel Corp.

3. Dependent Station (STA): A STA that is not registered (with the FCC) and whose operational parameters are dictated by messages it receives from an enabling STA. Once enabled by the dynamic STA enablement (DSE) process, a dependent STA's continued operation becomes contingent upon being able to receive messages from its Enabling Station. • Enabling Station (STA): A registered STA that has the authority to control when and how a dependent STA can operate. An enabling STA is required to transmit an enabling signal to the Dependent STA over the wireless channel in which the Dependent STA is allowed to operate. An enabling STA may choose for other dynamic STA enablement (DSE) messages to be exchanged over the air, over the distribution system (DS), or by mechanisms that rely on transport via higher layers. • Dynamic station (STA) enablement (DSE): The process by which an enabling STA grants permission and dictates operational procedures to STAs that are subject to its control. A dependent STA cannot transmit in a channel in the restricted band unless it receives the enabling signal from the enabling STA on the channel in the restricted band. Definitions Bahareh Sadeghi et al, Intel Corp.

4. TGad FST State Machine -- Deadlock • Dependent STAs cannot FST ACK or initiate a frame exchange in a channel in the restricted band before receiving the enabling signal in the channel from the Enabling STA. • But the Enabling STA is waiting for FST ACK or a frame exchange to be initiated by the Dependent STA. • Hence the FST State Machine deadlocks when transitioning to a channel in a DSE band. Bahareh Sadeghi et al, Intel Corp.

5. TVWS FST Session Setup Bahareh Sadeghi et al, Intel Corp.

6. Assumptions – The peer devices know of each other capabilities: Dependent STA or Enabling STA • If a Dependent STA initiates FST Session Setup (by sending the FST Session Setup Request message) • If the recipient of the FST Session Setup Request Message is an Enabling STA, the Enabling STA rejects the FST Session Setup Request with the Status Code set to 90. • The Enabling STA initiates a FST Session Setup (probably using the parameters that it received in the FST Session Setup Request from the Dependent STA). • If the recipient of the FST Session Setup Request Message is NOT an Enabling STA, the Enabling STA rejects the FST Session Setup Request with the Status Code set to Unspecified Failure. Proposal Bahareh Sadeghi et al, Intel Corp.

7. Alternate Proposal: Flow diagrams Enabling STA Dependent STA FST Session Setup Request FST Session Setup Response: Time-to-Start, Status = 90 Time-to-Start FST Session Setup Request • Notes: • No new action frames introduced • Timeout Interval added as an optional element to FST Session Setup Response frame; Time-to-Start indicates the time duration (in TUs) that the responder may take in order to start FST • A new status code for FST Setup Request rejection is defined. • If the FST Session Setup initiator’s capability is not known or if both the initiator and responder are dependent STA, the responder will reject the Session Setup with a failure status code. Bahareh Sadeghi et al, Intel Corp.