IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-08-0197-00-MRPM Title: Different modes of operation Date Submitted: July, 2008 Presented at IEEE 802.21 July 14-17 at Denver Authors or Source(s):   H Anthony Chan (Huawei) Abstract: The modes of operation defined in different networks are different and are not consistent in naming them. A useful classification is according to the response time of these modes.

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802.21 Modes of operation: Tradeoff between power saving and response time

Background DCN: 21-08-0072-00-MRPM attempts to explain the different power saving modes, realizing the inconsistency in naming the different modes for different networks. DCN: 21-08-0072-00-MRPM addresses the need to better understand and define the possible modes along with the meaning behind. DCN: 21-08-0166-00-MRPM describes the definitions of different modes in each of the different networks: 802.11, 802.16, 3GPP, and 3GPP2. DCN: 21-08-0177-02-MRPM attempts to categorize the different modes (in addition to explaining many other things).

Power saving versus application requirements There are tradeoffs between power-saving and operational capabilities. The operations involved include: Handover Response to paging Location update, etc. The capability to perform each operation while optimizing power saving depends on Application requirements Capabilities of MN Capabilities of Network

Application time scale The needed operations (Call continuity, Handover, Response to paging, Location update, etc.) place QoS requirements according to the applications, which may be broadly categorized into Conversational Interactive Streaming Background A relevant QoS requirements here lies in the time scale. The QoS requirement against packet loss may also transform to time constraint during active data transfer. >10s Background 10s Streaming Record (interactive) 1s Play back (interactive) Delay in voice, video (conversational) 100ms Lip synchronization 10ms 1ms Jitter in voice and video

Response times handover paging Conversational Interactive Streaming Background Ongoing call with active data transfer (against packet loss) ~20 – 200 ms Ongoing call not actively transferring data ~100 – 400 ms ~1 – 2 s New call ~2 s >2 s < 10 s > 10 s handover paging

802.11 time scale The interval of beacon frame, which contains traffic indication map (TIM), is typically 100 ms Power saving mode listens to every Delivery traffic indication message (DTIM), which are sent from AP. The DTIM period is number of TIM intervals. Typically 1 DTIM may be several TIM intervals. Sleep is extended power saving mode without GTK update. The sleep interval is up to 255 (1 octet) times of DTIM interval. Use of a large sleep interval corresponds to deep sleep.

802.11 time scale In active mode, need RTS/CTS in CSMA/CA before sending. Response time depends on traffic and QoS class. In power-saving (PS) mode, response time is several beacon intervals: fraction of a second. In sleep mode (extended PS mode), may adjust DTIM period, but no GTK update. Location and BSS change: during wake at the designated DTIM >10s Deep sleep 10s Sleep mode 1s PS mode DTIM interval 100ms Beacon interval CSMA (Active mode) 10ms 1ms