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Synchronous non-adaptive Hybrid ARQ for distributed subcarrier mode Document Number: S80216m-08_290 Date Submitted: 2008-05-05 Source: Alexei Davydov Voice: +7 831 4162444 Alexander Maltsev E-mail: alexei.davydov@intel.com, alexander.maltsev@intel.comalexei.davydov@intel.comalexander.maltsev@intel.com Intel Russia, Nizhny Novgorod, Ul. Turgeneva, 30 Venue: Session #55 Macao, PRC Base Contribution: IEEE C80216m-08_290 Purpose: For discussion and adoption by IEEE 802.16m group Notice: This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.16. Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and.http://standards.ieee.org/guides/bylaws/sect6-7.html#6http://standards.ieee.org/guides/opman/sect6.html#6.3 Further information is located at and.http://standards.ieee.org/board/pat/pat-material.htmlhttp://standards.ieee.org/board/pat
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Types of HARQ protocol timing In terms of the retransmission scheduling timing the HARQ protocols are usually classified into two groups: –Synchronous HARQ: retransmissions occur at a pre-determined time- frequency instances –Asynchronous HARQ: retransmissions time-frequency allocation is flexible Synchronous HARQ: –Advantages: Low control signalling overhead No packet reordering is required => Lower delay –Disadvantages No possibility to postpone the retransmission No possibility to use the channel information for more effective allocation of the retransmissions
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Data Burst Allocation for Conventional Synchronous HARQ Illustration of data burst allocation for convention synchronous HARQ: Retransmission happens at the predetermined time instances Data burst allocation remains the same within sub frame
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Problem Statement and Solution For conventional synchronous HARQ protocol the retransmission allocation does not change from frame to frame and occurs at the same time-frequency position as an initial transmission For applications that require short latencies (comparing to channel coherence time) the channel is almost static across the retransmissions. The expected post-processing SNR (Signal-to-Noise Ratio) improvement due to retransmission is about 3dB for Chase Combining and provided by time diversity and coherent combining only For distributed subcarrier mode the additional frequency and spatial diversity (additionally to time diversity) may be provided for the each next retransmission thus giving additional efficiency and robustness for the HARQ The new parameters that define the sub channel and spatial stream rotation offsets may be signaled via L1/L2 control channel(s)
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Data Burst Allocation for Proposed Synchronous HARQ Illustration of data burst allocation for proposed synchronous HARQ: Retransmission happens at the predetermined time instance Data burst allocation is rotated with predetermined offset within sub frame
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Spatial Stream Rotation for Vertical MIMO HARQ Illustration of data spatial stream rotation for vertical spatial multiplexing for proposed synchronous HARQ: Retransmission happens at the predetermined time instances Spatial streams are rotated with predetermined offset Spatial stream Time of Transmission
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Performance Comparison Initial Transmission1st retransmission for conventional synchronous HARQ 1st retransmission for proposed synchronous HARQ MS speed 3 kmph, retransmission delay 10 ms, Chase Combining
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Performance Comparison (Cont’d) Initial Transmission1st retransmission for conventional synchronous HARQ 1st retransmission for proposed synchronous HARQ MS speed 3 kmph, retransmission delay 10 ms, Chase Combining
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Proposed Text for SDD
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Proposed Text for SDD (Cont’d)
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