Understanding LTE Model Internals and Interfaces
Understanding LTE Model Internals and Interfaces
Understanding LTE Model Internals and Interfaces
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1581 <strong>Underst<strong>and</strong>ing</strong> <strong>LTE</strong> <strong>Model</strong> <strong>Internals</strong> <strong>and</strong> <strong>Interfaces</strong><strong>Underst<strong>and</strong>ing</strong> How to Interface to the DLFrame Generator• Entry function: lte_enb_as_frame_dl_frame_for_harq_tx_generate()• Pass 1: Called for all queues. For GBR queues, only a maximum of contract bits served.• Pass 2: Called only for the GBR queues. Excess traffic in GBRs served.• Pass 3: Called if PDCCH gets congested before PDSCH.• In order to prevent creating new control channel elements, all unserved UEs areblocked, <strong>and</strong> remaining PDSCH resources are distributed only to the served UEs.• At the start of the framing, set scheduling callbacks:• lte_sched_support_q_selection_proc_set()• Procedure that finds the “next queue”• lte_sched_support_bit_selection_proc_set()• Procedure that “recommends” bits to be taken from the queue’s buffer• That’s pretty much it! Interface reduced potentially to 2 lines only• Frame generator in turn calls (until resources remain, or buffers are nonempty):• lte_sched_support_next_q_get(): Gets the queue ID (crnti, RB) <strong>and</strong> the “recommendedbits”• Frame generator has the ability to determine termination, reset the scheduler system, potentiallyset different callbacks each time, exclude/include queues in the scheduling process etc!• We recommend you leave the frame generator undisturbed!CONFIDENTIAL ─ RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. © 2010 OPNET Technologies, Inc.47