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UPLINK SCHEDULING IN NON-ADAPTIVE HYBRID AUTOMATIC REPEAT REQUEST

IP.com Disclosure Number: IPCOM000244415D
Publication Date: 2015-Dec-09
Document File: 5 page(s) / 92K

Publishing Venue

The IP.com Prior Art Database

Related People

Qing Zhao: AUTHOR [+4]

Abstract

Mechanisms and systems for uplink resource allocation are provided to maximize resource utilization efficiency and fairness for new transmissions using non-adaptive hybrid automatic repeat request (HARQ) mechanisms. Resource utilization efficiency and fairness are maximized by using an approach similar to sphere decoding, i.e., by searching a global optimum in a series of modified-spaces that are typically much smaller than that of the original problem in terms of degree of freedom. By using the mechanisms provided herein, the number of required operations is reduced.

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UPLINK SCHEDULING IN NON-ADAPTIVE HYBRID AUTOMATIC REPEAT REQUEST

AUTHORS:

    Qing Zhao Kedar Shirali Vikram Chandrasekhar

Ritesh Madan

CISCO SYSTEMS, INC.

ABSTRACT

    Mechanisms and systems for uplink resource allocation are provided to maximize resource utilization efficiency and fairness for new transmissions using non-adaptive hybrid automatic repeat request (HARQ) mechanisms. Resource utilization efficiency and fairness are maximized by using an approach similar to sphere decoding, i.e., by searching a global optimum in a series of modified-spaces that are typically much smaller than that of the original problem in terms of degree of freedom. By using the mechanisms provided herein, the number of required operations is reduced.

DETAILED DESCRIPTION

    In communication networks such as Long Term Evolution (LTE) networks, HARQ mechanisms are used. HARQ mechanisms combine high-rate forward error- correcting coding and Automatic Repeat request (ARQ) error-control. Generally, HARQ may be adaptive or non-adaptive. Although adaptive HAQR is preferred at uplink scheduling to offer more flexibility in resource allocation, non-adaptive HAQR is still needed in some scenarios, e.g., in scenarios with a lack of Physical Downlink Control Channel (PDCCH) resources to send adaptive-HARQ downlink control information (DCI). When non-adaptive HARQ is used, very often available resources for new transmissions are divided into multiple non-contiguous fragments, each of which is separated by resources reserved for non-adaptive retransmissions.

    FIG. 1 is a diagram illustrating multiple non-contiguous fragments (available segments) separated by resources (retx) reserved for non-adaptive retransmissions.

Copyright 2015 Cisco Systems, Inc.

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FIG. 1

    Since resources assigned to each user equipment (UE) on uplink must be contiguous (i.e., contiguity constraint), any UE can be allocated onto only one segment. In order to maximize resource utilization efficiency and fairness for new transmissions, the above problem can be formulated by using the following formula


(1)

    in which
����: is the index of UE, ���� = 0, … , ���� − 1,
����: is the total number of UEs to be considered in scheduling,
����: is the index of segment, ���� = 0, … , ���� − 1,
����: is the total number of sub bands to be considered in scheduling,
����: is a utility function,
���: is a set if a-prior parameters for the ����-th UE (such as queue size, head-of-line delay, average throughput, guaranteed bit rate, etc.),

    ��������,����: is an instantaneous rate of the i-th UE per resource unit on the j-th segment and an average rate is calculated on each segment if each RB in the i-th segment is of different channel gain,

    ��������,����: is the number of resource units assigned to the i-th UE on the j-th segment, ��������,����...