ADAPTIVE POWER ALLOCATION AND CALL ADMISSION CONTROL IN MULTISERVICE WIMAX ACCESS NETWORKS

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ADAPTIVE POWER ALLOCATION ANDCALL ADMISSION
CONTROL INMULTISERVICE WIMAX ACCESS NETWORKS

• IEEE Wireless Communications February 2007
• Radio Resource Management And Protocol
• Engineering For IEEE 802.16
• Reporter ???

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Outline

• 1. Abstract
• 2. Introduction
• 3. Wimax Downlink APA Optimization
• 4. Deploying CAC In Wimax Access Networks
• 5. The Cooperation Between APA and CAC
• 6. Conclusions

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Abstract

• From a technical viewpoint, WiMAX is a feasible
  alternative to the wired internet access
  solutions such as cable modem and DSL
• From the commercial viewpoint, whether the
  promise of WiMAX will be materialized still
  depends on its revenue rate to telecom operators
  and its service quality to the subscribers

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Introduction

• The choice of broadband Internet access
• T1?ADSL?CABLE
• However, these wired infrastructures can be
  considerably more expensive and time consuming to
  deploy than wireless ones
• WiMAX, an IEEE 802.16 standardized wireless
  technology
• 10Km
• single-channel data rate of up to 75 Mb/s on both
  the uplink and downlink.
• use multiple WiMAX channels for a single
  transmission to reach a bandwidth of up to 350
  Mb/s.

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Introduction

• WiMAX technology supports both mesh and
  point-to-multipoint (PMP) networks.
• mesh network is usually used for constructing
  wide-area wireless backhaul network
• PMP network aims at providing the last-mile
  access to a broadband ISP.

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Introduction
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Introduction
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Introduction

• Transmission
• OFDM (orthogonal frequency division multiplexing)
• OFDMA (orthogonal frequency division multiple
  access)
• Duplex
• FDD (Frequency Division Duplex)
• TDD (Time Division Duplex)
• TDD is more flexible

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Introduction

• As one of the most expected features, WiMAX is
  supposed to have the capability of accommodating
  a variety of traffics, including data transfer,
  voice, and video.
• WiMAX Forum define
• Unsolicited Grant Service (UGS)
• Real-Time Polling Service (rtPS)
• Non-Real-Time Polling Service (nrtPS)
• Best Effort (BE)

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Introduction

• This article addresses two resource management
  mechanisms in WiMAX access networks
• Adaptive power allocation (APA)
• Call admission control (CAC)

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Wimax Downlink APA Optimization

• The WiMAX uplink and downlink transmission can be
  optimized by APA, which allows the transmitter to
  grant different power levels to different
  subcarriers according to the channel state
  information from the physical layer
• The service providers usually expect a power
  allocation scheme that produces optimal revenue.

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Wimax Downlink APA Optimization

• To investigate the APA revenue of a certain
  scheme, we define the revenue rate of each type
  of service as the revenue generated by a
  bandwidth unit. We let rerUGS, rerrtPS, rernrtPS,
  and rerBE be the revenue rates of the following
• Unsolicited Grant Service
• Real-Time Polling Service
• Non-Real-Time Polling Service
• Best-Effort Service

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Wimax Downlink APA Optimization

• arriving downlink traffic load in subscriber k's
  local network
• traffic load can generate potential revenue in
  subscriber k's local network
• revenue-to-bandwidth ratio of the kth subscriber
• The optimal revenue-criterion-based APA allocate
  more power resource to the subcarriers that
  belong to the subscriber of high
  revenue-to-bandwidth ratio.

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Wimax Downlink APA Optimization

• This consideration leads to fairness-constrained
  optimal revenue criterion
• Simulation
• OFDMA
• 32 subscribers
• BS-SS distances ? 2 to 10 km
• Power level ? MQAM
• M-ary quadrature amplitude modulation
• is 80
• In our simulation, the channel is assumed to have
  a bad-urban (BU) delay profile Principles of
  Mobile Communication

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Wimax Downlink APA Optimization
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Deploying CAC In Wimax Access Networks

• To handle a multiservice WiMAX access network, it
  is very important to employ the CAC mechanism.
• CAC is a crucial step for the provision of QoS
  guaranteed service, because it can prevent the
  system capacity from being overused.
• We suppose a CAC manager is placed in a WiMAX
  base station.

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Deploying CAC In Wimax Access Networks

1. When an application in subscriber k's local
   network initiates a connection to the Internet,
   it sends connection request to the CAC manager
   with upstream bandwidth requirement bU and
   downstream bandwidth requirement bD.
2. the CAC manager employs uplink CAC policy and
   downlink CAC policy to make admission tests on
   the uplink and downlink separately, and only the
   connection request passing both admission tests
   can be accepted eventually

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Deploying CAC In Wimax Access Networks
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Deploying CAC In Wimax Access Networks

• From the perspective of service provider, the
  admission control policy that produces optimal
  revenue is desired.
• From the perspective of WiMAX subscribers, the
  admission control policy of optimal utility is
  expected, since it can produce the maximum access
  bandwidth.

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The Cooperation Between APA and CAC
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Conclusion

• Since the current standardization activities of
  IEEE 802.16 leave service providers a chance to
  have their own selections in these two technical
  aspects, distinct designing criteria that follows
  can be chosen.
• From the perspective of service providers,
  optimal revenue is the major concern of both APA
  and CAC design

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Conclusion

• From the perspective of subscribers, fairness is
  the requirement of APA design, while optimal
  utility is the requirement of CAC design.
• To successfully deploy a commercial WiMAX system,
  we have to take into account the demands of both
  service providers and subscribers.