Hierarchical cellularbased management for mobile hosts in adhoc wireless networks

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Hierarchical cellular-based management for mobile
hosts in ad-hoc wireless networks

• Chih-Yung Chang Chao-Tsun Chang Tsung-Tien
  Hsieh
• Information Networking, 2001. Proceedings. 15th
  International Conference on , 2001
• Presented by George Lee

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Abstract

• This paper proposes a hierarchical Cell-Based
  management model for Mobile Ad-hoc Networks
  (MANET).
• Under the proposed management model, mobile hosts
  can construct a stable communication path with
  fewer flooding messages and smaller number of hop
  count.

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1. Introduction (1)

• Packet flooding is the general technique to
  establish a routing path from one source mobile
  host to the destination.
• To reduce the amount of flooding packets
• 2 proposed Routing in Clustered Multihop
  Mobile Wireless Networks with Fading Channel
• 5 proposed GRID A Fully Location-Aware
  Routing Protocol for Mobile Ad Hoc Networks

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1. Introduction (2)

• 2 proposed Routing in Clustered Multihop
  Mobile Wireless Networks with Fading Channel
• The MANET is partitioned into several clusters.
• Hosts in each cluster will vote for a header as
  the manager of this cluster.
• Hosts desired to establish a communication path
  should firstly send a request to its manager.
• Manager that receives the request packet will
  relay the packet to neighboring manages in a
  flooding manner until the manager of the
  destination host is found.
• ? It alleviates the flooding phenomenon
• ? It introduces the management overhead

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1. Introduction (3)

• 5 proposed GRID A Fully Location-Aware
  Routing Protocol for Mobile Ad Hoc Networks
• The MANET is partitioned into several grids (or
  called zones).
• Equipped with GPS, a host can identify which grid
  it is located.
• In each grid, a host that is geographically near
  the center location of this grid will be
  considered as a manager for executing the route
  search.
• The size of grid is not determined.
• In a large grid, a gateway host is needed to
  relay the managers message to neighboring
  managers.
• ? It alleviates the flooding phenomenon
• ? It introduces the management overhead

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1. Introduction (4)

• To efficiently establish a communication path,
  to alleviate the flooding phenomenon, to
  minimize the data of routing table, and to
  increase the stability
• This paper offers a two-level Cell-Based
  management protocol.

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2. One-Level Cell-Based Management

• Cell-based management
• MANET is geographically partitioned into several
  disjoint and equal-sized cellular regions.
• Assume that the manager of one region can
  directly communicate with managers of the
  neighboring regions.
• Comparing units of Triangles, Zones, and Cells

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2. One-Level Cell-Based Management

• 2.1 The Selection of Manager (1)
• Assume that each host is equipped with GPS.
• A host that is the nearest to the center location
  of a cell will be voted as a manager by all hosts
  in the cell.
• This will guarantee that the manager will not be
  changed frequently due to mobility.

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2. One-Level Cell-Based Management

• 2.1 The Selection of Manager (2)
• A manager should broadcast its ID to other
  members, receive all members IDs, and keep these
  IDs in its cache table.
• Managers should update the member information.
• Whenever the manager is going to move to another
  cell, it should select a candidate host that is
  the nearest to the center of the old cell to be
  manager.
• The manager then transfers the contents of its
  table to the new candidate manager.

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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell
• If the size of the cell is too large, the manager
  cannot directly communicate with neighboring
  managers.
• This will cause additional overhead such as
  maintaining gateway.

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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell (1)
• Size of Cell
• (S signal strength)

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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell (2)
• Size of Triangle

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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell (3)
• Size of Zone

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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell (4)
• (1) The ratio of flooding cost
• Flooding cost (amount of flooding packets) ? size
• T Triangle
• Z Zone
• C Cell
• CostT CostZ 0.144337S2 0.125S2 ?0.875 (T
  Save 12.5)
• CostC CostZ 0.125S2 0.199852S2 ?0.624 (C
  Save 37)
• ?
• The cell-based partition is cost effective in
  reducing flooding packets.

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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell (5)
• (2) Measurement of hop count of routing path
• Optimal flooding
• Cellular Optimal / Cell
• Zone Optimal / Zone

2 hops
1 hops
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2. One-Level Cell-Based Management

• 2.2 The Size of a Cell (6)
• (2) Measurement of hop count of routing path
• In most cases, the Cell-Based management has
  better behavior than Zone-Based management.

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2. One-Level Cell-Based Management

• 2.3 Cell-Based Routing Protocol (1)
• Member host that hopes to build a communication
  path to another host will issue a route request
  packet RREQ (source-id, broadcast-id,
  destination-id, hop-count, timeout) to its
  manager.
• As the manager receives the RREQ packet, it
  checks first whether the destination host is
  appeared in its table or not.
• If it is, the manager will issue a reply packet
  RREP (source-id, destination-id, my-id,
  previous-id) back to the manager of the source
  host.
• The flooding operation is then performed in
  manager level until the destination is found.

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2. One-Level Cell-Based Management

• 2.3 Cell-Based Routing Protocol (2)
• Figure 3 Route construction from S to D

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2. One-Level Cell-Based Management

• 2.3 Cell-Based Routing Protocol (3)
• In one-level cell-based management model
• The number of flooding during path construction
  is largely reduced.
• The number of hop count may increase, compared
  with the flooding case.
• It is possible that two routing paths pass
  through the same cell. Under this condition, a
  QoS routing request is difficult to be satisfied.
  (Bandwidth-Congestion problemThe manager may
  not afford the bandwidth requests of two routing
  paths. ) ???

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2. One-Level Cell-Based Management

• A special caseS1 ? D1
• Figure 4(a)
• By host-level flooding
• One-hop direct link
• Figure 4(b)
• By manager-level flooding
• 4-hop links

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3. Two-Level Cell-Based Management

• 3.1 Two-Level Cell-Based Partitioning (1)
• To group seven small cells as a super cell
• One of the seven managers that is nearest the
  center location of the super cell will be
  considered as the header of the super cell.
• The header of a super cell will record the seven
  managers of the grouped cell.

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3. Two-Level Cell-Based Management

• 3.1 Two-Level Cell-Based Partitioning (2)
• Only headers will participate the flooding
  operation in constructing a routing path.
• When the path is constructed, the header can
  assign one of its manager to server as a relay
  node in the constructed path.
• Avoiding the bandwidth-congestion problem since
  the header can assign two different managers to
  serve as relay nodes for two different paths
  which pass through the same super cell
  simultaneously.

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3. Two-Level Cell-Based Management

• 3.1 Two-Level Cell-Based Partitioning (3)
• To guarantee direct communication between two
  headers of neighboring super cells, the size of
  small cell should be reduced.

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3. Two-Level Cell-Based Management

• 3.2 Two-Level Cell-Based Management
• Among super cells, only headers can communicate
  with each other.
• Whenever a header moves from its current cell to
  another cell, a new header will be selected.
• Within a basic cell, the management rules are
  similar to those in one-level cell-based
  management.

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3. Two-Level Cell-Based Management

• 3.3 QoS Routing Protocol for Two-Level Cell-Based
  Management (1)
• A header maintains a bandwidth table (49 rows by
  49 columns)
• Whenever the header of the destination host
  receives the RREQ packet, it selects a path with
  minimal hop count and issues the RREP packet back
  to the header of the source host.

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3. Two-Level Cell-Based Management

• 3.3 QoS Routing Protocol for Two-Level Cell-Based
  Management (2)
• When an intermediate header receives a RREP
  packet, it looks up the bandwidth table and
  determines that whether the route path can jump
  itself and directly relay message from one
  manager of neighboring super cell to another
  manager of other neighboring super cell.

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3. Two-Level Cell-Based Management

• 3.3 QoS Routing Protocol for Two-Level Cell-Based
  Management (3)
• C0 receives the RREP packet issued by B0, it
  checks whether downstream manager Bi can directly
  communicate with upstream manager Ej.
• Since B6 - E6 directly connected the bandwidth
  meets the QoS minimal requirement, C0 determines
  to jump itself and one hop is saved.

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4. Performance Study (1)

• Size of MANET 100100 basic units
• Signal strength 10 basic units
• Figure 8
• Number of flooding packets
• Zone-based vs. one-level cell-based

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4. Performance Study (2)

• Figure 9
• Successful rate of finding a routing path
• Zone-based vs. one-level cell-based

Zone-based Lower rate of successful path finding
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4. Performance Study (3)

• Figure 10
• Number of hop count
• Zone-based vs. one-level cell-based

Cell-based smaller number of hop counts
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4. Performance Study (4)

• Figure 11
• Number of hops
• One-level zone-based vs. two-level cell-based

Two-level Cell-based smaller number of hops
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5. Conclusions and Future Works

• Cell-based management has better behavior in
  reducing the number of flooding packets and the
  number of hops, compared with that of flooding.
• Two-level cell-based management performs better
  than that one-level cell-based management.
• Future works protocols based on the cell-based
  management model
• Multicasting
• Geocasting
• Broadcasting