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A Lantern-Tree-Based QoS Multicast Protocol with Reliable Mechanism for Wireless Ad-Hoc Networks Yuh-Shyan Chen, Yun-Wen Ko, and Ting-Lung Lin Department of Statistics, National Taipei University Taipei, Taiwan, R.O.C. Email:
[email protected] Abstract In this paper, we propose a lantern-tree-based QoS multicast protocol with reliable mechanism for wireless ad-hoc networks, where the MAC sub-layer is adopted the CDMA-over-TDMA channel model. In this paper, we identify a lantern-tree for developing on-demand QoS multicast protocol with reliable mechanism to satisfy certain bandwidth requirement from a source to a set of destination nodes. The lantern-tree servers as the multucast-tree. Our lantern-tree-based scheme offers a higher success rate to construct the QoS multicast tree due to using the lantern-tree. The lantern-tree is a tree whose sub-path of the tree is the lanternpath. The lantern-path is a special multi-path structure. This greatly improves the success rate by means of multi-path routing. Specially, our proposed scheme can directly perform on all existing on-demand multicast protocols. Performance analysis results demonstrate the achievements of our proposed protocol. Keywords CDMA-over-TDMA, mobile ad hoc network (MANET), mobile computing, quality-of-service (QoS) routing, multi-path, wireless network. time division multiple access (TDMA), wireless network.
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I. I NTRODUCTION OBILE ad-hoc network (MANET) [10] consists of wireless hosts that communicate with each other in the absence of a fixed infrastructure. In a MANET, host mobility can cause frequent unpredictable topology changes,
thus the design of a MANET QoS routing protocol is more complicated than that of traditional networks because it requires strong fault-tolerant capabilities. Since the MANET is characterized by its fast changing topology, extensive research efforts have been devoted to the design of routing protocols for MANETs [4][5]. These protocols, when searching for a route to a destination, are concerned with shortest-path routing and the availability of multiple routes in the MANET’s dynamically changing environment. Some works recently have been intensively studied QoS issues in MANETs. These problems have been addressed in several studies in the literature [2][3][6][8][9][10][12][13][14][15][17][18][19][21]. Initially, in a quite ideal model, it is assumed that the bandwidth of a link can be determined on its neighboring links [2]. This strong assumption may be realized by a costly multi-antenna model such that a host can send/receive using different antennas independently and simultaneously. Under such a model, a ticket-based QoS routing protocol was proposed in [2]. Using the same model, Liao et al. recently proposed a QoS multi-path routing protocol [12]. Observe that Liao et al.’s routing protocol presents a multi-path concept to satisfy bandwidth constraints. A CDMA-over-TDMA channel model was recently assumed in [13][14] to develop a QoS routing protocol in a MANET, where the use of a time slot on a link is only dependent on the status of its one-hop neighboring links. Based on such a model, Lin and Liu calculated the end-to-end path bandwidth to develop DSDV-based QoS routing [14] and on-demand QoS routing [13] in a MANET. The multicast protocol is a primitive communication operation to send the same message from a source node to a group of destination nodes, which Yuh-Shyan Chen is with Department of Statistics, National Taipei University Taiwan, R.O.C., Email:
[email protected]. This work is supported by the National Science Council of the Republic of China under Grant #NSC90-2213-E-305-001, and the Ministry of Education, the the Republic of China, under Grant 90A-H-FA07-1-4 (Learning Technology).
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Fig. 1. Examples of (a) link, (b) lantern, (c) path, (d) lantern-path, and (e) worse case of lantern-path.
is very significant for many applications to offering service to many users without overloading the network resource. There are many existing MANET multicast protocols, CBT [7], AODV [18], DVMRP[6] , CAMP [16], FGMP [20], ODMRP [11], and SOM [4] protocol, etc, which do not provide the QoS function. The design difficulty of designing QoS multicast protocols in MANET is more difficult than traditional MANET multicast protocols due to taking the bandwidth-reservation into consideration. Efforts are made in this paper to develop a QoS on-demand multicast protocol in a MANET. In this paper, we propose a lantern-tree-based QoS multicast protocol with reliable mechanism for MANETs, where the MAC sub-layer is adopted the well-known CDMA-over-TDMA channel model [13][14]. Under such model, we identify a lantern-tree in MANET to provide an on-demand QoS multicast protocol with reliable mechanism to satisfy certain bandwidth requirement from a source to a group of destination nodes. In addition, our protocol also offers the reliable mechanism to guarantee the reliable communications. The lantern-tree servers as the multicast-tree. Our lantern-tree-based scheme offers a higher success rate to construct the QoS multicast tree due to using the lanterntree. The lantern-tree is a multicast tree whose sub-path of the tree is the lantern-path. The lantern-path is a special multi-path structure. This greatly improves the success rate by means of multi-path routing. Specially, our proposed scheme can directly perform on all existing on-demand multicast protocols. Performance analysis results demonstrate the achievements of our proposed protocol. The rest of this paper is organized as follows. Section 2 presents the basic ideas and challenge of our multicast protocol. Our protocol is presented in section 3. Section 4 shows the simulation results. Finally, section 5 concludes this paper.
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Fig. 2. Examples of (a) conventional-tree, (b) lantern-tree, and (c) wores case of lantern-tree.
II. BASIC I DEA AND C HALLENGE This paper mainly introduces and identifies a special multicast tree structure, namely lantern-tree, from a source to a set of destination nodes to satisfy a given bandwidth requirement. The MAC sub-layer in our model is adopted the well-known CDMA-over-TDMA channel model [13][14], that the CDMA (code division multiple access) is overlaid on top of the TDMA infrastructure. Under such a model, the use of a time slot on a link is only dependent on the status of its one-hop neighboring links. This model may be emulated by wireless LAN cards which follow the IEEE 802.11 standard [1]. Each data phase of a TDMA frame is assumed to be partitioned into time slots.
In the following, we introduce the terms of lantern, lantern-path, and lantern-tree. In this paper, a QoS path is a path which satisfy a given bandwidth requirement under the CDMA-over-TDMA channel model from a source to a destination node. Initially, the lantern is defined. A lantern is a special structure of the multi-path. A path is a lanternpath if each component of the path maybe a lantern or an uni-path. This paper eventually constructs a lantern-tree, where the path of a multicast tree is the lantern-path. The lantern-tree is constructed for the purpose of increasing the success rate on the tree-searching phase and prompting the stability on the tree-maintenance phase. Consider a pair of two-hop neighbor nodes A and B , a QoS path is requested between nodes A to B under satisfying a bandwidth requirement Br as shown in Fig. 1(a).
Definition 1: Lantern: Given a pair of two-hop neighboring nodes A and B , one or more sub-paths exist between A
and B , and the total bandwidth of one or more sub-paths is equal to Br . One or more sub-paths and the total bandwidth
Br are denoted as a lantern.
Fig. 1(b) shows a lantern. Each sub-path in a lantern is responsible for a sub-bandwidth requirement. The number of sub-paths of a lantern is dependent on the network bandwidth. The value of the lantern is in its flexibility: (i) when the network bandwidth is very limited, the lantern offers a multi-path routing as illustrated in Fig. 1 (b), and (2) when the network bandwidth is sufficient, the lantern just only provides a uni-path routing as illustrated in Fig. 1(a). The lantern nature is to increase the success rate of identifying a QoS route and provide a robust and reliable mechanism.
Continually, consider a QoS path is requested from node S to node D and to satisfy the bandwidth requirement Br as given in Fig. 1(c). An alterative path from S to D , namely lantern-path, can be constructed, where the components of
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Fig. 3. Examples of (a) lantern-tree, and (b) lantern-tree with reliable mechanism.
the path are lanterns. The lantern-path inherits the advantage of high success rate of searching a QoS route and robust and reliable mechanisms from the lantern nature. Definition 2: Lantern-path: A path is denoted as a lantern-path if zero or more lanterns exist in the path. For instance as illustrated in Fig. 1(d), only one lantern exists in the path. Five lanterns occur in the path as shown in Fig. 1(e). Each lantern in the lantern-path is viewed as a multi-path routing. Comparing Fig. 1(d) with Fig. 1(e), path
S to D, is found except for the sub-paths from A to B . In the worse case, if we cannot search an uni-path from S to D , a lantern-path with the greater number of lanterns is identified. A in Fig. 1(d) indicates that a QoS uni-path, from
lantern-path with the less number of lantern will be recognized if the network bandwidth is sufficient. A lantern-path with the greater number of lanterns will be constructed if the network bandwidth is limited. This paper presents a new multicast tree structure, namely lantern-tree. The lantern-tree is a tree if the path of the tree is the lantern-path. Definition 3: Lantern-tree: A tree is denoted as a lantern-tree if path of the tree is replaced with the lantern-path. For example, Fig. 2(a) is a tree, and Fig. 2(b) and Fig. 2(c) are examples of lantern-tree with different number of lanterns. Similarly, a lantern-tree with the less number of lantern is recognized if the network bandwidth is sufficient as shown in 2(b). A lantern-tree with the greater number of lanterns is constructed if the network bandwidth is limited as illustrated in Fig. 2(c). In summary, the advantage of the proposed lantern-tree is (1) task sharing: each sub-path of a lantern-tree is responsible for the partial bandwidth requirement; (2) high stability capability: it is easier to search backup sub-path of a lantern-tree to maintain the QoS-route stability due to the lower bandwidth requirement. In addition, the proposed lantern-tree offers a reliable mechanism to provide a reliable multicast transmission. The reliable mechanism is accomplished by adding the ACK. short message within each lantern of the lantern-tree. Fig. 3(a) is a lantern-tree and Fig. 3(b) shows a lantern-tree with a reliable mechanism. III. LTM: L ANTERN -T REE -BASED Q O S M ULTICAST P ROTOCOL We first give an overview of our proposed LTM: Lantern-Tree-based QoS Multicast routing protocol. The LTM protocol mainly constructs a lantern-tree to perform the on-demand QoS multicast routing operation. The LTM protocol is achieved by three phases of lantern identification, lantern-tree construction and lantern-tree maintenance. The lantern
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identification phase identifies the lantern for each node in a MANET. The lantern-tree construction phase constructs the lantern-tree by merging lantern-paths from a source to all destinations. The lantern-tree maintenance phase maintains the lantern-tree structure for the sake of enhancing the robustness and keeping its stability. A. Phase 1: Lantern Identification To identify the lantern, the local link-state information is collected for each node in the MANET. This work is accomplished by periodically maintaining the beacon message, where the beacon lifetime is two-hop. Since the beacon message floods into MANET within two-hops, each node acquires the local link-state information from all two-hop neighboring nodes before identifying the lantern.
A free time slot list is denoted as f1 2 g where 1 2 is a set of free time slots. The link-state in-
formation includes all one-hop and two-hop neighboring nodes and all corresponding free time slot list of these nodes.
A is B and free time slot list of B is 3 4 5 6 7 8 , and two-hop neighboring node of A is E and free time slot list of E is 1 3 4 5 6 : If free time slot lists of two neighboring nodes A and B are 1 2 1 and 1 2 2 1 = 2 we use an intersection function ( 1 2 1 1 2 2 ) = ( 1 2 r3 ) where 3 min 1 2 : Let ( 1 2 r3 ) represented as shared free time slots between nodes A and B . This indicates that communicating between A and B should r3 ): For example as shown in Fig. 4(a), free time slot lists of A and be selected from shared free time slots (1 2 B are 1 2 4 7 8 and 3 4 5 6 7 8 , respectively, so ( 1 2 4 7 8 3 4 5 6 7 8 ) = (4 7 8) as illustrated in Fig. 4(a). Node A communicates with node B in time slots (4 7 8): Similarly, B communicates with E in time slots (3 5 6): For instance as shown in 4(a), one-hop neighboring node of
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The lantern is identified after collecting the local link-state information for all nodes in the MANET. Given a pair of
e and e , if one or more disjoint sub-paths exist from e to e , then a lantern is constructed between e and e . A counterexample is founded that a lantern is not existed from node A as illustrated in Fig. 4(b), although there are many sub-paths from A. Denote n1 n2 nk ] as a path from node n1 to node nk , and n1 n2 ] as a link connecting n1 and n2 . ¿From table as illustrated in Fig. 4(a), three disjoint sub-paths B C G] B E G] and 2 n1 3 B F G] exist between B and G, a lantern is occurred from B to G: Let 64 ... 75 denote as a lantern between and nk 2 where 3 n1 ] and nk ] are k disjoint sub-paths between and : For example as shown in Fig. 4(b), C 7 6 B 4 E G5 is a lantern. Further, free time slot lists of B C E F and G are known from the local link-state information. F 1 1 2 2 ), where free The shared time slot list on link n1 n2 ] is denoted as S n1 n2 ] = ( 1 2 1 and 1 2 2 respectively. Therefore, S B C ] = (1 4) time slot lists of n1 and n2 are 1 2 S B E ] = (7 8) S B F ] = (2) S C G] = (5 6) S E G] = (3) and S F G] = (4): The number of shared time slots of S n1 n2 ] is denoted as S n1 n2 ] : For example, S B C ] = 2 S B E ] = 2 S B F ] = 1 S C G] = 2 S E G] = and S F2G] = 1 as shown in Fig. 4(b). n1(sn1) 3 6 75 as a lantern between and where sni denotes the maximum number of reWe further denote 4 ... nk (snk ) 3 2 C (2) 7 6 served time slots for sub-path ni ]: Following the above example, a lantern 4B E (1) G5 is identified for node B , F (1) 0
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Fig. 4. Identifying the lantern and its link bandwidth.
2 6 and the maximum number of reserved time slots of the lantern 4B
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C 7 E G5 is four. This information is useful for conF 2 n1 (sn1 ) 3 6 75 can be an uni-path (sn) ] if structing the lantern-path as described below. Observe that, a lantern 4 ... nk (snk ) k P the uni-path exists, where sn = sni : This indicates that the lantern identification is dependent on the network bandi=1 2 n1 (sn1) 3 6 75 is width. If the network bandwidth is sufficient, then a (sn) ] is identified. Otherwise, a lantern 4 ... nk (snk )
constructed if the network bandwidth is limited..
sub-layer is adopted the CDMA-over-TDMA channel model [13][14], the time slot reservation of 2 Since the MAC n1(sn1) 3 6 75 has the following rules. 4 .. .
nk (snk )
(r1) The time-slot reserves on link ni (sni )] and ni (sni ) ] must be different, where 1 i k: (r2) The time-slot reserves on link ni (sni )] and nj (snj ) ] can be same, where 1 i 6= j (r3) The time-slot reserves on all links ni (sni )] must be different, for 1 i k .
(r4) The time-slot reserves on all links ni (sni ) ] must be different, where 1 i k: As illustrated in Fig. 4(b), an instance of the time-slot reservation is given.
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(r1) The time slots (1 4) on link B C ] are different with slots (5 6) on link C G]: (r2) The time slot (4) on link B C ] is same with slot (4) on link F G]:
(r3) The time slots (1 4) (7 8) (2) on links B C ] B E ] and B F ] are different.
(r4) The time slots (5 6) (3) (4) on links C G] E G] and F G] are different.
This time-slot reservation is used as a primitive operation by constructing the lantern-path and lantern-tree. Our protocol can easily apply to MANETs with different MAC sub-layer assumptions. This work is accomplished by providing the different time-slot reservation for different MAC sub-layer channel models. B. Phase 2: Lantern-Tree Construction The lantern-tree construction phase is divided into two operations. 1) The Lantern-Path Searching Operation: Based on identified lanterns, many lantern-paths from a source to a given set of destinations are constructed. 2) The Lantern-Path with Reliable Mechanism: The lantern-path with a reliable mechanism is provided. 3) The Lantern-Tree Constructing Operation: Based on multiple lantern-paths, the lantern-tree is established. 4) The Lantern-Tree with Reliable Mechanism: The lantern-tree with a reliable mechanism is provided. These three operations are described as follows. B.1 The Lantern-Path Searching Operation
22 n11 (sn11) 6 6 Let 44 .. 1
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njk (snjk )
33 2 ni1(sni1 ) 7 7 6 j 55 denote as a lantern-path, where 4i ...
is i-th lantern of the lantern-path, i = i+1 and 1 i j ; 1: Observe that ki uni-subpath only if ki = 1: The searching lantern-path operation is given. j
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nik (snik ) 1, and the i-th lantern can be an i
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(A1) Source node initiates and floods a lantern-path request packet into the MANET to check if one or more lanterns ex-
22 n11 (sn11) 6 6 ist for the source node. If a lantern exists, then a lantern path with one lantern44 .. 1
"" An instance is given in Fig. 5, a lantern-path
(2) C SA B (1)
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is constructed.
(A2) We repeatedly perform step A1 until a possible lantern-path arriving at a destination node, then a lantern-path
22 n11 (sn11 ) 6 6 44 .. 1
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Fig. 6. Time-slot reservation for searching a lantern-tree.
22 n11(sn11) 6 6 The 44 .. 1
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2 C E (3) F ] 64F
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G(1) 77 6 A(2) C H (1) D55 is constructed. On ited. An example is shown in Fig. 5, a lantern-path 4 S B (1) I (1) 2 ni1 (sni1) 3 6 i 75 is given as the contrary, if the network bandwidth is sufficient, the construction of i-th lantern 4i ... nik (snik ) follows. 2 ni1(sni1) 3 k 6 i75 can be a two-hop uni-path i i (sni ) i ] if sni = P snit. This condition (B1) The i-th lantern 4i ... t=1 nik (snik ) is occurred if the network bandwidth, from i through i to i , is sufficient. 2 ni1 (sni1) 3 k 6 i 75 can be a one-hop uni-path i i] if the link bandwidth of i i] is P (B2) The i-th lantern 4i ... t=1 nik (snik ) snit. This condition is occurred if the network bandwidth between i and i is sufficient. 22 3 2 33 n11 (sn11) nj1(snj1) 66 1 75 64j ... j 7575 satisfy B1 and B2 Observe that if all lanterns of lantern path 441 ... njk (snjk ) n1k1 (sn1k1 ) i
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conditions, then our QoS route result is same as the result of Lin’s hop-by-hop reservation scheme [13][14]. That is, if the network bandwidth is sufficient, our result is same as the well-known hop-by-hop reservation scheme [13][14]. If the network bandwidth is limited, Lin’s approach is failed to search a QoS route, but our lantern-path approach can successfully identify a QoS route. These important effects are discussed in the Section IV.
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Fig. 7. The details of time-slot reservation for identifying a lantern-tree.
B.2 The Lantern-Path with Reliable Mechanism
22 n11(sn11) 6 6 . Consider a lantern path 44 . 1
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j
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n (sn ) 3 njk (snjk ) i75 of the lantern-path, and node i transmits messages to node i under i . nik (snik ) k P snit. Observe that a simple ACK. message must be sent from node i and received the bandwidth requirement t=1 i k: If each lantern of the lantern-path guarantees its successful transmission, then our by node i where 1 2 1k1 1k1 ni1 (sni1) 6 on the lantern path. For each 4 .. i
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Fig. 8. The lantern-tree merging cirterion.
B.3 The Lantern-Tree Constructing Operation This paper mainly constructs the multicast tree which is modified from the spiral-fat-tree on-demand multicast (SOM) protocol [4]. Observe that, the construction of our multicast tree can use the results of CBT [7], AODV [18], DVMRP[6], CAMP [16], FGMP [20], and ODMRP [11]. In this work, all spiral-paths of the spiral-fat-tree [4] are replaced with the lantern-path for the purpose of providing the reliable/QoS capability. An example of lantern-tree is illustrated in Fig. 7. (a). Let l1 l2 lj
2 ni1(sni1) 6 4 ..
22 n11(sn11 ) 6 6 . . ](b) represents as a lantern-path 44 1
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n (sn )
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1k1 1k1 3 k 75 is the i-th lantern of the lantern-path, and bandwidth b =P i
t=1
njk (snjk ) j
33 j 7575, where li =
j
snit: Given that two lantern-paths
nik (snik ) l1 l2 lp lp+1 lk ](b) and l1 l2 lp lp+1 lk ](b) have the same lantern sub-path l1 l2 lp ](b) we lp lp+1 lk ](b) l1 l2 lp lp+1 lk ](b)) = l1 l2 lp](b): Further, let l1 l2 lp] denote ( l1 l2 (b s) denote as s lantern-paths with same l1 l2 lp ] (b). We also denote l1 l2 lp ](b) = p to be the number of lanterns, which indicates the number of shared lantern sub-path for given s lantern-paths. Given each pair of s and s i
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0
replied lantern-paths, among many replied lantern-paths from destination nodes to the source node, we have the merging criterion to construct the lantern-tree according to values of p s and b. (C1) If the
s replied lantern-paths with the maximum values of p s and b, then these s lantern-paths are merged
together with the highest priority. (C2) If there are
s and s
replied lantern-paths with the same values of
p and s, then s lantern-paths with the greater
(C3) If there are
s and s
replied lantern-paths with the same values of
b and s, then s lantern-paths with the greater
(C4) If there are
s and s
replied lantern-paths with the same values of
b and p, then s lantern-paths with the greater
0
value of b are merged together. 0
value of p are merged together. 0
value of s are merged together.
(C5) If there are s and s0 replied lantern-paths with the same values of p , then s lantern-paths with the greater value of
b are merged together.
11
S
S B G H D1 J D2
S
Ack.
B
C
A
S B G H D1
A
B G H D1 J D2
B
E
C
B G H D1
Ack.
E
G H D1 J D2
F
F
G
G
Ack. G H D1 H D1
G J D2
J D2
I
H
J
J
I
H
K
L
H D1
L
K J D2
Ack. D1
M
D1
D2
M
D1
D2
D2
(d)
(c)
Fig. 9. Example of a lantern-tree with reliable mechanism.
(C6) If there are s and s0 replied lantern-paths with the same values of s , then s lantern-paths with the greater value of
b are merged together. (C7) If there are s and s
replied lantern-paths with the same values of b , then s lantern-paths with greater value of s
0
are merged together. (C8) If there are
s and s
0
replied lantern-paths with the different values of
greater value of b are merged together.
p b and s then s lantern-paths with the
Figs. 8(a) and (b) are example of (C6) case, and Figs. 8(b) and (c) are instance of (C7) case. B.4 The Lantern-Tree with Reliable Mechanism
2 ni1 (sni1) 6 . Consider a lantern-tree, each lantern 4 . i .
nik (snik ) i
i
3 7 5 of the lantern-tree performs a simple reliable mechanism.
i
Node i transmits messages to node i under the bandwidth requirement
must be sent from node i and received by node i where 1
k P i
t=1
snit . Observe that a simple ACK. message
i k: If each lantern of the lantern-tree guarantees its
successful transmission, then the lantern-tree guarantees the successful transmission. An example is illustrated in Fig. 9. C. Phase 3: Lantern-Tree Maintenance
22 n11 (sn11) 6 6 . Given a lantern path 441 ..
1
3 2 nj1(snj1) 7 6 5 4 .. j .
33 2 ni1(sni1 ) 7 7 6 j 55, if 4i ...
3 i 75 is the i-th
n1k1 (sn1k1 ) njk (snjk ) nik (snik ) lantern of the lantern-path and sub-path i nit (snit ) i ] is failed, then we try to search a backup sub-path " i b(sn#it ) i ] to replace with the failure sub-path i nit(snit) i]: An example is shown in Fig. 10, the lantern B CE (3) (3) G is j
j
i
i
12
S
B C C1
E
G
D1
D2
Fig. 10. Example of the lantern-tree maintenance.
" replaced by lantern
#
(3) G B CE1(3)
if node C runs away. IV. E XPERIMENTAL R ESULTS
To examine the effectiveness of our approach, two well-known on-demand QoS multicast protocols, AODV [18] and ODMRP [11], are mainly compared with our approach. Observe that, AODV [18] and ODMRP [11] do not provide the QoS capability. In addition, Lin designed an on-demand QoS routing protocol in [13]. To make a fair comparison, we specially provide the QoS-version AODV [18] and ODMRP [11] protocols such that each path in the AODV [18] and ODMRP [11] protocols adopts the Lin’s QoS routing result [13]. In this simulation, these two integrated results are denoted as AODV(Lin) and ODMRP(Lin), respectively. The simulation parameters are given below.
The mobility speed is from 10 to 90 km/h.
The message length is ranging from 1 to 30K.
The transmission radius is from 50 to 150 m.
The number of mobile hosts ranges from 50, 75 and 100.
The bandwidth requirement are 1, 2 and 4 time slots.
The number of time slots in the data phase of a frame is assumed to be 16 slots.
Each simulated result is obtained by average values through 5000 runs. The simulator is simulated in a 1000
1000-m2 area. The data rate is 2 Mb/s. The duration of each time slot
of a time frame is assumed to be 5 ms, and the duration of a control time slot is assumed 0.1 ms. The source and destination are selected randomly. Once a QoS request is successful, a time slot is reserved for all subsequent packets. The reservation is released when either the data transmission process is finished or the link is broken. A packet is dropped if the packet residing in a node exceeds the maximal queuing delay time, which is set to four frame lengths (328 ms). The performance metrics contain.
Success Rate (SR): The number of successful QoS multicast route divided by the total number of QoS multicast
13
100
100 A O D V (L in )
90
O u rs
80
80
70
70
60
60
50
O D M R P (L in )
90
Success Rate
Success Rate
A O D V (L in )
O D M R P (L in )
O u rs
50
40
40
30
30
20
20
10
10 0
0 n=50
75
100
10
50
75
100
30
50
75
100
50
50
75
100
70
50
75
100
90
QoS=1
2
10
4
1
2
30
4
1
2
4
1
50
Mobility
Mobility
(a)
(b)
2
70
4
1
2
4
90
Fig. 11. Performance of success rate (SR) vs. effect of (a) number of mobile hosts, and (b) number of bandwidth requirement.
requests, which initiated from a source to all destination hosts.
OverHead (OH ): The total numbers of transmitted packets, including the control and data packets. ThroughPut (TP ): The number of received data packets for all destination hosts divided by the total number of
data packets sent from the source host.
Average Latency (AL):
The interval from the time the multicast is initiated to the time the last host finishing its
multicasting.
SR, a low OH , a high we illustrate our simulation results of SR, OH , TP and AL from various
It is worth mentioning that an efficient QoS multicast protocol is achieved by having a high
TP , and a low AL.
In the following,
prospects. A. Performance of success rate vs: mobility The simulation results of AODV(Lin), ODMRP(Lin), and LTM protocols are shown in Fig. 11 to reflect the perfor-
mance of SR vs. mobility. The average SR is obtained by calculating the average value of all estimate SR values. Two kind of effects are discussed. 1A) Effect of number of mobile hosts: Each value in Fig. 11(a) was obtained by assumed transmission radius of 100 m, while the bandwidth requirement is 1 time slot and the number of mobile hosts ranged from 50 to 100. A higher SR indicates that a better scheme was achieved. Fig, 11(a) shows that LTM scheme has a higher SR than do the other scheme have even with various numbers of mobile hosts and values of mobility. For example, the average SRs of AODV(Lin), ODMRP(Lin), and LTM are 74%, 82%, and 85%, respectively, when the mobility of hosts was 0˜90km/h. To see the effect of the number of mobile host, two situations can be observed. For low mobility (at 0˜10km/hour), the greater the number of mobile host is, the higher the SR will be. For high mobility (at 0˜90km/hour), the greater the number of mobile host is, the lower the SR will be. This is because the probability of re-constructing a multicast route increases with a greater number of mobile hosts and higher mobility. 1B) Effect of number of bandwidth requirement: Each value in Fig. 11(b) was obtained by assuming the number of mobile hosts to be 75 and the number of bandwidth requirement is 1, 2, and 4. Fig. 11(b) shows the success rate
14 (Packets)
(Packets)
60000
60000 A O D V (L in )
A O D V (L in )
O D M R P (L in )
O D M R P (L in ) O u rs
50000
50000
40000
40000
Overhead
Overhead
O u rs
30000
30000
20000
20000
10000
10000
0
0 n=50
75
10
100
50
75
100
50
30
75
50
100
75
50
70
100
50
75
100
90
QoS=1
2
4
10
1
2
4
1
30
2
50
Mobility
Mobility
(a)
(b)
4
1
2
4
1
70
2
4
90
Fig. 12. Performance of overhead (OH) vs. effect of (a) number of mobile hosts, and (b) number of bandwidth requirement.
of searching a QoS multicast route vs. bandwidth requirement. Observe that our approach has a higher success rate compared to AODV(Lin) and ODMRP(Lin) schemes under bandwidth requirement ranges from 1 to 4. This indicates that our proposed protocol outperforms the AODV(Lin) and ODMRP(Lin), even if the bandwidth requirement is high. This is because our lantern-tree scheme actually improves the SR. B. Performance of overhead vs: mobility The simulation result shown in 12 illustrate the performance of overhead vs. mobility. The average OH was obtained
by calculating the average value of all estimated OH values. Two kinds of effect are described below.
2A) Effect of number of mobile hosts: Each value in Fig. 12(a) is obtained by assumed transmission radius be 100 meters, QoS requirement be 1 and number of mobile hosts is ranging from 50 to 100. A lower OH indicates that a better scheme will be. Fig. 12(a) shows that our scheme has higher OH than others. In MANET, network topology will frequently changes when we have more mobile host and higher mobility. Because our protocol collect the network information usually, when network topology often changes will results our protocol have higher overhead. 2B) Effect of number of bandwidth requirement: Each value in Fig. 12(b) is obtained by assuming that the number of mobile hosts is 75 and the number of bandwidth requirement is 1, 2, and 4. Fig. 12(b) shows the OH of searching a QoS route vs. bandwidth requirement. Observe that our approach acquires a stable OH than does the AODV(Lin) and ODMRP(Lin) under bandwidth requirement from 1 to 4. Our lantern-tree scheme can indeed control and down the overhead because we collect network information in usual time, when QoS requirement is limited, our protocol can recognize the suitable path easily and reduce forward packages substantially. C. Performance of throughput The simulation results of AODV(Lin), ODMRP(Lin), and LTM protocols are shown in Fig. 13 to reflect the effects
of throughput. To examine the performance of TP , two kinds of effects are discussed.
3A) Effect of number of message length: Each value in Fig. 13(a) was obtained by assuming the transmission radius to be 100 m, the number of mobile hosts to be 75, the number of bandwidth requirement to be 1, while the mobility is 50 and the number of message length ranges from 1K to 30K. A higher TP indicates that a better scheme. Fig. 13(a) shows
15
110
110 A O D V (L in )
A O D V (L in )
O D M R P (L in )
90
90
80
80
70
70
60
60
50
50
40
40
30
(Kbytes)
1
5
10
20
O u rs
100
Throughput TP
Throughput
O D M R P (L in )
O u rs
100
30
30 QoS=1
2
10
4
1
2
30
4
1
2
4
1
50
Message Length
Mobility
(a)
(b)
2
70
4
1
2
4
90
Fig. 13. Performance of throughput (TP) vs. effect of (a) number of message length, and (b) number of bandwidth requirement.
that LTM scheme has better TP than do the other schemes at various message lengths. For example, TP of AODV(Lin), ODMRP(Lin), and LTM are 43%, 63%, and 82%, respectively, when the message length is 30K. 3B) Effect of number of bandwidth requirement: Each value in Fig. 13(b) was obtained by assuming that the number of mobile hosts to be 75 and the number of bandwidth requirement to be 1, 2, and 4. Fig. 13(b) shows the throughput of searching a QoS multicast route vs. bandwidth requirement. Observe that our approach has a stable and higher throughput. This indicates that LTM protocol is better than the AODV(Lin) and ODMRP(Lin), even if the bandwidth requirement is high. This is because our lantern-tree scheme improves TP. For example, Fig. 13(b) illustrates that if the bandwidth requirement is 4 and the mobility is 90, our TP (68%) is higher than the AODV(Lin)’s TP (36%) and ODMRP(Lin)’s TP (47%). D. Performance of average latency The simulation results are illustrated in Fig. 14 to reflect the performance of AL vs. load and mobility. Two kinds of effects are discussed below. 4A) Effect of number of message Length: The simulation assumption is the same as in case 3A. A lower AL indicates that a better scheme. Fig. 14(a) shows that our scheme has lower AL than do other schemes. For example, average AL of AODV(Lin), ODMRP(Lin), and LTM are 6534ms, 5973ms, and 4757ms, respectively, when message length is 30K. This is because that our protocol has extra backup paths and to keep the better AL. 4B) Effect of number of bandwidth requirement: The simulation assumption is the same as in case 3B. Fig. 14(b) shows the AL vs. bandwidth requirement. Observe that our approach obtains a lower AL than does the AODV(Lin) and ODMRP(Lin), when the bandwidth requirement ranges from 1 to 4. This indicates that our proposed protocol outperforms other schemes, even if the bandwidth requirement is high. This is because our lantern-tree scheme actually decrease the AL. For instance, Fig. 14(b) illustrates that if the bandwidth requirement is 4 and the mobility is 90, LTM’s AL (4087ms) is lower than the AODV(Lin)’s AL (5653ms) and ODMRP(Lin)’s AL (4721ms).
Apparently, it is desirable to have a high SR as well as AL. Generally, the higher the SR is, the higher the AL will
be. It is always beneficial to use our LTM protocol as demonstrated by the simulation results.
16 (ms)
(ms) 8000
8000
A O D V (L in )
A O D V (L in )
O D M R P (L in )
O D M R P (L in ) O u rs
7000
6000
6000
5000
5000
AL
Average Latency
AL
Average Latency
7000
4000
4000
3000
3000
2000
2000
1000
1000
0
(Kbytes)
1
5
10
20
O u rs
0 QoS=1
30
2
10
4
1
2
30
4
1
2
50
Message Length
Mobility
(a)
(b)
4
1
2
70
4
1
2
4
90
Fig. 14. Performance of average latency (AL) vs. effect of (a) number of message length, and (b) number of bandwidth requirement.
V. C ONCLUSIONS This article presents a lantern-tree-based QoS multicast protocol with reliable mechanism for a wireless ad-hoc network, especially the MAC sub-layer is adopted the CDMA-over-TDMA channel model. Our approach can be easily apply to different MAC sub-layers, likes the TDMA channel model. Our lantern-tree-based scheme greatly improves the success rate by means of multi-path routing. More specially, our proposed scheme can directly perform on all existing on-demand multicast protocols. Performance analysis results demonstrate the achievements of our proposed protocol. R EFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
IEEE Std 802.11-1997. Wireless LAN Medium Access Control (MAC) and Physical layer (PHY) specifications. Institute of Electrical and Electronics Engineers, Inc. S. Chen and K. Nahrstedt. Distributed Quality-of-Service Routing in Ad Hoc Networks. IEEE Journal on Selected Areas in Communications, 17(8):1488–1505, aug. 1999. S. Chen, K. Nahrstedt, and Y. Shavitt. A QoS-Aware Multicast Routing Protocol. In Proc. of IEEE INFOCOM, pages 1594–1603, 2000. Y.-S. Chen, T.-S. Chen, and C.-J. Huang. SOM: Spiral-Fat-Tree-Based On-Demand Multicast Protocol in a Wireless Ad-Hoc Network. Computer Communications (to appear), 2002. Y.-S. Chen and K.-C. Lai. MESH: Multi-Eye Spiral-Hopping Protocol in a Wireless Ad Hoc Network. IEICE Transactions on Communications, E84-B(8):2237–2248, aug. 2001. S. E. Deering and D. R. Cheriton. Multicast routing in datagram internetworks and extended lans. ACM Transactions on Computer Systems, 8(2):85–110, May 1990. R. Dube, C. D. Rais, K.-Y. Wang, and S. K. Tripathi. Signal stability-based adaptive routing (ssa) for ad hoc mobile networks. IEEE Personal Communications, pages 36–45, feb 1997. Y.-K. Ho and R.-S. Liu. On-demand QoS-based Routing Protocol for Ad Hoc Mobile Wireless Networks. In Proc. of the Fifth IEEE Symposium on Computers and Communications (ISCC), pages 560–565, 2000. Y.-C. Hu and D. B. Johnson. Caching Strategies in On-Demand Routing Protocols for Wireless Ad Hoc Networks. In Proc. of MOBICOM, pages 231–242, 2000. D. B. Johnson and D. A. Maltz. Dynamic Source Routing in Ad Hoc Wireless Networks. In Mobile Computing, edited by Tomasz Imielinski and Hank Korth, Chapter 5, pages 81–153, 1996. S.-J. Lee, W. Su, and M. Gerla. On-demand multicast routing protocol (odmrp) for ad hoc networks. IETF manet(draft-ietf-manet-odmrp02.txt), 2000. W.-H. Liao, Y.-C. Tseng, J.-P. Sheu, and S.-L. Wang. A Multi-Path QoS Routing Protocol in a Wireless Mobile Ad Hoc Network. In IEEE ICN’01: International Conference on Networking, July 2001. C.-R. Lin. On-Demand QoS Routing in Multihop Mobile Networks. In Proc. of IEEE INFOCOM 2001, pages 1735–1744, April 2001. C.-R. Lin and J.-S. Liu. QoS Routing in Ad Hoc Wireless Networks. IEEE Journal on Selected Areas in Communications, 17(8):1426–1438, aug. 1999.
17
[15] H. C. Lin and P. C. Fung. Finding Available Bandwidth in Multihop Mobile Wireless Networks. In Proc. of the IEEE Vehicular Technology Conference, pages 15–18, May, 2000. [16] S. Murthy and J. J. Garcia-Luna-Aceves. An efficient routing protocol for wireless networks. ACM Mobile Networks and APP. J., pages 183–197, October 1996. [17] C. E. Perkings and P. Bhagwat. High dynamic destination-sequenced distance-vector routing(dsdv) for mobile computers. Comp. Commun. Rev, pages 233–244, October 1994. [18] E. M. Royer and C. E. Perkins. Ad-hoc on-demand distance vector routing. Second IEEE Workshop on Mobile Computer Systems and Applications, pages 25–26, February 1999. [19] A. K. Talukdar and B. R. Badrinath. Rate Adaptation Schemes in Networks with Mobile Hosts. In Proc. of MOBICOM, pages 169–180, 1998. [20] C.-K. Toh. Associativity-based routing for ad-hoc mobile networks. Wireless Pers. Commun., 4(2):1–36, March 1996. [21] Y.-C. Tseng, J.-P. Sheu, and C.-Y. Lin. A New Mutli-Channel MAC Protocol with On-Demand Channel Assignment for Mobile Ad Hoc Networks. Int’l Symp. on Parallel Architectures, Algorithms and Networks (I-SPAN), pages 232–237, 2000.
