In a wireless multihop network, a sequence of data messages

are transmitted from a source wireless node to a destination

one through a sequence of intermediate wireless nodes. Each

pair of successive intermediate wireless nodes are included in

wireless transmission ranges each other and data messages are

forwarded one by one along a wireless multihop transmission

route. In order to conﬁgure a wireless multihop transmission

route between arbitrary pair of a source and a destination

wireless nodes, enough high density of distribution of wireless

nodes is required. However, in a wireless multihop network

with sparsely or unevenly distributed wireless nodes, it is

difﬁcult to detect a wireless multihop transmission route, i.e.,

it is difﬁcult to transmit a sequence of data messages by

successive forwarding by a sequence of intermediate wireless

nodes. Hence, some method have been proposed in which a

part of intermediate wireless nodes carry data messages in

transmission. That is, an intermediate wireless node receives

a data message from its previous-hop one, holds the message

in its communication buffer and moves until it becomes a

neighbor of its next-hop one and forward the message to it.

Then, it moves back its original position to receive the next

data message from its previous hop intermediate wireless node.

In the conventional wireless multihop transmission methods by

combination of carrying and forwarding data messages, only

part of the intermediate wireless nodes carry data messages

and consume their battery capacity for mobility. In addition, a

previous-hop intermediate wireless node Ni−1of an interme-

diate wireless node Nicarrying a data message might holds

data messages in its buffer and waits for being a neighbor of

Ni. Hence, end-to-end transmission delay of data messages

becomes longer.

This paper proposes a novel method to transmit data mes-

sages by combination of carrying and forwarding with even

battery power consumption among intermediate wireless nodes

and shorter end-to-end transmission delay of data messages.

Here, though battery consumption does not evenly share

among intermediate wireless nodes and additional transmis-

sion delay of data messages due to longer wireless multihop

transmission route and unreasonable synchronization between

successive intermediate wireless nodes in an initial wireless

multihop transmission route, the route is modiﬁed gradually in

accordance with transmissions of a sequence of data messages.

Each intermediate wireless node modiﬁes its mobility section

in local relation to its previous- and next-hop intermediate

wireless nodes and the wireless multihop transmission route

gradually modiﬁed as a result. Required overhead for carrying

data messages becomes to be shared evenly among the in-

termediate wireless nodes, the wireless multihop transmission

route gradually resembles a line segment whose terminals

are the source and the destination wireless nodes and shorter

additional transmission delay is required for data messages due

to synchronization between successive intermediate wireless

nodes. As discussed later, mobility section of each interme-

diate wireless node is modiﬁed locally and the modiﬁcation

Gradual Route Modification in Mobile Wireless Multihop Network

with Combination of Carrying and Forwarding

RYOTA KURABAYASHI, HIROAKI HIGAKI

Department of Robotics and Mechatronics, Tokyo Denki University, Tokyo, JAPAN

Abstract: In a wireless multihop network, data messages are transmitted along a wireless multihop transmission route

composed of a sequence of intermediate wireless nodes forwarding the data messages. However, it is difficult to detect a

wireless multihop transmission route from a source wireless node to a destination one if a wireless nodes are not evenly

distributed and there are some areas in which wireless nodes are sparsely distributed. Some methods have been proposed

to solve this problem by combination of forwarding data messages between neighbor intermediate wireless nodes as in a

usual wireless multihop network and carrying data messages to pass through such areas. In the conventional methods with

the combination of forwarding and carrying data messages, some dedicated intermediate mobile wireless nodes serve the

role of carrying. Hence, such nodes are required to consume more battery power which results in lower connectivity of the

network. In addition, transmissions of data messages might be suspended for waiting the carrying intermediate wireless

nodes which results in longer end-to-end transmission delay. In order to solve the problems, this paper proposes a novel

carrying and forwarding method which gradually modifies a wireless multihop transmission route to evenly share the

required mobility overhead among all the intermediate mobile wireless nodes and to reduce end-to-end transmission delay

of data messages by making the route shorter. The proposed method ensures that no successive intermediate wireless nodes

pass each other without neighboring.

Keywords: Wireless Multihop Network, Delay Tolerant, Carrying and Forwarding, Ad-Hoc Routing, Node Mobility.

Received: June 2, 2022. Revised: June 13, 2023. Accepted: July 12, 2023. Published: August 2, 2023.

1. Introduction

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Volume 22, 2023

does not share with its previous- and next-hop intermediate

wireless nodes instantaneously. Thus, it is possible for succes-

sive intermediate wireless nodes to pass each other without

neighboring. This paper also shows the restriction of node

mobility to avoid such passing each other.

Various communication methods with carrying data mes-

sages by intermediate wireless nodes for supporting DTN

(Delay-Tolerant Network) have been proposed [2]. Here, not

only forwarding data messages to neighbor wireless nodes

but also carrying data messages, i.e., holding data messages

in communication buffers and moving, are expected to con-

tribute to wireless multihop transmissions of data messages.

In Epidemic Routing [4], each mobile wireless node carrying

copies of data messages encounters another node and forwards

the copies to it. Mobile wireless nodes carrying a copy of

a data message increases and one of them is expected to

encounter its destination node and forwards the data message

to it. In Message Ferrying [5], dedicated mobile wireless nodes

called ferry nodes carry data messages between clusters of

wireless nodes to support data message transmissions between

the clusters where it is difﬁcult to transmit data messages only

by forwarding.

In these methods, only one or a few data messages are

transmitted along a wireless multihop transmission route.

Thus, it is difﬁcult for them to be applied to a sequence of

data messages for large-scale data transmissions or for time-

continuous streaming data transmissions. Hence, as shown

in Figure 1, it is expected for combination of carrying and

forwarding of data messages by a sequence of intermediate

mobile wireless nodes to contribute to transmit such a se-

quence of data messages.

NDBAR (Node Density-Based Adaptive Routing) [1] is an

ad-hoc routing protocol to support such data message multihop

transmissions with carrying and forwarding. This is a ﬂooding-

based routing protocol as well-known ad-hoc routing protocol

such as AODV and DSR. For detection and conﬁguration of

a wireless multihop transmission route from a source wireless

node to a destination one, ﬂooding of a route request control

message Rreq is applied. In usual ﬂooding-based routing

protocol, all the node broadcast a Rreq control message

with the same transmission power. However, in NDBAR,

if a wireless node receiving the ﬁrst Rreq control message

have a less neighbor wireless nodes than the predetermined

threshold, it broadcasts the Rreq control message with higher

transmission power to reach farther wireless nodes. In data

message transmissions, the intermediate wireless node having

transmitted an Rreq control message with higher transmis-

sion power becomes a ferry node and repeats carrying data

messages from its previous-hop intermediate wireless node to

its next-hop one. This routing and data message transmission

protocol provides the combination of carrying and forwarding,

part of the intermediate wireless nodes are required to consume

more battery power capacity to broadcast an Rreq control

message with higher transmission power and to carry data

messages along its mobility section.

Carrying

Forwarding Forwarding

Fig. 1. Multihop Data Message Transmissions by Combination of Carrying

and Forwarding.

In this paper, it is assumed that a sequence of data messages

are continuously transmitted from a source wireless node to a

destination one along a wireless transmission route consisting

of a sequence of intermediate mobile wireless nodes. In our

proposal, not only a part of the intermediate nodes but also

all the possible intermediate nodes carry and forward data

messages in transmission, i.e., overhead for carrying data

messages are evenly shared among all the intermediate nodes.

Here, a source and a destination wireless nodes are stationary

and it is assumed that the source wireless node have the

location information of the destination one in advance. In

addition, location acquisition devises such as GPS receivers

are equipped in all the mobile wireless nodes which are

possible intermediate wireless nodes in a wireless multihop

transmission route. Hence, all the mobile wireless nodes are

assumed to get their own current location information in

a realtime manner. As explained in the following subsec-

tions, an initial wireless multihop transmission route from

the source stationary wireless node to the destination one is

detected where data message transmissions along the route

are realized by combination of carrying and forwarding by

the intermediate mobile wireless nodes. In the initial route,

lengths of mobility of the intermediate wireless nodes for

carrying data messages are distributed and the total length of

the wireless multihop transmission route is longer than that

of a line segment between the source and the destination

nodes. During the continuous data message transmissions,

the mobility segments of the intermediate mobile wireless

nodes are modiﬁed gradually. The lengths of the mobility

segments become equal and the total length of the end-to-

end route becomes shorter. In the following subsections, a

routing protocol for detection of the initial route and a data

message transmission protocol by combination of carrying and

forwarding with route modiﬁcations are discussed.

An initial wireless multihop transmission route from a

source stationary node Nsto a destination one Ndis de-

tected by location based forwarding of a route request control

message Rreq in accordance with GEDIR [3] ad-hoc routing

protocol. Ndand each intermediate mobile wireless node Ni

2. Related Works

3. Proposal

3.1 Initial Route Detection

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NsNd

Route Modification

Fig. 2. Gradual Route Modiﬁcation in Proposed Method.

having received an Rreq control message from its previous-

hop intermediate wireless node Ni−1sends the Rreq control

message to the neighbor wireless node Ni+1 nearest to Ndif

|Ni+1Nd|<|NiNd|is satisﬁed as shown in Figure 3.

Ni+1

Rreq

Fig. 3. Rreq Forwarding in Initial Routing.

If there are no such neighbor wireless node Ni+1, the route

detection is aborted in the original GEDIR, which is called

a deadend. Different from the original GEDIR, since data

message transmissions along a wireless multihop transmission

route are realized by combination of carrying and forwarding,

Nicarries the Rreq control message along a line segment

NiNduntil it detects the Ni+1 satisfying |Ni+1Nd|<|NiNd|

in our proposal. Then, Nistops at the instance and sends the

Rreq control message to Ni+1 as shown in Figure 4.

For the following discussion, LN −

iand LN +

iare the

locations where Nireceives an Rreq control message from

Ni−1and Nisends it to Ni+1, respectively. If Nihas the

neighbor wireless node nearer to Ndthan Niwhen it receieves

an Rreq control message from Ni−1,LN −

i=LN +

i. A route

reply control message Rrep is transmitted along the detected

Ni+1

Ni-1

Carrying Rreq

LNi

−

LNi

No Neighbor Node

Nearer to

Detecting Nearer Neighbor

Node and Forwarding Rreq

Fig. 4. Rreq Carrying in Initial Routing.

wireless multihop transmission route from Ndto Nsfor con-

ﬁrmation of the route detection and for update of routing tables

in the intermediate wireless nodes in the original GEDIR. In

our proposal, the Rrep control message is also transmitted by

combination of carrying and forwarding. Ndsends an Rrep

control message to Nn−1since it is surely a neighbor wireless

node of Ndand an Rreq control message has been forwarded.

Each intermediate mobile wireless node Nireceives an Rrep

control message from Ni+1 at LN +

i, carries the Rrep control

message along a line segment LN +

iLN −

i, stops at LN −

iand

sends the Rrep control message to Ni−1which is at LN +

i−1.

Finally, the Rrep control message reaches Ns.

By this route detection and conﬁguration, it is possible for

data messages to be transmitted along the wireless multihop

transmission route by combination of carrying and forwarding.

Each intermediate mobile wireless node Niwaits for receiving

a data message from Ni−1at LN −

i. On receipt of a data

message, Nicarries the data message along its mobility seg-

ment LN −

iLN +

i. Then, Niwaits for Ni+1 being its neighbor

wireless node at LN −

i+1, sends the data message to Ni+1 and

moves back to LN −

ifor the transmission of the next data

message. By this combination of carrying and forwarding, a

sequence of data messages are transmitted from Nsto Nd

along the wireless multihop transmission route. However, as

shown in Figure 5, the initial transmission route is longer than

the line segment NsNdwhich results in longer transmission

delay of data messages and higher mobility overhead in the

intermediate mobile wireless nodes. In addition, the lengths

of the mobility segments of the intermediate mobile wireless

nodes are widely distributed. Since some intermediate mobile

wireless nodes have to wait for receiving data messages from

its previous-hop wireless nodes and for sending data messages

to its next-hop wireless nodes at the ends of their mobility

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DOI: 10.37394/23204.2023.22.8

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E-ISSN: 2224-2864

Volume 22, 2023

segments, end-to-end transmission delay of data messages

becomes longer. Uneven sharing of mobility overhead among

multiple intermediate mobile wireless nodes cause uneven

battery power consumption and mobile wireless nodes with

exhausted battery capacities have to be removed from the

wireless multihop network. Therefore, the connectivity of the

wireless multihop network becomes lower.

Fig. 5. Initial Wireless Multihop Transmission Route.

In order to solve the problems shown in the previous

subsection, the ends LN −

iand LN +

iof a line segment

LN −

iLN +

iwhich is the mobility segment of an intermediate

mobile wireless node Niare updated at the instances of

receiving and sending data messages by Ni. If the previous-

hop intermediate mobile wireless node Ni−1does not reach

LN +

i−1when Nireaches LN −

i, it is impossible for Nito

receive a data message from Ni−1. Though Niwaits for Ni−1

to reach LN +

i−1at LN −

iin the conventional methods such

as NDBAR, Nicontiguously moves along a line segment

LN −

iLN −

i−1to LN −

i−1as shown in Figure 6. This is because

the mobility segment of Ni−1seems to be relatively longer

than the mobility segment of Niand it is required for the

mobility segments of Ni−1and Nito become shorter and

longer, respectively. During the contiguous mobility of Ni

along the extended mobility segment from LN −

ito LN −

i−1,

if Niencounters Ni−1, i.e., Niand Ni−1become included

in the wireless signal transmission ranges each other, both Ni

and Ni−1stop and a data message is forwarded from Ni−1to

Ni. Here, LN −

iis updated to the current location of Niand

LN +

i−1is updated to the current location of Ni−1as shown

in Figure 7.

LN i

−

LN i

LNi-1

−

Contiguous Mobility

Fig. 6. Contiguous Mobility (Backward) of Ni.

On the other hand, if the next-hop intermediate mobile

wireless node Ni+1 does not reach LN −

i+1 when Nireaches

LN +

i, it is impossible for Nito send a data message to

Ni+1. Though Niwaits for Ni+1 to reach LN −

i+1 at LN +

iin

the conventional methods such as NDBAR, Nicontiguously

LN i

−

LN i

LN i-1

−Ni-1

LN i-1

LN i

LN i-1

−

Ni-1

LN i

−

(New)LN i-1

+(New)LN i-1

+(Old)LN i

−

(Old)Data Message Forwarding

Previous Node Detection

Update of

Mobility Sections

Fig. 7. Contiguous Mobility (Backward) and Updating of Mobility Section

of Ni.

moves along a line segment LN +

iLN +

i+1 to LN +

i+1 as shown

in Figure 8. This is because the mobility segment of Ni+1

seems to be relatively longer than the mobility segment of Ni

and it is required for the mobility segments of Ni+1 and Nito

become shorter and longer, respectively. During the contiguous

mobility of Nialong the extended mobility segment from

LN +

ito LN +

i+1, if Niencounters Ni+1 , i.e., Niand Ni+1

become included in the wireless signal transmission ranges

each other, both Niand Ni+1 stop and a data message is

forwarded from Nito Ni+1. Here, LN −

iis updated to the

current location of Niand LN +

i−1is updated to the current

location of Ni−1as shown in Figure 9.

LN i

−LN i

LN i+1

Contiguous Mobility

of Data Message

Fig. 8. Contiguous Mobility (Forward) of Ni.

LN i

−

LN i

LN i+1

−

LN i+1

Ni+1

LN i

−LN i

(New)LN i

(Old)LN i-1

+(New)LN i+1

LN i-1

+(Old)Ni

Ni+1

Data Message Forwarding

Next Node Detection

Update of

Mobility Sections

Fig. 9. Contiguous Mobility (Forward) and Updating of Mobility Section of

Ni.

The proposed contiguous mobility of Niis limited only

one extended mobility segment LN −

iLN −

i−1or LN +

iLN +

i+1.

3.2 Gradual Route Modification

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Thus, if Nireaches LN −

i−1or LN +

i+1 without encountering

Ni−1or Ni+1,Niwaits for Ni−1or Ni+1 to become its

neighbor wireless node, i.e., to be included in its wireless

signal transmission range for forwarding a data message as

shown in Figures 10 and 11, respectively.

LN i

−

LN i

LN i-1

−NiWaiting for Previous

Node at LN i-1

−

Fig. 10. Termination of Contiguous Mobility (Backward) and Waiting for

Previous Node.

LN i

−LN i

NiLN i+1

Waiting for Next

Node at LN i+1

Fig. 11. Termination of Contiguous Mobility (Forward) and Waiting for Next

Node.

In order to realize such modiﬁcation of mobility segments

of intermediate mobile wireless nodes, it is required for Nito

get the most current LN −

i−1and LN +

i+1 updated by Ni−1and

Ni+1, respectively. In the initial route detection protocol, LN −

is determined by Niat the time when Nireceives an Rreq

control message from Ni−1before Nisends an Rreq control

message to Ni+1. Thus, it is possible for Ni+1 to get LN −

by piggybacking LN −

ito an Rreq control message forwarded

from Nito Ni+1. On the other hand, LN +

iis determined

by Niat the time when Nisends an Rreq control message

to Ni+1 before Nisends an Rrep control message to Ni−1.

Thus, it is possible for Ni−1to get LN +

iby piggybacking

LN +

ito an Rrep control message forwarded from Nito

Ni−1. In this way, Nigets the far ends LN −

i−1and LN +

i+1 of

the mobility segments of its previous-hop Ni−1and next-hop

Ni+1 intermediate nodes in transmissions of Rreq and Rrep

control messages in the initial route detection.

In data message transmissions, the two ends of the mobility

segments of each intermediate mobile wireless node Niis

updated each time when Nireceives a data message from

its previous-hop node Ni−1and sends a data message to its

next-hop node Ni+1. That is, LN −

iis updated by Niwhen

it receives a data message from Ni−1to its current location

and is informed Ni+1 when the data message is forwarded

to Ni+1. Thus, it is possible for Nito inform Ni+1 of LN −

by piggybacking it to the data message. On the other hand,

LN +

iis updated by Niwhen it sends a data message to Ni+1

to its current location and is informed Ni−1when the next

data message is forwarded from Ni−1. Thus, it is possible for

Nito inform Ni−1of LN +

iby piggybacking it to the Ack

control message for response to the data message. Therefore,

LN −

i−1and LN +

iare exchanged each time a data message

is forwarded from Ni−1to Niand LN −

iand LN +

i+1 are

exchanged each time a data message is forwarded from Ni

to Ni+1.

By applying the proposed route modiﬁcation method, the

lengths of the mobility segments is adjusted locally to be more

equal between the successive intermediate mobile wireless

nodes. In addition, sumation of the lengths of the mobil-

ity segments are locally reduced since |LN −

i(new)LN +

i|<

|LN −

i(new)LN −

i(old)|+|LN −

i(old)LN +

i|due to the triangle

inequality and |LN −

i−1LN +

i−1(new)|<|LN −

i−1LN +

i+1(old)|

are satisﬁed. Therefore, the wireless multihop transmission

route becomes to resemble a line segment NsNdas a sequence

of data messages are transmitted along the route.

The two ends LN −

iand LN +

iof a line segment which

is the mobility segment of an intermediate mobile wireless

node Niare modiﬁed when Niis a neighbor node of Ni−1

and Ni+when a data message is forwarded. The location

information of these ends are used for extending mobility seg-

ments of Ni+1 and Ni−1, respectively. However, the updated

location information is notiﬁed to these previous- and next-

hop intermediate node when these nodes become neighbor.

That is, these neighbor nodes are notiﬁed later after the time

when they are updated so that it is possible for Ni−1and

Nito have different value for LN −

i−1and for Niand Ni+1

to have different value for LN +

i+1, i.e., Nigets only delayed

information of the location information of these ends. Thus,

due to the unsynchronized update of the location information,

it is possible for Nimoving along its updated mobility seg-

ment LN −

i(new)LN +

iand Ni+1 moving along the extended

mobility segment LN −

i+1LN −

i(old) to pass each other without

being neighbor and forwarding a data message carried by Ni

as shown in Figure 12. In order for avoidance of such passing,

difference between LN −

i(old) and LN −

i(new) is restricted.

The necessary and sufﬁcient condition for avoidance of pass-

ing each other without forwarding a data message from Nito

Ni+1 is to assure the time instance when the distance between

Niand Ni+1 is less than the wireless signal transmission range

Rduring the mobility of Nialong LN −

i(new)LN +

iand Ni+1

along the extended mobility segment LN −

i+1LN −

i(old).

LN i

LN i-1

−

LN i+1

Ni+1

LN i+1

−

LN i

−

(New)LN i

−

(Old)

Fig. 12. Pass Each Other without Neighboring of Niand Ni+1.

[Passing Avoidance Condition]

3.3 Avoidance of Passing Without Forwarding

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The necessary and sufﬁcient condition for avoidance of pass-

ing each other without forwarding a data message from Ni

to Ni+1 is that the distance between LN −

i(old) and the

line segment LN −

i(new)LN +

iis less than the wireless signal

transmission range R.□

In order for satisfying the condition, the mobility distance

of Nialong its extended mobility segment LN −

iLN −

i−1

is restricted. Suppose Has a point on a line segment

LN −

i(new)LN +

iwhere LN −

i(old)H⊥LN −

i(new)LN +

Since |LN −

i(old)H|monotonically increases according to

|LN −

iNi|which is the mobility distance of Nialong the

extended mobility segment LN −iLN −

i−1, the following is

the necessary and sufﬁcient condition in order to assure

|LN −

i(old)H|< R.

[Restriction on Node Mobility for Passing Avoidance]

LR(Rcos θ+(L2−R2)1/2sin θ)/(R2−L2sin2θ)where L:=

|LN −

i(old)LN +

i|and θ:= ∠LN +

iLN −

i(old)LN −

i−1.□

The followings are descriptions of the proposed initial route

detection protocol and the proposed data message transmission

protocol with route modiﬁcation.

[Initial Route Detection Protocol]

(Source Stationary Node Ns)

1) Ns=N0sends a route request control message Rreq to

which its current location LN −

0and the location LN dof

the destination node Ndof a sequence of data messages

are piggybacked to its neighbor mobile wireless node N1

nearest to Nd.N1is the next-hop mobile wireless node of

N0for data messages destined to Ndwhich is registered

in a routing table of N0.

2) Nsreceives a route reply control message Rrep from

N1.Nsgets LN +

1piggybacked to the Rrep control mes-

sage.

(Intermediate Mobile Node Ni)

1) Nireceives an Rreq control message from Ni−1.Ni

gets LN −

i−1and LN dpiggybacked to the Rreq control

message. Here, LN −

iis the current location of Ni.

2) While there are no neighbor wireless nodes Nsatisfying

|NNd|<|NiNd|,Nimoves along a line segment

LN −

iNdto Nd.

3) On detection of a neighbor wireless node Nsatisfying

|NNd|<|NiNd|,Nistops at once. Nisends the

Rreq control message to which LN −

iand LN dare

piggybacked to N.Nis the next-hop mobile wireless

node Ni+1 of Nifor data messages destined to Ndwhich

is registered in a routing table of Ni. Here, LN +

iis the

current location of Ni.

4) Nireceives an Rrep control message from Ni+1.Nigets

LN +

i+1 piggybacked to the Rrep control message.

5) If LN −

i=LN +

i,Nimoves along a line segment

LN +

iLN −

ito LN −

6) Nistops at LN −

iand sends an Rrep control message to

Ni−1.

(Destination Stationary Node Nd)

1) Nd=Nnreceives an Rreq control message from

Nn−1.Ndgets LN −

n−1piggybacked to the Rreq control

message.

2) Ndsends an Rrep control message destined to Nsto

Nn−1to which the location of Ndas LN +

nis piggy-

backed.

[Data Message Transmission Protocol with Route Modiﬁ-

cation]

(Source Stationary Node Ns)

1) Ns=N0waits for its next-hop mobile wireless node N1

to be its neighbor.

2) Nssends a data message to which its current location is

piggybacked as LN −

0to N1.

3) Nsreceives an acknowledgement control message Ack

from N1.

4) Go back to (1).

(Intermediate Mobile Node Ni)

1) When Niencounters its previous-hop intermediate node

Ni−1, i.e., Nibecomes a neighbor node of Ni−1,Ni

receives a data message from Ni−1.Niupdates its

keeping LN −

i−1by that piggybacked to the received data

message. In addition, Niupdates LN −

iby its current

location.

2) Nisends back an Ack control message to Ni−1to which

LN +

iis piggybacked.

3) Until Niencounters Ni+1, i.e., Nibecomes a neighbor

node of Ni+1,Nicarries the data message from Ni−1

along a line segment LN −

iLN +

ithat is its mobility

segment to LN +

i. If Nidoes not encounter Ni+1 before

reaching LN +

i,Nicontiguously carries the data message

along a line segment LN +

iLN +

ias its extended mobility

segment. If Nireaches LN +

i+1 without encountering

Ni+1,Niwaits for encountering Ni+1 at LN +

i+1.

4) On encountering Ni+1,Nistops at once and sends

the carrying data message to Ni+1 to which LN −

iis

piggybacked. LN +

iis updated to its current location.

5) Nireceives an Ack control message from Ni−1.Ni

updates LN +i+ 1 to that piggybacked to the Ack control

message. In addition, Niupdates LN +

ito its current

location.

6) Until Niencounters Ni−1, i.e., Nibecomes a neighbor

node of Ni−1,Nimoves along a line segment LN +

iLN −

that is its mobility segment to LN −

i. If Nidoes not

encounter Ni−1before reaching LN −

i,Nicontiguously

moves along a line segment LN −

iLN −

i−1as its extended

mobility segment. If Nireaches LN −

i−1without encoun-

tering Ni−1,Niwaits for encountering Ni−1at LN −

i−1.

7) Go back to (1).

(Destination Stationary Node Nd)

1) Nd=Nnwaits for encountering Nn−1.

2) Ndreceives a data message from Nn−1.

3) Ndsends back an Ack control message to which its

current location is piggybacked as LN +

4) Go back to (1) □

3.4 Protocols

WSEAS TRANSACTIONS on COMMUNICATIONS

DOI: 10.37394/23204.2023.22.8

Ryota Kurabayashi, Hiroaki Higaki

E-ISSN: 2224-2864

102

Volume 22, 2023

This paper has proposed the initial route detection and

gradual route modiﬁcation methods by multihop data message

transmissions realized by combination of carrying and for-

warding by each intermediate mobile wireless node. In route

modiﬁcation, each intermediate mobile wireless node updates

its mobility segment locally by cooperation with its previous-

and next-hop node. This results in even sharing of mobility

overhead among all the intermediate mobile wireless nodes

and in shorter end-to-end transmission delay by reduction of

total length of the transmission route and by reduction of

synchronization overhead between the successive intermediate

nodes. Finally, this paper has proposed the method to avoid

situations where successive intermediate wireless nodes pass

each other without forwarding a data message. By introduction

of the limitation to the node mobility along the extended

mobility segment, though the critical problem is solved, it

is expected to be required longer time for the multihop

transmission route to converge. This effect will be evaluated

in simulation experiments.

[1] Chuah, M. and Yang, P., “Node Density-Based Adaptive Routing

Scheme for Disruption Tolerant Networks,” Millitary Communicationas

Conference, pp. 1–6 (2006).

[2] Farrel, S. and Cahill, V., “Delay- and Disruption-Tolerant Networking,”

Artec House (2006).

[3] Lin, X. and Stojmenovic, I., “Geographic Distance Routing in Ad Hoc

Wireless Networks,” Technical Report TR-98-10, SITE, University of

Ottawa (1998).

[4] Vahdat, A. and Becker, D., “Epidemic Routing for Partially-Connected

Ad Hoc Networks,” Technical Repotr CS-200006, Duke University

(2000).

[5] Zhao, W., Ammar, M. and Zegura, E., “A Message Ferrying Approach

for Data Delivery in Sparce Mobile Ad Hoc Networking,” Proccdings

of the International Symposium on Mobile Ad Hoc Networking and

Computing, pp. 187–198 (2004).

4. Conclusion

References

Contribution of Individual Authors to the

Creation of a Scientific Article (Ghostwriting

Policy)

The authors equally contributed in the present

research, at all stages from the formulation of the

problem to the final findings and solution.

Sources of Funding for Research Presented in a

Scientific Article or Scientific Article Itself

No funding was received for conducting this study.

Conflict of Interest

The authors have no conflicts of interest to declare

that are relevant to the content of this article.

Creative Commons Attribution License 4.0

(Attribution 4.0 International, CC BY 4.0)

This article is published under the terms of the

Creative Commons Attribution License 4.0

https://creativecommons.org/licenses/by/4.0/deed.en

_US

WSEAS TRANSACTIONS on COMMUNICATIONS

DOI: 10.37394/23204.2023.22.8

Ryota Kurabayashi, Hiroaki Higaki

E-ISSN: 2224-2864

103

Volume 22, 2023