1772 IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 68, NO. 2, FEBRUARY 2019
Location-Based Online Task Assignment and Path
Planning for Mobile Crowdsensing
Wei Gong , Baoxian Zhang , Senior Member, IEEE,andChengLi , Senior Member, IEEE
Abstract—Mobile crowdsensing has been a promising and cost-
effective sensing paradigm for the Internet of Things by exploit-
ing the proliferation and prevalence of sensor-rich mobile devices
held/worn by mobile users. In this paper, we study the task as-
signment and path planning problem in mobile crowdsensing,
which aims to maximize total task quality under constraints of
user travel distance budgets. We first formulate the problem math-
ematically when all task and user arrival information is known
aprioriand prove it to be NP-hard. Then, we focus on studying
the scenarios where users and t asks arrive dynamically and ac-
cordingly design four online task assignment algorithms, including
quality/progress-based algorithm (QPA), task-density-based algo-
rithm (TDA), travel-distance-balance-based algorithm (DBA), and
bio-inspired travel-distance-balance-based algorithm (B-DBA). All
the four algorithms work online for task assignment upon arrival
of a new user. The former three algorithms work in a greedy man-
ner for assigning tasks, one task each time, where the QPA prefers
the task leading to largest ratio of task quality increment to travel
cost, the TDA tends to guide user to high-task-density areas, and
the DBA further considers travel distance balance information. The
last algorithm B-DBA integrates the travel-distance-balance-aware
metric in the DBA and bio-inspired search for further improved
task assignment performance. Complexities of the proposed algo-
rithms are deduced. Simulation results validate the effectiveness of
our algorithms; B-DBA has the best performance among the four
algorithms in terms of task quality, and furthermore, it outper-
forms existing work in this area.
Index Terms—Mobile crowdsensing, participatory sensing, on-
line task assignment, path planning.
I. INTRODUCTION
T
HE prevalence of sensor-rich mobile devices (e.g., smart-
phones, wearable devices, and smart vehicles) has been
playing an increasing crucial role in the Internet of Things (IoT)
[1], [2]. This has promoted the emergence of a new mobile-
user-centric sensing paradigm, mobile crowdsensing [3], [4]. In
Manuscript received July 15, 2018; revised September 28, 2018; accepted
November 25, 2018. Date of publication November 30, 2018; date of current
version February 12, 2019. This work was supported in part by the National
Natural Science Foundation of China under Grants 61872331, 61531006, and
61471339, in part by the Natural Sciences and Engineering Research Council
of Canada under Discovery Grant RGPIN-2018-03792, and in part by the In-
novateNL SensorTECH Grant 5404-2061-101. The review of this paper was
coordinated by Prof. J. Misic. (Corresponding author: Baoxian Zhang.)
W. Gong and B. Zhang are with the Research Center of Ubiquitous Sensor
Networks, University of Chinese Academy of Sciences, Beijing 100049, China
(e-mail:,gongwei11@mails.ucas.ac.cn; bxzhang@ucas.ac.cn).
C. Li is with the Faculty of Engineering and Applied Science, Memorial
University, St. John’s, NL A1B 3X5, Canada. He is also affiliated with Tianjin
Chengjian University (e-mail:,licheng@mun.ca).
Digital Object Identifier 10.1109/TVT.2018.2884318
the past, in most IoT systems, static wireless sensor networks
(WSNs) played major role in data collection where sensors
are typically untended and have limited resources (e.g., energy,
communications, storage, and computation), which largely af-
fect their capability for providing high quality IoT services.
Mobile crowdsensing integrates the prevalence of smart devices
held/worn by mobile users and also their powerful capability
(e.g., their sensing, computing, and wireless communication
capabilities) into the provisioning of ubiquitous IoT services.
Compared with static WSN based IoT solutions, mobile crowd-
sensing has many advantages: low cost for deployment, inherent
mobility by mobile users, and huge population of mobile devices
and extensive coverage of such devices. Mobile crowdsensing
facilitates wide-range longtime multidimensional sensing data
collection for monitoring the physical world. With the partici-
pation of mobile crowdsensing users, many phenomena in their
vicinity can be easily observed such as noise pollution, road
congestion, surrounding context and environmental pollution.
In this way, mobile crowdsensing has promoted various IoT
services and applications, such as environmental monitoring,
indoor localization, pervasive cloud services, road traffic moni-
toring, smart cities, etc. (see [5]–[12]).
In a typical mobile crowdsensing system, task requesters pub-
lish a set of tasks with task requirement details such as task
deadlines, incentive rewards, and required data amount, accu-
racy, and granularity on a service platform. The platform re-
cruits some mobile users ( also called mobile workers in some
work [13], [14]) to undertake these tasks. Mobile users col-
lect required sensing data when moving to task locations. They
get compensated if they upload valid sensing data to the plat-
form. Based on whether mobile users perform sensing tasks
consciously, mobile crowdsensing is divided into two classes:
opportunistic sensing and participatory sensing. In opportunistic
sensing, active involvement of mobile users is not necessary and
mobile users typically move along pre-determined paths (e.g.,
along with track-based transportation systems) or follow cer-
tain mobility patterns affected by their daily routines, habits, or
preferences (e.g., go to workplace or visit friends). Mobile de-
vices can be programmed to collect sensing data automatically
as the device holders move. In participatory sensing, mobile
users are required to move to specific task locations to under-
take certain tasks. The moving paths of such users are planned
based on assigned tasks and their involvements are intentional
and controllable.
Task assignment [15] is a crucial problem in mobile crowd-
sensing. One key issue in task assignment is to achieve
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