Identifying
attractive business models for the network/service provider and users based on
cooperation is essential in order to secure the adoption of 5G technology. This
article identifies the Cooperation of Nodes as a driver of new business models
showing how we can exploit cooperation between user terminals and heterogeneous
networks and operators.
The ability to use
mobile terminals at any time and any place without being weary of battery
supply seems to be a futuristic approach. However by exploiting smart cooperative
networking concepts, this vision can take a step closer to reality.
Exploiting these
technology paradigm in tandem, can lead to new radio topologies that are able
to provide energy efficient connectivity
and thus battery lifetime in mobile phones enabling the use of services that
require greater bandwidth than legacy services currently provided by UMTS technology.
Most of the research in cooperative networking technology has addressed the
technical and engineering ways to save energy.
In present days, to
support cooperative networking in the cellular network market, it is absolutely
necessary to have good business models that show the main benefits of this new architecture and the
revenues associated.
Cooperation is a
strategy of a group of entities working or acting together towards a common or
individual goal. Correspondingly, the connotation of cooperative networking is
described as devices working together to achieve a goal, within a network.
Wireless devices, controlled ultimately by human, can be considered as selfish, without any incentive to cooperate
by nature.
The reason, that
this phenomenon occurs, is that a wireless device is always interested in
maximizing its own benefits. So cooperation
adds costs to mobile devices, but bringing new services that can increase the
performance of a mobile device. However, in any cooperation network, the
communication ultimately depends on the willingness of the nodes to cooperate.
Such cooperation can only be established and maintained if fairness and profitability are guaranteed among cooperating
nodes. Therefore, to avoid the collapse of cooperation, robust cooperation
rules and good incentives are required.
To understand the
incentives and basic rules for cooperation, an observation from cooperation
used in nature is needed. The cooperative network is often realized in the form
of a composite access network, which is composed of heterogeneous networks.
With the rapid development of technologies and mobile networks, especially with
the arrival of LTE, certain characteristics have not been able to compete or keep
up with the technology growth, mainly the battery autonomy of mobile devices
and other features such as quality of service, higher throughput or spectral efficiency. Dealing with this paradigm provided
the impetus for new ideas and possible innovations in the area of cooperation, aimed
at combating the negative features resulting from the progress in mobile
networks. This cooperation could create, through network operators, mechanisms
to encourage customers to cooperate using their mobile devices.
As shown
in the illustration besides, one of the main methods of cooperation is the
cooperation among mobile devices that can be done through short-range
communication technologies such as Bluetooth, UWB or WLAN. These technologies
promote low energy consumption, while providing high quality of service. The main avantages of cooperative communications are ;
§ Reducing the power
consumption of mobile devices and decreasing the transmission power of base
stations;
§ Increasing the
quality of service, since with strong signal, customers can achieve better
services without failure, e.g. higher data rates;
§ Lower delay between
cooperative users;
§ Possibility to
create more services like context exchanges between nodes or parallel
processing;
§ Decreasing the
carbon footprint. Base stations and mobile devices consume much electricity in
their use phase, which makes energy saving a valuable contribution for these
facilities;
§ Better use of
wireless spectrum;
§ Overcoming the
limited cellular capacity. For multicast services such as video streaming or file downloading the benefit is obvious. In this case the cooperative
devices receive partially the original stream and collaboratively merge it over
the short-range communication links.
Nowadays,
infrastructure networks (i.e. cellular networks) do not expect or anyhow permit
cooperation among connected mobile devices. However, as some wireless environments
enable the realization of ad hoc cooperative behaviors, it seems natural that
infrastructure networks could also benefit from such cooperation.
From a general
perspective, the most interesting business cases are related to battery power
savings at mobile devices. Due to its locality and gain from statistical multiplexing
(traffic aggregation),
such energy saving gain can be observed with ad hoc cooperative networks. Still,
wireless ad hoc cooperative networks are to be successful only if they are able
to align the current individual and selfish assumptions of the mobile devices into a cooperative
paradigm that succeeds to benefit all the entities
involved in the cooperation. Current assumptions for wireless ad hoc networking
are:
§ Mobile devices are
expected to achieve selfish goals, enforced
by users or running services;
§ Mobile devices
belong to different users;
§ Mobile devices are
served by different PLMNs (different network operators).
The enlisted
assumptions, which are obstacles to cooperation, can be overcome with the
introduction of motivational and incentives systems, which encourage various
forms of cooperative behavior. Examples of such cooperative behavior are
altruistic cooperation, non-altruistic cooperation or reciprocal cooperation.
Each of these forms of behavior has its stability and thus, it has to be
resilient to the number of challenges derived from the transient nature of the
wireless communication system.
A number of cooperation challenges that
need to be addressed to encourage cooperation in ad hoc networks and include;
Motivation
and fairness—the two
concepts need to be addressed by the cooperative network to encourage
cooperation among users, to provide fair access to the resources and to punish
the adversaries (to discourage malicious and greedy behaviors). Fairness
problems affect also the design of the motivational mechanisms. Furthermore,
another known fairness problem is related to location, as mobile devices with
more favorable location receive more incentives, leading to even higher income.
• Malicious
behaviors—although
authentication and access control can reinforce cooperation through prevention
against external attacker, there are still possibilities for users to exploit
the cooperation even in the presence of effective authentication and access
control mechanisms.
• Privacy
protection: the
key to the success of any reciprocity based cooperation strategy is the ability
to identify (and possibly also punish) the defective nodes, and thus, mobile
devices cannot stay anonymous. Furthermore, the reputation ratings have to be
assigned to correct mobile device and payments or reciprocal behavior returned
to correct initiator.
• Cooperation
maintenance: as a
consequence of mobility or in general, transient changes in channel quality,
the node which realizes a cooperative scenario may experience reduction of the
quality in provided relaying service or decrease in the reliability of provided
information. This may lead to a situation where users are unfairly treated due
to decrease in incentives or reputation. Thus, reputation system has to
recognize faulty behavior and distinguish it from malicious behavior.
Observability—the
results of the cooperation are highly dependent also on the ability to identify
and distinguish cooperative behavior from selfish. In wireless networks, a
typical situation is that nodes have non-equal information, leading to
information asymmetry.
