PHS Seminar (3)
PHS with Ad hoc Networking Function
Prof. Shoji Shinoda / Chuo University, Tokyo, Japan
PHS is one of the
mobile communication systems and its service supports not only high-quality
voice communications but also high-speed data communications including
the enriched contents.
The number of subscribers in the
world has exceeded 75 million, and PHS services have been extended
or are now extending.
Such situations accelerate an improvement
and R&D of the PHS by the PHS MoU Group.
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In this talk, I
would like to put a special emphasis on the transceiver mode of
the PHS or its extended version or its related.
At present, PHS terminals have a
capability of communicating directly with each other in transceiver
mode without the intervention of the CSs (Cell Stations) if they
are close enough. This makes the PHS terminals more attractive to
the users in different situations such as outdoors, offices, public
spaces, and so forth.
Recently, the requirements of the
applications for mobile communication are increasing sharply. One
of the solutions of these requirements is the concept of
ad hoc networks.
Ad hoc network is a wireless network
consisting of the mobile nodes connected by wireless links without
the intervention of any CSs.
Ad hoc networks are realized by using
recent communication devices such as the PHS, Bluetooth, IEEE 802.11
RF-devices, UWB (Ultra Wide Band) etc. supporting direct connection
between nodes and by adding routing protocols and relay functions
to each node of the networks.
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However, the capability of the ad hoc networking function of the present PHS is insufficient for the realization of practical ad hoc networks to be needed at real-life situations.
So, it is necessary to develop a new PHS with ad hoc networking function whose capability for realizing practical ad hoc networks is better than the capability of Bluetooth. For the convenience' sake, we say that such a new PHS is a PHS-ad hoc.
One of the essential features of PHS-ad hoc is that two PHS ad hocs can directly communicate with each other without the intervention of any CSs, if they are close enough.
The use of ad hoc networking function is free.
So, most of you will perhaps feel or think that the increase of the number of mobile nodes with more convenient ad hoc networking function than ever may make the decrease of the profit of the PHS business.
However, I would like to say the following:
The more the attraction of the PHS capabilities is,
the higher the popularity of the PHS on the market becomes,
the bigger the number of subscribers in the PHS services becomes
the larger the profit of the PHS business becomes.
Finally, I hope that the PHS technology offers a great potential for further growth because of the diversity of its applications.
