Mobile communication system

Details Mobile communication system Mobile communication system

1998-02-25

2001-08-28

Marcelo, Melvin (Department: 2732)

Multiplex communications

Diagnostic testing

Determination of communication parameters

C370S345000, C370S468000

Reexamination Certificate

active

06282174

ABSTRACT:

BACKGROUND ART
This invention relates to a mobile communication system, and particularly to a mobile communication system comprised of a base station and a mobile station connected to this base station by a radio link.
TECHNICAL FIELD
Mobile communication systems as well as cellular systems are rapidly becoming widespread. This had led to the number of mobile communication terminals (hereinafter referred to as a mobile station) also increasing dramatically. Together with the increase in the number of mobile stations, the amount of traffic has also increased. This results in the system approaching the limit of its ability to accommodate mobile stations. Because of this type of situation, there has been a demand for an increase in the mobile station accommodating capacity of a system.
As one example of a cellular system, the transmission format of the IS-136TDMA (Time Division Multiple Access) digital portable telephone system currently utilized in the USA is as shown in FIG.
1
. As shown in
FIG. 1
(A), one frame of a TDMA data stream has a length of 20 msec, and one frame is divided into three time slots TS#
1
-TS#
3
. Thus one time slot has a length of 6.67 msec. A base station carries out communication to a mobile station, and that mobile station is assigned to a free time slot. For example, mobile station A is assigned to time slot #
1
and mobile station B is assigned to time slot #
2
. As a result, mobile station A receives a signal from the base station in the time zone of time slot #
1
. Mobile station A also transmits a signal to the base station in a separate time slot, for example the time zone of time slot #
2
. Specifically, as shown in
FIG. 1
, for transmission from the base station to the mobile stations, time slots #
1
, #
2
, and #
3
are repeatedly and continuously transmitted. For individual mobile stations, communication from the base station is cyclic. Communication from the mobile stations to the base stations is carried out using burst transmission, as shown in
FIG. 1
(B). Each time slot has the same bit rate as all of the other time slots.
The detailed organization of a time slot when the base station transmits to a mobile station will be described using FIG.
2
. As shown in
FIG. 2
, a synchronization sequence is arranged at the head of each time slot. After this synchronization sequence, there is a control code followed by data. A separate control code is inserted into the data portion. The end of the time slot contains reserved bits. The number of bits of each essential element of the time slot is shown in FIG.
2
. Namely, one time slot includes an overall total of 324 bits made up of 260 data bits and 64 bits of control code other than the data.
In current TDMA cellular systems, a specific carrier frequency is used as a control channel. One time slot from among the time slots of this control channel is used for sending and receiving various control information. This means that the number of time slots that can be used for subscriber communication is reduced. Accordingly, it has been considered to increase the number of time slots used in subscriber communication by increasing the number of time slots multiplexed at the carrier frequency of the control channel. This can be expected to increase the mobile station accommodating capacity of the system. Also in this case, it has been considered to increase the mobile station accommodating capacity of the overall system by automatically setting a mode for every individual mobile station.
DISCLOSURE OF THE INVENTION
The object of the current invention is to provide a mobile communication system that can increase the number of mobile stations multiplexed at a single carrier frequency.
Another object of the present invention is to provide a mobile communication system that can dynamically establish a communication mode of individual mobile stations.
Specifically, the present invention is a mobile communication system comprising at least one base station and at least one mobile station. The base station has an encoding circuit for encoding a transmission signal for a mobile station. This encoding circuit has a number of encoding methods for encoding the transmission signal for the mobile station. The base station selects an appropriate encoding method based on traffic conditions, the surrounding environment of the mobile station, etc. As a result, the base station encodes the transmission signal for the mobile station using the selected encoding method. The base station then adds a decoding method to the signal to be received by the mobile station, and transmits them to the mobile station. The mobile station decodes the signal received from the base station using the decoding method notified from the base station.
The base station dynamically selects an encoding method for every individual mobile station and for every single coded unit. That is, the base station can select a mode in which the number of bits in a code string is small while taking into consideration the communication quality demanded by a user at that time.


REFERENCES:
patent: 4754450 (1988-06-01), Lynk, Jr. et al.
patent: 5761223 (1998-06-01), Ando et al.
patent: 63-175537 (1988-07-01), None
patent: 7 231292 (1995-08-01), None
patent: 8-162977 (1996-06-01), None
patent: 8 186543 (1996-07-01), None

Affiliated with

Also associated with

Rating

Mobile communication system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Mobile communication system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mobile communication system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2464120