U.S. patent application number 11/931499 was filed with the patent office on 2008-03-13 for mobile radio communication system, communication apparatus applied in a mobile radio communication system, and mobile radio communication method.
This patent application is currently assigned to MITSUBISHI DENKI KABUSHIKI KAISHA. Invention is credited to Hideshi Murai, Nicolas VOYER, Yasuhiro Yano.
Application Number | 20080062950 11/931499 |
Document ID | / |
Family ID | 14626634 |
Filed Date | 2008-03-13 |
United States Patent
Application |
20080062950 |
Kind Code |
A1 |
VOYER; Nicolas ; et
al. |
March 13, 2008 |
MOBILE RADIO COMMUNICATION SYSTEM, COMMUNICATION APPARATUS APPLIED
IN A MOBILE RADIO COMMUNICATION SYSTEM, AND MOBILE RADIO
COMMUNICATION METHOD
Abstract
In the mobile radio communication system where the UMTS and an
another system coexist an idle slot for observing the frequency
component of another system is inserted in one superframe of UMTS.
The duration of this idle slot is at most half of the duration of
one frame that form the superframe and it is inserted at an
interval of a specified number of frames. Therefore, the frequency
component of the another system can be observed securely from the
UMTS. Further, the deterioration of interleaving performance of the
compressed mode frames during such observation can be
suppressed.
Inventors: |
VOYER; Nicolas; (Rennes,
FR) ; Yano; Yasuhiro; (Tokyo, JP) ; Murai;
Hideshi; (Tokyo, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
MITSUBISHI DENKI KABUSHIKI
KAISHA
Chiyoda-ku
JP
100-8310
|
Family ID: |
14626634 |
Appl. No.: |
11/931499 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11754946 |
May 29, 2007 |
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11931499 |
Oct 31, 2007 |
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11372121 |
Mar 10, 2006 |
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11754946 |
May 29, 2007 |
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11048906 |
Feb 3, 2005 |
7218646 |
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11372121 |
Mar 10, 2006 |
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10208813 |
Aug 1, 2002 |
6898196 |
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11048906 |
Feb 3, 2005 |
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09467063 |
Dec 20, 1999 |
6469995 |
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10208813 |
Aug 1, 2002 |
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PCT/JP99/01051 |
Mar 4, 1999 |
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09467063 |
Dec 20, 1999 |
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Current U.S.
Class: |
370/342 ;
370/331; 370/470 |
Current CPC
Class: |
H04B 7/2656 20130101;
H04W 36/00 20130101; H04L 1/0071 20130101; H04W 36/14 20130101;
H04W 72/08 20130101; H04W 72/12 20130101; H04W 88/06 20130101; H04L
1/004 20130101; H04W 24/00 20130101; H04B 7/2634 20130101; H04W
52/44 20130101; H04W 36/0088 20130101; H04W 52/267 20130101; H04W
84/04 20130101; H04W 24/10 20130101; H04W 36/0085 20180801 |
Class at
Publication: |
370/342 ;
370/331; 370/470 |
International
Class: |
H04B 7/216 20060101
H04B007/216; H04J 13/00 20060101 H04J013/00; H04Q 7/00 20060101
H04Q007/00; H04Q 7/20 20060101 H04Q007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 23, 1998 |
JP |
10-114003 |
Claims
1. A mobile radio communication system employing a CDMA method,
comprising a transmitter (1) transmitting a plurality of frames in
a normal mode and a plurality of compressed frames in a compressed
mode within a first frame transmission period, which is formed of
plural frames and required to transmit a predetermined number of
frames, and a receiver (2) receiving said frames and said
compressed frames transmitted by said transmitter (1), said
transmitter (1) comprises an interleaver (13) which performs
interleaving of data in a frame in bit units; a spreading unit
(14), in which a plurality of frames processed by said interleaver
(13) are inputted, wherein said spreading unit (14) compresses
frames within said first frame transmission period to produce
compressed frames, and divides each of said compressed frames into
two divided parts, and allocates one of said divided parts at the
beginning of a frame period and the other one of said divided parts
at the end of said frame period, and creates, into each of said
compressed frames, an idle period whose length is half as much as
that of each frame or less, in a compressed mode; and a radio
frequency transmitter (15) which transmits said compressed frames
processed by said spreading unit (14) in said compressed mode; and
said receiver (2) comprises a radio frequency receiver which
monitors, within said idle period in each of said compressed
frames, a frequency component in a control channel, said control
channel having a second frame transmission period and being
employed in a different mobile radio communication system.
2. The mobile radio communication system according to claim 1,
wherein said different mobile radio communication system is GSM
system.
3. A receiver used in a mobile radio communication system employing
a CDMA method, wherein a transmitter (1) of said mobile radio
communication system transmits a plurality of frames in a normal
mode and a plurality of compressed frames in a compressed mode
during a first frame transmission period, which is formed of plural
frames, performs interleaving of data to be transmitted in bit
units, and said first frame transmission period is defined as a
period required to transmit a predetermined number of frames, said
receiver comprises: a radio frequency receiver (25), to which said
compressed frames received by an antenna are inputted, for
monitoring a frequency component in a control channel within an
idle period in each of said compressed frames within said first
frame transmission period, wherein said control channel has a
second transmission period which is employed in a different mobile
radio communication system, and each of said compressed frames has
an idle period whose length is half as much as that of each frame
or less, and each of said compressed frames is divided into two
divided parts such that one of the divided parts is allocated at
the beginning of a frame period and the other one of said divided
parts is allocated at the end of said frame period.
4. A transmitter used in a mobile radio communication system
employing a CDMA method, wherein said transmitter (1) transmits a
plurality of frames in a normal mode and a plurality of compressed
frames in a compressed mode within a first frame transmission
period, which is formed of plural frames, and said first
transmission period is defined as a period required to transmit a
predetermined number of frames, said transmitter (1) comprises: an
interleaver (13) which performs interleaving of data in a frame in
bit units; and a spreading unit (14), in which a plurality of
frames processed by said interleaver (13) are inputted, wherein
said spreading unit (14) compresses frames within said first frame
transmission period to produce compressed frames, divides each of
said compressed frames into two divided parts, allocates one of
said divided parts at the beginning of a frame period and the other
one of said divided parts at the end of said frame period, and
creates, into each of said compressed frames, an idle period whose
length is half as much as that of each frame or less, in a
compressed mode; and a radio frequency transmitter (15) which
transmits said compressed frames processed in said spreading unit
(14) in said compressed mode.
5. A mobile radio communication method used in a CDMA system,
wherein said system includes a transmitter (1) which performs
interleaving of data to be transmitted in bit units, and transmits
a plurality of frames in a normal mode and a plurality of
compressed frames in a compressed mode within a first frame
transmission period, which is formed of plural frames, and a
receiver (2) that receives said frames and said compressed frames
transmitted by said transmitter (1), said first frame transmission
period is defined as a period required to transmit a predetermined
number of frames, said mobile radio communication method comprises:
steps, executed by said transmitter (1), for compressing frames
within said first frame transmission period; dividing each of said
compressed frames into two divided parts for allocating one of said
divided parts at the beginning of a frame period and the other one
of said divided parts at the end of said frame period; allocating
in each of said frames an idle period whose length is half as much
as that of each frame or less; transmitting said frames with said
idle period to said receiver (2); and a step, executed by said
receiver (2) for monitoring frequency components in a control
channel having a second frame transmission period within said idle
period allocated in each of said compressed frames, wherein said
second frame transmission period is employed in a different mobile
radio communication system.
6. A mobile radio communication method used in a receiver (2) for a
CDMA system, wherein a transmitter (1) of said mobile radio
communication system transmits a plurality of frames in a normal
mode and a plurality of compressed frames in a compressed mode
during a first frame transmission period, which is formed of plural
frames, and said first frame transmission period is defined as a
period required to transmit a predetermined number of frames,
performs interleaving of data to be transmitted in bit units, said
mobile radio communication method comprises: receiving said
compressed frames within said first frame transmission period, each
of said compressed frames having an idle period whose length is
half as much as that of each frame or less and being divided into
at least two parts such that one of said divided frames is
allocated at the beginning of a frame period and the other one of
said divided parts is allocated at the end of said frame period;
and monitoring a frequency component in a control channel within
said idle period in each of said compressed frames, wherein said
control channel has a second frame transmission period which is
employed in a different mobile radio communication system.
7. A mobile radio communication method used in a transmitter (1)
for a CDMA system, wherein said transmitter (1) transmits a
plurality of frames in a normal mode and a plurality of compressed
frames in a compressed mode within a first frame transmission
period, which is formed of plural frames, and said first frame
transmission period is defined as a period required to transmit a
predetermined number of frames, said mobile radio communication
method comprises: generating said compressed frames through
processes of compressing a plurality of frames within said first
transmission period, dividing each of said compressed frames into
at least two parts for allocating one of said divided parts at the
beginning of a frame period and the other one of said divided parts
at the end of said frame period, and creating in each of said
compressed frames an idle period whose length is half as much as
that of each frame or less, and; transmitting said compressed
frames generated by said generating step.
Description
[0001] This application is a continuation of International
Application PCT/JP99/01051, with an international filing date of
Mar. 4, 1999, which designated the United States, the entire
contents of which are hereby incorporated by references.
TECHNICAL FIELD
[0002] The present invention relates to a mobile radio
communication system in which UMTS (Universal Mobile Terrestrial
communication System) and GSM (Group Specific Mobile) system
coexist, communication apparatus applied in mobile radio
communication system, and mobile radio communication method. More
particularly this invention, relates to a technology of observing
the control channel of a GSM system that is another system in the
mobile radio communication system by making use of an idle
period.
BACKGROUND ART
[0003] In a CDMA cellular system, because the same carrier
frequency is used repeatedly in every cell there is no need for
handovers between frequencies within the same system. However,
considering a case such as when existing systems are present
together, there is a need for handovers between different carrier
frequencies. Three points pertaining to detailed cases are
described below.
[0004] As a first point, in a cell where there is considerable
traffic, a separate carrier frequency is used to accommodate the
increased number of subscribers, and a handover may be performed
between those cells. As a second point, when an umbrella cell
constitution is used, different frequencies are allocated to large
and small cells, and handovers are performed between the cells.
Then, as a third point, there are cases of handovers between a
third generation system, such as a W (Wideband)-CDMA system, and a
second-generation system, such as a current mobile telephone
system.
[0005] When performing handovers in cases such as those mentioned
above, it is necessary to detect the power of carriers at the
different frequencies. To achieve this detection, the receiver need
only have a structure capable of detecting two frequencies.
However, this increases the size of the constitution of the
receiver, or makes the constitution complicated.
[0006] Furthermore, two types of handover method may be considered:
a mobile assisted handover (MAHO) and a network assisted handover
(NAHO). Comparing the MAHO and NAHO methods, NAHO reduces the
burden of the mobile device. However, it is necessary to
synchronize the mobile device and the base station, whereby the
constitution of the base station and the network becomes
complicated and large in order to be capable of tracking each
dedicated mobile device.
[0007] For such reasons, the realization of the MAHO method is more
desirable, but to determine whether or not to handover, it is
necessary to measure the strength of carriers of different
frequencies at the mobile devices. However, a CDMA cellular system
differs from a time division multiple access (TDMA) system used in
a second generation, in that it uses ordinarily continuous
transmission for both transmission/reception. In this continuous
transmission/reception technique, unless receivers corresponding to
two frequencies are prepared, it is necessary to stop the timing of
the transmission or the reception and measure the other
frequency.
[0008] There has been disclosed a technique relating to a
compressed mode method, for time-compressing the transmission data
in the normal mode and transmitting it in a short time, thereby
creating some spare time which can be utilized to measure the other
frequency carrier. As an example of this, there is Japan Patent
Application National Publication (Laid-Open) (JP-A) No. 8-500475
"Non-continuous Transmission for Seamless Handovers in DS-Mobile
Radio Communications Systems". This application discloses a method
of realizing a compressed mode, wherein the spreading factor of the
spreading code used is lowered to compress the transmission
timing.
[0009] The method of realizing the compressed mode according to the
above application will be explained below. FIG. 13 shows an example
of transmissions in a normal mode and a compressed mode in a
conventional CDMA system. In FIG. 13, the vertical axis represents
transmission rate/transmission power, and the horizontal axis
represents time. In the example of FIG. 13, the compressed mode
transmission is inserted between normal transmission frames. In the
transmission in the compressed mode, a non-transmission period is
provided in the downlink frame, and can be set to a desired period
of time (duration). This non-transmission period represents idle
period during which the strength of the other frequency carrier is
measured. In this way, slot transmission can be achieved by
inserting the idle period between transmission of compressed mode
frames.
[0010] In this type of compressed mode transmission, transmission
power is increased in accordance with the time ratio between the
idle period and the frame (compressed mode frame) transmission
duration. Therefore, as shown in FIG. 13, the compressed mode frame
is transmitted at a higher transmission power than the frame in
normal transmission. Consequently, transmission quality can be
maintained even in frame transmission in compressed mode.
[0011] Usually, between the GSM and GSM, different frequency
component (control channel) is observed by using one observation
period (no-transmission period) assigned in every one superframe.
However, when a mobile radio communication system in which the UMTS
and GSM systems coexist is considered, it requires operation for
observing the frequency components between different systems, that
is, from UMTS to GSM system. In this case, too, same as in the case
of observation between GSM and GSM, an idle period for observing
the frequency component of GSM is set in the superframe of the
UMTS.
[0012] That is, for one frame of superframe in the UMTS, it is
necessary to assign the observation period composed of the same
number of idle slots as in the case of GSM-GSM observation.
However, in the existing technology, due to restrictions in the
error correction code and spreading factor for frame transmission,
it is difficult to insert all observation period in one frame, and
there are many other problems. Therefore, a technology for
observing the frequency component of GSM system from the UMTS is
expected in the future.
[0013] It is an object of the present invention to solve the
problems mentioned above by providing a mobile radio communication
system, communication apparatus applied in mobile radio
communication system, and mobile radio communication method,
capable of observing securely the frequency component of an another
system from the UMTS even when the UMTS and the another system
coexist, and suppressing deterioration of interleaving performance
of compressed mode frame in such a case.
SUMMARY OF THE INVENTION
[0014] The mobile radio communication system according to one
aspect of the invention is a mobile radio communication system
comprising a first communication system employing a code division
multiple access method of transmitting frames by using a first
superframe which is formed of a plural frames which expresses a
frame transmission period, and a second communication system for
observing frequency component of control data transmission channel
by making use of a specified idle period, the specified idle period
being inserted in a second superframe for downlink user data
transmission channel on the basis of the difference between the
number of frames of integer multiple of second superframe
expressing a frame transmission period in user data transmission
channel and the number of frames of third superframe expressing a
frame transmission period in control data transmission channel,
error correction and interleaving of frames being performed when
the first communication system transmits the frames, wherein the
specified idle period is at most half of the time of one frame that
forms the first superframe and inserted in the first superframe at
intervals of a specified number of frames, and wherein the
frequency component of control data transmission channel of the
second communication system is observed from the first
communication system by making use of the idle period.
[0015] According to the above invention, when the first
communication system and second communication system coexist, since
the idle period for observing the frequency component of the second
communication system is inserted at most in 1/2 time of one frame
duration for composing one superframe of first communication
system, at intervals of a specified number of frames, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0016] In the mobile radio communication system according to
another aspect of the invention, wherein the first communication
system is the UMTS that transmits frames by using a first
superframe which is formed of a plural frames and which expresses a
frame transmission period, and wherein the second communication
system is an another system that transmits frames by using a second
superframe of an equal transmission period as the first superframe
of the UMTS.
[0017] According to the above invention, in a case where the UMTS
and another system coexist, since the idle period for observing the
frequency component of the another system is inserted at most in
1/2 time of one frame duration for composing one superframe of
UMTS, at intervals of a specified number of frames, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed at this time. Besides, in
the invention, the first superframe corresponds to the one UMTS
superframe mentioned in an embodiment described later, the second
superframe to the one GSM superframe, the third superframe to the
one FCCH/SCH superframe, the user data transmission channel to the
dedicated traffic channel, and the control data transmission
channel to the common control channel, respectively.
[0018] In the mobile radio communication system according to
another aspect of the invention, the interval of a specified number
of frames is determined according to the difference in the
transmission period between the UMTS and the another system.
[0019] According to the above invention, since the interval of a
specified number of frames is determined by the difference in the
transmission period between the UMTS and another system, the
different frequency components can be observed completely depending
on the difference in the transmission period.
[0020] In the mobile radio communication system according to
another aspect of the invention, the specified idle period is
placed in the center of the frame that is the unit of a superframe
of the UMTS.
[0021] According to the above invention, since the idle period is
placed in the center of the frame which is the unit of superframe
of the UMTS, the interleaving effect can be obtained securely.
[0022] The mobile radio communication system according to another
aspect of the invention is a mobile radio communication system
comprising a first communication system employing a code division
multiple access method of transmitting frames by using a first
superframe which is formed of a plural frames and which expresses a
frame transmission period, and a second communication system for
observing frequency component of control data transmission channel
by making use of a specified idle period, the specified idle period
being inserted in a second superframe for downlink user data
transmission channel on the basis of the difference between the
number of frames of integer multiple of second superframe
expressing a frame transmission period in user data transmission
channel and the number of frames of third superframe expressing a
frame transmission period in control data transmission channel,
error correction and interleaving of frames is performed when the
first communication system transmits the frames, wherein the
specified idle period is at most half of the time of one frame that
forms the first superframe and inserted in the first superframe at
not necessarily regular intervals of a specified number of slots,
and wherein the frequency component of control data transmission
channel of the second communication system is observed from the
first communication system by making use of the idle period.
[0023] According to the above invention, in the case where the
first communication system and second communication system coexist,
since the idle period for observing the frequency component of the
second communication system is inserted at most in 1/2 time of one
frame duration for composing one superframe of first communication
system, at intervals of a specified number of slots, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0024] In the mobile radio communication system according to
another aspect of the invention, wherein the first communication
system is the UMTS that transmits frames by using a first
superframe which is formed of a plural frames and which expresses a
frame transmission period, and wherein the second communication
system is an another system that transmits frames by using a second
superframe of an equal transmission period as the first superframe
of the UMTS.
[0025] According to the above invention, in the case where the UMTS
and another system coexist, since the idle period for observing the
frequency component of the another system is inserted at most in
1/2 time of one frame duration for composing one superframe of
UMTS, at intervals of a specified number of slots, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed. Besides, according to the
invention, the first superframe corresponds to the one UMTS
superframe mentioned in the embodiment described later, the second
superframe to the one GSM superframe, the third superframe to the
one FCCH/SCH superframe, the user data transmission channel to the
dedicated traffic channel, and the control data transmission
channel to the common control channel, respectively.
[0026] In the mobile radio communication system according to
another aspect of the invention, the interval of a specified number
of slots is determined according to the difference in the
transmission period between the UMTS and the another system.
[0027] According to the above invention, since the interval of a
specified number of slots is determined by the difference in the
transmission period between the UMTS and another system, the
different frequency components can be observed completely depending
on the difference in the transmission period.
[0028] In the mobile radio communication system according to
another aspect of the invention, the plural numbers of the
specified idle periods are placed in the UMTS superframe and the
idle period may be differently set in each frame.
[0029] According to the above invention, since the plural idle
periods in the superframe of the UMTS are placed separately in each
frame, the necessary idle duration is held in one superframe.
[0030] In the mobile radio communication system according to
another aspect of the invention, the total of the idle period is
equal to the specified idle period provided for observing the
frequency component of the another systems.
[0031] According to the above invention, since the total of the
plural idle periods is equal to the specified idle period provided
for observing the frequency component of the other systems, the
total idle periods is equal to the observation duration of
different frequencies between other systems can be held in one
superframe.
[0032] In the mobile radio communication system according to
another aspect of the invention, the frame in which the specified
idle period is inserted is compressed and transmitted
intermittently.
[0033] According to the above invention, since the frame in which
the specified idle time is inserted is compressed and transmitted
intermittently, a frame transmission of a high decodability is
realized even when an idle period is inserted in one frame
period.
[0034] In the mobile radio communication system according to
another aspect of the invention, the compressed frame is generated
by increasing the coding rate.
[0035] According to the above invention, since the compressed frame
is generated by increasing the coding rate, the compression ratio
is lowered, and the number of spreading codes of a shorter code
length can be suppressed.
[0036] In the mobile radio communication system according to
another aspect of the invention, the compressed frame is generated
at a spreading factor that is the same as the spreading factor at
which a frame that do not contain the specified idle period is
generated.
[0037] According to the above invention, since the compressed frame
is generated at a same spreading factor as another frame in which
the specified idle period is not inserted, the interference and
noise resistant characteristic to the compressed frame is
assured.
[0038] The communication apparatus applied in a mobile radio
communication system according to another aspect of the invention
is a communication apparatus applied in a mobile radio
communication system comprising a first communication system
employing a code division multiple access method of transmitting
frames by using a first superframe which is formed of a plural
frames and which expresses a frame transmission period, and a
second communication system for observing frequency component of
control data transmission channel by making use of a specified idle
period, the specified idle period being inserted in a second
superframe for downlink user data transmission channel on the basis
of the difference between the number of frames of integer multiple
of second superframe expressing a frame, transmission period in
user data transmission channel and the number of frames of third
superframe expressing a frame transmission period in control data
transmission channel, error correction and interleaving of frames
being performed when the first communication system transmits the
frames, frames being transmitted continuously in the case of normal
mode, and compressed frames being transmitted intermittently in the
case of compressed mode, wherein the communication apparatus
comprises a control unit for inserting a specified idle period,
during the compressed mode, in the first superframe, having a
duration that is at most portion of one frame that forms the first
superframe, and at intervals of a specified number of frames, and
wherein the frequency component of control data transmission
channel of the second communication system is observed from the
first communication system by making use of the specified idle
period inserted by the control unit.
[0039] According to the above invention, in the case where the
first communication system and second communication system coexist,
since it is controlled so that the idle period for observing the
frequency component of the second communication system is inserted
at most in 1/2 time of one frame duration for composing superframe
in the superframe of the first communication system, it is not
required to observe the frequency component by one observation in
one, superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0040] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
wherein the first communication system is the UMTS that transmits
frames by using a first superframe which is formed of a plural
frames and which expresses a frame transmission period, and wherein
the second communication system is an another system that transmits
frames by using a second superframe of an equal transmission period
as the first superframe of the UMTS.
[0041] According to the above invention, in the case where the UMTS
and another system coexist, since the idle period for observing the
frequency component of the another system is inserted at most in
1/2 time of one frame duration for composing one superframe of
UMTS, at intervals of a specified number of frames, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed. Besides, in the invention,
the first superframe corresponds to the one UMTS superframe
mentioned in the embodiment described later, the second superframe
to the one GSM superframe, the third superframe to the one FCCH/SCH
superframe, the user data transmission channel to the dedicated
traffic channel, and the control data transmission channel to the
common control channel, respectively.
[0042] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit determines the interval of a specified number of
frames according to the difference in the transmission period
between the UMTS and the another system.
[0043] According to the above invention, since the interval of a
specified number of frames is determined by the difference in the
transmission period between the UMTS and another system at the time
of controlling, the different frequency components can be observed
completely depending on the difference in the transmission
period.
[0044] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit places the specified idle period in the center of
the frame that is the unit of superframe of the UMTS.
[0045] According to the above invention, since the specified idle
period is placed in the center of the frame which is the unit of
superframe of the UMTS at the time of controlling, the interleaving
effect may be obtained securely.
[0046] The communication apparatus applied in a mobile radio
communication system in a different aspect of the invention is a
communication apparatus applied in a mobile radio communication
system comprising a first communication system employing a code
division multiple access method of transmitting frames by using a
first superframe which is formed of a plural frames and which
expresses a frame transmission period, and a second communication
system for observing frequency component of control data
transmission channel by making use of a specified idle period, the
specified idle period being inserted in a second superframe for
downlink user data transmission channel, on the basis of the
difference between the number of frames of integer multiple of
second superframe expressing a frame, transmission period in user
data transmission channel and the number of frames of third
superframe expressing a frame transmission period in control data
transmission channel, error correction and interleaving of frames
being performed when the first communication system transmits the
frames, frames being transmitted continuously in the case of normal
mode, and compressed frames being transmitted intermittently in the
case of compressed mode, wherein the communication apparatus
comprises a control unit for inserting a specified idle period,
during the compressed mode, in the first superframe, having a
duration that is at most portion of one frame that forms the first
superframe, and at not necessarily regular intervals of a specified
number of slots, and wherein the frequency component of control
data transmission channel of the second communication system is
observed from the first communication system by making use of the
specified idle period inserted by the control unit.
[0047] According to the above invention, in the case where the
first communication system and second communication system coexist,
since it is controlled so that the idle period for observing the
frequency component of the second communication system is inserted
at most in 1/2 time of one frame duration for composing superframe
in the superframe of the first communication system and at an
interval of a specified number of slots, it is not required to
observe the frequency component by one observation in one
superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0048] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the first communication system is the UMTS that transmits frames by
using wherein the first communication system is the UMTS that
transmits frames by using a first superframe which is formed of a
plural frames and which expresses a frame transmission period, and
wherein the second communication system is an another system that
transmits frames by using a second superframe of an equal
transmission period as the first superframe of the UMTS.
[0049] According to the above invention, in the case where the UMTS
and another system coexist, since the idle period for observing the
frequency component of the another system is inserted at most in
1/2 time of one frame duration for composing one superframe of
UMTS, at intervals of a specified number of slots, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied, and
therefore even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed. Besides, according to the
invention, the first superframe corresponds to the one UMTS
superframe mentioned in the embodiment described later, the second
superframe to the one GSM superframe, the third superframe to the
one FCCH/SCH superframe, the user data transmission channel to the
dedicated traffic channel, and the control data transmission
channel to the common control channel, respectively.
[0050] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit determines the interval of a specified number of
frames according to the difference in the transmission period
between the UMTS a nd the another system.
[0051] According to the above invention, since the interval of a
specified number of slots is determined by the difference in the
transmission period between the UMTS and another system at the time
of controlling, different frequency components can be observed
completely depending on the difference in the transmission
period.
[0052] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit provides the specified idle period at many places
in the UMTS superframe and the sets each idle period differently in
each frame.
[0053] According to the above invention, since plural idle periods
are disposed in each frame in the superframe of the UMTS at the
time of controlling, a necessary idle duration can be held in one
superframe.
[0054] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit sets the idle period in such a way that the total
of then is equal to the specified idle duration provided for
observing the frequency component between the another systems.
[0055] According to the above invention, since the total of the
plural idle periods is set equal to the specified idle duration
provided for observing the frequency component between the other
systems at the time of controlling, an idle duration equal to
observation of different frequencies between other systems can be
held in one superframe.
[0056] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit increases the coding rate when generating the
compressed frame.
[0057] According to the above invention, since the compressed frame
is generated by increasing the coding rate at the time of
controlling, the compression ratio is lowered, and the number of
spreading codes of a shorter code length can be suppressed.
[0058] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit sets a spreading factor when generating the
compressed mode frame that is the same as the spreading factor at
which a frame that do not contain the specified idle period is
generated.
[0059] According to the above invention, since the compressed frame
is generated at a same spreading factor as another frame in which
the specified idle period is not inserted at the time of
controlling, the interference and noise resistant characteristic of
the compressed frame is assured.
[0060] In the communication apparatus applied in a mobile radio
communication system according to another aspect of the invention,
the control unit increases the average transmission power during
the compressed mode.
[0061] According to the above invention, since the average
transmission power is increased in the compressed mode at the time
of controlling, the characteristic deterioration may be suppressed
to a minimum limit.
[0062] The mobile radio communication method according to another
aspect of the invention is a mobile radio communication method,
applied in a mobile radio communication system having, a first
communication system employing a code division multiple access
method of transmitting frames by using a first superframe which is
formed of a plural frames and which expresses a frame transmission
period, and a second communication system for observing frequency
component of control data transmission channel by making use of a
specified idle period, the specified idle period being inserted in
a second superframe for downlink user data transmission channel on
the basis of the difference between the number of frames of integer
multiple of second superframe expressing a frame transmission
period in user data transmission channel and the number of frames
of third superframe expressing a frame transmission period in
control data transmission channel, error correction and
interleaving of frames being performed when the first communication
system transmits the frames, frames being transmitted continuously
in the case of normal mode, and compressed frames being transmitted
intermittently in the case of compressed mode, the method
comprising a first step of compressing frames to be transmitted
intermittently during the compressed mode, and a second step of
transmitting the frames compressed in the first step intermittently
by inserting a specified idle period, in the first superframe,
having a duration that is at most portion of one frame that forms
the first superframe, and at intervals of a specified number of
frames determined by the relation of the frame structure between
the first communication system and the second communication system,
and the frequency component of control data transmission channel of
the second communication system being observed from the first
communication system by making use of the specified idle period
inserted in the second step.
[0063] According to the above invention, by compressing the frames
transmitted intermittently at the time of compressed mode, and
inserting an idle period for observing the frequency component of
the second communication system at most in 1/2 time of one frame
duration for composing the superframe of the first communication
system in the superframe of the first communication system and at
an interval of a specified number of frames determined by the
relation of the frame structure between the first communication
system and second communication system, since the step for
transmitting intermittently the compressed frames is set up, it is
not required to observe the frequency component by one observation
in one superframe, and the restrictions in frame transmission such
as error correction code and spreading factor can be satisfied.
Therefore even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0064] The mobile radio communication method according to another
aspect of the invention is a mobile radio communication method,
applied in a mobile radio communication system having, a first
communication system employing a code division multiple access
method of transmitting frames by using a first superframe which is
formed of a plural frames and which expresses a frame transmission
period, and a second communication system for observing frequency
component of control data transmission channel by making use of a
specified idle period, the specified idle period being inserted in
a second superframe for downlink user data transmission channel on
the basis of the difference between the number of frames of integer
multiple of second superframe expressing a frame transmission
period in user data transmission channel and the number of frames
of third superframe expressing a frame transmission period in
control data transmission channel, error correction and
interleaving of frames being performed when the first communication
system transmits the frames, frames being transmitted continuously
in the case of normal mode, and compressed frames being transmitted
intermittently in the case of compressed mode, the method
comprising a first step of compressing frames to be transmitted
intermittently during the compressed mode, and a second step of
transmitting the frames compressed in the first step intermittently
by inserting a specified idle period, in the first superframe,
having a duration that is at most half of one frame that forms the
first superframe, and at intervals of a specified number of slots
determined by the relation of the frame structure between the first
communication system and the second communication system, and the
frequency component of control data transmission channel of the
second communication system being observed from the first
communication system by making use of the specified idle period
inserted in the second step.
[0065] According to the above invention, by compressing the frames
transmitted intermittently at the time of compressed mode, and
inserting an idle period for observing the frequency component of
the second communication system at most in 1/2 time of one frame
duration for composing the superframe of the first communication
system in the superframe of the first communication system and at
an interval of a specified number of slots determined by the
relation of the frame structure between the first communication
system and second communication system, since the step for
transmitting intermittently the compressed frames is set up, it is
not required to observe the frequency component by one observation
in one superframe, and the restrictions in frame transmission such
as error correction code and spreading factor can be satisfied.
Therefore even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0066] In the mobile radio communication method in another aspect
of the invention, the first communication system is the UMTS that
transmits frames by using a first superframe expressing a frame
transmission period, wherein the first communication system is the
UMTS that transmits frames by using a first superframe which is
formed of a plural frames and which expresses a frame transmission
period, and wherein the second communication system is an another
system that transmits frames by using a second superframe of an
equal transmission period as the first superframe of the UMTS.
[0067] According to the above invention, in particular, in the case
where the UMTS and another system coexist, since the idle period
for observing the frequency component of the another system is
inserted at most in 1/2 time of one frame duration for composing
one superframe of UMTS, at intervals of a specified number of
frames or at an interval of a specified number of slots, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied, and
therefore even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed. Besides, according to the
invention, the first superframe corresponds to the one UMTS
superframe mentioned in the embodiment described later, the second
superframe to the one GSM superframe, the third superframe to the
one FCCH/SCH superframe, the user data transmission channel to the
dedicated traffic channel, and the control data transmission
channel to the common control channel, respectively.
[0068] In the mobile radio communication method according to
another aspect of the invention, the compressed frames are
generated in the first step by increasing the coding rate.
[0069] According to the above invention, since the compressed frame
is generated by increasing the coding rate at this step, the
compression ratio is lowered, and the number of spreading codes of
a shorter code length can be suppressed.
[0070] In the mobile radio communication method according to
another aspect of the invention, the compressed frame is generated
in the first step at a spreading factor that is the same as the
spreading factor at which a frame that do not contain the specified
idle period is generated.
[0071] According to the above invention, since the compressed frame
is generated at a same spreading factor as another frame in which
the specified idle period is not inserted at this step, the
interference and noise resistant characteristic to the compressed
frame is assured.
[0072] In the mobile radio communication method according to
another aspect of the invention, average transmission power is
increased in the second step during the compressed mode.
[0073] According to the above invention, since the average
transmission power is increased in the compressed mode at this
step, the characteristic deterioration may be suppressed to a
minimum limit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0074] FIG. 1 shows a frame format applied in a GSM system, FIG.
1(a) is a diagram for explaining the frame format of dedicated
traffic channel, and FIG. 1(b) is a diagram for explaining the
frame format of common control channel;
[0075] FIG. 2 is a diagram for explaining the observation period of
GSM superframe applied in the GSM system;
[0076] FIG. 3 shows an observation method of different frequency
components between GSM and GSM, FIG. 3(a) is a diagram for
explaining the frame format of common control channel, FIG. 3(b) is
a diagram for explaining the frame format of dedicated traffic
channel in relation to the common control channel, and FIG. 3(c) is
a diagram for explaining the observation period inserted in every
GSM superframe;
[0077] FIG. 4 is a diagram for explaining an observation method in
the GSM system;
[0078] FIG. 5 show a frame format applied in the UMTS, FIG. 5(a) is
a diagram for explaining the frame format of dedicated traffic
channel applied in the GSM system, and FIG. 5(b) is a diagram for
explaining the format of superframe of UMTS;
[0079] FIG. 6 shows an observation method of different frequency
components between GSM and UMTS, FIG. 6(a) is a diagram for
explaining the frame format of common control channel applied in
the GSM system, FIG. 6(b) is a diagram for explaining the relation
of superframe between the UMTS and GSM systems, and FIG. 6(c) is a
diagram for explaining the observation period inserted in every
superframe in the UMTS;
[0080] FIG. 7 is a diagram for explaining the frame transmission of
downlink according to a first embodiment of the invention;
[0081] FIG. 8 is a block diagram showing a mobile radio
communication system according to the first embodiment of the
invention;
[0082] FIG. 9 is a flowchart for explaining the transmission
operation in compressed mode according to the first embodiment of
the invention;
[0083] FIG. 10 is a flowchart for explaining the reception
operation in compressed mode according to the first embodiment of
the invention;
[0084] FIG. 11 is a diagram for explaining the frame transmission
of downlink according to a second embodiment of the invention;
[0085] FIG. 12 is a diagram for explaining the frame transmission
of downlink according to a third embodiment of the invention;
and
[0086] FIG. 13 is a diagram for explaining the frame transmission
of downlink in a prior art.
BEST MODE FOR CARRYING OUT THE INVENTION
[0087] Referring now to the accompanying drawings, preferred
embodiments of mobile radio communication system, communication
apparatus applied in mobile radio communication system, and mobile
radio communication method of the invention are described in detail
below.
[0088] First, the principle of a first embodiment of the invention
is described. In the first embodiment of the invention, a mobile
radio communication system in which UMTS and GSM systems coexist is
presented as an example. To begin with, the existing system, GSM
system, is explained. FIG. 1 shows a frame format applied in the
GSM system. More specifically, FIG. 1(a) is a diagram for
explaining the frame format of dedicated traffic channel, and FIG.
1(b) is a diagram for explaining the frame format of common control
channel.
[0089] In the GSM system, TACH (Traffic and Associated Channel) is
defined as the dedicated traffic channel, and FCCH (Frequency
Correction Channel) and SCH (Synchronization Channel) are defined
as the common control channel. In the dedicated traffic channel
TACH, as shown in FIG. 1(a), the period of transmitting the
transmission unit of frame from #1 to #26 is designated as one GSM
superframe. One frame has a duration of 8 BP (burst period). One BP
is 0.577 ms. Therefore, one GSM superframe has a transmission
period of 120 ms. In the common control channel FCCH/SCH, as shown
in FIG. 1(b), the period of transmitting 8 BP frame from #1 to #51
is one FCCH/SCH superframe.
[0090] The observation method of different frequency components
between GSM and GSM is described next. FIG. 2 is a diagram for
explaining the observation period of GSM superframe applied in the
GSM system. FIG. 3 shows an observation method of different
frequency components between GSM and GSM. More specifically, FIG.
3(a) is a diagram for explaining the frame format of common control
channel. FIG. 3(b) is a diagram for explaining the frame format of
dedicated traffic channel in relation to the common control
channel. FIG. 3(c) is a diagram for explaining the observation
period inserted in every GSM superframe. FIG. 4 is a diagram for
explaining an observation example in the dedicated traffic channel
of the GSM system. This FIG. 4 is disclosed in the publication "The
GSM System for Mobile Communication" by Michel MOULY and
Marie-Bernadette PAUTET (international standard book number
2-9507190-0-7).
[0091] In the GSM system, the no-transmission period (idle period)
assigned for one GSM superframe is 12 BP (=6.9 ms) as shown in FIG.
2. At the time of handover, different frequency component (control
channel) of another GSM system is observed and detected by making
use of this no-transmission period. The FCCH/SCH superframe is
composed of 51 frames (see FIG. 3(a)). On the contrary, the GSM
superframe (see FIG. 3(b)) has 52 frames in two periods. Comparing
these two superframes, therefore, there is a difference of one
frame. That is, the FCCH/SCH superframe is short of one frame.
Since the observation period is once in one GSM superframe, in two
GSM superframes, the frequency is observed and detected two times
(see FIG. 3(c)).
[0092] This observation and detection procedure is shown in FIG. 4.
There is a difference of one frame between one FCCH/SCH superframe
in common control channel and two GSM superframes in dedicated
traffic. The position of the observation period assigned for one
GSM superframe is fixed in the dedicated traffic channel TACH/F.
Therefore, frequency is observed in a specified frame of every GSM
superframe. When the FCCH/SCH superframe is composed of the same
number of frames as the two GSM superframes, the same frame number
is observed between GSM and GSM all the time. However, since there
is a difference of one frame between FCCH/SCH superframe and two
GSM superframes, observation is shifted by one frame each in every
observation.
[0093] Incidentally, one FCCH/SCH superframe corresponds to two
periods of GSM superframe so that the frequency is observed and
detected twice in every one FCCH/SCH superframe. That is, the time
difference in this pair of observation periods is one GSM
superframe, and the pair of observations progress in a form shifted
by one period of one GSM superframe. Therefore, in a frequency
handover between GSM and GSM, the frequency is observed and
detected in such a manner that the timing of the observation and
detection is shifted twice in every one period of FCCH/SCH
superframe and by one frame each in every one period.
[0094] The next-generation system, UMTS, is explained below. FIG. 5
shows a frame format applied in the UMTS. More specifically, FIG.
5(a) is a diagram for explaining the frame format of dedicated
traffic channel applied in the GSM system. FIG. 5(b) is a diagram
for explaining the format of superframe of UMTS.
[0095] In the GSM system, in the dedicated traffic channel TACH
mentioned above, as shown in FIG. 5(a), the period of transmitting
the frames, which is the unit of transmission, from #1 to #26 is
designated as one GSM superframe. One frame has duration of 8 BP
(burst period). In the UMTS, on the other hand, the UMTS superframe
is composed of the same period as in this GSM superframe. That is,
in the UMTS, in all channels, as shown in FIG. 5(b), the period of
transmitting frames from #1 to #12, each having duration of 10 ms,
is one UMTS superframe.
[0096] The observation method of different frequency components
between GSM and UMTS is described next. FIG. 6 shows the
observation method of different frequency components between GSM
and UMTS. More specifically, FIG. 6(a) is a diagram for explaining
the frame format of common control channel applied in the GSM
system. FIG. 6(b) is a diagram for explaining the relation of
superframe between the UMTS and GSM systems. FIG. 6(c) is a diagram
for explaining the observation period inserted in every superframe
in the UMTS.
[0097] As mentioned above, the FCCH/SCH superframe is composed of
51 frames (see FIG. 6(a)). On the contrary, the GSM superframe has
52 frames in two periods (see FIG. 3(b)). The GSM superframe and
UMTS superframe are equal in the duration of one period. Therefore,
the relation between the FCCH/SCH superframe and the UMTS
superframe coincides with the relation between the FCCH/SCH
superframe and the GSM superframe explained above. That is, there
is a difference of one frame in the FCCH/SCH superframe and two
UMTS superframes (see FIG. 6(b)).
[0098] Herein, in frequency handover between UMTS and GSM, in order
to obtain the same function as in frequency handover between GSM
and GSM mentioned above, observation period of about 6.9 ms is
required in one UMTS superframe. Accordingly, as shown in FIG.
6(c), observation and detection is carried out twice in two UMTS
superframes. Only when 12 BP=6.9 ms, it is same as the handover
between GSM and GSM.
[0099] In this handover between UMTS and GSM, however, due to
restrictions of error correction code and spreading factor, it is
impossible to assign all necessary observation period for one frame
in one superframe. That is, the operation for increasing the coding
rate of the error correction code cannot be increased more than the
number of information bits of the non-coding case. Further, in the
UMTS, the frame length is 10 ms, and since the no-transmission
period of about 6.9 ms for observation of different frequency
components is more than half of the frame length, deterioration of
interleaving performance is predicted. Further, in order to prepare
the no-transmission period of about 6.9 ms in one frame, it is
required to reduce the transmission period to about 3.1 ms.
Therefore the transmission power in the compressed mode
transmission should be increased. This results in a problem that
the interference power on another channels is instantly
increased.
[0100] It may be hence considered to observe and detect different
frequency components in one UMTS superframe by dividing in plural
times. In this case, the time performance for compensating for
control channel of GSM channel is same as when preparing an
observation period once in every one UMTS superframe. Consequently,
the number of idle slots for obtaining one observation period can
be set smaller than in the case between GSM and GSM. The idle slots
can be generated by using punctured code or higher coding rate of
error correction coding.
[0101] In the first embodiment, the frequency is observed and
detected twice in every one UMTS superframe. Hence, in two UMTS
superframes, the frequency is observed and detected four times.
[0102] The observation and detection method is explained by
referring to FIG. 7. FIG. 7 is a diagram for explaining the frame
transmission of downlink in the first embodiment of the invention.
In FIG. 7, the axis of ordinates denotes the transmission rate or
transmission power, and the axis of abscissas represents the time.
There is a difference of one frame between one FCCH/SCH superframe
and two UMTS superframes in the common control channel. In the
dedicated traffic channel TACH/F, the position of observation
period assigned in one GSM superframe is fixed. Similarly, in the
UMTS also the positions of two observation periods assigned in one
UMTS superframe in the downlink traffic channel are fixed.
Therefore, frequency is observed and detected in specified frames
(two positions) of every UMTS superframe. Thus, since there is a
difference of one frame between one FCCH/SCH superframe and two
UMTS superframes, one frame is shifted each in each
observation.
[0103] Since one FCCH/SCH superframe corresponds to two periods of
UMTS superframe, the frequency is observed and detected four times
in one FCCH/SCH superframe. That is, the time difference in the
pair of observation periods corresponds to one UMTS superframe in
every UMTS superframe, and the pair of observations progress in a
form shifted by one period of one FCCH/SCH superframe. Therefore,
in frequency handover between UMTS and GSM, the frequency is
observed and detected four times in every period of FCCH/SCH
superframe, and while shifting by one frame each in every period of
observation.
[0104] The observation period, that is, the idle slot is set in the
center of a specified frame. Hence, interleaving effect is obtained
in the compressed mode frame transmission. Further, by increasing
the coding rate in punctured coding or error correction coding, the
redundancy is further decreased, and the idle period can be set
longer proportionally. In this case, the quantity of information to
be transmitted is decreased, the spreading factor can be kept
unchanged. That is, the interference and noise resistant
characteristic may be maintained. Incidentally, the characteristic
deteriorates when transmitting compressed frames so that the
transmission power must be slightly increased as compared to the
normal transmission.
[0105] A specific example of mobile communication system is
discussed below. FIG. 8 is a block diagram showing a mobile radio
communication system according to the first embodiment of the
invention. The mobile radio communication system consists of a
transmitter 1 and a receiver 2. Such a system is installed at both,
a base station and a mobile station. In this mobile radio
communication system, for example, W (wideband)-CDMA (code division
multiple access) communication method is applied.
[0106] The transmitter 1 comprises, as shown in FIG. 8, a
controller 11, an error correction encoder 12, an interleaver 13, a
framing/spreading unit 14, a radio frequency transmitter 15, etc.
The controller 11 controls the operation of the interleaver 13,
framing/spreading unit 14, and radio frequency transmitter 15
mainly through negotiation with the receiver 2. This controller 11
controls the operation suited to normal mode (non-compressed mode)
and compressed mode by negotiation with the receiver 2. More
specifically, the controller 11 instructs the transmission timing
for transmitting the compressed mode frames, in compressed mode, to
the framing/spreading unit 14. The controller 11 also instructs
increase of average transmission power when transmitting compressed
mode frames to the radio frequency transmitter 15.
[0107] The error correction encoder 12 obtains coded data by error
correction coding of transmission data stream. The interleaver 13
permutes the time sequence of (interleaves) the coded data in bit
units in order to minimize the effects of transmission error in the
event of, for example, loss of continuous bits of transmission
signal due to fading during transmission. The interleaver 13 has a
memory for interleaving one frame.
[0108] The framing/spreading unit 14 spreads wider by using a
spreading code of each user, depending on normal mode or compressed
mode, and forms a frame depending on each mode. When transmission
timing depending on the mode is instructed from the controller 11,
this framing/spreading unit 14 sends out the frame to the radio
frequency transmitter 15 at the transmission timing. The radio
frequency transmitter 15 converts the transmission signal obtained
from the framing/spreading unit 14 into radio frequency, and
transmits. The radio frequency transmitter 15 increases the average
transmission power in the compressed mode as compared with that of
the normal mode according to the control of the controller 11, and
outputs a transmission signal.
[0109] The receiver 2 comprises, as shown in FIG. 8, a controller
21, an error correction decoder 22, a deinterleaver 23, a
deframing/de-spreading unit 24, a radio frequency receiver 25, etc.
The controller 21 controls the operation of the deinterleaver 23
and deframing/de-spreading unit 24 mainly through negotiation with
the transmitter 1. This controller 21 controls the operation suited
to the normal mode and compressed mode by negotiation with the
transmitter 1. More specifically, the controller 21 instructs
reception timing for receiving the compressed mode frames in the
compressed mode to the deframing/de-spreading unit 24.
[0110] The radio frequency receiver 25 demodulates the reception
signal sent from an antenna not shown. The deframing/de-spreading
unit 24 de-spreads using the spreading signal assigned to the user
of the receiver 2 depending on the normal mode or compressed mode,
and forms a frame suited to each mode. When reception timing
depending on each mode is instructed from the controller 21, the
deframing/de-spreading unit 24 receives the reception signal from
the radio frequency receiver 25 at this reception timing.
[0111] The deinterleaver 23 permutes the time sequence
(de-interleaves) of the coded data in bit units in the reverse
sequence of interleaving in the transmitter 1. The deinterleaver
23, like the interleaver 13, has a memory for interleaving one
frame. The error correction decoder 22 decodes the de-interleaved
signal, and obtains decoded data, that is, reception data
stream.
[0112] Explained next is the frame transmission including
compressed mode. In this mobile radio communication system, in
compressed mode, a period of transmitting intermittently by forming
frames into slots is provided, and by making use of no-transmission
period in this period, the intensity of different frequency carrier
is measured. For this purpose, frames formed into slots must be
compressed, but when interleaved same as in ordinary transmission,
sufficient interleaving time is not available, and enough
interleaving effect cannot be obtained.
[0113] Accordingly, the transmission period of compressed frame in
one frame is divided. One portion is assigned at the beginning of a
frame area, and the other portion is set at the end of the same
frame area, so that a required interleaving time may be obtained.
That is, the idle slot corresponding to the observation period is
placed in the center of a frame. In the receiver 2, this operation
is reverse.
[0114] Herein, the relation between the number of idle slots and
the number of slots in the compressed mode frame is described.
Supposing one frame to be composed of 16 slots, the number of slots
in the first half to be A, the number of idle slots to be B, and
the number of slots in the second half to be C, the following
combinations can be considered. That is, (A, B, C)=(7, 1, 8)/(7, 2,
7)/(6, 3, 7)/(6, 4, 6)/(5, 5, 6)/(5, 6, 5) According to these
combinations, for example, supposing the number of slots in the
first half and second half to be 7 slots and 8 slots respectively,
one slot in the center of the frame is inserted as an idle
slot.
[0115] When a short idle slot such as one or two slots is assigned
per frame, only punctured coding may be used. The position of the
idle slot in principle should be in the frame center, but it may be
deviated forward or backward.
[0116] In such short idle slot, by properly determining the
compressed mode frame of first half and second half and position of
the idle slot, the same acquisition time as in the case of
frequency handover between GSM and GSM may be obtained.
[0117] In the first embodiment, the compressed mode frame is
divided into first portion and second portion bounded by the idle
slot within one frame. The following is to explain how to insert
the observation period, that is, the idle,slot in which frame in
one UMTS superframe, and how to determine the inserting
position.
[0118] One UMTS superframe is composed of 12 frames. In the GSM,
one GSM superframe is composed of 26 frames, and one frame is 8 BP
long, and hence the total period is 208 BP. The idle slot
equivalent to 8 BP is observed in two compressed mode operation,
and hence one observation in, compressed mode has an idle slot
length equivalent to 4 BP. Thus, when a first frame is specified
arbitrarily in one UMTS superframe, the equation between the
position of the second frame and the first frame is as shown in
equation (1). In the case shown in equation (1), it is assumed that
the frame number of the first portion is even, and the frame number
in the second portion is odd. This equation (1) is 4(2n+1)=K(208
BP)/12 2n+1=13K/3. (1) In equation (1), the position that can be
observed in the compressed mode of the first half is the same, but
since the observation period is 4 BP, half of 8 BP, and hence the
equation shows the relation for observing the portion of 4 BP that
can be observed in the compressed mode in the second half,
equivalently to 4 BP corresponding to the second half of 8 BP
missing in the first half. That is, 4(2n+1) denotes an odd-number
multiple of 4 BP (when the first half is even, the second half is
odd), and it suggests that the interval may be K times the UMTS
frame length. When the UMTS frame length is expressed by BP, it is
208 BP (number of BP of UMTS superframe)/12 (number of UMTS frames
included in UMTS superframe). Here, n is an arbitrary natural
number.
[0119] When combinations of K and n that satisfy equation (1), two
kinds of combination can be obtained as shown in equation (2). That
is, (K, n)=(3, 6)/(9,19) (2) According to equation (2), the frame
three frames after the first frame may be defined as the second
frame, or the frame nine frames after the first frame may be
defined as the second frame. In FIG. 7, for example, supposing
frame #2 to be the first frame, frame #5 is the second frame.
[0120] The compressed mode operation when observing and detecting
from the UMTS to the GSM system is explained below. Herein, only
the compressed mode is described. FIG. 9 is a flowchart for
explaining the transmission operation in the compressed mode, and
FIG. 10 is a flowchart for explaining the reception operation in
the compressed mode. In the compressed mode of the transmitter 1 at
the UMTS side (see FIG. 9), interleaving in one frame is instructed
to the interleaver 13 (step S101), and the interleaver 13
interleaves in one frame. When the time reaches the timing of
either first half or second half of the first frame timing or
second frame timing to be observed (step S102), the transmission
timing is instructed to the framing/spreading unit 14 (step
S103).
[0121] Further, increase of average transmission power is
instructed to the radio frequency transmitter 15 (step S103), and
the frames are transmitted at a higher power in the compressed mode
than in the normal mode. Thus, the frequency is observed and
detected twice in one UMTS superframe. In this compressed mode, the
frames are transmitted intermittently (discontinuously).
[0122] On the other hand, in the compressed mode of the receiver 2
at the UMTS side (see FIG. 10), when the time reaches the timing of
either first portion or second portion of the first frame timing or
second frame timing to be observed (step S111), the reception
timing is instructed to the deframing/de-spreading unit 24 (step
S112). After receiving the signal of the portion of one frame,
deinterleaving by one frame is instructed to the deinterleaver 23
(step S113), and the deinterleaver 23 deinterleaves is one frame.
Thus, in the compressed mode, the frames are received
intermittently (discontinuously), and the signal of the GSM system
is observed in an idle period.
[0123] As explained herein, according to the first embodiment,
where the UMTS and another system coexist, an idle period for
observing the frequency component of the another system is inserted
in the superframe of the UMTS. This idle period is at most half of
one frame of the superframe of UMTS and is inserted at an interval
of certain frames. Hence it is not required to observe the
frequency component by one observation in one superframe, and the
restrictions, in frame transmission such as error correction code
and spreading factor can be satisfied. As a result, even when the
UMTS and an another system coexist, the frequency component of the
another system can be securely observed from the UMTS, and
deterioration of interleaving performance of the compressed mode
frame can be suppressed at this time.
[0124] Moreover, in one UMTS superframe, since the interval of the
specified number of frames is determined by the difference in the
transmission period between the UMTS and another system, different
frequency components can be observed completely depending on the
difference in the transmission period.
[0125] Since the idle slot time is placed in the center of the
frame that is the unit of superframe of UMTS, the interleaving
effect can be obtained securely.
[0126] In the superframe of UMTS, since plural idle periods are
disposed separately in each frame, a necessary idle duration can be
held in one superframe.
[0127] The total of plural idle slot durations is set at about 6.9
ms equal to the case of GSM, so that the equal idle duration for
the observation period of different frequencies of other systems
can be held in one UMTS superframe.
[0128] The frame in which the idle slot duration is inserted is
compressed and transmitted intermittently, and therefore even when
idle period is inserted in the duration of one frame, frame
transmission of high decodability can be realized.
[0129] Since the compressed frame is generated by increasing the
coding rate the compression ratio is reduced, and the number of use
of spreading codes of shorter code length can be suppressed.
[0130] In the compressed mode, moreover, frames compressed at the
same spreading factor as in normal mode are generated, and
therefore the interference and noise resistant characteristic to
the compressed frames can be assured.
[0131] Since the average transmission power is increased when
transmitting compressed mode frames, the characteristic
deterioration can be suppressed to a minimum limit.
[0132] In the foregoing first embodiment, at the time of frequency
handover, the observation period (about 6.9 ms) is divided into two
portions in one UMTS superframe for observing and detecting
frequency. However, the invention is not limited to this embodiment
alone. As a second embodiment explained below, the observation
period may be divided in more than two portions. In the second
embodiment, for example, the observation period is divided into
four portions. The entire constitution in the second embodiment is
same as in the first embodiment, and only the difference in
operation is described below.
[0133] The observation and detection method of the second
embodiment is explained below. FIG. 11 is a diagram for explaining
the frame transmission of downlink according to the embodiment of
the invention. In FIG. 11, the axis of ordinates denotes the
transmission rate or transmission power, and the axis of abscissas
represents the time. In comparison between one FCCH/SCH superframe
and two UMTS superframes in the common control channel, there is a
difference of one frame. In the dedicated traffic channel TACH/F,
the position of observation period assigned in one GSM superframe
is fixed. Similarly in the UMTS, the positions of four observation
periods assigned in one UMTS superframe in the downlink traffic
channel are fixed. Therefore, the frequency is observed and
detected in specified frames (four positions) of every UMTS
superframe. Thus, since there is a difference of one frame between
one FCCH/SCH superframe and two UMTS superframes, one frame is
shifted each in each observation.
[0134] Since one FCCH/SCH superframe corresponds to two periods of
UMTS superframe, the frequency is observed and detected eight times
in one FCCH/SCH superframe. That is, in every UMTS superframe, the
difference in the pair of observation periods corresponds to one
UMTS superframe, and the pair of observations progress in a form
shifted by one period of one UMTS superframe. Therefore, in
frequency handover between UMTS and GSM, the frequency is observed
and detected eight times in every FCCH/SCH superframe, and while
shifting by one frame each in every period of observation.
[0135] In the second embodiment, same as in embodiment 1, the
compressed mode frame is divided into first portion and second
portion bounded by the idle slot within one frame. The following is
to explain how to insert the observation period, that is, the idle
slot in which frame of one UMTS superframe, and how to determine
the inserting position.
[0136] In the foregoing first embodiment, since one UMTS superframe
is composed of 12 frames, the method of dividing the UMTS
superframe by unit of a frame is employed. However, the UMTS
superframe can be divided into a shorter time unit and a position
for assigning the idle slot can be set. For example, since one
frame in UMTS is composed of 16 slots, the UMTS superframe is
divided by unit of a slot in the second embodiment.
[0137] The case of four divisions is shown in equation (3). It
requires first frame to fourth frame for assigning the each
observation period in this case. Equation (3) shows a case in which
the frame number of the first frame is even. Equation (3) is an
equation for determining the second frame. In the same concept as
in the first embodiment, this equation (3) is expressed as
2(4n+1)=K1(208 BP)/12.times.16 4n+1=13K1/24. (3) In equation (3),
K1 shows the frame number of the second frame of UMTS superframe,
and n is an arbitrary natural number. At the right side of equation
(3), since one frame is composed of 16 slots, it is multiplied by
12 frames in the denominator.
[0138] When combinations of K1 and n that satisfy equation (3) are
calculated, two types of combination can be obtained as shown in
equation (4). That is, (K1, n)=(24, 3)/(120, 16). (4) In this case,
since K1=24 indicates the number of slots, the second frame can be
determined by dividing K1 by 16. In the case of K1=24, the solution
is 1.5 frames, and when expressed by the frame number, the frame in
which the second observation period is assigned is the frame 1.5
frames after the first frame.
[0139] Equation (5) is for determining the third frame. This
equation (5) is 2(4n+2)=K2(208 BP)/12.times.16 2n+1=13K2/48. (5) In
equation (5), K2 denotes the frame number of the third frame of
UMTS superframe, and n is an arbitrary natural number.
[0140] When combinations of K2 and n that satisfy equation (5) are
calculated, two types of combination are obtained as shown in
equation (6). That is, (K2, n)=(48, 6)/(144, 19). (6) In this case,
since K=48 indicates the number of slots, the third frame can be
determined by dividing K by 16. In the case of K=48, the solution
is 3 frames, and when expressed by the frame number, the frame in
which the third observation period is assigned is the frame 3
frames after the first frame.
[0141] Equation (7) is for determining the fourth frame. This
equation (7) is 2(4n+3)=K3(208 BP)/12.times.16 2n+1=13K3/48. (7) In
equation (7), K3 denotes the frame number of the fourth frame of
UMTS superframe, and n is an arbitrary natural number.
[0142] When combinations of K3 and n that satisfy equation are
calculated (7), two types of combination are obtained as shown in
equation (8). That is, (K3, n)=(72, 9)/(168, 22). (8) In this case,
since K=72 indicates the number of slots, the fourth frame can be
determined by dividing K by 16. In the case of K=72, the solution
is 4.5 frames, and when expressed by the frame number, the frame in
which the fourth observation period is assigned is the frame 4.5
frames after the first frame.
[0143] As explained herein, the number of divisions of observation
period in one UMTS superframe can be four, and the same effects as
in the first embodiment are also obtained in this case. However,
unlike the first embodiment, the division interval is not the
specified number of frames interval, but is an interval of a
specified number of slots.
[0144] In the foregoing second embodiment, at the time of frequency
handover, the observation period (about 6.9 ms) is divided into
four portions in one UMTS superframe for observing and detecting
frequency in four frames, but the invention is not limited to this
embodiment alone. However, as a third embodiment explained below,
the observation period can be divided in more than four portions.
In the third embodiment, for example, it is divided into eight
portions. The entire constitution in the third embodiment is same
as in the first embodiment described above, and only the difference
in operation is described below.
[0145] The observation and detection method of the third embodiment
is explained below. FIG. 12 is a diagram for explaining the frame
transmission of downlink in the third embodiment of the invention.
In FIG. 12, the axis of ordinates denotes the transmission rate or
transmission power, and the axis of abscissas represents the time.
As mentioned above, in comparison between one FCCH/SCH superframe
and two UMTS superframes in the common control channel, there is a
difference of one frame. In the dedicated traffic channel TACH/F
the position of observation period assigned in one GSM superframe
is fixed. Similarly, in the UMTS, the positions of eight
observation periods assigned in one UMTS superframe in the downlink
traffic channel are fixed. Therefore, the frequency is observed and
detected in specified frames (four positions) of every UMTS
superframe. Thus, since there is a difference of one frame between
one FCCH/SCH superframe and two UMTS superframes, one frame is
shifted each in each observation.
[0146] Since one FCCH/SCH superframe corresponds to two periods of
UMTS superframe, the frequency is observed and detected 16 times in
one FCCH/SCH superframe. That is, in every UMTS superframe, the
difference in the set of observation periods corresponds to one
UMTS superframe, and the set of observations progress in a form
shifted by one period of one UMTS superframe. Therefore, in
frequency handover between UMTS and GSM, the frequency is observed
and detected 16 times in every period of FCCH/SCH superframe, while
shifting by one frame each in every period of observation.
[0147] In the third embodiment, too, same as in the foregoing first
and second embodiments, the compressed mode frame is divided into
first portion and second portion bounded by the idle slot within
one frame. The following is to explain how to insert the
observation period, that is, the idle slot in which frame in one
UMTS superframe, and how to determine the inserting position.
[0148] In the third embodiment, same as in the foregoing second
embodiment, the UMTS superframe is divided by the shorter time
unit, and the position for placing the idle slot is set.
[0149] Thus, in the third embodiment, the number of divisions of
observation period in one UMTS superframe can be eight, and the
same effects as in the first embodiment are also obtained in this
case. However, unlike the first embodiment, the division interval
is not the specified number of frames interval, but is an interval
of a specified number of slots.
[0150] In the foregoing first to third embodiments, the observation
period is divided up to eight divisions, but the invention is not
limited to these examples only. The number of divisions may be
further increased as required on the basis of the smaller unit than
the slot.
[0151] The invention is thus described while referring to preferred
embodiments, but the invention may be modified in various forms
within the claimed scope, and such changes shall not be excluded
from the scope of the invention.
[0152] As described herein, according to the mobile radio
communication system in one aspect of the invention, in the case
where the first communication system and second communication
system coexist, since the idle period for observing the frequency
component of the second communication system is inserted at most in
1/2 time of one frame duration for composing one superframe of
first communication system, at intervals of a specified number of
frames, it is not required to observe the frequency component by
one observation in one superframe, and the restrictions in frame
transmission such as error correction code and spreading factor can
be satisfied. Therefore, even when the first communication system
and second communication system coexist, the frequency component of
the second communication system can be securely observed from the
first communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0153] According to the mobile radio communication in another
aspect of the invention, in the case where the UMTS and another
system coexist, since the idle period for observing the frequency
component of the another system is inserted at most in 1/2 time of
one frame duration for composing one superframe of UMTS, at
intervals of a specified number of frames, it is not required to
observe the frequency component by one observation in one
superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied, and
therefore even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed at this time.
[0154] According to the mobile radio communication apparatus in
another aspect of the invention, since the interval of a specified
number of frames is determined by the difference in the
transmission period between the UMTS and another system, the
different frequency components can be observed completely depending
on the difference in the transmission period.
[0155] According to the mobile radio communication apparatus in
another aspect of the invention, since the idle period is placed in
the center of the frame that is the unit of superframe of the UMTS,
the interleaving effect is obtained securely.
[0156] According to the mobile radio communication apparatus in a
different aspect of the invention, in the case where the first
communication system and second communication system coexist, since
the idle period for observing the frequency component of the second
communication system is inserted at most in 1/2 time of one frame
duration for composing one superframe of first communication
system, at intervals of a specified number of slots, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0157] According to mobile radio communication apparatus in another
aspect of the invention, in the case where the UMTS and another
system coexist, since the idle period for observing the frequency
component of the another system is inserted at most in 1/2 time of
one frame duration for composing one superframe of UMTS, at
intervals of a specified number of slots, it is not required to
observe the frequency component by one observation in one
superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied, and
therefore even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS, and deterioration of interleaving performance of the
compressed mode frame can be suppressed at this time.
[0158] According to the mobile radio communication system in
another aspect of the invention, since the interval of a specified
number of slots is determined by the difference in the transmission
period between the UMTS and another system, the different frequency
components can be observed completely depending on the difference
in the transmission period.
[0159] According to the mobile radio communication system in
another aspect of the invention, since the plural idle periods in
the superframe of the UMTS are placed separately in each frame, the
necessary idle duration is held in one superframe.
[0160] According to the mobile radio communication system in
another aspect of the invention, since the total of the plural idle
periods is equal to the specified idle duration provided for
observing the frequency component between the other systems, an
idle period equal to the observation of different frequencies of
other systems can be held in one superframe.
[0161] According to the mobile radio communication system in
another aspect of the invention, since the frame in which the
specified time is inserted is compressed and transmitted
intermittently, a frame transmission of a high decodability is
realized even when an idle period is inserted in one frame
period.
[0162] According to the mobile radio communication system in
another aspect of the invention, since the compressed frame is
generated by increasing the coding rate, the compression rate is
lowered, and the number of spreading codes of a shorter code length
can be suppressed.
[0163] According to the mobile radio communication system in
another aspect of the invention, since the compressed frame is
generated at a same spreading factor as another frame in which the
specified idle duration is not inserted, the interference and noise
resistant characteristic to the compressed frame is assured.
[0164] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, in the case where the first communication system and
second communication system coexist, since it is controlled so that
the idle period for observing the frequency component of the second
communication system is inserted at most in 1/2 time of one frame
duration for composing superframe in the superframe of the first
communication system, it is not required to observe the frequency
component by one observation in one superframe, and the
restrictions in frame transmission such as error correction code
and spreading factor can be satisfied. Therefore, even when the
first communication system and second communication system coexist,
the frequency component of the second communication system can be
securely observed from the first communication system. Further,
deterioration of interleaving performance of the compressed mode
frame during such observation can be suppressed.
[0165] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, in the case where the UMTS and another system coexist,
since the idle period for observing the frequency component of the
another system is inserted at most in 1/2 time of one frame
duration for composing one superframe of UMTS, at intervals of a
specified number of frames, it is not required to observe the
frequency component by one observation in one superframe, and the
restrictions in frame transmission such as error correction code
and spreading factor can be satisfied. Therefore, even when the
UMTS and another system coexist, the frequency component of the
another system can be securely observed from the UMTS. Further,
deterioration of interleaving performance of the compressed mode
frame during such observation can be suppressed.
[0166] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the interval of a specified number of frames is
determined by the difference in the transmission period between the
UMTS and another system at the time of controlling, the different
frequency components can be observed completely depending on the
difference in the transmission period.
[0167] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the specified idle period is placed in the center
of the frame which is the unit of superframe of the UMTS at the
time of controlling, the interleaving effect may be obtained
securely.
[0168] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, in the case where the first communication system and
second communication system coexist, since it is controlled so that
the idle period for observing the frequency component of the second
communication system is inserted at most in 1/2 time of one frame
duration for composing superframe in the superframe of the first
communication system and at an interval of a specified number of
slots, it is not required to observe the frequency component by one
observation in one superframe, and the restrictions in frame
transmission such as error correction code and spreading factor can
be satisfied. Therefore even when the first communication system
and second communication system coexist, the frequency component of
the second communication system can be securely observed from the
first communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0169] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, in the case where the UMTS and another system coexist,
since the idle period for observing the frequency component of the
another system is inserted at most in 1/2 time of one frame
duration for composing one superframe of first communication
system, at intervals of a specified number of frames of UMTS, at
intervals of a specified number of slots, it is not required to
observe the frequency component by one observation in one
superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS. Further, deterioration of interleaving performance
of the compressed mode frame during such observation can be
suppressed.
[0170] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the interval of a specified number of slots is
determined by the difference in the transmission period between the
UMTS and another system at the time of controlling, different
frequency components can be observed completely depending on the
difference in the transmission period.
[0171] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since plural idle periods are disposed in separate
frames in the superframe of the UMTS at the time of controlling, a
necessary idle duration can be held in one superframe.
[0172] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the total of the plural idle periods is set equal
to the specified idle duration provided for observing the frequency
component between the other systems at the time of controlling, an
idle duration equal to observation of different frequencies between
other systems can be held in one superframe.
[0173] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the compressed frame is generated by increasing
the coding rate at the time of controlling, the compression rate is
lowered, and the number of spreading codes of a shorter code length
can be suppressed.
[0174] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the compressed frame is generated at a same
spreading factor as another frame in which the specified idle
duration is not inserted at the time of controlling, the
interference and noise resistant characteristic to the compressed
frame is assured.
[0175] According to the communication apparatus applied in a mobile
radio communication system according to another aspect of the
invention, since the average transmission power is increased in the
compressed mode at the time of controlling, the characteristic
deterioration may be suppressed to a minimum limit.
[0176] According to the mobile radio communication method according
to aspect of the invention, by compressing the frames to be
transmitted intermittently at the time of compressed mode, and
inserting an idle period for observing the frequency component of
the second communication system at most in 1/2 time of one frame
duration for composing the superframe of the first communication
system in the superframe of the first communication system and at
an interval of a specified number of frames determined by the
relation of the frame structure between the first communication
system and second communication system, since the step for
transmitting intermittently the compressed frames is set up, it is
not required to observe the frequency component by one observation
in one superframe, and the restrictions in frame transmission such
as error correction code and spreading factor can be satisfied.
Therefore, even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0177] According to the mobile radio communication method according
to another aspect of the invention, by compressing the frames to be
transmitted intermittently at the time of compressed mode, and
inserting an idle period for observing the frequency component of
the second communication system at most in 1/2 time of one frame
duration for composing the superframe of the first communication
system in the superframe of the first communication system and at
an interval of a specified number of slots determined by the
relation of the frame structure between the first communication
system and second communication system, since the step for
transmitting intermittently the compressed frames is set up, it is
not required to observe the frequency component by one observation
in one superframe, and the restrictions in frame transmission such
as error correction code and spreading factor can be satisfied.
Therefore, even when the first communication system and second
communication system coexist, the frequency component of the second
communication system can be securely observed from the first
communication system. Further, deterioration of interleaving
performance of the compressed mode frame during such observation
can be suppressed.
[0178] According to the mobile radio communication method according
to another aspect of the invention, in particular, in the case
where the UMTS and another system coexist, since the idle period
for observing the frequency component of the another system is
inserted at most in 1/2 time of one frame duration for composing
one superframe of UMTS, at intervals of a specified number of
frames or at an interval of a specified number of slots, it is not
required to observe the frequency component by one observation in
one superframe, and the restrictions in frame transmission such as
error correction code and spreading factor can be satisfied.
Therefore, even when the UMTS and another system coexist, the
frequency component of the another system can be securely observed
from the UMTS. Further, deterioration of interleaving performance
of the compressed mode frame during such observation can be
suppressed.
[0179] According to the mobile radio communication method according
to another aspect of the invention, since the compressed frame is
generated by increasing the coding rate at this step, the
compression ratio is lowered, and the number of spreading codes of
a shorter code length can be suppressed.
[0180] According to the mobile radio communication method according
to another aspect of the invention, since the compressed frame is
generated at a same spreading factor as another frame in which the
specified idle period is not inserted at this step, the
interference and noise resistant characteristic to the compressed
frame is assured.
[0181] According to the mobile radio communication method according
to another aspect of the invention, since the average transmission
power is increased in the compressed mode at this step, the
characteristic deterioration may be suppressed to a minimum
limit.
INDUSTRIAL APPLICABILITY
[0182] As described herein, the mobile radio communication system,
the communication apparatus applied in the mobile radio
communication system, and the mobile radio communication method of
the invention are useful for observing the control channel of
another system by making use of idle period in the mobile radio
communication system. In particular this invention can suitably
used in the mobile radio communication system in which the UMTS
(Universal Mobile Terrestrial communication System) and GSM (Group
Specific Mobile) system coexist.
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