U.S. patent application number 13/255968 was filed with the patent office on 2012-01-05 for mobile station apparatus, base station apparatus, integrated circuit, and method of detecting random access problems.
Invention is credited to Yasuyuki Kato, Daiichiro Nakashima, Wataru Ohuchi, Katsunari Uemura, Shohei Yamada.
Application Number | 20120002555 13/255968 |
Document ID | / |
Family ID | 42728188 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120002555 |
Kind Code |
A1 |
Ohuchi; Wataru ; et
al. |
January 5, 2012 |
MOBILE STATION APPARATUS, BASE STATION APPARATUS, INTEGRATED
CIRCUIT, AND METHOD OF DETECTING RANDOM ACCESS PROBLEMS
Abstract
A method of detecting random access problems in a mobile station
apparatus which uses multiple component carriers to perform random
access. To achieve this, the mobile station apparatus, which is in
a mobile communication system comprised of a base station apparatus
and mobile station apparatuses, uses one random access channel
transmission counter to detect random access problems in the
plurality of component carriers.
Inventors: |
Ohuchi; Wataru; (Osaka,
JP) ; Yamada; Shohei; (Osaka, JP) ; Kato;
Yasuyuki; (Osaka, JP) ; Nakashima; Daiichiro;
(Osaka, JP) ; Uemura; Katsunari; (Osaka,
JP) |
Family ID: |
42728188 |
Appl. No.: |
13/255968 |
Filed: |
February 17, 2010 |
PCT Filed: |
February 17, 2010 |
PCT NO: |
PCT/JP2010/052325 |
371 Date: |
September 12, 2011 |
Current U.S.
Class: |
370/244 |
Current CPC
Class: |
H04L 61/6022 20130101;
H04W 72/0413 20130101; H04W 74/0833 20130101; H04W 88/02 20130101;
H04W 24/08 20130101 |
Class at
Publication: |
370/244 |
International
Class: |
H04W 24/00 20090101
H04W024/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 13, 2009 |
JP |
2009-060436 |
Claims
1-29. (canceled)
30. A random access problem detecting method of a mobile station
apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: setting one counter for counting the number of transmissions of
a random access channel to a master component carrier specified by
the base station apparatus; transmitting the random access channel
to the base station apparatus; counting the number of transmissions
of the random access channel transmitted by the counter using the
master component carrier; and recognizing that a random access
problem is detected for all the component carriers if the number of
transmissions reaches a predetermined maximum number of
transmissions.
31. The random access problem detecting method as defined in claim
30, wherein the master component carrier is an uplink component
carrier that is paired with a downlink component carrier that the
mobile station apparatus accesses first.
32. The random access problem detecting method as defined in claim
30, wherein the master component carrier is an uplink component
carrier that is paired with a downlink component carrier having a
highest priority specified with broadcast information transmitted
from the base station apparatus.
33. A random access problem detecting method of a mobile station
apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: setting a counter for counting the number of transmissions of a
random access channel one-by-one to each of the plurality of
component carriers; transmitting the random access channel to the
base station apparatus; counting the number of transmissions of the
random access channel transmitted by the counter using the
component carriers; and recognizing that a random access problem is
detected if all the numbers of transmissions for the plurality of
component carriers reach a predetermined maximum number of
transmissions.
34. A random access problem detecting method of a mobile station
apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: forming multiple component carrier groups from the plurality of
component carriers in accordance with information for forming the
component carrier groups transmitted from the base station
apparatus; setting a counter for counting the number of
transmissions of a random access channel one-by-one to each of the
plurality of component carrier groups; transmitting the random
access channel to the base station apparatus; counting the number
of transmissions of the random access channel by the counter; and
recognizing that a random access problem is detected if all the
numbers of transmissions for the component carrier groups reach a
predetermined maximum number of transmissions.
35. The random access problem detecting method as defined in claim
34, at least comprises the step of setting a master component
carrier for each of the component carrier groups.
36. The random access problem detecting method as defined in claim
35, at least comprises the step of setting the counter to a master
component carrier included in each of the component carrier
groups.
37. A random access problem detecting method of a mobile station
apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: transmitting a random access channel to the base station
apparatus; activating a timer for detecting a random access problem
if the number of transmissions of the random access channel reaches
a predetermined maximum number of transmissions; and recognizing
that a random access problem is detected if the timer reaches a
predetermined time.
38. A mobile station apparatus using multiple component carriers to
communicate with a base station apparatus, wherein one counter for
counting the number of transmissions of a random access channel is
set to a master component carrier specified by the base station
apparatus out of the plurality of component carriers, the random
access channel is transmitted to the base station apparatus, the
counter counts the number of transmissions of the random access
channel transmitted using the master component carrier, and
detection of a random access problem is recognized for all the
component carriers if the number of transmissions reaches a
predetermined maximum number of transmissions.
39. The mobile station apparatus as defined in claim 38, wherein
the master component carrier is an uplink component carrier that is
paired with a downlink component carrier that the mobile station
apparatus first accesses.
40. The mobile station apparatus as defined in claim 38, wherein
the master component carrier is an uplink component carrier that is
a paired with a downlink component carrier having a highest
priority specified with broadcast information transmitted from the
base station apparatus.
41. A mobile station apparatus using multiple component carriers to
communicate with a base station apparatus, wherein a counter for
counting the number of transmissions of a random access channel
one-by-one is set to each of the plurality of component carriers,
the random access channel is transmitted to the base station
apparatus, the counter counts the number of transmissions of the
random access channel transmitted using the component carriers for
each of the component carriers, and detection of a random access
problem is recognized if all the numbers of transmissions reach a
predetermined maximum number of transmissions.
42. A mobile station apparatus using multiple component carriers to
communicate with a base station apparatus, wherein multiple
component carrier groups are formed from the plurality of component
carriers in accordance with information for forming the component
carrier groups transmitted from the base station apparatus, a
counter for counting the number of transmissions of a random access
channel one-by-one is set to each of the plurality of component
carrier groups; the random access channel is transmitted to the
base station apparatus, the counter counts the number of
transmissions of the random access channel transmitted from the
component carrier groups for each of the component carrier group,
and detection of a random access problem is recognized if all the
numbers of transmissions reach a predetermined maximum number of
transmissions.
43. A mobile station apparatus using multiple component carriers to
communicate with a base station apparatus, wherein a random access
channel is transmitted to the base station apparatus, the number of
transmissions of the random access channel is counted, a timer for
detecting a random access problem is activated if the number of
transmissions reaches a predetermined maximum number of
transmissions, and detection of a random access problem is
recognized if the timer reaches a predetermined expiration
time.
44. An integrated circuit, when mounted on a mobile station
apparatus, making the mobile station apparatus implement multiple
functions of: setting one counter for counting the number of
transmissions of a random access channel to a master component
carrier specified by a base station apparatus; transmitting the
random access channel to the base station apparatus; counting the
number of transmissions of the random access channel transmitted by
the counter using the master component carrier; and recognizing
that a random access problem is detected for all the component
carriers if the number of transmissions reaches a predetermined
maximum number of transmissions.
45. An integrated circuit, when mounted on a mobile station
apparatus, making the mobile station apparatus implement multiple
functions of: setting a counter for counting the number of
transmissions of a random access channel one-by-one to each of
multiple component carriers; transmitting the random access channel
to the base station apparatus; counting the number of transmissions
of the random access channel transmitted by the counter using the
component carriers for each of the component carriers; and
recognizing that a random access problem is detected if all the
numbers of transmissions reach a predetermined maximum number of
transmissions.
46. An integrated circuit, when mounted on a mobile station
apparatus, making the mobile station apparatus implement multiple
functions of: setting a counter for counting the number of
transmissions of a random access channel one-by-one to each of
multiple component carrier groups made up of multiple component
carriers; transmitting the random access channel to the base
station apparatus; counting the number of transmissions of the
random access channel transmitted from the component carrier groups
for each of the component carrier groups by the counter; and
recognizing that a random access problem is detected if all the
numbers of transmissions reach a predetermined maximum number of
transmissions.
47. An integrated circuit, when mounted on a mobile station
apparatus, making the mobile station apparatus implement multiple
functions of: transmitting a random access channel to a base
station apparatus; counting the number of transmissions of the
random access channel; activating a timer for detecting a random
access problem if the number of transmissions reaches a
predetermined maximum number of transmissions; and recognizing that
a random access problem is detected if the timer reaches a
predetermined time.
Description
TECHNICAL FIELD
[0001] The present invention relates to a mobile station apparatus
in a mobile communication system, and, more particularly, to a
method of detecting a random access problem for multiple component
carriers.
BACKGROUND ART
[0002] The standard-setting organization 3GPP (3rd Generation
Partnership Project) is discussing Evolved Universal Terrestrial
Radio Access (hereinafter, EUTRA) evolved from the third generation
mobile communication method and an advanced version thereof, i.e.,
Advanced EUTRA (also referred to as LTE-Advanced).
[0003] In Advanced EUTRA, the SC-FDMA (Single Carrier-Frequency
Division Multiple Access) method is proposed as the uplink
communication method.
[0004] Processing of a medium access control layer related to
random access is proposed in EUTRA (Nonpatent Literature 1).
[0005] In Advanced EUTRA, carrier aggregation (frequency band
aggregation) is proposed as a technique enabling higher-speed data
transmission while maintaining the compatibility with EUTRA
(Nonpatent Literature 2). The carrier aggregation is a technique
for improving a data rate in downlink communication by preparing a
transmitting apparatus and a receiving apparatus that has a
reception bandwidth greater than the transmission bandwidth of the
transmitting apparatus, by transmitting data from multiple
transmitting apparatuses to which multiple respective different
frequency bands (hereinafter, component carriers (CC)) are set, and
by receiving the data transmitted from the plurality of
transmitting apparatuses in the receiving apparatus. The carrier
aggregation is also a technique for improving a data rate in uplink
communication by preparing a receiving apparatus and a transmitting
apparatus that has a transmission bandwidth greater than the
reception bandwidth of the receiving apparatus and by receiving
data transmitted from the transmitting apparatus by multiple
receiving apparatuses to which respective different frequencies are
set bands.
PRIOR ART DOCUMENTS
Nonpatent Literatures
[0006] Nonpatent Literature 1: 3GPP TS36.321, Medium Access Control
(MAC) protocol specification. V8.4.0
http://www.3gpp.org/ftp/Specs/html-info/36321.htm [0007] Nonpatent
Literature 2: Ericsson, R1-082468, 3GPP TSG-RAN1 Meeting #53bis,
Warsaw, Poland, Jun. 30-Jul. 4, 2008
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0008] However, if the carrier aggregation is applied in the uplink
communication, an uplink channel transmitting method suitable for
Advanced EUTRA must be examined since a mobile station apparatus
uses multiple component carriers for transmission.
[0009] Particularly when a mobile station apparatus uses multiple
component carriers for transmitting a signal, a problem of random
access must appropriately be detected to appropriately execute
processing related to communication connection.
[0010] When a mobile station apparatus uses multiple component
carriers to transmit a random access channel, if the mobile station
apparatus waits the completion of random access procedures of all
the component carriers and then detects a random access problem to
execute reestablishment processing, a time until uplink data
transmission is wasted. To prevent such a waste, a means for
promptly detecting a random access problem and promptly executing
reestablishment processing is necessary for the mobile station
apparatus.
[0011] The present invention was conceived to solve the problem and
it is therefore an object of the present invention to provide a
mobile station apparatus, a base station apparatus, an integrated
circuit, and a detecting method of a random access problem capable
of detecting a random access problem in multiple component carriers
by using one random access channel transmission counter (counter
for counting the number of transmissions of a random access
channel).
Means for Solving the Problem
[0012] A mobile station apparatus of one aspect of the present
invention is characterized by using a counter for multiple
component carriers to mange a random access procedure.
[0013] A first technical means of one aspect of the present
invention is a random access problem detecting method of a mobile
station apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: setting one counter for counting the number of transmissions of
a random access channel to the plurality of component carriers;
transmitting the random access channel to the base station
apparatus; counting the number of transmissions of the random
access channel to the plurality of component carriers by the
counter; and recognizing that a random access problem is detected
if the number of transmissions reaches a predetermined maximum
number of transmissions.
[0014] A second technical means of one aspect of the present
invention is a random access problem detecting method of a mobile
station apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: selecting any one of the plurality of component carriers to set
one counter for counting the number of transmissions of a random
access channel to the selected component carrier; transmitting the
random access channel to the base station apparatus; counting the
number of transmissions of the random access channel transmitted by
the counter using the selected component carrier; and recognizing
that a random access problem is detected if the number of
transmissions reaches a predetermined maximum number of
transmissions.
[0015] A third technical means of one aspect of the present
invention is the random access problem detecting method as defined
in the second technical means, wherein, at the transmitting step,
only the selected component carrier is used for transmitting the
random access channel to the base station apparatus.
[0016] A fourth technical means of one aspect of the present
invention is a random access problem detecting method of a mobile
station apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: setting one counter for counting the number of transmissions of
a random access channel to a master component carrier specified by
the base station apparatus; transmitting the random access channel
to the base station apparatus; counting the number of transmissions
of the random access channel transmitted by the counter using the
master component carrier; and recognizing that a random access
problem is detected if the number of transmissions reaches a
predetermined maximum number of transmissions.
[0017] A fifth technical means of one aspect of the present
invention is the random access problem detecting method as defined
in the fourth technical means, wherein the master component carrier
is an uplink component carrier that is paired with a downlink
component carrier that the mobile station apparatus accesses
first.
[0018] A sixth technical means of one aspect of the present
invention is the random access problem detecting method as defined
in the fourth technical means, wherein the master component carrier
is an uplink component carrier that is paired with a downlink
component carrier having a highest priority specified with
broadcast information transmitted from the base station
apparatus.
[0019] A seventh technical means of one aspect of the present
invention is a random access problem detecting method of a mobile
station apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: setting a counter for counting the number of transmissions of a
random access channel one-by-one to each of the plurality of
component carriers; transmitting the random access channel to the
base station apparatus; counting the number of transmissions of the
random access channel transmitted by the counter using the
component carriers; and recognizing that a random access problem is
detected if all the numbers of transmissions for the plurality of
component carriers reach a predetermined maximum number of
transmissions.
[0020] An eighth technical means of one aspect of the present
invention is a random access problem detecting method of a mobile
station apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: forming multiple component carrier groups from the plurality of
component carriers in accordance with information for forming the
component carrier groups transmitted from the base station
apparatus; setting a counter for counting the number of
transmissions of a random access channel one-by-one to each of the
plurality of component carrier groups; transmitting the random
access channel to the base station apparatus; counting the number
of transmissions of the random access channel by the counter; and
recognizing that a random access problem is detected if all the
numbers of transmissions for the component carrier groups reach a
predetermined maximum number of transmissions.
[0021] A ninth technical means of one aspect of the present
invention is a random access problem detecting method of a mobile
station apparatus using multiple component carriers that are usable
frequency bands to communicate with a base station apparatus,
wherein the mobile station apparatus at least comprises the steps
of: transmitting a random access channel to the base station
apparatus; activating a timer for detecting a random access problem
if the number of transmissions of the random access channel reaches
a predetermined maximum number of transmissions; and recognizing
that a random access problem is detected if the timer reaches a
predetermined time.
[0022] A tenth technical means of one aspect of the present
invention is a mobile station apparatus using multiple component
carriers to communicate with a base station apparatus, wherein one
counter for counting the number of transmissions of a random access
channel is set to the plurality of component carriers, the random
access channel is transmitted to the base station apparatus, the
counter counts the number of transmissions of the random access
channel transmitted using the plurality of component carriers, and
detection of a random access problem is recognized if the number of
transmissions reaches a predetermined maximum number of
transmissions.
[0023] An eleventh technical means of one aspect of the present
invention is a mobile station apparatus using multiple component
carriers to communicate with a base station apparatus, wherein any
one of the plurality of component carriers is selected and one
counter for counting the number of transmissions of a random access
channel is set to the selected component carrier, the random access
channel is transmitted to the base station apparatus, the counter
counts the number of transmissions of the random access channel
transmitted using the selected component carrier, and detection of
a random access problem is recognized if the number of
transmissions reaches a predetermined maximum number of
transmissions.
[0024] A twelfth technical means of one aspect of the present
invention is the mobile station apparatus as defined in the
eleventh technical means, wherein the random access channel is
transmitted using only the selected component carrier.
[0025] A thirteenth technical means of one aspect of the present
invention is a mobile station apparatus using multiple component
carriers to communicate with a base station apparatus, wherein one
counter for counting the number of transmissions of a random access
channel is set to a master component carrier specified by the base
station apparatus out of the plurality of component carriers, the
random access channel is transmitted to the base station apparatus,
the counter counts the number of transmissions of the random access
channel transmitted using the master component carrier, and
detection of a random access problem is recognized if the number of
transmissions reaches a predetermined maximum number of
transmissions.
[0026] A fourteenth technical means of one aspect of the present
invention is the mobile station apparatus as defined in the
thirteenth technical means, wherein the master component carrier is
an uplink component carrier that is paired with a downlink
component carrier that the mobile station apparatus first
accesses.
[0027] A fifteenth technical means of one aspect of the present
invention is the mobile station apparatus as defined in the
thirteenth technical means, wherein the master component carrier is
an uplink component carrier that is a paired with a downlink
component carrier having a highest priority specified with
broadcast information transmitted from the base station
apparatus.
[0028] A sixteenth technical means of one aspect of the present
invention is a mobile station apparatus using multiple component
carriers to communicate with a base station apparatus, wherein a
counter for counting the number of transmissions of a random access
channel one-by-one is set to each of the plurality of component
carriers, the random access channel is transmitted to the base
station apparatus, the counter counts the number of transmissions
of the random access channel transmitted using the component
carriers for each of the component carriers, and detection of a
random access problem is recognized if all the numbers of
transmissions reach a predetermined maximum number of
transmissions.
[0029] A seventeenth technical means of one aspect of the present
invention is a mobile station apparatus using multiple component
carriers to communicate with a base station apparatus, wherein
multiple component carrier groups are formed from the plurality of
component carriers in accordance with information for forming the
component carrier groups transmitted from the base station
apparatus, a counter for counting the number of transmissions of a
random access channel one-by-one is set to each of the plurality of
component carrier groups; the random access channel is transmitted
to the base station apparatus, the counter counts the number of
transmissions of the random access channel transmitted from the
component carrier groups for each of the component carrier group,
and detection of a random access problem is recognized if all the
numbers of transmissions reach a predetermined maximum number of
transmissions.
[0030] An eighteenth technical means of one aspect of the present
invention is a mobile station apparatus using multiple component
carriers to communicate with a base station apparatus, wherein a
random access channel is transmitted to the base station apparatus,
the number of transmissions of the random access channel is
counted, a timer for detecting a random access problem is activated
if the number of transmissions reaches a predetermined maximum
number of transmissions, and detection of a random access problem
is recognized if the timer reaches a predetermined expiration
time.
[0031] A nineteenth technical means of one aspect of the present
invention is a base station apparatus using multiple component
carriers to communicate with a mobile station apparatus, wherein
multiple component carrier groups are formed from the plurality of
component carries, and a signal including information indicative of
the formation is transmitted to the mobile station apparatus.
[0032] A twentieth technical means of one aspect of the present
invention is an integrated circuit, when mounted on a mobile
station apparatus, making the mobile station apparatus implement
multiple functions of: setting one counter for counting the number
of transmissions of a random access channel to multiple component
carriers; transmitting the random access channel to the base
station apparatus; counting the number of transmissions of the
random access channel transmitted by the counter using the
plurality of component carriers; and recognizing that a random
access problem is detected if the number of transmissions reaches a
predetermined maximum number of transmissions.
[0033] A twenty-first technical means of one aspect of the present
invention is an integrated circuit, when mounted on a mobile
station apparatus, making the mobile station apparatus implement
multiple functions of: selecting any one of multiple component
carriers to set one counter for counting the number of
transmissions of a random access channel to the selected component
carrier; transmitting the random access channel to the base station
apparatus; counting the number of transmissions of the random
access channel transmitted by the counter using the selected
component carrier; and recognizing that a random access problem is
detected if the number of transmissions reaches a predetermined
maximum number of transmissions.
[0034] A twenty-second technical means of one aspect of the present
invention is the integrated circuit as defined in the twenty-first
technical means, transmitting the random access channel using only
the selected component carrier in the mobile station apparatus.
[0035] A twenty-third technical means of one aspect of the present
invention is an integrated circuit, when mounted on a mobile
station apparatus, making the mobile station apparatus implement
multiple functions of: setting one counter for counting the number
of transmissions of a random access channel to a master component
carrier specified by a base station apparatus; transmitting the
random access channel to the base station apparatus; counting the
number of transmissions of the random access channel transmitted by
the counter using the master component carrier; and recognizing
that a random access problem is detected if the number of
transmissions reaches a predetermined maximum number of
transmissions.
[0036] A twenty-fourth technical means of one aspect of the present
invention is an integrated circuit, when mounted on a mobile
station apparatus, making the mobile station apparatus implement
multiple functions of: setting a counter for counting the number of
transmissions of a random access channel one-by-one to each of
multiple component carriers; transmitting the random access channel
to the base station apparatus; counting the number of transmissions
of the random access channel transmitted by the counter using the
component carriers for each of the component carriers; and
recognizing that a random access problem is detected if all the
numbers of transmissions reach a predetermined maximum number of
transmissions.
[0037] A twenty-fifth technical means of one aspect of the present
invention is an integrated circuit, when mounted on a mobile
station apparatus, making the mobile station apparatus implement
multiple functions of: setting a counter for counting the number of
transmissions of a random access channel one-by-one to each of
multiple component carrier groups made up of multiple component
carriers; transmitting the random access channel to the base
station apparatus; counting the number of transmissions of the
random access channel transmitted from the component carrier groups
for each of the component carrier groups by the counter; and
recognizing that a random access problem is detected if all the
numbers of transmissions reach a predetermined maximum number of
transmissions.
[0038] A twenty-sixth technical means of one aspect of the present
invention is an integrated circuit, when mounted on a mobile
station apparatus, making the mobile station apparatus implement
multiple functions of: transmitting a random access channel to a
base station apparatus; counting the number of transmissions of the
random access channel; activating a timer for detecting a random
access problem if the number of transmissions reaches a
predetermined maximum number of transmissions; and recognizing that
a random access problem is detected if the timer reaches a
predetermined time.
[0039] A twenty-seventh technical means of one aspect of the
present invention is an integrated circuit, when mounted on a base
station apparatus, making the base station apparatus implement
multiple functions of: forming multiple component carrier groups
from multiple component carries; and transmitting a signal
including information indicative of the formation to a mobile
station apparatus.
Effects of the Invention
[0040] The present invention can provide a detecting method of a
random access problem that arises when a mobile station apparatus
uses multiple different component carriers to execute a random
access procedure, and reestablishment processing can efficiently be
executed.
[0041] The detecting method of a random access problem can be
provided in the random access procedure using multiple component
carriers.
[0042] Reestablishment processing can be provided in the case of a
random access problem that occurred in the random access procedure
using multiple component carriers.
BRIEF DESCRIPTION OF DRAWINGS
[0043] FIG. 1 is a block diagram of a general configuration of a
mobile station apparatus according to a first embodiment of the
present invention.
[0044] FIG. 2 is a block diagram of a general configuration of a
base station apparatus according to the first embodiment of the
present invention.
[0045] FIG. 3 is a diagram of a general configuration of uplink
channels.
[0046] FIG. 4 is a diagram of an example of a procedure of
contention-based random access.
[0047] FIG. 5 is a flowchart of general processing for the mobile
station apparatus performing the random access problem detection
using a counter.
[0048] FIG. 6 is a flowchart of a setting method of a random access
channel transmission counter of the first embodiment.
[0049] FIG. 7 is a flowchart of a setting method of a random access
channel transmission counter in a basic form of a second
embodiment.
[0050] FIG. 8 is a flowchart of a setting method of a random access
channel transmission counter of a third embodiment.
[0051] FIG. 9 is a flowchart of a setting method of a random access
channel transmission counter of a fourth embodiment.
[0052] FIG. 10 is a flowchart of a setting method of a random
access channel transmission counter of a fifth embodiment.
[0053] FIG. 11 is a flowchart of general processing for the mobile
station apparatus performing the random access problem detection
using a timer.
MODES FOR CARRYING OUT THE INVENTION
[0054] Before specifically describing embodiments, a summary of a
communication technology used in the present invention will briefly
be described.
(1) Interface Protocols of Layers
[0055] Layers of a radio interface protocol between a mobile
station apparatus and a network are classified into L1 (a first
layer), L2 (a second layer), and L3 (a third layer) based on a
reference model of Open System Interconnection (hereinafter,
OSI).
[0056] A physical layer belongs to the first layer and uses a
physical channel to provide information transmission service to a
higher layer. The physical layer is coupled with a medium access
control (hereinafter, MAC) layer of the second layer through a
transport channel (also referred to as a transmission channel).
Data is transmitted between the MAC layer and the physical layer
through the transport channel.
[0057] The MAC layer belongs to the second layer and provides a
service such as resource allocation between a logical channel and
the transport channel to a radio link control (hereinafter, RLC)
layer through the logical channel. The RLC layer assists reliable
data transmission. The function of the RLC layer is implemented by
a functional block in the MAC layer in some cases and, therefore,
the RLC layer sometimes does not exist.
[0058] The second layer also includes a packet data convergence
protocol (hereinafter, PDCP) layer along with the MAC layer and the
RLC layer.
[0059] The PDCP layer enables efficient transmission through a
radio link by compressing header information added to packet data
and prevents lack of data by managing the order of packets.
[0060] A radio resource control (hereinafter, RRC) layer belongs to
the third layer and controls transport channels and physical
channels in relation to setting, resetting, and cancelling of a
radio bearer. The RRC layer performs broadcasting etc., of system
information and call information from a network to mobile station
apparatuses and also performs the control of the first and second
layers necessary for the broadcasting etc. The RRC layer also
controls radio resources between a mobile station apparatus and a
network.
(2) Physical Channels
[0061] The physical channels used in the present invention include
a physical broadcast channel, a physical uplink data channel, a
physical downlink data channel, a physical downlink control
channel, a physical uplink control channel, a physical random
access channel, a downlink reference signal, an uplink reference
signal, etc. Even if a different type physical channel is added to
the physical channels, the physical channel is applicable to the
embodiments of the present invention described later.
[0062] The physical broadcast channel (PBCH) is transmitted for the
purpose of notification of control parameters (broadcast
information) commonly used by mobile station apparatuses within a
cell. For the broadcast information not supplied through the
physical broadcast channel, the physical downlink control channel
is used for notification of a resource and a physical downlink
shared channel is used for the transmission. A cell global ID
indicative of a cell-specific ID (identity) etc., are supplied as
the broadcast information. In the PBCH, the broadcast channel (BCH)
is mapped at intervals of 40 milliseconds. Blind detection is
performed for the timing of 40 milliseconds in a mobile station
apparatus. Therefore, explicit signaling is not transmitted to a
mobile station apparatus for the presentation of the timing of the
physical broadcast channel. A sub-frame including the physical
broadcast channel (PBCH) can be decoded by itself
(self-decodable).
[0063] A physical channel related to the embodiments of the present
invention is mainly a random access channel and, therefore, other
physical channels will not be described in detail or will briefly
be described.
[0064] The physical downlink control channel (PDCCH) is a downlink
channel transmitted from a base station apparatus to a mobile
station apparatus and is commonly used for multiple mobile station
apparatuses. The base station apparatus uses the downlink control
channel for transmitting transmission timing information and
scheduling information (uplink/downlink resource allocation
information).
[0065] The physical downlink data channel (PDSCH: Physical Downlink
Shared Channel) is a channel used for transmitting downlink data or
paging information.
[0066] The downlink reference signal (DL-RS: Downlink Reference
Signal or Cell-specific Reference Signal) is transmitted from a
base station apparatus to a mobile station apparatus by utilizing a
downlink channel. The mobile station apparatus measures the
downlink reference signal to determine the reception quality of the
downlink. The reception quality is supplied to a base station
apparatus as a quality information indicator CQI (Channel Quality
Indicator) by using the physical uplink control channel (PUCCH).
The base station apparatus schedules downlink communication to
mobile station apparatuses based on CQI supplied from the mobile
station apparatuses.
[0067] SIR (Signal-to-Interference Ratio), SINR
(Signal-to-Interference plus Noise Ratio), SNR (Signal-to-Noise
Ratio), CIR (Carrier-to-Interference Ratio), BLER (Block Error
Rate), path-loss, etc., can be used as the reception quality.
[0068] The physical uplink data channel (PUSCH: Physical Uplink
Shared Channel) is a channel used mainly for transmitting uplink
data (UL-SCH: Uplink Shared Channel). If a base station apparatus
schedules a mobile station apparatus, the physical uplink data
channel (PUSCH) is used for transmitting channel state information
(the downlink channel quality indicator CQI, a precoding matrix
indicator (PMI), a rank indicator (RI)), and an acknowledgement
(ACK)/a negative acknowledgement (NACK) of a hybrid automatic
repeat request (HARQ) for downlink transmission.
[0069] The uplink data (UL-SCH) indicates transmission of user
data, for example, and UL-SCH is a transport channel. UL-SCH
supports HARQ and dynamic adaptive radio link control and can
utilize the beamforming. UL-SCH supports dynamic resource
allocation and quasi-static resource allocation.
[0070] The physical uplink control channel (PUCCH) is a channel
used for transmitting control data. The control data includes, for
example, the channel state information (CQI, PMI, and RI)
transmitted (fed back) from a mobile station apparatus to a base
station apparatus, a scheduling request (SR) of a mobile station
apparatus requesting allocation of resource for transmitting the
uplink data (requesting transmission through UL-SCH), and ACK/NACK
of HARQ for downlink transmission.
[0071] The uplink reference signal (UL-RS) is transmitted from a
mobile station apparatus to a base station apparatus by utilizing
an uplink channel. The base station apparatus measures the uplink
reference signal to determine the reception quality of the uplink
radio transmission signal of the mobile station apparatus. The base
station apparatus schedules uplink communication based on the
reception quality. The uplink reference signal is also used as a
reference signal for calculating the variation of the amplitude,
phase, and frequency of the uplink data channel to demodulate a
signal transmitted by utilizing the uplink data channel.
[0072] The physical random access channel (PRACH) is a physical
channel used for transmitting a random access preamble and has a
guard time. The primary purpose of PRACH is to synchronize a mobile
station apparatus with a base station apparatus and PRACH is also
used for an initial access, a handover, a reestablishment request,
and a scheduling request.
[0073] The random access channel (RACH) is a transport channel and
is mapped on PRACH for transmission.
[0074] The physical random access channel (PRACH) uses code
sequences orthogonal to each other and transmits these orthogonal
code sequences to enable a base station apparatus to separate a
radio signal if the orthogonal code sequence is different even when
the uplink transmission timing is identical. The orthogonal code
sequence is referred to as a signature and is used by a base
station apparatus for identifying a mobile station apparatus. A
signal made up of a signature is referred to as a random access
preamble. The random access preamble includes a signal pattern
indicative of information and several-bit information can be
represented by preparing several tens of types of the random access
preambles. It is currently assumed to transmit 6-bit information
and it is assumed to prepare 64 types of the random access
preambles. The 64 types of the random access preambles are
classified into two groups (e.g., preamble groups A and B) based on
broadcast information specified by a base station apparatus, and a
mobile station apparatus determines which group of the random
access preambles is selected, based on a path-loss and a message
size of downlink. However, the number of allocations of the random
access preambles configured to a group can freely be set.
[0075] FIG. 3 is a diagram of a general configuration of the uplink
channels. In FIG. 3, the horizontal axis indicates time and the
vertical axis indicates frequency. In the time axis direction, 14
symbols are arranged. Seven symbols correspond to one slot and the
length of one slot is 0.5 milliseconds (ms). 14 symbols
(corresponding to two slots) correspond to one sub-frame and the
length of one sub-frame is one millisecond.
[0076] One resource block is made up of 12 sub-carriers and 7
symbols. Two resource blocks are used for allocating PUSCH to at
least one mobile station apparatus. With regard to PRACH, six
resource blocks are used as one physical random access channel and
multiple PRACHs are prepared to deal with accesses from a number of
mobile station apparatuses. As depicted, PUCCH is allocated in both
the lowermost part (band closer to the lowest frequency) and the
uppermost part (band closer to the highest frequency) in each
bandwidth portion. PUSCH is allocated in an intermediate band
located between those PUCCHs. PRACH is allocated and transmitted at
a frequency position specified by the system information.
(3) Random Access Method
[0077] PRACH has access methods of contention-based random access
and non-contention-based random access. The contention-based random
access is random access having a possibility of a collision between
mobile station apparatuses and is an access method of normally
performed random access. On the other hand, the
non-contention-based random access is random access not causing a
collision between mobile station apparatuses and performed at the
initiative of the base station apparatus in a special case such as
a handover so as to rapidly achieve synchronization of uplink
between the mobile station apparatus and the base station
apparatus. If the base station apparatus is unable to drive the
mobile station apparatus to perform the non-contention-based random
access, the base station apparatus may drive the mobile station
apparatus to perform the contention-based random access.
[0078] Only a random access preamble is transmitted through
PRACH.
[0079] FIG. 4 is a diagram of an example of a procedure of the
contention-based random access. First, the mobile station apparatus
selects a random access preamble from a random ID, downlink
path-loss information, etc., and transmits the random access
preamble through PRACH (message 1 (Msg1) (L101)).
[0080] When receiving the random access preamble from the mobile
station apparatus, the base station apparatus calculates a gap of
synchronizing timing between the mobile station and the base
station from the random access preamble, performs scheduling for
transmitting an L2/L3 message, assigns a temporary cell-radio
network temporary identity (hereinafter, temporary C-RNTI), assigns
RA-RNTI (Random Access-Radio Network Temporary Identity) in PDCCH
to indicate that PDSCH includes a response to the mobile station
apparatus that transmits the random access preamble, and transmits
to PDSCH a random access response that includes synchronization
timing gap information (timing advance), scheduling information,
Temporary C-RNTI, and the random access preamble number (or random
ID) of the received random access preamble (message 2 (Msg2)
(L102)).
[0081] Different RA-RNTI is used for different PRACH.
[0082] When confirming that PDCCH has RA-RNTI, the mobile station
apparatus checks the contents of the random access response
assigned in PDSCH, extracts the response including the transmitted
random access preamble number (or random ID), acquires the
synchronization timing gap information to correct the uplink
transmission timing, and uses a scheduled radio resource to
transmit the L2/L3 message that at least includes C-RNTI (or a
contention resolution ID (a random value for initial access or UEID
(mobile station ID) such as s-TMSI (System Architecture
Evolution-Temporary Mobile Subscriber Identity))) (message 3 (Msg3)
(L103)).
[0083] When receiving the L2/L3 message from the mobile station
apparatus, the base station apparatus uses the C-RNTI (or Temporary
C-RNTI) included in the received L2/L3 message to transmit to the
mobile station apparatus a contention resolution for determining
whether a collision occurs between mobile station apparatuses
(message 4 (Msg4) (L104)). If the contention resolution ID is
transmitted through the message 3 (if the message 3 is a common
control channel (CCCH)), the mobile station apparatus determines
whether the random access processing is successful, depending on
whether the contention resolution ID included in the L2/L3 message
received through the contention resolution is identical to that
transmitted by the mobile station apparatus. If C-RNTI is
transmitted through the message 3, the mobile station apparatus
detects C-RNTI through PDCCH from the base station apparatus to
determine whether the random access processing is successful. With
regard to the contention resolution, the mobile station apparatus
ID (C-RNTI or contention resolution ID) is included in the message
3 (L2/L3 message) and transmitted to the base station apparatus,
and the base station apparatus transmits to the mobile station
apparatus the message 4 (contention resolution) as a response to
the message 3. The base station apparatus includes and transmits
the mobile station apparatus ID transmitted from the mobile station
apparatus in the response to the message 3. The mobile station
apparatus can confirm the access to the base station apparatus by
confirming its own ID within the message 4.
[0084] If the mobile station apparatus fails to receive the message
2 or the contention resolution fails, the procedure is reattempted
from the message 1.
(4) Random Access Problem In order to connect to the base station
apparatus, the mobile station apparatus transmits a random access
preamble to the base station apparatus by randomly selecting the
random access preamble or incorporating the random access preamble
assigned in a network into a signal. If the mobile station
apparatus fails in the line contention of the random access process
because the transmitted RACH signal collides with another mobile
station apparatus, because the base station apparatus cannot be
distinguished due to excessively low transmission electric power
etc., or because of the randomly selected random access preamble,
or if a response to RACH (L102 and L104 of FIG. 4) is not returned
from the base station apparatus in certain time, the mobile station
apparatus retransmits RACH. The mobile station apparatus uses a
random access channel transmission counter to count the number of
RACH transmissions each time the mobile station apparatus transmits
RACH. If the number of RACH transmissions exceeds a specified value
(maximum number of transmissions), the MAC layer in the mobile
station apparatus considers that a random access problem is
detected, and notifies the RRC layer. When the RRC layer is
notified of the random access problem by the MAC layer, the RRC
layer considers that a radio link failure (hereinafter, RLF)
occurs, and instructs a lower layer to execute a reestablishment
processing such as changing a parameter of RACH and releasing a
radio resource. The mobile station apparatus temporarily stops the
transmission of RACH and the lower layer sets a new parameter and
performs reestablishment based on the instruction. Even if the
maximum number of transmissions of RACH is exceeded, the mobile
station apparatus continues transmitting RACH with the same
parameter to the base station apparatus until a new instruction is
issued from a higher layer. A random access problem processing is
defined herein as the processing until the reestablishment
processing is executed after the random access problem is detected
from the RACH transmission.
[0085] Embodiments of the present invention will now specifically
be described in view of the matters described above. Component
carriers (CCs) are respectively correlated in downlink and uplink,
and RACH of a certain CC means RACH correlated with a certain
downlink CC. Therefore, if multiple RACHs is allocated in one
uplink CC and the RACHs are respectively correlated with different
downlink CCs, the RACHs are interpreted as RACHs of different
CCs.
First Embodiment
[0086] FIG. 1 is a block diagram of a general functional
configuration of a mobile station apparatus 100 (first
communicating apparatus) according to this embodiment. The mobile
station apparatus 100 includes a transmitting portion 110, a
receiving portion 120, a scheduling portion 130, and an antenna
107.
[0087] The transmitting portion 110 includes a data control portion
101, a modulating portion 102, and a radio transmitting portion
103.
[0088] The receiving portion 120 includes a radio receiving portion
104, a demodulating portion 105, and a data extracting portion
106.
[0089] The scheduling portion 130 includes a timer control portion
140, a counter control portion 150, and a transmission information
control portion 160.
[0090] The timer control portion 140 includes a timer portion 108.
The timer portion 108 has multiple timers set in advance. The
timers include a timer with a purpose of use/application determined
and a spare timer to which a new purpose of use can be assigned
depending on system extension etc.
[0091] The counter control portion 150 includes a counter portion
109. The counter portion 109 has multiple counters set in advance.
The counters include a counter with a purpose of use/application
determined and a spare counter to which a new purpose of use can be
assigned depending on system extension etc.
[0092] The transmission information control portion 160 includes an
RACH generating portion 111.
[0093] User data and control data are input from a higher layer to
the data control portion 101. The data control portion 101 assigns
the input data in PUSCH or PUCCH in accordance with instructions
from the scheduling portion 130. The uplink reference signal
(UL-RS) is also assigned at this time. The modulating portion 102
modulates data and executes signal processing such as discrete
Fourier transform (hereinafter, DFT), sub-carrier mapping, inverse
fast Fourier transform (hereinafter, IFFT), CP (cyclic prefix)
insertion, and filtering, to generate a transmission signal. The
modulating portion 102 outputs the modulated signal to the radio
transmitting portion 103.
[0094] The radio transmitting portion 103 up-converts the
demodulated data to a radio frequency and then transmits the data
to the base station apparatus via the antenna 107.
[0095] The radio receiving portion 104 receives and down-converts a
downlink signal from the base station apparatus to a baseband
signal to output the reception signal to the demodulating portion
105.
[0096] The demodulating portion 105 demodulates the reception data.
The data extracting portion 106 divides the reception data into
user data and control data. The data extracting portion 106 outputs
the scheduling information, a random access response message, the
control data related to intermittent reception control, and other
control data of the second layer to the scheduling portion 130 and
outputs the user data to the higher layer.
[0097] The scheduling portion 130 analyzes the control data input
from the data extracting portion 106 and outputs the scheduling
information and the scheduling information included in the random
access response message to the transmission information control
portion 160.
[0098] The transmission information control portion 160 instructs
the data control portion 101 to allocate the user data and the
control data to PUSCH and PUCCH in accordance with the scheduling
information. The RACH generating portion 111 randomly selects a
random access preamble number used for random access in accordance
with instructions from the scheduling portion 130 and generates and
outputs a random access preamble of the selected random access
preamble number to the modulating portion 102.
[0099] The timer control portion 140 is used for adjusting the
transmission timing between the mobile station apparatus and the
base station apparatus, measures a time from signal transmission to
a response to the signal, and measures a time corresponding to a
purpose (such as a transmission time and a synchronization time) by
using a different timer depending on a signal and CC to be
measured. For example, the timer control portion 140 can measure a
connection time between the mobile station apparatus and the base
station apparatus in a radio communication system. If the timer
reaches the expiration time, the mobile station apparatus considers
that the mobile station apparatus and the base station apparatus
cannot be connected and changes a parameter to attempt new
connection.
[0100] The counter control portion 150 sets a transmission counter
or a reception counter to a certain signal in a certain frequency
band to count the number of transmissions or the number of
receptions. For example, when it is desired to transmit PUSCH
allocated to four CCs of CC#0 to CC#3 and to dispose a transmission
counter in each of the CCs to count the number of transmissions,
the counter control portion 150 selects and sets an arbitrary
counter from the counter portion 109 to each of the CCs. In this
patent, the counter control portion 150 sets a random access
channel transmission counter for counting the number of
transmissions of the random access channel transmitted from a
certain CC.
[0101] FIG. 2 is a block diagram of a general functional
configuration of a base station apparatus 200 (second communicating
apparatus) according to this embodiment. The base station apparatus
200 includes a transmitting portion 210, a receiving portion 220, a
scheduling portion 230, and an antenna 207.
[0102] The transmitting portion 210 includes a data control portion
201, a modulating portion 202, and a radio transmitting portion
203.
[0103] The receiving portion 220 includes a radio receiving portion
204, a demodulating portion 205, a data extracting portion 206, and
an RACH detecting portion 212.
[0104] The scheduling portion 230 includes a timer control portion
240, a counter control portion 250, and a transmission information
control portion 260.
[0105] The timer control portion 240 includes a timer portion 208.
The timer portion 208 has multiple timers set in advance. The
timers include a timer with a purpose of use/application determined
and a spare timer to which a new purpose of use can be assigned
depending on system extension etc.
[0106] The counter control portion 250 includes a counter portion
209. The counter portion 209 has multiple counters set in advance.
The counters include a counter with a purpose of use/application
determined and a spare counter to which a new purpose of use can be
assigned depending on system extension etc.
[0107] The transmission information control portion 260 includes a
random access response (hereinafter, RAR) message generating
portion 211.
[0108] The data control portion 201 inputs user data and control
data, and maps the control data to PDCCH and the transmission data
and the control data for mobile station apparatuses to PDSCH in
accordance with instructions from the scheduling portion 230. The
modulating portion 202 executes signal processing such as data
modulation, serial/parallel conversion of an input signal, IFFT, CP
insertion, and filtering, to generate a transmission signal. The
radio transmitting portion 203 up-converts the demodulated data to
a radio frequency and then transmits the data to the mobile station
apparatus via the antenna 207.
[0109] The radio receiving portion 204 receives and down-converts
an uplink signal from the mobile station apparatus to a baseband
signal to output the reception data to the demodulating portion 205
and the RACH detecting portion 212.
[0110] The data extracting portion 206 checks whether the reception
data is correct or incorrect and notifies the scheduling portion
230 of a result of the check. If the reception data is correct, the
data extracting portion 206 divides the reception data into the
user data and the control data. The data extracting portion 206
outputs control data of the second layer such as downlink CQI
information and success/failure (ACK/NACK) of downlink data in the
control data to the scheduling portion 230 and outputs other
control data of the third layer etc., and the user data to the
higher layer.
[0111] If the reception data is incorrect, the data extracting
portion 206 saves the data for combining with retransmission data
and executes combining processing when receiving the retransmission
data.
[0112] The scheduling portion 230 performs scheduling for mapping
the user data and the control data to PDSCH and PDCCH.
[0113] The transmission information control portion 260 performs
scheduling for mapping the user data to PUSCH based on a resource
allocation request from the base station apparatus 100.
[0114] The RAR message generating portion 211 generates ACK/NACK
from the correctness of the uplink reception data and a random
access response message (corresponding to the message 2 of FIG. 4)
from a detection result of the RACH detecting portion 212. The RACH
detecting portion 212 detects a random access preamble, calculates
a synchronization timing deviation amount, and reports the random
access preamble number and the synchronization timing deviation
amount to the scheduling portion 230.
[0115] The timer control portion 240 is used for adjusting the
transmission timing between the mobile station apparatus and the
base station apparatus, measures a time from signal transmission to
a response to the signal, and measures a time corresponding to a
purpose (such as a transmission time and a synchronization time) by
using a different timer depending on a signal and CC to be
measured. For example, the timer control portion 240 can measure a
connection time between the mobile station apparatus and the base
station apparatus in a radio communication system. If the timer
reaches the expiration time, the base station apparatus considers
that the mobile station apparatus and the base station apparatus
cannot be connected and changes a parameter to attempt new
connection.
[0116] The counter control portion 250 sets a transmission counter
or a reception counter from the counter portion 209 for counting
the number of transmissions or the number of receptions of a
certain signal of a certain CC.
[0117] When the mobile station apparatus 100 selects multiple CCs
to transmit RACH, one random access channel transmission counter
counts the numbers of random access channel transmissions of all
the CCs. Each time RACH is transmitted from the selected CC, the
mobile station apparatus 100 counts the number of random access
channel transmissions with the random access channel transmission
counter and, if a predetermined maximum number of transmissions is
reached, the MAC layer determines that a random access problem is
detected, and notifies the RRC layer of the detection of the random
access problem. The RRC layer considers that all of the plurality
of CCs has RLF in response to the information, and stops the
transmission of RACH to execute the reestablishment processing.
[0118] The mobile station apparatus selects multiple CCs. The
transmission information control portion 160 instructs the RACH
generating portion 111 to generate a random access preamble
assigned to the CCs. The transmission information control portion
160 instructs the counter control portion 150 to set one counter
for counting the number of transmissions of the random access
channel transmitted by using the CCs. The counter control portion
150 arbitrarily sets a counter for counting the number of RACH
transmissions from the counter portion 109.
[0119] FIG. 5 is a general process flowchart of a random access
procedure and a random access problem detecting method utilizing a
random access channel transmission counter of this embodiment. The
mobile station apparatus 100 sets the random access problem
detecting method. Description will hereinafter be made in
accordance with the procedure.
[0120] First, the mobile station apparatus 100 executes an
initializing processing of the random access channel transmission
counter (step s101). The mobile station apparatus 100 compares the
current number of random access channel transmissions recorded in
the random access channel transmission counter with the
predetermined maximum number of random access channel transmissions
(step s102). If the current number of random access channel
transmissions is not greater than the predetermined maximum number
of random access channel transmissions (step s102: NO), the mobile
station apparatus 100 generates RACH (Msg1) in the RACH generating
portion 111 based on an instruction from the transmission
information control portion 160 so as to perform random access to
the base station apparatus and transmits the RACH from the radio
transmitting portion 103 via the antenna 107 to the base station
apparatus 200 (step s103). The random access channel transmission
counter counts the number of random access channel transmissions
(step s104). The scheduling portion 130 instructs the timer control
portion 140 to allocate and activate a message 2 reception timer
(Msg2_Rx_Timer) from the timer portion 108 (step s105). The mobile
station apparatus 100 continuously monitors the message 2 (step
s106) until the message 2 reception timer reaches the expiration
time (step s107). Before the mobile station apparatus 100 receives
the message 2 (step s106: NO), if the message 2 reception timer
reaches the expiration time (step s107: YES), the timer control
portion 140 initializes the message 2 reception timer and restarts
the random access procedure (step s108) from the transmission of
RACH (Msg1) (step s102). If the message 2 is received (step s106:
YES) before the message 2 reception timer reaches the expiration
time (step s107: NO), the mobile station apparatus 100 generates a
new uplink signal (Msg3) based on the scheduling information
included in the message 2 and transmits the uplink signal from the
radio transmitting portion 103 via the antenna 107 to the base
station apparatus 200 (step s109). The scheduling portion 130
instructs the timer control portion 140 to allocate and activate a
message 4 reception timer (Msg4_Rx_Timer) from the timer portion
108 (step s110). The mobile station apparatus 100 continuously
monitors the message 4 (step sill) until the message 4 reception
timer reaches the expiration time (step s112). Before the mobile
station apparatus 100 receives the message 4 (step s111: NO), if
the message 4 reception timer reaches the expiration time (step
s112: YES), the timer control portion 140 initializes the message 4
reception timer and restarts the random access procedure (step
s113) from the transmission of RACH (Msg1) (step s102). If the
receiving portion 120 receives the message 4 (step sill: YES)
before the message 4 reception timer reaches the expiration time
(step s112: NO), the mobile station apparatus 100 considers that
the ransom access to the base station apparatus 200 is successful,
and terminates the random access procedure. The maximum number of
transmissions of the random access channel may uniquely be
determined in the system in advance, may concurrently be supplied
as broadcast information from the base station apparatus to the
mobile station apparatuses, or may be supplied from the base
station apparatus to the individual mobile station apparatuses.
[0121] The case that the current number of random access channel
transmissions is greater than the predetermined maximum number of
random access channel transmissions (step s102: YES) will be
described next.
[0122] The MAC layer of the mobile station apparatus 100 recognizes
that a random access problem is detected (step s114) and notifies
the RRC layer, i.e., the higher layer of the MAC layer of the
random access problem (step s115). In response to the notification,
the RRC layer recognizes that a radio link failure (RLF) is
detected for the component carrier (CC) in which the random access
problem is detected (step s116). The RRC layer releases the radio
resource used for the RACH transmission and executes
reestablishment processing. For example, the reestablishment
processing includes changing a parameter such as a transmission
frequency and restarting the random access procedure from step
s101. However, the mobile station apparatus 100 continues
transmitting RACH to the base station apparatus 200 until the RRC
layer recognizes that RLF occurs (except step s102).
[0123] FIG. 6 is a flowchart of a setting method of the random
access channel transmission counter of the first embodiment.
[0124] First, the mobile station apparatus 100 selects one or more
CC to which RACH is allocated (step s201). The counter control
portion 150 sets one counter (random access channel transmission
counter) for counting the number of transmissions of RACH in the
counter portion 109 (step s202). This counter counts the number of
random access channel transmissions regardless of which CC
transmits the RACH. The subsequent random access procedure is based
on that of FIG. 5 and, therefore, the details will not be
described.
[0125] In the first embodiment, one random access channel
transmission counter manages the numbers of random access channel
transmissions of all the selected CCs and, if the random access
channel transmission counter reaches the maximum number of
transmissions, it is recognized that the random access problem is
detected and, therefore, the random access problem of all the
selected CCs can be detected by one random access channel
transmission counter. As a result, the mobile station apparatus can
easily control the random access channel transmission counter.
<Basic Form of Second Embodiment>
[0126] A basic form of a second embodiment of the present invention
will be described. The functional configuration of devices in the
second embodiment is the same as that depicted in the first
embodiment and will not be described.
[0127] When the mobile station apparatus selects multiple CCs to
transmit RACH, any one CC is selected from the plurality of CCs and
the random access channel transmission counter is set to the CC.
Although CCs other than the CC having the random access channel
transmission counter set may or may not perform the RACH
transmission, the random access channel transmission counter does
not count the number of transmissions if CCs other than the CC
having the random access channel transmission counter set perform
the RACH transmission. Each time RACH is transmitted from the CC,
the mobile station apparatus counts the number of RACH
transmissions with the random access channel transmission counter
and, if a predetermined maximum number of transmissions is reached,
the MAC layer notifies the RRC layer of the detection of the random
access problem. The RRC layer considers that all of the plurality
of CCs has RLF in response to the information, and stops the
transmission of RACH to execute the reestablishment processing.
However, if a random access response message is received for a CC
other than the CC having the random access channel transmission
counter set before the maximum number of transmissions is counted,
the mobile station apparatus uses the CC to communicate with the
base station apparatus.
[0128] FIG. 7 is a flowchart of a setting method of the random
access channel transmission counter of the second embodiment.
[0129] First, the mobile station apparatus 100 selects one or more
CC to which RACH is allocated (step s301). The counter control
portion 150 sets one counter for counting the number of
transmissions of RACH from the counter portion 109 (step s302). The
mobile station apparatus 100 selects one CC to which the random
access channel transmission counter is set (step s303). The random
access channel transmission counter counts only the RACH
transmission of this CC. The subsequent processing is the same as
the first embodiment and will not be described.
[0130] In the basic form of the second embodiment, the mobile
station apparatus selects one CC for setting the random access
channel transmission counter from multiple CCs to detect the random
access problem only for the one CC and, therefore, if multiple CCs
are used for performing communication, the mobile station apparatus
can easily control the random access channel transmission
counter.
<Variation of Second Embodiment>
[0131] A variation of the second embodiment of the present
invention will be described. The functional configuration of
devices in the variation of the second embodiment is the same as
that depicted in the first embodiment and will not be
described.
[0132] The mobile station apparatus 100 selects an arbitrary CC
from multiple CCs and uses only the CC to perform the random access
procedure. Therefore, the mobile station apparatus 100 transmits
RACH to the base station apparatus 200 only through the selected
CC. The mobile station apparatus 100 sets the random access channel
transmission counter only to the selected CC to detect the random
access problem. Each time RACH is transmitted from the CC, the
mobile station apparatus 100 counts the number of RACH
transmissions with the random access channel transmission counter
and, if the predetermined maximum number of transmissions is
reached, the MAC layer notifies the RRC layer of the detection of
the random access problem. The RRC layer considers that all of the
plurality of CCs has RLF in response to the information, and stops
the transmission of RACH to execute the reestablishment
processing.
[0133] In the variation of the second embodiment, since the random
access channel transmission counter is set only to the selected CC
to detect the random access problem, the number of RACHs
transmitted from the mobile station apparatus to the base station
apparatus can be reduced to save electric power.
Third Embodiment
[0134] A third embodiment of the present invention will be
described. The functional configuration of devices in the third
embodiment is the same as that depicted in the first embodiment and
will not be described.
[0135] When the mobile station apparatus uses multiple CCs to
perform communication, the mobile station apparatus sets a master
component carrier (hereinafter, M-CC). The mobile station apparatus
uses only the M-CC to perform the RACH transmission. Each time RACH
is transmitted from the M-CC, the mobile station apparatus counts
with the random access channel transmission counter and, if the
number of transmissions of the RACH reaches a predetermined maximum
number of transmissions, the MAC layer notifies the RRC layer of
the detection of the random access problem. The RRC layer considers
that all of the plurality of CCs has RLF in response to the
notification, and stops the transmission of RACH to execute the
reestablishment processing. The master component carrier is an
uplink component carrier that is paired with the downlink component
carrier that the mobile station apparatus accesses first.
Alternatively, the master component carrier is an uplink component
carrier that is paired with the downlink component carrier
individually specified to the mobile station apparatus by the base
station apparatus using an RRC message. Alternatively, the master
component carrier is an uplink component carrier that is paired
with the downlink component carrier having the highest priority of
downlink component carriers included in the broadcast information.
Alternatively, the master component carrier is an uplink component
carrier that is paired with the arbitrary downlink component
carrier selected at the discretion of the mobile station apparatus
out of the downlink component carriers received by the mobile
station apparatus.
[0136] FIG. 8 is a flowchart of a setting method of the random
access channel transmission counter of the third embodiment.
[0137] First, the mobile station apparatus 100 selects M-CC as CC
to which RACH is allocated (if CC is already broadcasted by the
base station apparatus, the CC is selected) (step s401). The mobile
station apparatus 100 sets the random access channel transmission
counter to the M-CC (step s402). The random access channel
transmission counter counts only the RACH transmission of the M-CC.
The subsequent processing is the same as the first embodiment and
will not be described.
[0138] In the basic form of the third embodiment, since the RACH
transmission is performed only through the M-CC, the radio resource
used for RACH can be saved and, since the random access problem is
detected only for the M-CC, electric power can be saved and the
random access problem detection in multiple CCs can be
simplified.
Fourth Embodiment
[0139] A fourth embodiment of the present invention will be
described. The functional configuration of devices in the fourth
embodiment is the same as that depicted in the first embodiment and
will not be described.
[0140] If multiple CCs is selected to transmit RACH, the mobile
station apparatus sets a random access channel transmission counter
to each of the plurality of CCs to detect the random access problem
for each CC.
[0141] FIG. 9 is a flowchart of a setting method of the random
access channel transmission counter of the fourth embodiment.
[0142] First, the mobile station apparatus 100 selects one or more
CC to which RACH is allocated (step s501). The mobile station
apparatus 100 drives the counter control portion 150 to set a
counter for counting the number of transmissions of RACH (a random
access channel transmission counter) from the counter portion 109
to the CC selected at step s501 (step s502) The random access
channel transmission counter counts only the number of RACH
transmissions of the CC to which the counter is set. A parameter
(such as the maximum number of transmissions) of the random access
channel transmission counters may be the same or different for each
of CCs. The subsequent processing is the same as the first
embodiment and will not be described.
[0143] If RACHs are concurrently transmitted through multiple
different CCs, the mobile station apparatus 100 allocates different
random access channel transmission counters among the CCs and
detects the random access problem for each CC; however, if the
random access channel is transmitted only one-by-one from the
mobile station apparatus 100, a random access channel transmission
counter can be reused for multiple CCs. For example, if the mobile
station apparatus 100 sets a random access channel transmission
counter to a certain CC and detects the random access problem in
the CC, the mobile station apparatus 100 sets the random access
channel transmission counter to another CC and counts the number of
random access channel transmissions to detect the random access
problem. However, if allocating to another CC, the mobile station
apparatus 100 initializes the number of transmissions of the random
access channel transmission counter.
[0144] In the fourth embodiment, since the random access problem is
managed for each CC, if it is recognized that a certain CC has RLF
and radio resource is released, an attempt to connect to the base
station apparatus can be continued through another CC and a
continuous access attempt can be made until the random access to
the base station apparatus is completed.
Fifth Embodiment
[0145] A fifth embodiment of the present invention will be
described. The functional configuration of devices in the fifth
embodiment is the same as that depicted in the first embodiment and
will not be described.
[0146] A component carrier making up a wide frequency band itself
may be made up of multiple component carriers. In this embodiment,
a component carrier made up of multiple component carriers will
hereinafter be referred to as a component carrier group (CCG). In
this embodiment, a wider system band (e.g., a system band having a
bandwidth of 100 MHz) can be made up of two component carrier
groups (e.g., a component carrier group (CCG-0) having a bandwidth
of 40 MHz and a component carrier group (CCG-1) having a bandwidth
of 60 MHz) and each of the two component carrier groups can further
be made up of multiple component carriers (e.g., the component
carrier group (CCG-0) having a bandwidth of 40 MHz can be made up
by aggregating two component carriers (CC-0 and CC-1) each having a
bandwidth of 20 MHz, and the component carrier group (CCG-1) having
a bandwidth of 60 MHz can be made up by aggregating three component
carriers (CC-2, CC-3, and CC-4) each having a bandwidth of 20 MHz).
A component carrier and/or a component carrier group may be
arranged in continuous frequency bands or in discontinuous
frequency bands, and a wide system band can be made up by
aggregating multiple component carriers and/or component carrier
groups that are continuous and/or discontinuous frequency bands. A
downlink frequency band (DL system band, DL system bandwidth) and
an uplink frequency band (UL system band, UL system bandwidth) made
up of component carriers and/or component carrier groups may not
have the same bandwidth. If the DL system band and the UL system
band have different bandwidths, the base station apparatus and the
mobile station apparatus can use these frequency bands to perform
communications.
[0147] The mobile station apparatus can manage the random access
problem in the certain number of CCGs acquired by aggregating
multiple CCs to apply the random access problem detecting methods
of the first to fourth embodiments to each of the CCGs.
[0148] The mobile station apparatus can manage a different random
access problem for each CCG.
[0149] FIG. 10 is a flowchart of a setting method of the random
access channel transmission counter in the fifth embodiment.
[0150] First, the mobile station apparatus 100 selects one or more
CC to which RACH is allocated (step s601). The scheduling portion
130 allocates information (e.g., CCGID) for forming CCG to each CC
to form multiple CCGs (in the case of one CCG, this is the same as
the first to fourth embodiments) (step s602). The scheduling
portion 130 applies any one of the first to fourth embodiments to
each of the CCGs to count the number of random access channel
transmissions (step s603). However, the setting method of the
random access channel transmission counter may be the same or
different for each of the CCGs. The subsequent processing is the
same as the first embodiment and will not be described.
[0151] The information for forming CCG may uniquely be determined
in the system in advance, may concurrently be supplied as broadcast
information from the base station apparatus to the mobile station
apparatuses, or may be supplied from the base station apparatus to
the individual mobile station apparatuses.
[0152] In the fifth embodiment, since the setting methods of the
random access channel transmission counter of the first to fourth
embodiments are applicable to each CCG, the random access problem
can flexibly be detected.
Sixth Embodiment
[0153] A sixth embodiment of the present invention will be
described. The functional configuration of devices in the sixth
embodiment is the same as that depicted in the first embodiment and
will not be described.
[0154] The timer control portion 140 activates a random access
problem detecting timer at the timing after the random access
channel transmission counters of the first to fifth embodiments
reach the maximum number of transmissions.
[0155] FIG. 11 is a flowchart of a general process of a random
access procedure and a random access problem detecting method using
and a timer of this embodiment.
[0156] First, if the random access problem detecting method using a
timer is applied, the mobile station apparatus 100 executes an
initializing processing of the random access problem detecting
timer (step s701). If the random access channel transmission
counter counts the maximum number of transmissions, the timer
control portion 140 activates the random access problem detecting
timer (step s702). The mobile station apparatus 100 checks whether
the random access problem detecting timer reaches the expiration
time (step s703). If the random access problem detecting timer is
not expired (step s703: NO), the mobile station apparatus 100
checks whether the RACH transmission is successful (step s704). If
the RACH transmission is successful (step s704: YES), the mobile
station apparatus 100 recognizes that the random access to the base
station apparatus 200 is successful, and terminates the random
access procedure. The expiration time measured by the random access
problem detecting timer may uniquely be determined in the system in
advance, may concurrently be supplied as broadcast information from
the base station apparatus to the mobile station apparatuses, or
may be supplied from the base station apparatus to the individual
mobile station apparatuses.
[0157] The case that the random access problem detecting timer is
expired (step s703: YES) will be described next.
[0158] The MAC layer of the mobile station apparatus 100 recognizes
that a random access problem is detected (step s705) and notifies
the RRC layer, i.e., the higher layer of the MAC layer of the
random access problem (step s706). In response to the notification,
the RRC layer recognizes that a radio link failure (RLF) is
detected for the component carrier (CC) in which the random access
problem is detected (step s707). The RRC layer executes a
reestablishment processing. For example, the reestablishment
processing includes changing a parameter such as a transmission
frequency and restarting the random access procedure from step
s701.
[0159] However, an existing timer may be substituted for the timer
to be used or a new timer may be set as a random access problem
detecting timer. This existing timer is a timer set to
application/purpose other than measuring a transmission time of the
random access channel. For example, a radio link failure detecting
timer may be used as the random access problem detecting timer. The
information thereof may uniquely be determined in the system in
advance, may concurrently be supplied as broadcast information from
the base station apparatus to the mobile station apparatuses, or
may be supplied from the base station apparatus to the individual
mobile station apparatuses.
[0160] The random access problem detecting times of the random
access problem detecting timers set to CCs may be the same or
different.
[0161] In the sixth embodiment, the random access problem detecting
timer can give an extension time for performing the RACH
transmission in another CC rather than releasing all the CCs
allocated to the base station apparatus on the assumption that the
CCs have RLF immediately after the random access channel
transmission counter reaches the maximum number of transmissions.
If the RACH transmission succeeds during the extension time, the
random access between the mobile station apparatus and the base
station apparatus is completed.
[0162] A portion of the functions of the base station apparatus and
the mobile station apparatus in the embodiments may be implemented
by a computer. In this case, a program for implementing the control
function may be recorded in a computer readable recording medium
and the program recorded in this recording medium may be read and
executed by a computer system to implement the function. A
"computer system" as used herein is assumed to include OS and
hardware such as peripherals. A "computer readable recording
medium" means a portable medium such as a flexible disk, a magnetic
optical disk, ROM, or CD-ROM, and a storage device such as a hard
disk built into a computer system. A "computer readable recording
medium" may include those dynamically retaining a program for a
short time like communication wires when a program is transmitted
through a network such as the internet and a communication line
such as a telephone line, and those retaining a program for a
certain time like a volatile memory within a computer system acting
as a server or a client in such a case. The program may be for the
purpose of implementing a portion of the functions and may be a
program capable of implementing the functions in combination with a
program already recorded in a computer system.
[0163] A portion or whole of the mobile station apparatus and the
base station apparatus in the embodiments may be realized by LSI
(Large Scale Integration) that is typically an integrated circuit.
The functional blocks of the mobile station apparatus and the base
station apparatus may individually be formed as chips, or a portion
or all of the functional blocks may be integrated into a chip. A
technique of forming an integrated circuit may be realized not only
in LSI but also in a dedicated circuit or a general purpose
processor. If advance in semiconductor technology leads to
emergence of a technique of forming an integrated circuit
alternative to LSI, the integrated circuit from the technique is
also usable.
[0164] Although the embodiments have been described in terms of a
mobile communication system including a base station apparatus and
a mobile station apparatus, the present invention is applicable to
a fixed radio communication system. In this case, a system is made
up of a fixed radio apparatus having the same function as the base
station apparatus and a fixed radio apparatus having the same
function as the mobile station apparatus.
[0165] Although the embodiments of the present invention have been
described in detail with reference to the drawings, specific
configurations are not limited to the embodiments and the claims
include designs etc., within a range not departing from the spirit
of the present invention.
EXPLANATIONS OF REFERENCE NUMERALS
[0166] 100 . . . mobile station apparatus; 101 . . . data control
portion; 102 . . . demodulating portion; 103 . . . radio
transmitting portion; 104 . . . radio receiving portion; 105 . . .
demodulating portion; 106 . . . data extracting portion; 107 . . .
antenna; 108 . . . timer portion; 109 . . . counter portion; 110 .
. . transmitting portion; 111 . . . RACH generating portion; 120 .
. . receiving portion; 130 . . . scheduling portion; 140 . . .
timer control portion; 150 . . . counter control portion; 160 . . .
transmission information control portion; 200 . . . base station
apparatus; 201 . . . data control portion; 202 . . . demodulating
portion; 203 . . . radio transmitting portion; 204 . . . radio
receiving portion; 205 . . . demodulating portion; 206 . . . data
extracting portion; 207 . . . antenna; 208 . . . timer portion; 209
. . . counter portion; 210 . . . transmitting portion; 211 . . .
RAR message generating portion; 212 . . . RACH detecting portion;
220 . . . receiving portion; 230 . . . scheduling portion; 240 . .
. timer control portion; 250 . . . counter control portion; and 260
. . . transmission information control portion.
* * * * *
References