U.S. patent application number 11/469005 was filed with the patent office on 2007-03-08 for apparatus and method for forming and ascertaining system information from system information medium access control protocol messages.
This patent application is currently assigned to INFINEON TECHNOLOGIES AG. Invention is credited to Maik Bienas, Hyung-Nam Choi, Michael Eckert, Florian Steinmann.
Application Number | 20070053383 11/469005 |
Document ID | / |
Family ID | 37137179 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070053383 |
Kind Code |
A1 |
Choi; Hyung-Nam ; et
al. |
March 8, 2007 |
APPARATUS AND METHOD FOR FORMING AND ASCERTAINING SYSTEM
INFORMATION FROM SYSTEM INFORMATION MEDIUM ACCESS CONTROL PROTOCOL
MESSAGES
Abstract
Apparatus and method for forming system information medium
access control protocol messages, wherein system information data
packets are received from a logical channel, with at least some of
the packets having associated prioritization information which is
used to indicate the priority of the respective packets, and the
system information medium access control protocol messages are
formed using at least some of the packets from the logical channel
taking into account the prioritization information. Also, apparatus
and method for ascertaining system information from system
information medium access control protocol messages, wherein a
first system information medium access control protocol message is
received from a transport channel which contains a statement
indicating how a second system information medium access control
protocol message is transmitted, the statement is ascertained from
the first system information medium access control protocol
message, and the second system information medium access control
protocol message is received taking into account the ascertained
statement.
Inventors: |
Choi; Hyung-Nam; (Hamburg,
DE) ; Eckert; Michael; (Braunschweig, DE) ;
Bienas; Maik; (Hannover, DE) ; Steinmann;
Florian; (Wolfenbuettel, DE) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1177 AVENUE OF THE AMERICAS 6TH AVENUE
NEW YORK
NY
10036-2714
US
|
Assignee: |
INFINEON TECHNOLOGIES AG
Munich
DE
81669
|
Family ID: |
37137179 |
Appl. No.: |
11/469005 |
Filed: |
August 31, 2006 |
Current U.S.
Class: |
370/469 ;
370/230; 370/363; 709/246 |
Current CPC
Class: |
H04W 84/042 20130101;
H04W 72/005 20130101; H04W 4/06 20130101; H04L 5/0007 20130101;
H04W 48/10 20130101; H04L 67/34 20130101; H04W 48/12 20130101; H04W
72/12 20130101; H04W 36/0061 20130101; H04W 72/1273 20130101 |
Class at
Publication: |
370/469 ;
370/230; 370/363; 709/246 |
International
Class: |
H04J 3/16 20060101
H04J003/16 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2005 |
DE |
10 2005 041 273.4 |
Claims
1. A method for the computer-aided formation of system information
medium access control protocol messages, comprising: receiving
system information data packets from at least one logical channel,
with at least some of the system information data packets having
associated prioritization information which is used to indicate the
priority of the respective system information data packets; and
forming the system information medium access control protocol
messages using at least some of the system information data packets
from the logical channel taking into account the prioritization
information.
2. The method according to claim 1, further comprising mapping the
system information medium access control protocol messages onto at
least one transport channel.
3. The method according to claim 1, further comprising receiving
system information data packets from at least one logical broadcast
channel.
4. The method according to claim 2, further comprising mapping the
system information medium access control protocol messages onto at
least one broadcast transport channel.
5. The method according to claim 2, further comprising mapping the
system information medium access control protocol messages onto a
plurality of broadcast transport channels.
6. The method according to claim 1, further comprising grouping the
received system information data packets into at least a first
group and a second group in line with the prioritization
information, the system information data packets in the first group
having at least a first system information medium access control
protocol message formed for them, and the system information data
packets in the second group having at least a second system
information medium access control protocol message formed for
them.
7. The method according to claim 6, the first system information
medium access control protocol message containing system
information which is updated after a prescribable time interval has
elapsed; and the second system information medium access control
protocol message containing system information which is updated,
needs to be updated, or loses its validity before the prescribable
time interval has elapsed.
8. The method according to claim 7, the first system information
medium access control protocol message containing at least some of
the following system information: PLMN identity, radio cell
identity, configuration of system-related timers and constants,
configuration of the physical joint radio resources, and
information for performing measurements, and the second system
information medium access control protocol message containing at
least some of the following system information: interference
situation on the uplink, transmission parameters for random access
channels in the uplink, and time validity of the dynamic system
information.
9. The method according to claim 1, further comprising transmitting
the system information medium access control protocol messages
using a multiple access method.
10. The method according to claim 9, further comprising
transmitting the system information medium access control protocol
messages using a frequency-division multiple access method.
11. The method according to claim 10, further comprising
transmitting the system information medium access control protocol
messages using a multiple carrier frequency-division multiple
access method.
12. The method according to claim 10, further comprising
transmitting the system information medium access control protocol
messages using a frequency hopping multiple access method.
13. The method according to claim 12, further comprising
transmitting the system information medium access control protocol
messages using an orthogonal frequency-division multiple access
method.
14. The method according to claim 10, further comprising
transmitting the system information medium access control protocol
messages using a frequency division multiple access/time-division
multiple access method.
15. The method according to claims 6, further comprising forming
the first system information medium access control protocol message
such that it contains a statement indicating how the second system
information medium access control protocol message is
transmitted.
16. The method according to claim 15, further comprising forming
the first system information medium access control protocol message
such that it contains a statement indicating the frequency band in
which the second system information medium access control protocol
message is transmitted.
17. The method according to claim 16, further comprising forming
the first system information medium access control protocol message
such that it contains a statement indicating the frequency band and
the time slot in which the second system information medium access
control protocol message is transmitted.
18. The method according to claim 1, being used in a cellular
mobile radio communication system.
19. The method according to claim 18, being used in a 3GPP mobile
radio communication system or in a 3GPP2 mobile radio communication
system.
20. The method according to claim 18, being used in a UMTS mobile
radio communication system, a CDMA2000 mobile radio communication
system, or a FOMA mobile radio communication system.
21. The method according to claim 3, further comprising receiving
the system information data packets from at least one Broadcast
Control Channel channel.
22. The method according to claim 3, further comprising mapping the
system information medium access control protocol message onto at
least one Broadcast Channel transport channel.
23. A method for the computer-aided ascertainment of system
information from system information medium access control protocol
messages, comprising: receiving a first system information medium
access control protocol message from a transport channel which
contains a statement indicating how a second system information
medium access control protocol message is transmitted; ascertaining
the statement from the first system information medium access
control protocol message; and receiving the second system
information medium access control protocol message taking into
account the ascertained statement.
24. A medium access control unit for forming system information
medium access control protocol messages, comprising: a reception
unit receiving system information data packets from at least one
logical channel, at least some of the system information data
packets having associated prioritization information which is used
to indicate the priority of the respective system information data
packets; and an encoding unit forming the system information medium
access control protocol messages using at least some of the system
information data packets from the logical channel taking into
account the prioritization information.
25. A mobile radio communication device having a medium access
control unit according to claim 24.
26. The mobile radio communication device according to claim 25,
being set up as a mobile radio base station.
27. A medium access control unit for ascertaining system
information from system information medium access control protocol
messages, comprising: a reception unit receiving a first system
information medium access control protocol message from a transport
channel, which message contains a statement indicating how a second
system information medium access control protocol message is
transmitted; and an ascertainment unit ascertaining the statement
from the first system information medium access control protocol
message, the reception unit changing the reception characteristics
based on the ascertained statement in order to receive the second
system information medium access control protocol message.
28. A mobile radio communication device having a medium access
control unit according to claim 27.
29. The mobile radio communication device according to claim 28,
being set up as a mobile radio communication terminal.
30. A computer program element for forming system information
medium access control protocol messages, said computer program
element, when executed by a processor, performing a method
comprising: receiving system information data packets from at least
one logical channel, at least some of the system information data
packets having associated prioritization information which is used
to indicate the priority of the respective system information data
packets; and forming the system information medium access control
protocol messages using at least some of the system information
data packets from the logical channel taking into account the
prioritization information.
31. A computer program element for ascertaining system information
from system information medium access control protocol messages,
said computer program element, when executed by a processor,
performing a method comprising: receiving a first system
information medium access control protocol message from a transport
channel which contains a statement indicating how a second system
information medium access control protocol message is transmitted;
ascertaining the statement from the first system information medium
access control protocol message; and receiving the second system
information medium access control protocol message taking into
account the ascertained statement.
32. A medium access control unit for forming system information
medium access control protocol messages, comprising: a reception
means for receiving system information data packets from at least
one logical channel, at least some of the system information data
packets having associated prioritization information which is used
to indicate the priority of the respective system information data
packets; and an encoding means for forming the system information
medium access control protocol messages using at least some of the
system information data packets from the logical channel taking
into account the prioritization information.
33. A medium access control unit for ascertaining system
information from system information medium access control protocol
messages, comprising: a reception means for receiving a first
system information medium access control protocol message from a
transport channel, which message contains a statement indicating
how a second system information medium access control protocol
message is transmitted; and an ascertainment means for ascertaining
the statement from the first system information medium access
control protocol message, wherein the reception means changes the
reception characteristics based on the ascertained statement in
order to receive the second system information medium access
control protocol message.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to German Patent
Application Serial No. 10 2005 041 273.4-31, which was filed on
Aug. 31, 2005, and is incorporated herein by reference in its
entirety.
TECHNICAL FIELD
[0002] The invention relates to a method for the computer-aided
formation of system information medium access control protocol
messages, a method for the computer-aided ascertainment of system
information from system information medium access control protocol
messages, medium access control units, mobile radio communication
devices and computer program elements.
BACKGROUND OF THE INVENTION
[0003] In a cellular mobile communication system, system
information needs to be broadcast to mobile terminals such that the
mobile terminals can use the communication system. There is a need
for methods which allow efficient and flexible broadcast of system
information.
SHORT DESCRIPTION OF THE FIGURES
[0004] FIG. 1 shows a communication system based on an exemplary
embodiment of the invention;
[0005] FIG. 2 shows an illustration of a protocol structure for the
UMTS air interface;
[0006] FIG. 3 shows an illustration of BCCH data packets being
mapped onto P-CCPCH data packets in line with an exemplary
embodiment of the invention;
[0007] FIG. 4 shows an MAC-b unit based on an exemplary embodiment
of the invention;
[0008] FIGS. 5A and 5B show an illustration of a first BCCH data
packet (FIG. 5A) and of a second BCCH data packet (FIG. 5B) based
on an exemplary embodiment of the invention;
[0009] FIG. 6 shows a graph showing an OFDMA/TDMA transmission
method based on an exemplary embodiment of the invention;
[0010] FIG. 7 shows an illustration of a BCCH data packet;
[0011] FIGS. 8A to 8C show graphs illustrating different
transmission methods, namely a TDMA transmission method (FIG. 8A),
an OFDMA transmission method (FIG. 8B) and an OFDMA/TDMA
transmission method (FIG. 8C); and
[0012] FIG. 9 shows a graph showing an OFDMA transmission method
combined with a frequency hopping transmission method.
DETAILED DESCRIPTION
[0013] In the current UMTS mobile radio communication standard
(Universal Mobile Telecommunications Systems communications
standard), also called Release 6, a maximum net transmission rate
of 10 Mbps is permitted in the downlink transmission direction and
of 2 Mbps is permitted in the uplink transmission direction. The
uplink transmission direction, also called the uplink, denotes
signal transmission from the mobile radio communication terminal to
the respective UMTS base station. The downlink transmission
direction also called the downlink, denotes signal transmission
from the respective associated UMTS base station to the mobile
radio communication terminal. Radio transmission technologies
currently specified are Frequency Division Duplex (FDD) and Time
Division Duplex (TDD). The multiple access method used is based on
Code Division Multiple Access (CDMA) technology.
[0014] A current topic on the 3GPP standardization committees
(3GPP: 3.sup.rd Generation Partnership Project) is the further
development of UMTS to form a mobile radio communication system
optimized for packet data transmission by improving the system
capacity and by improving the spectral efficiency. The aim is to
increase the maximum net transmission rate significantly in future,
namely to 100 Mbps in the downlink transmission direction and to 50
Mbps in the uplink transmission direction. To improve transmission
via the air interface, new multiple access methods are also being
examined, inter alia. One possible candidate for a multiple access
method which could be used for the downlink transmission direction
is OFDMA (Orthogonal Frequency Division Multiple Access) in
combination with TDMA (Time Division Multiple Access).
[0015] OFDMA in combination with TDMA, subsequently also called
OFDMA/TDMA, is a multicarrier multiple access method in which a
subscriber is provided with a defined number of subcarriers in the
frequency spectrum and a defined transmission time for the purpose
of data transmission.
[0016] In a cellular mobile radio communication network such as GSM
(Global System for Mobile Communications) communication system or
the UMTS communication system, important system information from a
mobile radio cell is transmitted by a base station using broadcast
signals to all subscriber appliances situated in the mobile radio
cell. Examples of such system information are information specific
to network operators, such as the identity of the network and of
the mobile radio cell, and also the configuration of the joint
radio resources. In a UMTS mobile radio communication network, the
system information is scheduled by the RRC (Radio Resource Control)
protocol layer in the UMTS base station (also called NodeB). The
current MAC-b protocol unit has no significant function in the UMTS
base station in the current UMTS communication network.
[0017] As described above, a base station in a cellular mobile
radio communication network based on GSM or UMTS therefore uses
broadcasting to transmit mobile radio cell information which is
relevant to the communication system and to mobile radio cells to
all subscriber appliances situated in the mobile radio cell. In the
case of UMTS, this is done using the logical channel BCCH
(Broadcast Control Channel), which is mapped on the transport
channel BCH (Broadcast Channel) and is physically transmitted on
the P-CCPCH (Primary Common Control Physical Channel) via the air
interface.
[0018] FIG. 7 shows a data format of a BCCH protocol message 700
for transmitting system information. The BCCH protocol message 700
has a system frame number (SFN) field 701 with a length of 12 bits
and also a useful data field 702 for transmitting the actual system
information (also called System Information Block data, SIB Data)
702 with a length of 234 bits. The system frame number field 701
depicts the timing used in the mobile radio cell and is used to
synchronize the data transmission.
[0019] Overall, a large amount of system information is transmitted
to the mobile radio cell.
[0020] According to the nature of the information, this information
is grouped into various blocks. In this context, a distinction is
usually drawn between MIB (Master Information Block) blocks, SB
(Scheduling Block) blocks and SIB (System Information Block)
blocks. The MIB is used to signal, inter alia, the PLMN (Public
Land Mobile Network) identity and also, to a limited degree,
scheduling information for the SIBs. An SB block is used to signal
the scheduling information for the SIB blocks. In line with UMTS,
there are currently 18 SIB types defined.
[0021] Examples of such SIB types currently defined in the line
with UMTS are: [0022] SIB 1: [0023] contains the information for
the UMTS core network (CN) and also the configuration of
system-related timers and constants; [0024] SIB 3: [0025] contains
the parameters for mobile radio cell selection and mobile radio
cell change; [0026] SIB 5: [0027] contains the configuration of the
physical joint radio resources for subscriber appliances in idle
mode; [0028] SIB 6: [0029] contains the configuration of the
physical joint radio resources for subscriber appliances in
connected mode; and [0030] SIB 11: [0031] contains the information
for performing measurements.
[0032] In line with UMTS, the system information is scheduled using
the RRC layer or its protocol unit in the base station. Although
the MAC layer (Medium Access Control layer) in the base station
contains a MAC-b protocol unit, this currently has no significant
function, i.e. in line with UMTS the MAC-b protocol unit currently
merely maps the data from the logical channel BCCH transparently on
to the transport channel BCH.
[0033] Significant properties for the transmission of the system
information are as follows: [0034] The P-CCPCH is broadcast at
relatively high power so that all subscribers in the mobile radio
cell can receive this channel with as little disturbance and error
as possible, even if the subscribers or their mobile radio
communication terminals are close to the edge of the mobile radio
cell. [0035] The transmission parameters for BCCH/BCH/P-CCPCH, such
as packet data length, transmission period, spreading code,
spreading factor and channelling coding are defined statically and
are known throughout the system so that all subscribers or their
mobile radio communication terminals in a mobile radio cell can
find and receive this important system information quickly.
[0036] However, transmitting the system information conventionally
has the following drawbacks, inter alia: [0037] The gross
transmission rate of 30 kbps (based on a spreading factor SF=256
and a transmission time interval TTI=20 ms) is low, which means
that a relatively long time is required in order to transmit or,
from the point of view of a subscriber, to receive the full system
information i.e. all defined SIBs in a mobile radio cell. Depending
on the mobile radio cell configuration (also called cell
configuration) this reading time is in the order of magnitude of
between 640 ms and a few seconds. [0038] The transmission capacity
is defined statically, which means that it is not possible to match
the capacity to the respective traffic load in the mobile radio
cell dynamically.
[0039] Normally, a mobile radio channel is a time-variant and
frequency-variant selective channel. In the case of a
fixed-location transmitter, the time variance is caused by the
movement of the mobile receiver. The frequency selectivity is
caused by the multipath propagation. The properties of the mobile
radio channel result in the signal from the transmitter reaching
the mobile receiver not only on the direct path but also on various
paths with different propagation times and damping influences. The
received signal is thus made up of a multiplicity of components,
with their amplitudes, propagation times and phases having a random
response. The received signal is therefore a distorted and
disturbed version of the transmitted signal. A basic task of the
receiver is thus to reverse the disturbances introduced into the
transmitted signal by the mobile radio channel again and to
reconstruct the transmitted signals correctly.
[0040] To transmit data from various subscribers via the mobile
radio channel, "multiple access methods" are often used. It is a
task of a multiple access method to regulate the subscribers'
access to the mobile radio channel, so that the subscribers do not
disturb one another. In doing this, the properties of the mobile
radio channel are also taken into account.
[0041] By way of example the following fundamental multiple access
methods are known: [0042] Time-division multiple access methods
(TDMA methods); [0043] Frequency-division multiple access methods
(FDMA methods); and [0044] Code Division Multiple Access methods
(CDMA methods).
[0045] In the case of TDMA, each subscriber has the full frequency
band, but just a defined transmission period, also called
Transmission Time Interval (TTI), available for transmission.
During a TTI, only one transmitter is active.
[0046] In the case of FDMA, each subscriber has the full time
available, but just a defined (narrow) frequency bandwidth from the
total bandwidth, for transmitting the data. In each of these
frequency bands, only one subscriber may ever be active.
[0047] In the case of CDMA, each subscriber has the full time and
the full frequency band available for transmission. To avoid
reciprocal influence on the signals from the different
transmitters, each subscriber is allocated a binary code pattern,
the binary code patterns being independent of one another and being
used to encode or spread the useful signal on a subscriber-specific
basis.
[0048] For future further development of mobile radio communication
systems, high transmission rates are demanded, for example, up to
100 Mbps or above. This also requires appropriately large
bandwidths. As the bandwidth increases, however, the frequency
selectivity of the mobile radio channel increases, resulting in
high levels of distortion in the received signal. This necessitates
the use of complex receivers.
[0049] OFDMA is a suitable method which is also used for minimizing
negative channel influences caused by the frequency selectivity,
which means that the receiver complexity can also be significantly
reduced.
[0050] OFDMA is a multicarrier method in which the signal bandwidth
B is divided into M orthogonal sub bands. This means that not one
frequency carrier with a large bandwidth is provided, but rather M
frequency carriers with the bandwidth .DELTA.f=B/M. The OFDMA
method therefore involves splitting the data stream to be
transmitted over a multiplicity of subcarriers and transmitting it
in parallel at an appropriately reduced data rate. In this case,
the individual subcarrier frequency interval .DELTA.f is stipulated
such that the influence of the frequency selectivity is kept as low
as possible. On the other hand the effects of the time variance
increase as the bandwidth becomes smaller, which means that channel
estimation is usually carried out as before.
[0051] In the case of OFDMA, a subscriber can be provided with the
full time and a defined number of subcarriers for transmission. To
improve the data transmission, OFDMA can be combined with other
multiple access methods, for example, OFDMA combined with TDMA
(OFDMA/TDMA) or OFDMA combined with a frequency hopping method.
[0052] FIG. 8a, FIG. 8b and FIG. 8c illustrate the principle of
TDMA (cf. FIG. 8a), OFDMA (cf. FIG. 8b) and OFDMA/TDMA (cf. FIG.
8c).
[0053] The respective graphs 800, 810, 820 respectively plot the
time, split into transmission time intervals TTI 802, 812, 822 of
10 ms, for example, along a time axis 801, 811, 821. A frequency
axis F 803, 813, 823 respectively shows the frequency range,
possibly split into frequency subranges .DELTA.f 814, 824.
[0054] FIG. 8a shows that in the TDMA method the respective full
frequency range is available to a subscriber for transmission in
each time frame 802 (shaded area in FIG. 8a).
[0055] FIG. 8b shows that the full time range is available to a
subscriber for transmission for a respective frequency subrange
.DELTA.f 814 (shown by way of example in FIG. 8b by means of the
shaded areas).
[0056] In line with the OFDMA/TDMA method, as shown in FIG. 8c, a
subscriber is allocated a respective discrete time frame 822,
paired with a discrete frequency subrange .DELTA.f 824, as
symbolized by way of example in FIG. 8c using the shaded areas.
[0057] FIG. 9 uses a graph 900 to show the principle of OFDMA in
combination with a frequency hopping method. The graph 900 again
shows a time axis 901, the time being split into transmission time
intervals of equal size, also called time frames TTI 902. A second
axis of the graph is the frequency axis F 903, the total frequency
being split into frequency subranges .DELTA.f 904 which are
likewise of equal size, for example. In line with OFDMA in
combination with a frequency hopping method, the data are
transmitted in the frequency band in interleaved form, i.e. after
each time frame 902 the subcarrier is changed on the basis of a
defined set of rules in order to reduce frequency-selective
disturbances in the mobile radio channel further. A frequency
hopping method is therefore a type of CDMA method in principle.
FIG. 9 uses numbers in the respective time slots and "frequency
slots" to show the allocated time ranges for transmission.
[0058] OFDMA or OFDM is already being used today in various
application areas, for example, in a WLAN (Wireless Local Area
Network) communication system based on IEEE 802.11a and IEEE
802.11g and also in DVB-T (Digital Video Broadcasting-Terrestrial)
and DVB-H (Digital Video Broadcasting-Handheld).
[0059] According to one embodiment of the invention system
information in a mobile radio communication network is transmitted
more efficiently compared to conventional methods.
[0060] According to one embodiment of the invention, a method for
the computer-aided formation of system information medium access
control protocol messages is provided, wherein system information
data packets are received from at least one logical channel, with
at least some of the system information data packets having
associated prioritization information which is used to indicate the
priority of the respective system information data packet. The
system information medium access control protocol messages are
formed using at least some of the system information data packets
from the logical channel taking into account the prioritization
information.
[0061] According to another embodiment of the invention, a method
for the computer-aided ascertainment of system information from
system information medium access control protocol messages is
provided, wherein a first system information medium access control
protocol message from a transport channel is received, the system
information medium access control protocol message containing a
statement indicating how a second system information medium access
control protocol message is transmitted. The statement is
ascertained from the first system information medium access control
protocol message and the second system information medium access
control protocol message is received taking into account the
ascertained statement.
[0062] According to a further embodiment of the invention, a medium
access control unit for forming system information medium access
control protocol messages is provided which has a reception unit
for receiving system information data packets from at least one
logical channel, at least some of the system information data
packets having associated prioritization information which is used
to indicate the priority of the respective system information data
packet. In addition, an encoding unit is provided for forming the
system information medium access control protocol message using at
least some of the system information data packets from the logical
channel taking into account the prioritization information.
[0063] Furthermore, according to another embodiment of the
invention, a mobile radio communication device having a medium
access control unit as described above is provided, which can be
set up as a mobile radio base station for example.
[0064] In addition, according to a further embodiment of the
invention, a medium access control unit for ascertaining system
information from system information medium access control protocol
messages is provided, having a reception unit for receiving a first
system information medium access control protocol message from a
transport channel, which message contains a statement indicating
how a second system information medium access control protocol
message is transmitted. Furthermore, an ascertainment unit is
provided for ascertaining the statement on the first system
information medium access control protocol message. The reception
unit is set up such that it can change reception characteristics on
the basis of the ascertained statement in order to receive the
second system information medium access control protocol message.
The reception parameters of the reception unit are thus set such
that the latter can receive the second system information medium
access control protocol message.
[0065] In addition, a mobile radio communication device having a
medium access control unit as described above is provided according
to one embodiment of the invention which is set up as a mobile
radio communication terminal, for example.
[0066] In addition, appropriate computer program elements for
implementing the functionalities described above or the methods
described above are provided according to embodiment of the
invention.
[0067] In this connection, it should be pointed out that the
embodiments of the invention can be implemented in software, i.e.
using a computer program, in hardware, i.e. using an electronic
circuit set up specifically for this purpose, or in hybrid form,
i.e. using arbitrary components in hardware and in software.
[0068] By prioritizing the system information data packets from the
logical channel and appropriately taking into account the
prioritization information at the level of the medium access
control protocol layer (MAC protocol layer) when mapping these
messages onto the transport channel, in other words when forming
the MAC protocol messages, it is possible to adjust to possibly
changing transmission constraints very quickly. It is also possible
to send information with appropriate prioritization of static, only
slowly changing system information on a secure mobile radio
channel, which can always be received by all subscriber terminals
in a mobile radio cell, and to distribute quickly changing
information over temporarily changing radio resources, for example,
or even temporarily not transmit the information when there is
insufficient available bandwidth for appropriate use. The system
information data packets from the logical channel are therefore
scheduled on the basis of the nature or type of the system
information when mapping on to the respective transport
channel.
[0069] The exemplary embodiments described below relate, as far as
appropriate, both to the methods, the medium access control units
and the mobile radio communication device and to the computer
program elements according to the embodiments of the invention.
[0070] In line with one refinement of the invention, the system
information medium access control protocol messages are mapped onto
at least one transport channel.
[0071] The system information data packets can be received from at
least one logical broadcast channel, for example, from the
Broadcast Control Channel (BCCH) logical channel in line with
UMTS.
[0072] In line with another refinement of the invention, the system
information medium access control protocol message is mapped onto
at least one broadcast transport channel, for example, on to the
Broadcast Channel (BCCH) transport channel when used within the
context of UMTS.
[0073] However, the system information medium access control
protocol messages can also be mapped onto a plurality of broadcast
transport channels.
[0074] The received system information data packets can be grouped
into at least system information data packets of a first group and
system information data packets of a second group in line with the
prioritization information. The system information data packets in
the first group have at least a first system information medium
access control protocol message formed for them, and the system
information data packets in the second group have at least a second
system information medium access control protocol message formed
for them. In this case, the prioritization information corresponds
to the statement of the type of the system information which is to
be transmitted using the system information data packets from the
logical channel.
[0075] Examples of the system information which is to be
transmitted are as follows: [0076] information for the UMTS core
network and also the configuration of system-related timers and
constants; [0077] parameters for mobile radio cell selection and
mobile radio cell change; [0078] a configuration of the physical
joint radio resources for subscriber appliances in idle mode;
[0079] a configuration of the physical joint radio resources for
subscriber appliances in connected mode; [0080] information for
performing measurements.
[0081] The first system information medium access control protocol
message can contain system information which is not updated in the
course of a prescribable time interval, in other words only slowly
changing system information, also called static system information.
The second system information medium access control protocol
message can contain system information which is updated, needs to
be updated or generally loses its validity before the prescribable
time interval has elapsed, i.e. normally system information which
is faster-changing system information also called dynamic system
information.
[0082] This makes it a very simple and type-matched matter to
transmit the system information in optimized and efficient
fashion.
[0083] The first system information medium access control protocol
message can contain at least some of the following system
information, for example: [0084] PLMN identity; [0085] radio cell
identity; [0086] configuration of system-related timers and
constants; [0087] configuration of the physical joint radio
resources; [0088] information for performing measurements.
[0089] The second system information medium access control protocol
message can contain at least some of the following system
information, for example: [0090] interference situation on the
uplink; [0091] transmission parameters for random access channels
in the uplink; [0092] time validity of the dynamic system
information.
[0093] The system information medium access control protocol
messages can be transmitted using a multiple access method, for
example using a frequency-division multiple access method and in
this context using a multiple carrier frequency-division multiple
access method, for example, the multiple access method being able
to be a combined multiple access method, for example, a multiple
carrier frequency-division multiple access method combined with a
frequency hopping multiple access method or combined with a
time-division multiplex multiple access method.
[0094] The multiple carrier frequency-division multiple access
method used may be the Orthogonal Frequency-division multiple
access method (OFDMA method) for example.
[0095] In line with another refinement of the invention, the first
system information medium access control protocol message is formed
such that it contains a statement indicating how the second system
information medium access control protocol message is transmitted,
for example the frequency band in which the second system
information medium access control protocol message is transmitted
and/or the time slot in which the second system information medium
access control protocol message is transmitted.
[0096] In this way, it is a very simple matter to include, by way
of example, a reference in the first system information medium
access control protocol message, for example, in a field provided
especially for this purpose, and to use this field to refer to the
respective time slot or to the respective frequency band which is
used for transmitting the respective second system information
medium access control protocol message.
[0097] By way of example, the invention may be used in a cellular
mobile radio communication system, for example in a GSM mobile
radio communication system, in addition in a 3GPP mobile radio
communication system or in a 3GPP2 mobile radio communication
system, for example. In particular, the invention may be used in a
UMTS mobile radio communication system or in a CDMA2000 mobile
radio communication system or in a FOMA (Freedom of Multimedia
Access) mobile radio communication system.
[0098] Exemplary embodiments are illustrated in the figures and are
explained in more detail below.
[0099] FIG. 1 shows a UMTS mobile radio communication system 100,
for reasons of simpler illustration particularly the components of
the UMTS mobile radio access network (UMTS Terrestrial Radio Access
Network, UTRAN), which has a plurality of mobile radio network
subsystems (RNS) 101, 102, which are respectively connected to the
UMTS core network (CN) 105 by means of what is known as an Iu
interface 103, 104. A mobile radio network subsystem 101, 102
respectively has a mobile radio network control unit (Radio Network
Controller, RNC) 106, 107 and one or more UMTS base stations 108,
109, 110, 111, which are also called NodeB in line with UMTS.
[0100] Within the mobile radio access network, the mobile radio
network control units 106, 107 of the individual mobile radio
network subsystems 101, 102 are connected to one another by means
of what is known as an Iur interface 112. Each mobile radio network
control unit 106, 107 respectively monitors the allocation of
mobile radio resources in all mobile radio cells in a mobile radio
network subsystem 101, 102.
[0101] A UMTS base station 108, 109, 110, 111 is respectively
connected to a mobile radio network control unit 106, 107
associated with the UMTS base station 108, 109, 110, 111 by means
of what is known as an Iub interface 113, 114, 115, 116.
[0102] Each UMTS base station 108, 109, 110, 111 provides radio
coverage for one or more mobile radio cells (CE) within a mobile
radio network subsystem 101, 102. Message signals or data signals
are transmitted between a respective UMTS base station 108, 109,
110, 111 and a subscriber appliance 118 (User Equipment, UE),
subsequently also called a mobile radio terminal, in a mobile radio
cell using an air interface, called a Uu air interface 117 in line
with UMTS, for example on the basis of a multiple access
transmission method.
[0103] In line with the UMTS-FDD (Frequency Division Duplex) mode,
for example, separate signal transmission in the uplink and
downlink (uplink: signal transmission from the mobile terminal 118
to the respective UMTS base station 108, 109, 110, 111; downlink:
signal transmission from the respective associated UMTS base
station 108, 109, 110, 111 to the mobile radio terminal 118) is
achieved through appropriate separate allocation of frequencies or
frequency ranges.
[0104] A plurality of subscribers, in other words a plurality of
activated--or registered in the mobile radio access network--mobile
radio terminals 118, in the same mobile radio cell are for example
isolated from one another in terms of signalling by means of
orthogonal codes, particularly in line with what is known as the
CDMA (Code Division Multiple Access) method.
[0105] In this connection, it should be noted that FIG. 1 shows
just one mobile radio terminal 118 for reasons of simple
illustration. In general, however, any number of mobile radio
terminals 118 are provided in the mobile radio system 100.
[0106] The communication between a mobile radio terminal 118 and
another communication appliance can be set up using a complete
mobile radio communication link to another mobile radio terminal,
alternatively to a landline communication appliance.
[0107] As FIG. 2 shows, the UMTS air interface 117 is logically
divided into three protocol layers (symbolized in FIG. 2 by a
protocol layer arrangement 200). The units (entities) which ensure
and implement the functionality of the respective protocol layers
described below are implemented both in the mobile radio terminal
118 and in the UMTS base station 108, 109, 110, 111 or in the
respective mobile radio network control unit 106, 107.
[0108] The bottommost layer shown in FIG. 2 is the physical layer
PHY 201, which is protocol layer 1 in line with the OSI (Open
System Interconnection) reference model based on ISO (International
Standardisation Organisation).
[0109] The protocol layer arranged above the physical layer 201 is
the data link layer 202, protocol layer 2 in line with the OSI
reference model, which for its part has a plurality of protocol
sublayers, namely the Medium Access Control protocol layer (MAC
protocol layer) 203, the Radio Link Control protocol layer 204 (RLC
protocol layer), the Packet Data Convergence Protocol protocol
layer 205 (PDCP protocol layer), and the Broadcast/Multicast
Control protocol layer 206 (BMC protocol layer).
[0110] The topmost layer of the UMTS air interface Uu is the mobile
radio network layer (protocol layer 3 in line with the OSI
reference model) having a mobile radio resource control unit 207
(Radio Resource Control protocol layer, RRC protocol layer).
[0111] Each protocol layer 201, 202, 203, 204, 205, 206, 207
provides the protocol layer situated above it with its services via
prescribed, defined service access points.
[0112] To provide a better understanding of the protocol layer
architecture the service access points are provided with generally
customary and unique names, such as logical channels 208 between
the MAC protocol layer 203 and the RLC protocol layer 204,
transport channels 209 between the physical layer 201 and the MAC
protocol layer 203, Radio Bearer (RB) 210 between the RLC protocol
layer 204 and the PDCP protocol layer 205 or the BMC protocol layer
206, and Signalling Radio Bearer (SRB) 213 between the RLC protocol
layer 204 and the RRC protocol layer 207.
[0113] In line with UMTS, the protocol structure 200 shown in FIG.
2 is not just split horizontally into the protocol layers and units
of the respective protocol layers which are described above but
also vertically into what is known as a control protocol level 211
(Control plane, C plane), which contains parts of the physical
layer 201, parts of the MAC protocol layer 203, parts of the RLC
protocol layer 204 and the RRC protocol layer 207, and the user
protocol level 212 (User plane, U plane), which contains parts of
the physical layer 201, parts of the MAC protocol layer 203, parts
of the RLC protocol layer 204, the PDCP protocol layer 205 and the
BMC protocol layer 206.
[0114] The units of the control protocol level 211 are used
exclusively to transmit control data, which are required for
setting up and clearing down and also maintaining a communication
link, whereas the units of the user level 212 are used to transport
the actual useful data.
[0115] Each protocol layer or each unit (entity) of a respective
protocol layer has particular prescribed functions within the
context of mobile radio communication.
[0116] At the transmitter end, the task of the physical layer 201
or the units of the physical layer 201, is to ensure secure
transmission of data coming from the MAC protocol layer 203 via the
air interface 117. In this connection, the data are mapped onto
physical channels (not shown in FIG. 2). The physical layer 201
provides its services to the MAC protocol layer 203 via transport
channels 209, which are used to stipulate how and with what
characteristics the data are to be transported via the air
interface 117. The fundamental functions which are provided by the
units of the physical layer 201 comprise channel encoding,
modulation and CDMA code spreading. Accordingly, the physical layer
201 or the entities of the physical layer 201 at the receiver end
perform(s) the CDMA code de-spreading, the demodulation and the
decoding of the received data and then forward(s) these data to the
MAC protocol layer 203 for further processing.
[0117] The MAC protocol layer 203 or the units of the MAC protocol
layer 203 provide(s) its/their services to the RLC protocol layer
204 using logical channels 208 as service access points, which
characterize the file type which the transported data involve. The
task of the MAC protocol layer 203 in the transmitter, i.e. for
data transmission in the uplink in the mobile radio terminal 118,
is particularly mapping the data which are present on a logical
channel 208 above the MAC protocol layer 203 onto the transport
channels 209 of the physical layer 201. For this the physical layer
201 provides the transport channels 209 with discrete transmission
rates. An important function of the MAC protocol layer 203 or of
the entities of the MAC protocol layer 203 in the mobile radio
terminal 118 in the case of transmission is therefore selection of
a suitable transport format TF for each configured transport
channel on the basis of the respective current data transmission
rate and the respective data priority of the logical channels 208
which are mapped onto the respective transport channel 209, and
also the available transmission power of the mobile radio terminal
118 (UE). A transport format stipulates, inter alia how many MAC
data packet units, called a transport block, per transmission
period TTI (Transmission Time Interval) are sent, in other words
transferred, via the transport channel 209 to the physical layer
201. The permissible transport formats and also the permissible
combinations of transport formats for the various transport
channels 209 are signalled to the mobile radio terminal 118 via the
mobile radio network control unit 106, 107 in the form of what is
known as the uplink TFCS (Transport Format Combination Set, set of
permitted transport format combinations) when a communication link
is set up. In the receiver, the units of the MAC protocol layer 203
split the transport blocks received on the transport channels 209
over the logical channels 208 again.
[0118] The MAC protocol layer or the units of the MAC protocol
layer 203 normally has/have three logical units. What is known as
the MAC-d unit (MAC-dedicated unit) handles the useful data and the
control data, which are mapped onto the dedicated transport
channels DCH (Dedicated Channel) via the appropriate dedicated
logical channels DTCH (Dedicated Traffic Channel) and DCCH
(Dedicated Control Channel). The MAC-c/sh unit (MAC control/shared
unit) handles the useful data and the control data from logical
channels 208, which are mapped onto the common transport channels
209, such as the common transport channel RACH (Random Access
Channel) in the uplink or the common transport channel FACH
(Forward Access Channel) in the downlink. The MAC-b unit
(MAC-Broadcast unit) handles only the mobile-radio-cell-related
system information, which is mapped onto the transport channel BCH
(Broadcast Channel) via the logical channel BCCH (Broadcast Control
Channel) and is transmitted by broadcast to all mobile radio
terminals 118 in the respective mobile radio cells.
[0119] The RLC protocol layer 204 or the units of the RLC protocol
layer 204 is/are used to provide its/their services to the RRC
protocol layer 207 by means of Signalling Radio Bearer (SRB) 213 as
service access points and to the PDCP protocol layer 205 and the
BMC protocol layer 206 by means of Radio Bearer (RB) 210 as service
access points. The Signalling Radio Bearers and the Radio Bearers
characterize the way in which the RLC protocol layer 204 is to deal
with the data packets. To this end, by way of example, the RRC
protocol layer 207 stipulates the transmission mode for each
configured Signalling Radio Bearer or Radio Bearer. In line with
UMTS, the following transmission modes are provided: [0120]
Transparent Mode (TM), [0121] Unacknowledged Mode (UM), or [0122]
Acknowledged Mode (AM).
[0123] The RLC protocol layer 204 is modelled such that there is
one independent RLC entity per Radio Bearer or Signalling Radio
Bearer. In addition, the task of the RLC protocol layer or of its
entities 204 in the transmission device is to split or combine the
useful data and the signalling data from Radio Bearers or
Signalling Radio Bearers into data packets. The RLC protocol layer
204 transfers the data packets produced following the split or
combination to the MAC protocol layer 203 for the purpose of
further transport or for the purpose of further processing.
[0124] The PDCP protocol layer 205 or the units of the PDCP
protocol layer 205 is/are set up for the transmission or the
reception of data from what is known as the Packet-Switched domain
(PS domain). The main function of the PDCP protocol layer 205 is
compression and decompression of the IP header information
(Internet Protocol header information).
[0125] The BMC protocol layer 206 or its entities is/are used to
transmit and receive what are known as cell broadcast messages by
the air interface.
[0126] The RRC protocol layer 207 or the entities of the RRC
protocol layer 207 is/are responsible for setting up and clearing
down and reconfiguring physical channels, transport channels 209,
logical channels 208, Signalling Radio Bearers 213 and Radio
Bearers 210 and also for negotiating all the parameters of the
protocol layer 1, i.e. the physical layer 201 and the protocol
layer 2. To this end, the RRC units, i.e. the units of the RRC
protocol layer 207, in the mobile radio network control unit 106,
107 and the respective mobile radio terminal 118 interchange
appropriate RRC messages via the Signalling Radio Bearers 213.
[0127] In line with the embodiments below, the MAC unit described
above and for that reason particularly the MAC-b unit
(MAC-Broadcast unit) are set up such that the additional
functionalities described below are implemented for transmitting
system information to the mobile radio terminals 118, respectively
situated in a mobile radio cell. This applies to the respective
MAC-b unit both in the mobile radio communication terminal 118 and
in the UMTS base station 108, 109, 110, 111.
[0128] To provide better clarification of the exemplary embodiments
below, a general description of the embodiments is first of all
explained.
[0129] In general terms, the text below presents a solution for
efficiently transmitting system information to a mobile radio cell,
using the UMTS base station 108, 109, 110, 111, in respect of an
additional UMTS communication system on the basis of an OFDMA/TDMA
multiple access method, and it should be pointed out that other
multiple access methods and also other transmission methods may be
provided within the context of the invention instead of the
OFDMA/TDMA multiple access method.
[0130] By way of example, reference should be made to the following
aspects:
[0131] The MAC-b unit in the UMTS base station 108, 109, 110, 111
usually performs the scheduling. The scheduling is effected on the
basis of the respective type of the information which is to be
transmitted:
[0132] The static, i.e. slowly variable, system information is sent
using predefined subcarriers which are known throughout the system.
In this context, one alternative refinement of the invention also
provides for a combination with a frequency hopping method in order
to ensure additional frequency diversity.
[0133] Examples of static system information are: [0134] PLMN
identity; [0135] Radio cell identity; [0136] Configuration of
system-related timers and constants; [0137] Configuration of the
physical joint radio resources; [0138] information for performing
measurements.
[0139] The dynamic, i.e. more rapidly variable system information
is sent flexibly using available subcarriers and transmission time
intervals.
[0140] Examples of dynamic system information are: [0141]
interference situation on the uplink; [0142] transmission
parameters for random access channels in the uplink; [0143] time
validity of the dynamic system information.
[0144] In addition, the scheduling is effected on the basis of the
channel properties and the traffic load in the mobile radio cell,
i.e., by way of example [0145] when transmission conditions in the
mobile radio cell are poor, the transmission of the static system
information using the predefined subcarriers (individual
subcarriers or else all subcarriers) is temporarily stopped; [0146]
when the traffic load is low, the transmission capacity for dynamic
system information which is to be transmitted is temporarily
increased.
[0147] In line with the embodiments which follow, it is assumed
that a base station 108, 109, 110, 111 in cellular mobile radio
communication networks based on GSM or UMTS uses broadcasts to
transmit mobile radio cell information which is relevant to the
system and to mobile radio cells to all subscriber appliances
situated in the mobile radio cell, i.e. the mobile radio terminal
118, for example.
[0148] In the case of UMTS, this is done using the Broadcast
Control Channel (BCCH) logical channel 301 (cf. block diagram 300
in FIG. 3), which is mapped on to the Broadcast Channel (BCH)
transport channel 302 and is physically sent on the Primary Common
Control Physical Channel (P-CCPCH) physical channel 303 via the air
interface 117 (see FIG. 1). The BCCH 301 and the BCH 302 are
respectively used to send 246 information bits to the physical
layer 303, where they are then channel-encoded, modulated and
spread using a spreading code, known throughout the system, with
the spreading factor SF=256. Since a fixed transmission period of
TTI=20 ms is defined for the BCH, the channel-encoded data are
transmitted via the air interface 117 in the mobile radio cell with
a distribution over two P-CCPCH frames of length 10 ms.
[0149] FIG. 3 shows a BCCH frame 304 having 246 bits, which is
mapped on to a BCH frame 305, likewise having 246 bits, with a
transmission period TTI=20 ms, which BCH frame 305 for its part is
mapped onto the physical channel, in line with FIG. 3 onto two
P-CCPCH frames, namely a first P-CCPCH frame 306 and a second
P-CCPCH frame 307.
[0150] A block diagram 400 in FIG. 4 shows a MAC-b unit 401 based
on an exemplary embodiment of the invention. In line with these
embodiments of the invention, at least two logical channels, i.e. a
first logical channel BCCH1 402 and a second logical channel BCCH2
403, are provided and also at least two transport channels, namely
a first transport channel BCH1 404 and a second transport channel
BCH2 405.
[0151] The first logical channel BCCH1 402 is used to send the
static system information, i.e. the system information which is
grouped as static system information, and the second logical
channel BCCH2 403 is used to send the dynamic system information to
the MAC-b unit 401, in other words the system information which is
grouped as more rapidly changing system information.
[0152] Each transport channel BCH1 404 and BCH2 405 has a
respective set of transport formats defined for it which indicate
the permissible discrete transmission rates of the transport
channel.
[0153] The data on the first transport channel BCH1 404 are
physically sent using predefined subcarriers which are known
throughout the system, possibly in combination with a frequency
hopping method.
[0154] The data to be transmitted on the second transport channel
BCH2 405, on the other hand, are sent flexibly using available
subcarriers and transmission time intervals.
[0155] The transmission capacity configured by the mobile radio
communication network for the first transport channel BCH1 404 is
the "guaranteed" transmission capacity, whereas the transmission
capacity configured for the second transport channel BCH2 405 is,
together with the first transport channel BCH1 404, the maximum
permitted total capacity.
[0156] The MAC-b unit 401 based on these embodiments of the
invention has a function and hence a corresponding unit
implementing this function, for example, using a microprocessor,
for scheduling or for priority handling.
[0157] In this context, the following principles are applied:
[0158] The logical channels BCCH1 402 and BCCH2 403 can
respectively be multiplexed onto any of the two transport channels
BCH1 404 and BCH2 405. [0159] When data are multiplexed onto the
first transport channel BCH1 404, the data from the first logical
channel BCCH1 402 have higher priority that the data from the
second logical channel BCCH2 403. [0160] If permitted by the
transmission capacity of the first transport channel BCH1 404, both
data from the first logical channel BCCH1 402 and data from the
second logical channel BCCH2 403 can be multiplexed onto the first
transport channel BCH1 404. [0161] If the transmission capacity of
the first transport channel BCH1 404 is not sufficient, only data
from the first logical channel BCCH1 402 are multiplexed onto the
first transport channel BCH1 404.
[0162] As an alternative to the solution described above with (at
least) two logical broadcast channels 402, 403, a solution with
just one logical broadcast channel is alternatively possible, i.e.
in this case static system information and dynamic system
information is sent to the MAC-b unit 401, i.e. is supplied to it,
using the same logical channel.
[0163] In this case, provision is made for the logical channel BCCH
to be used to send or supply priority information to the MAC-b unit
401 besides the data which are to be transmitted, i.e. in addition
to the data which are to be transmitted, so that the MAC-b unit 401
can perform the scheduling and priority handling correctly on the
basis of the type of system information which is to be transmitted,
taking into account the priority information obtained which is
associated with the data supplied to the MAC-b unit 401 via the
logical channel BCCH.
[0164] In addition, FIG. 4 also shows a MAC control unit 406 for
controlling the MAC-b unit 401.
[0165] To transmit system information on the first transport
channel BCH1 404 and on the second transport channel BCH2 405,
these exemplary embodiments of the invention define new data
formats, as shown by way of example in FIG. 5a and FIG. 5b.
[0166] To improve clarification, the top of FIG. 5a shows the data
format of the BCH message 700, to date, as has been explained above
in connection with FIG. 7.
[0167] The data format for a first system information message 500
has three message fields, namely [0168] a first system information
indicator field 501 of length M bits (M is a fundamentally
arbitrary natural number), [0169] a system frame number field 502
of length 12 bits, and [0170] a useful data field 503 of length N
bits (also called SIB data).
[0171] The system information indicator (Sys-IND) field 501 is used
to signal to the subscribers where (for example, the subcarrier
used and the transmission time interval (TTI) are indicated) the
system information are sent using the second transport channel BCH2
405. The system information indicator field 501 is added in the
physical protocol layer. The first system information message 500
is transmitted using the first transport channel BCH1 404.
[0172] The data format of a second system information message 510
which is to be transmitted using the second transport channel BCH2
405 is shown in FIG. 5b.
[0173] The second system information message 510 has just one
useful data field, in other words a system information data field
511 of length L bits (L is a fundamentally arbitrary natural
number). This field contains exclusively system information ("SIB
data").
[0174] On the basis of these embodiments of the invention, the
following applies for signaling the position of the system
information: [0175] The position of the static system information
on the first transport channel BCH1 404 is stipulated by the mobile
radio communication network, i.e. it is assumed to be known
throughout the system for rapid finding. [0176] The dynamic system
information's position, which is transmitted on the second
transport channel BCH2 405, is signalled to the subscribers, i.e.
to the mobile radio terminals 118, in the mobile radio cell by
means of the system information indicator field 501, which is
transmitted using the first transport channel BCH 404.
[0177] The advantages of the signalling described above, in
particular, are as follows: [0178] The transmission of system
information is adapted for an OFDMA/TDMA multiple access method.
[0179] The transmission capacity for system information can be
adapted dynamically on the basis of the channel properties and the
traffic load in the mobile radio cell. [0180] The reading time for
the system information for the subscribers in a mobile radio cell
is reduced.
[0181] Without restricting general validity, the following
configuration is also considered by way of example: [0182] an
OFDMA/TDMA multiple access method is used; [0183] the FDD radio
transmission technology is used; [0184] a MAC-b unit 401 as shown
in FIG. 4 is used at MAC-b protocol layer level; [0185] the data
formats of the system information messages 500, 510 as shown in
FIGS. 5a and 5b, are used for the messages which are transmitted on
the first transport channel BCH1 404 and on the second transport
channel BCH2 405; [0186] the following transport formats are
provided for the first transport channel BCH1 404: (1.times.246,
2.times.246) in bits; [0187] the following transport formats are
provided for the second transport channel BCH2 405: (0.times.336,
1.times.336, 2.times.336) in bits.
[0188] FIG. 6 uses a graph 600 to show a structure for transmitting
the system information, in other words the system information
messages 500, 510. Along a time axis 601, the graph 600 shows nine
time frames t1, t2, . . . , t9. Along a frequency axis 602 it shows
that the frequency space under consideration is split into eight
frequency ranges F1, F2, . . . , F8, i.e. eight subcarriers are
used for transmitting system information via the transport channels
404, 405.
[0189] The system information on the first transport channel BCH1,
in other words, the first system information messages 501, are sent
permanently on two subcarriers (F3, F6), whereas the system
information on the second transport channel BCH2 405, in other
words the second system information messages 510, are sent as
required flexibly using available subcarriers and transmission time
intervals.
[0190] The position of the dynamic system information on the second
transport channel BCH2 405 is signalled to the subscribers in the
mobile radio cell using the system information indicator field 501
on the first transport channel BCH1, i.e. in a first system
information message 500. In this context, it is assumed that the
signalling takes place one time transmission interval (TTI) (or
several time transmission intervals) previously in time. The
signalling is effected in the form of a tuple (subcarrier, TTI),
i.e. the positions of a first second system information message 603
(F5, t4) for the second transport channel BCH2 405 are signalled in
a first first system information message 604, which is transmitted
in a time slot preceding this in time, for example in the third
time slot t3. The position of a second second system information
message 605 (F7, t6) is signalled in a second first system
information message 606 in a time transmission interval t5 which
precedes in time, in this case using the third subcarrier F3.
[0191] It is also assumed that the signalling for a third second
system information message 607 (F1, t8) is effected in a third
first system information message 608, which likewise precedes this
in time and which is transmitted via the sixth subcarrier F6. The
position of a fourth second system information message 609 (F1, t9)
is signalled using a fourth first system information message 610,
which is likewise transmitted at a time preceding this and which is
transmitted using the third subcarrier F3 in the eighth time slot
t8.
[0192] In summary, aspects of the invention can be seen in that the
system information is scheduled in the MAC-b unit in the UMTS base
station. The scheduling is performed on the basis of the respective
type of the information which is to be transmitted (static/dynamic)
and on the basis of the channel properties and the traffic load in
the mobile radio cell.
[0193] The new MAC-b architecture comprises a function for
scheduling or priority handling, for example, at least two logical
channels and two transport channels.
[0194] New data formats are defined for transmitting system
information on (at least) two transport channels. The data format
for transmitting the static system information also comprises a
field for signalling for the purpose of transmitting the dynamic
system information, in line with these embodiments of the
invention, the system information indicator field.
* * * * *