U.S. patent application number 13/728494 was filed with the patent office on 2013-09-05 for method and arrangement in a communication system.
This patent application is currently assigned to Unwired Planet, LLC. The applicant listed for this patent is UNWIRED PLANET, LLC. Invention is credited to Joakim Bergstrom, Gabor Fodor, Anders Furuskar, Muhammad Kazmi, Vera Kenehan, Stefan Parkvall, Magnus Stattin.
Application Number | 20130229962 13/728494 |
Document ID | / |
Family ID | 39344723 |
Filed Date | 2013-09-05 |
United States Patent
Application |
20130229962 |
Kind Code |
A1 |
Furuskar; Anders ; et
al. |
September 5, 2013 |
METHOD AND ARRANGEMENT IN A COMMUNICATION SYSTEM
Abstract
The present invention relates to a method and an arrangement of
efficiently utilizing radio resources in a communication network,
comprising a communication network node transmitting information on
shared control channels (SCCH) to one or more user equipments. The
information is transmitted over either a narrow or a wide bandwidth
depending on which mode said one or more user equipments are,
either a power saving mode or an active mode.
Inventors: |
Furuskar; Anders;
(Stockholm, SE) ; Parkvall; Stefan; (Stockholm,
SE) ; Kenehan; Vera; (Stockholm, SE) ; Fodor;
Gabor; (Hasselby, SE) ; Kazmi; Muhammad;
(Bromma, SE) ; Bergstrom; Joakim; (Stockholm,
SE) ; Stattin; Magnus; (Sollentuna, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNWIRED PLANET, LLC |
Reno |
NV |
US |
|
|
Assignee: |
Unwired Planet, LLC
Reno
NV
|
Family ID: |
39344723 |
Appl. No.: |
13/728494 |
Filed: |
December 27, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12513297 |
May 1, 2009 |
8345592 |
|
|
PCT/SE07/50750 |
Oct 18, 2007 |
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13728494 |
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Current U.S.
Class: |
370/311 |
Current CPC
Class: |
H04W 48/12 20130101;
H04W 52/0216 20130101; Y02D 70/1262 20180101; Y02D 30/70 20200801;
H04W 68/02 20130101; Y02D 70/24 20180101; Y02D 70/1242 20180101;
H04W 52/0219 20130101 |
Class at
Publication: |
370/311 |
International
Class: |
H04W 52/02 20060101
H04W052/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 1, 2006 |
SE |
0602307-1 |
Claims
1. A method for efficiently utilizing radio resources in a
communication network comprising a communication network node
transmitting information on control channels to one or more user
equipments, wherein defining a subset of Transmission Time
Intervals such as to determine at which instances a control channel
may address a user equipment in a power saving mode or non-power
saving mode; defining a first, wideband mapping pattern for user
equipments in a non-power saving mode; defining a second,
narrowband mapping pattern for user equipments in a power saving
mode; and transmitting, during Transmission Time Intervals of a
subset associated to a respective power mode, said information over
the control channel by using the mapping pattern that is defined
for the respective power mode of the user equipment.
2. The method according to claim 1, whereby said second mapping
pattern is used for signalling of indications pointing to a certain
message.
3. The method according to claim 1, whereby said second mapping
pattern is used for paging and/or broadcast messages.
4. The method according to claim 1, whereby using said second
mapping pattern implies mapping on a pseudo-random set of
subcarriers.
5. The method according to claim 1, whereby using said first
mapping pattern implies a mapping on a subset of non-contiguous
subcarriers covering a major part of the system bandwidth.
6. The method according to claim 1, whereby information is allowed
to be transmitted over the control channel to user equipments in
non-power saving modes by using the second mapping pattern if no
information is to be transmitted to user equipments in a power
saving mode.
7. The method according to claim 1, whereby using said second
mapping pattern implies a mapping on a subset of contiguous
subcarriers.
8. The method according to claim 1, whereby said control channel is
interleaved on a wide or narrow bandwidth depending on the power
mode of the user equipment.
9. The method according to claim 1, whereby the communication
network applies Orthogonal Frequency Division Multiplexing
(OFDM).
10. An arrangement for efficiently utilizing radio resources in a
communication network, said arrangement included in or associated
to a communication network node for transmitting information on
control channels to one or more user equipments, comprising a first
unit for providing subsets of Transmission Time Intervals such as
to determine at which instances a control channel may address a
user equipment in a power saving mode or non-power saving mode; a
second unit for providing a first, wideband mapping pattern for
user equipments in a non-power saving mode and a second, narrowband
mapping pattern for user equipments in a power saving mode; and a
transmitter adapted to transmit, during Transmission Time Intervals
of pre-defined subsets associated to a respective power mode, said
information over the control channel by using the mapping pattern
that is defined for the respective power mode of the user
equipment.
11. The arrangement according to claim 10, wherein the
communication network applies Orthogonal Frequency Division
Multiplexing (OFDM).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 12/513,297, filed May 1, 2009, now U.S. Pat. No. 8,345,592,
which was the National Stage of International Application No.
PCT/SE07/50750, filed Oct. 18, 2007, which claims the benefit of
Swedish Application No. 0602307-1, filed Nov. 1, 2006, the
disclosure of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a method and an arrangement
in a communication system, and in particular to an arrangement
allowing for efficiently utilizing radio resources in a
communication network as well as a method for such utilization.
BACKGROUND
[0003] In many wireless systems Shared Control Channels (SCCHs) are
used in the physical layer to carry transport channels in the
downlink direction. For example, in UMTS the Physical Downlink
Shared Channel (PDSCH) can be used to carry the Downlink Shared
Channel (DSCH) transport channel.
[0004] Shared Control Channels are used to convey information on
which user equipments are scheduled on what resources (including
time, frequency and code resources) and how user equipments should
decode the transmitted signal. The Shared Control Channels
typically address user equipments in active modes (i.e. non-power
saving modes). Recently, it has however been proposed to use Shared
Control Channels also for addressing user equipments in power
saving modes (e.g. in discontinuous reception modes or idle modes).
Thereby the need for a dedicated physical channel to support, e.g.,
the paging transport channel is eliminated. For example, in a
Universal Mobile Telecommunications System (UMTS) the Secondary
Common Control Physical Channel (S-CCPCH) has the (dedicated) task
to carry the Paging Channel (PCH) and the Forward Access Channel
(FACH).
[0005] In order to achieve frequency and intercell interference
diversity (such as to allow the Shared Control Channels to
experience an average of the intercell interference and to avoid
them being affected by single high power interferers), these
physical channels should be interleaved (or `spread`) over a wide
frequency band. In OFDM-based communication systems such channels
should, e.g., be interleaved over a pseudo-random set of
subcarriers covering a large part of the total system
bandwidth.
[0006] On the other hand, in order to limit power consumption in
user equipments that are receiving (and/or detecting) the Shared
Control Channels, it is desirable to interleave said Shared Control
Channels on a frequency band that is as narrow as possible. This is
due to the fact that power consumption can be regarded as a
function that increases with the receiver bandwidth, i.e. receiving
a wide-band signal consumes more power than receiving a narrow-band
signal. This is especially important for user equipments in power
saving modes because in such modes, in which user equipments
normally spend most of their time, the power that need to be spend
for reception of the Shared Control Channel constitutes a
considerable amount of the overall power consumption and, hence,
directly affects the stand-by time of the mobile.
SUMMARY
[0007] Accordingly, it is an object of the present invention to
provide an improved method for efficiently utilizing the radio
resources in a communication network, comprising a communication
network node transmitting information on control channels to one or
more user equipments.
[0008] Another object of the present invention is to provide an
improved arrangement for efficiently utilizing the radio resources
in a communication network, comprising a communication network node
transmitting information on control channels to one or more user
equipments.
[0009] Further embodiments are listed in the dependent claims.
[0010] Due to the provision of a method and arrangement in which a
shared control channel, SCCH, is mapped to physical resources
spanning a wide or narrow bandwidth, an improved robustness of
control channels and/or reduced power consumption in the user
equipment can be obtained.
[0011] Still other objects and features of the present invention
will become apparent from the following detailed description
considered in conjunction with the accompanying drawings. It is to
be understood, however, that the drawings are designed solely for
purposes of illustration and not as a definition of the limits of
the invention, for which reference should be made to the appended
claims. It should be further understood that the drawings are not
necessarily drawn to scale and that, unless otherwise indicated,
they are merely intended to conceptually illustrate the structures
and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the drawings:
[0013] FIG. 1 illustrates the architecture of a communication
network as assumed by the present invention.
[0014] FIG. 2 illustrates the default mapping of SCCHs on
subcarriers (depictive only, typically one L1/L2 would comprise
about 60 subcarriers).
[0015] FIG. 3 illustrates the special mapping of SCCHs on
subcarriers in TTIs where a paging indication may occur. The SCCH
with the paging indication is mapped to narrow frequency band
(depictive only, typically one L1/L2 would comprise about 60
subcarriers).
[0016] FIG. 4 illustrates an example arrangement in or associated
with a communication network node for transmitting information on
control channels to user equipments.
DETAILED DESCRIPTION
[0017] FIG. 1 depicts a communication system including a Radio
Access Network (RAN) 11, which can--as one conceivable example--be
a UMTS Terrestrial Radio Access Network (UTRAN) or evolved UTRAN
(E-UTRAN), comprising at least one Radio Base Station (RBS) (or
Node B/eNode B) 15 (two are shown in FIG. 1) connected to one or
more controller nodes 10, e.g. Radio Network Controllers (RNCs) in
the case of UTRAN. The Radio Access Network 11 is connected to a
Core network (CN) 12. Radio Access Network 11 and Core Network 12
provide communication and control for a plurality of user
equipments (UE) 18 (or mobile stations) that each uses downlink
(DL) channels and uplink (UL) channels. On the downlink channel,
the Radio Base Station 15 transmits to each user equipment 18 at
respective power level. On the uplink channel, the user equipments
18 transmit data to the Radio Base Station 15 at respective power
level.
[0018] The present invention provides a method for interleaving the
Shared Control Channel (SCCH) on a wide bandwidth when it addresses
user equipments in non-power saving modes (e.g. active mode) and
interleaving the Shared Control Channel on a narrow bandwidth when
it addresses user equipments in power-saving modes.
[0019] A further embodiment of the present invention assumes the
case that there is no SCCH information available for user
equipments in a power saving mode such that the narrow band SCCH
may be used to address user equipments in a non-power saving mode.
Hence, no resources are wasted in this case.
[0020] Thus, the present invention refers to a Shared Control
Channel (SCCH) that is mapped/transmitted over a wide frequency
band when the SCCH addresses user equipments in an active mode
(i.e. a non-power saving mode) and that is mapped/transmitted over
a narrow frequency band when the SCCH addresses user equipments in
an idle mode (i.e. a power saving mode).
[0021] Examples of signals addressing user equipments in power
saving modes include, for instance, Paging Indications (pointing to
a paging message), Paging Messages, Broadcast Indications (pointing
to a broadcast message), or Broadcast Messages.
[0022] In more detail, and interpreting the terms `non-power saving
mode` and `power saving mode` in a broad sense, the method
according to the present invention involves the following steps to
be performed: [0023] pre-defining a subset of Transmission Time
Intervals (TTI) that the base station and the user equipments have
"agreed upon". In said subset the Shared Control Channels (SCCH)
may address user equipments in power saving modes (likewise,
subsets can be defined for user equipments in a non-power saving
mode). As an example, this can be performed in every N.sup.th TTI.
Alternatively, the pre-defining implies that the network uses the
narrow bandwidth whenever it intends to page a user equipment while
using the wide bandwidth otherwise. [0024] defining a first
(wideband) SCCH mapping pattern for user equipments in a non-power
saving mode (e.g. an active mode); [0025] defining a second
(narrowband) SCCH mapping pattern for user equipments in a power
saving mode; [0026] applying the first mapping pattern for TTIs
that are not addressing user equipments in power saving modes;
[0027] applying the second mapping pattern for TTIs that are
addressing user equipments in power saving modes.
[0028] The present invention also relates to an arrangement for
achieving the afore-described method. The arrangement 40, as
depicted in FIG. 4, is included in or associated to a communication
network node 15 for transmitting information on control channels to
one or more user equipments 18 and comprises a first unit 41 for
providing subsets of Transmission Time Intervals such as to
determine at which instances a control channel may address a user
equipment in a power saving mode or non-power saving mode; and a
second unit 42 for providing a first, wideband mapping pattern for
user equipments in a non-power saving mode and a second, narrowband
mapping pattern for user equipments in a power saving mode. A
transmitter 43 is adapted to transmit, during Transmission Time
Intervals of pre-defined subsets associated to a respective power
mode, said information over the control channel 44 by using the
mapping pattern that is defined for said respective power mode of
the user equipment.
[0029] In a first additional feature of the method according to the
present invention one or more of the Shared Control Channels always
use the narrowband mapping/transmission in cases where many such
Shared Control Channels are sent in parallel.
[0030] In a second additional feature of the method according to
the present invention the Shared Control Channel using the
narrowband mapping/transmission is sent `on top of` the other
Shared Control Channels. In this case said other Shared Control
Channels loose the part of their signals that is covered by the
narrow banded Shared Control Channel.
[0031] A first embodiment of the present invention concerns
OFDM-based systems, for which a wide band transmission can be
realized by mapping the SCCH information on a subset of
non-contiguous subcarriers that cover almost the whole system
bandwidth. A narrow band transmission can be realized by mapping
the subcarriers on a contiguous subset of subcarriers.
[0032] FIG. 2 shows an example of a mapping of five Shared Control
Channels for the case where all of them address user equipments in
active modes.
[0033] FIG. 3 shows an example of how the same Shared Control
Channels are mapped for the case that one of them (the middle one)
addresses user equipments in a power saving mode.
[0034] According to a second embodiment, the method can
straightforwardly be used for 3G Long Term Evolution (LTE). The
paging channel indication is sent on the Shared Control Channel
which uses a narrowband interleaving.
[0035] To achieve frequency and intercell interference diversity
(in order for the sensitive L1/L2 control channels to experience an
average of the intercell interference and avoid being hit by single
high power interferers), these channels are mapped on a pseudo
random set of subcarriers. Such a mapping principle is depicted in
FIG. 2. This mapping achieves the desired frequency and
interference diversity characteristics.
[0036] For the paging indicator channel this implies that the
channels are spread over a large bandwidth up to the UE reception
capability (e.g. 15 MHz), which will lead to an increased power
consumption. For reference, the bandwidth monitored by WCDMA UEs is
5 MHz, and for GSM UEs 200 kHz.
[0037] Transmitting paging indications on L1/L2 control channels
which are mapped/spread over a wide bandwidth will lead to an
increased power consumption. One alternative to mitigate this is to
apply some special mapping of one L1/L2 control channel (with
limited bandwidth, e.g. 1.25 MHz as the BCH): This could be done in
every TTI, or only in TTIs where the paging indications occur, see
FIG. 3.
* * * * *