U.S. patent application number 12/980569 was filed with the patent office on 2011-04-28 for management method for radio resources in a radio telecommunication system.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. Invention is credited to HANS KRONER, JURGEN MAYER.
Application Number | 20110098036 12/980569 |
Document ID | / |
Family ID | 27735665 |
Filed Date | 2011-04-28 |
United States Patent
Application |
20110098036 |
Kind Code |
A1 |
KRONER; HANS ; et
al. |
April 28, 2011 |
MANAGEMENT METHOD FOR RADIO RESOURCES IN A RADIO TELECOMMUNICATION
SYSTEM
Abstract
The invention relates to a management method for radio resources
in a radio telecommunication system, in which a first radio
telecommunication system has a first decentralized functional unit
for managing radio resources, and a second radio telecommunication
system has a second decentralized functional unit for managing
radio resources. The first and the second decentralized function
unit signal information with respect to a work load of the radio
resources to a central functional unit for common radio resource
management. The central functional unit evaluates this information
and signals information with respect to load targets to at least
one of the decentralized functional units, said information being
taken into consideration by the decentralized functional unit in an
intersystem handover.
Inventors: |
KRONER; HANS;
(GEISLINGEN-WEILER, DE) ; MAYER; JURGEN;
(BLAUSTEIN, DE) |
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
MUNCHEN
DE
|
Family ID: |
27735665 |
Appl. No.: |
12/980569 |
Filed: |
December 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10504208 |
Sep 1, 2004 |
7890104 |
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12980569 |
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PCT/DE03/00355 |
Feb 7, 2003 |
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10504208 |
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Current U.S.
Class: |
455/424 |
Current CPC
Class: |
H04W 88/06 20130101;
H04W 36/14 20130101; H04W 36/22 20130101; H04L 41/00 20130101; H04W
36/24 20130101; H04W 36/00835 20180801; H04W 36/0083 20130101 |
Class at
Publication: |
455/424 |
International
Class: |
H04W 36/22 20090101
H04W036/22; H04W 24/00 20090101 H04W024/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 11, 2002 |
DE |
102 05 575.0 |
Apr 4, 2002 |
DE |
102 14 934.8 |
Claims
1. A management method for radio resources in a radio communication
system, wherein a first radio communications system features a
first local functional unit for managing radio resources and a
second radio communications system features a second local
functional unit for managing radio resources, and the method
comprises: with each of the first and second local functional
units, signaling information relating to load measurements of the
radio resources to a central functional unit for common radio
resources management; and evaluating the information with the
central functional unit, determining a ranking of potential targets
for controlling an Inter System handover, and making the ranking
available to at least one of the local functional units.
2. The method according to claim 1, wherein the first and second
radio communication systems support the same access
technologies.
3. The method according to claim 1, wherein the first and second
radio communication systems support different access
technologies.
4. The method according to claim 1, which comprises requesting
information relating to the load measurements by the central
functional unit.
5. The method according to claim 1, which comprises defining the
ranking by the central functional unit for specific radio cells,
services and/or speeds.
6. The method according to claim 1, wherein the local functional
units are divided into functional subunits, and method further
comprises: making a decision, with mobile functional subunits,
about a time and/or a target of an Inter System handover and
defining roles and/or parameters for Inter System handover with
network-linked functional subunits communicating directly with the
central functional unit on the basis of information received from
the central functional unit; signaling the roles and/or parameters
to the mobile functional subunits with the network-linked
functional subunits; and taking into account the roles and/or
parameters for the Inter System handover with the mobile functional
subunits.
7. The method according to claim 6, wherein the mobile functional
subunits are implemented in mobile stations.
8. A neighborhood of radio communication systems comprising a first
radio communications system with a first local functional unit for
managing radio resources, a second radio communications system with
a second local functional unit for managing radio resources, and a
central functional unit for common radio resources management, said
local and central functional units being conFIGUREd for executing
the method according to claim 1.
9. The neighborhood of radio communication systems according to
claim 8, wherein said central functional unit is implemented in a
central network node.
10. The neighborhood of radio communication systems according to
claim 8, further comprising a plurality of central network nodes
communicating with one another and conFIGUREd to implement said
central functional unit.
11. The neighborhood of radio communication systems according to
claim 8, wherein said central functional unit is implemented in at
least one network node having implemented therein a local
functional unit.
12. The neighborhood of radio communication systems according to
claim 8, wherein at least parts of said local functional units are
implemented in mobile stations, and said central functional unit is
conFIGUREd to signal to the mobile stations information relating to
loads of radio resources, load targets and/or rankings, and the
mobile stations are conFIGUREd to be involved in a decision about a
time and/or a target of an Inter System handover.
13. A central functional unit for managing radio resources of a
first local functional unit and a second local functional unit, the
central functional unit comprising: a unit conFIGUREd to receive
information relating to load measurements of radio resources from
the first local functional unit and from the second local
functional unit; and said unit additionally being conFIGUREd to
evaluate said load measurement information and to signal
information relating to a ranking of potential targets to at least
one of the first local functional unit and the second local
functional unit.
14. A local functional unit for managing radio resources in a radio
communication system including a central network unit, the local
functional unit comprising: a unit conFIGUREd to signal information
relating to load measurements of the radio resources to the central
network unit for radio resources management; and said unit
additionally being conFIGUREd to receive a ranking of potential
targets from the central network unit, and to consider said
received ranking of potential targets when making an Inter System
handover.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This is a divisional application of application Ser. No.
10/504,208, filed Sep. 1, 2004; which was a continuation under 35
U.S.C. .sctn.120, of International application PCT/DE2003/00355,
filed Feb. 7, 2003; the application also claims the priority, under
35 U.S.C. .sctn.119, to German patent application Nos. DE 102 05
575.0 and DE 102 14 934.8, respectively filed Feb. 11, 2002 and
Apr. 4, 2002; those prior applications being incorporated by
reference herein in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to a method for managing radio
resources in a radio communication system, especially to control an
intersystem handover.
[0003] In radio communication systems, for example the European
mobile radio system of the second generation GSM (Global System for
Mobile Communications), information (for example speech, picture
information or other data) is transmitted with the aid of
electromagnetic waves over a radio interface. The radio interface
relates to a connection between a base station and user equipment,
where the user equipment can be mobile stations or fixed-location
radio stations. The electromagnetic waves in such systems are
emitted using carrier frequencies which lie within the frequency
range provided for the relevant system. For future mobile radio
systems, for example UMTS (Universal Mobile Telecommunication
System) or other 3rd-generation systems, carrier frequencies in the
range of around 2000 MHz are provided. For third-generation mobile
radio there is provision for two modes, where one mode designates
FDD (Frequency Division Duplex) and the other mode TDD (Time
Division Duplex). These modes are each used in different frequency
bands. Both modes support what is known as the CDMA (Code Division
Multiple Access) user separation procedure.
[0004] These different radio communication systems will in future
exist in parallel in the same geographical region. Each of these
systems features its own management for the radio resources
available. This is also known as Radio Resources Management (RRM).
In the known systems such as GSM and UMTS this functionality is
implemented in the Base Station Controller (BSC) or in the Radio
Network Controller (RNC). Parts of this functionality can also be
realized in the User Equipment (UE). Future user equipment will
allow access to a number of radio communication systems, this
equipment will be referred to as multimode equipment. What is known
as an Inter System Handover (ISHO) will be implemented between the
various radio communication systems, which will allow user
equipment to continue or maintain a connection established in one
system in another system.
[0005] There is not currently any coordination between the RRM
functionalities of the different systems in the sense of Common
Resource Management (CRRM). An inter System Handover is therefore
undertaken "blind", i.e. without knowledge of the current load
situation of the target system or the target radio cell. It Is
therefore not possible to distribute or administer the load between
the systems.
[0006] Within the framework of 3GPP (3rd Generation Partnership
Program) of the UMTS system, different approaches to solving this
problem are being discussed. Two approaches to solutions for this
problem are known from the document 3GPP 3G TR 25.881, VO.4.0
(2001-11) "Improvement of RRM across RNS and RNS/BSS (Rel 5)". A
first proposal provides for a physical CRRM server which controls
the entire procedure of the Inter System Handover. The disadvantage
of this proposal is that, because of this central server the
process for handing over is additionally delayed, and the exchange
of information between the central CRRM server and the local RRM
node also becomes very time-critical. A second proposal makes
provision for an interface at each of RRM node for exchange of
measurements of the radio cell load with other RRM neighboring
systems. The decision about an Inter System handover is made solely
by the relevant RRM node. The disadvantage of this proposal is that
there is no uniform CRRM strategy since RRM nodes of different
vendors or system operators can implement different CRRM strategies
which may not be compatible with each other.
SUMMARY OF THE INVENTION
[0007] The object of the invention is thus to specify a method
which overcomes the disadvantages of the described solutions. This
object is achieved by the features of the independent claims.
Advantageous developments of the invention can be taken from the
dependent patent claims.
[0008] In accordance with a first aspect of the invention a central
functional unit for common management of the radio resources,
especially in the sense of a CRRM, is implemented, which
communicates with the local functional units involved, for example
RRM nodes. The central functional unit receives from the local
functional units information and for example measurements, relating
to a load, for example relating to radio cell load, and controls
the Inter System handover by definition of a methodology for Inter
System handover which is signaled to the local functional units.
The local functional units are responsible for executing the Inter
System handover in accordance with the specified methodology. This
means that the central functional unit is not directly involved in
the decision on an Inter System handover, meaning that
advantageously no real-time requirements have to be fulfilled.
Furthermore a CRRM global strategy which is independent of vendors
or operators can be followed.
[0009] In accordance with the second aspect of the invention the
information of the local functional units is evaluated in the
central functional unit and a ranking of potential targets for
controlling the Inter System handover is determined. This specific
ranking is subsequently made available to at least one of the local
functional units.
[0010] An advantageous development results in the local functional
units being split into functional subunits. In this case mobile
functional subunits, for example mobile stations of users make a
decision about a time and/or a target of an Inter System handover.
Furthermore network-linked functional subunits communicating
directly with the central functional unit define on the basis of
information received from the central functional unit rules and/or
parameters for the Inter System handover. The network-linked
functional subunits then signal the rules and/or parameters to the
mobile functional subunits are which in their turn take account of
these rules and/or parameters during Inter System handover.
[0011] The invention is described in more detail below on the basis
of an exemplary embodiment which refers to the sole FIGURE of the
drawing.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0012] The FIGURE shows the functional interfaces for implementing
the common management of radio resources.
DESCRIPTION OF THE INVENTION
[0013] The FIGURE shows the interfaces and the flow of signaling
between the units of one or more systems. The procedural steps
described below for an Inter System handover can be applied in the
same way to an Intra System handover.
[0014] User equipment UE is supplied with radio resources via
served cells. The management of the radio resources in the served
cells is undertaken in a first local functional unit (serving RRM
function). In addition to measurement of the transmission quality
(quality measurements) the first local functional unit also obtains
from the user equipment for at least one of the served cells
measurements of the transmission quality to at least one of the
neighboring cells of a parallel radio communication system which is
taken into account for execution of an Inter System handover (ISHO
execution). The neighboring radio cells or the neighboring radio
communication system which is taken into account (neighborhood
definition) is signaled to the first local functional unit if
necessary by what is referred to as an Operation and Maintenance
(O&M) center. This operation and maintenance center can a
furthermore specify the system-specific or global strategy of the
central radio resource management (CRRM strategy) of the central
functional unit for common radio resource management (CRRM
function). As well as the measurement of transmission quality, the
first local functional unit receives messages about a relevant load
(load measurements) of the served radio cells connected to it.
These measurements are signaled by the first local functional unit
after a request (load measurement request) to the central
functional unit. The same occurs in the second a local unit
(neighboring RRM function). After evaluation of the information,
the central functional unit determines a load target and/or a
ranking of the neighboring cells (neighbor cell ranking) and
signals this to the first local functional unit. Taking into
account this information or the methodology defined by it, the
first local functional unit subsequently controls the execution of
the Inter System handover (ISHO execution).
[0015] The CRRM methodology is specified to the local functional
units both by a definition of the load target of the radio cells
under its responsibility and by the definition of a ranking of the
neighboring radio cells. The local functional unit can select a
suitable radio cell or a suitable system for an Inter System
handover according to these specifications. Alternatively to the
structure shown in the FIGURE, there can, according to the
invention, be a number of central functional units which exchange
rankings and/or load messages with each other.
[0016] The functional units can be implemented in a different ways
in a radio communication system.
[0017] The central functional unit is implemented in one or more
CRRM servers. The local functional units are exclusively
implemented in the known radio network nodes, for example the RNC
or BSC, which are involved in the Inter System handover.
[0018] The central functional unit is implemented in one or more
CRRM servers. The local functional units are implemented in the
known radio network nodes, for example the RNC or BSC, and in the
user equipment. The rankings of the neighboring radio cells are
transferred, by broadcast messages for example, to the user
equipment which is affected by an Inter System handover
decision.
[0019] The central functional units are implemented in one radio
network node, in a number of nodes or in all nodes, for example the
RNC or BSC. The methodology, for example in the form of the
rankings of the relevant neighboring cells, is exchanged between
these radio network nodes. The local functional units are also
implemented, if necessarily exclusively, in radio network nodes,
for example in the RNC or BSC which are involved in the Inter
System handover decision or support this decision.
[0020] The central functional units are implemented in one radio
network node, in a number of nodes or in all nodes, for example the
RNC or BSC. The methodology, for example in the form of the
rankings of the relevant neighboring radio cells, is exchanged
between these radio network nodes. The local functional units are
also implemented, if necessarily exclusively, in radio network
nodes, for example in the RNC or BSC which are involved in the
Inter System handover decision or support this decision. The
rankings of the neighboring radio cells are transferred, for
example by broadcast messages, to the user equipment which is
affected by an Inter System handover decision or which supports
this decision.
[0021] In the last two implementation options the user equipment
can be informed about the methodology for example by using adapting
of the parameters for cell (re)selection and/or the parameters for
the reports of the interfrequency and intersystem measurements.
This advantageously allows known procedures to be used at the radio
interface to lead the user equipment to perform an Inter System
handover or an intersystem cell reselection in such a way that the
radio cell load reaches a suitable load target.
[0022] The implementation of the solution according to the
invention is explained again below Independently of the example
described in the environment of the prior art described at the
start of this document.
[0023] The task of common radio resources management (CRRM) is the
central management of the load. This can be the management of the
load between various radio communications systems but also between
different layers or hierarchy levels within one radio communication
system. User equipment can be assigned to a system or a layer
independently of the service or service combination and/or the
speed of the user equipment. The control of the Inter System
handover is thus a functionality of common radio resources
management. Although the case of an Inter System handover is
examined below, the functionalities and mechanisms described can
however equally be applied to Intra System handovers, for example
between hierarchical levels of a system.
[0024] For the decision about an Inter System handover the
following information is required or sensible and is taken into
account by the common radio resources management or the central
functional unit. This is on the one hand the service or the
services and where necessary the speed of the user equipment.
Furthermore neighboring radio cells must be available to which the
connection can be handed over. The actual radio link quality of the
served and neighboring radio cells in each case as well as their
target connection quality are further parameters which ought to be
known. Furthermore the relevant current radio cell load and the
corresponding target radio cell load of the served and the
neighboring radio cells ought to be known, in which case these can
additionally be determined for specific services and if necessary
speeds.
[0025] The following information is present in the local functional
units. The service or services of the user equipment are signaled
during connection setup by the core network. Possible targets for
Inter System handover, connection quality targets and a maximum
radio cell load in each case of the served radio cells will be
specified by the operations and maintenance center. The current
connection quality for the served and the neighboring radio cells
in each case is known through signaled measurements of the user
equipment. The current load level of the served radio cells is
known through the signaled measurements of the base stations (Node
B or BTS) of the radio cells.
[0026] Unknown in the local functional units are the current
dynamic target load of the served radio cells as well as the
current target load of the neighboring radio cells. The absence of
the first parameter has the disadvantage of leading to uncertainty
if a connection handover is to be undertaken and the absence of the
second parameter makes it more difficult to decide in which radio
cell the handover is to occur. In the known method described in the
introduction the load targets are specified by the O&M which
only allows a suboptimal Inter System load distribution whereas the
target load and the current load are unknown so that the connection
handover must be undertaken without this knowledge.
[0027] In accordance with the inventive solution the parameters are
merged in the central functional unit and made available to the
local functional units. In the load targets can be notified
dynamically if required, for example using abstract values (0% . .
. 100%), on a system, layer or radio cell service and/or
speed-specific basis. Furthermore the difference between the load
values and the target values can be notified to the neighboring
radio cells by a service and/or speed-specific ranking, for example
by the flag "handover is desired, allowed, not desired,
forbidden".
[0028] The function of common radio resources management or of the
central functional unit initially consists of requesting load
measurements from the local functional units and a merging of the
measurement results. Subsequently it decides on radio cell and
where necessary service-specific load targets. It subsequently
informs the local functional units about the load targets of the
radio cells assigned in each case. Furthermore it defines radio
cell and when necessary service-specific ranking values and informs
the local functional units about the relevant rankings of the
neighboring radio cells.
[0029] The function of the local functional unit of consists of
executing measurements as requested by the central functional unit.
Furthermore it accepts load targets signaled from the central
functional unit for the radio cells which it controls as well as
the signaled ranking of the neighboring radio cells: Taking this
information into account it decides independently about an Inter
System handover.
[0030] Advantageously the central functional unit only specifies
the methodology by specifying a target value and radio cell
rankings. These parameters are not real time-dependent and the
signaling load on the interfaces between the central and the local
functional units is limited. Furthermore only slight reliability
requirements are to be imposed on the central functional unit since
the local functional units can operate autonomously for example by
using in default values or the last parameters signaled by the
central unit as their parameters. The implementation can be
designed very flexibly. Thus the central functional unit can be
implemented both on a central server and also distributed on a
number of system components. The interface between the central and
the local units can be standardized whereas implementation of the
algorithms and decision-making strategies used in the local units
can be vendor or operator-specific.
* * * * *