U.S. patent application number 12/307746 was filed with the patent office on 2009-09-10 for radio resource allocation mechanism.
This patent application is currently assigned to NOKIA CORPORATION. Invention is credited to Kari Juhani Hooli, Kari Veikko Horneman, Kari Pekka Pajukoski, Esa Tapani Tiirola.
Application Number | 20090227261 12/307746 |
Document ID | / |
Family ID | 38894233 |
Filed Date | 2009-09-10 |
United States Patent
Application |
20090227261 |
Kind Code |
A1 |
Tiirola; Esa Tapani ; et
al. |
September 10, 2009 |
RADIO RESOURCE ALLOCATION MECHANISM
Abstract
A cellular communication system comprising a plurality of user
equipment and a network infrastructure. Radio resource of the
plurality of cells is divided into more than one radio resource
groups. A network infrastructure element detects a requirement of
radio resource allocation for a user equipment and determines
effective interference to be generated by the required radio
resource to a defined group of neighbouring cells. User equipment
is allocated a radio resource from one of the radio resource groups
on the basis of the determined effective interference to be
generated to the defined group of neighbouring cells. Inter-cell
interference decreases and the throughput of the cellular system
increases, but the exchange of physical layer information is not
increased.
Inventors: |
Tiirola; Esa Tapani;
(Kempele, FI) ; Pajukoski; Kari Pekka; (Oulu,
FI) ; Horneman; Kari Veikko; (Oulu, FI) ;
Hooli; Kari Juhani; (Oulu, FI) |
Correspondence
Address: |
Nokia, Inc.
6021 Connection Drive, MS 2-5-520
Irving
TX
75039
US
|
Assignee: |
NOKIA CORPORATION
Espoo
FI
|
Family ID: |
38894233 |
Appl. No.: |
12/307746 |
Filed: |
July 7, 2006 |
PCT Filed: |
July 7, 2006 |
PCT NO: |
PCT/FI06/50324 |
371 Date: |
January 6, 2009 |
Current U.S.
Class: |
455/450 |
Current CPC
Class: |
H04W 16/10 20130101;
H04W 72/08 20130101; H04W 72/082 20130101 |
Class at
Publication: |
455/450 |
International
Class: |
H04W 72/00 20090101
H04W072/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 7, 2006 |
FI |
PCT/FI2006/050324 |
Jan 10, 2007 |
FI |
PCT/FI2007/050010 |
Claims
1. A radio resource allocation method, comprising: dividing radio
resource of a plurality of cells into more than one radio resource
groups, detecting in a cell a requirement of radio resource
allocation for a user equipment; determining effective interference
to be generated by the required radio resource to a defined group
of neighbouring cells; and allocating to a user equipment a radio
resource from one of the radio resource groups on the basis of the
determined effective interference to be generated to the defined
group of neighbouring cells.
2. A method as claimed in claim 1, where in the radio resource is a
frequency band and the step of dividing comprises dividing the
frequency band into more than one frequency sub-bands, each
frequency sub-band comprising one or more frequency units.
3. A method as claimed in claim 1, where the step of determining
comprises: receiving in the user equipment information indicating
properties of one or more transmission paths to one or more
neighbouring cells; generating in the user equipment from the
received information corresponding one or more measurement
indication; sending from the user equipment the measurement
indication to a network infrastructure element responsible for
allocating the radio resource; and computing in the network
infrastructure element responsible for allocating the radio
resource the effective interference on the basis of the measurement
indications received from the user equipment; generating
measurement indications indicating path loss to a defined group of
cells; and the step of computing comprises computing the effective
interference as total path loss to the defined group of cells; and
wherein the defined group of cells is the active group of the user
equipment.
4-26. (canceled)
27. A method as claimed in claim 1, comprising: utilizing in a cell
a radio resource formed from a plurality of radio resource units, a
radio resource unit corresponding to a separable unit in time and
frequency domain, further divisioned by a channelization code, the
channelization code comprising a predefined spreading code;
dividing the radio resource units of the cell into two or more
radio resource groups, the channelization code of radio resource
units in a radio resource group comprising a same predefined
spreading code, and radio resource units in different radio
resource groups comprising different predefined spreading codes;
determining said effective interference on the basis of the
predefined spreading codes.
28. A method as claimed in claim 1, comprising: generating in a
user equipment a measurement indication indicating a property of a
transmission path between the user equipment and a transceiver in
the cell; sending from the user equipment the measurement
indication to a network infrastructure element responsible for
allocating the radio resource units of the cell; allocating to the
user equipment a radio resource unit from one of the radio resource
groups on the basis of the measurement indication.
29. A method as claimed in claim 1 comprising: arranging radio
resource groups to correspond with defined ranges of the
measurement indication values; allocating to the user equipment a
radio resource unit from the radio resource group that corresponds
to a range within which a measurement indication received from the
user equipment falls.
30. User equipment for a cellular communication system, configured
to receive information indicating properties of one or more
transmission paths to one or more cells; generate from the received
information corresponding one or more measurement indication; send
the measurement indication to a network infrastructure element
responsible for allocating the radio resource.
31. User equipment as claimed in claim 30, wherein the user
equipment is configured to receive information indicating
properties of one or more transmission paths to one or more
neighbouring cells; and wherein the defined group of neighbouring
cells is the active group of the user equipment.
32. User equipment as claimed in claim 30, wherein the user
equipment is configured to generate one or more measurement
indications indicating a property of a transmission path between
the user equipment and the cell.
33. A control unit for network infrastructure element controlling a
defined radio resource of a cell, the control unit being configured
to divide the radio resource of the cell into more than one radio
resource groups; detect a requirement of radio resource allocation
for a user equipment; determine effective interference to be
generated by the required radio resource to a defined group of
neighbouring cells; and allocate to the user equipment a radio
resource from one of the radio resource groups on the basis of the
determined effective interference to be generated to the defined
group of neighbouring cells.
34. A control unit as claimed in claim 33, where the radio resource
is a frequency band and the frequency band is divided into more
than one frequency sub-bands, each frequency sub-band comprising
one or more frequency units.
35. A control unit as claimed in claim 33, where the control unit
is configured to receive from the user equipment one or more
measurement indications corresponding to properties of one or more
transmission paths to one or more neighbouring cells; and compute
the effective interference on the basis of the one or more
measurement indications received from the user equipment.
36. A control unit as claimed in claim 35, where the one or more
measurement indications indicate path loss to a defined group of
cells; and the network infrastructure element is configured to
compute the effective interference as total path loss to the
defined group of cells.
37. A control unit as claimed in claim 36, wherein the defined
group of cells is the active group of the user equipment.
38. A control unit as claimed in claim 37, wherein the one or more
measurement indications provide channel quality indications (CQI);
and the network infrastructure element is configured to compute the
effective interference from the received channel quality
indications.
39. A control unit as claimed in claim 33, wherein the control unit
is configured to manage a radio resource of a cell formed from a
plurality of radio resource units, a radio resource unit
corresponding to a separable unit in time and frequency domain,
further divisioned by a channelization code, the channelization
code comprising a predefined spreading code; divide the radio
resource units of the cell into two or more radio resource groups,
the channelization code of radio resource units in a radio resource
group comprising a same predefined spreading code, and radio
resource units in different radio resource groups comprising
different predefined spreading codes; determine said effective
interference on the basis of the predefined spreading codes.
40. A control unit as claimed in claim 33, wherein the control unit
is configured to receive from a user equipment a measurement
indication indicating a property of a transmission path between the
user equipment and a transceiver of the cell; allocate to the user
equipment a radio resource unit from one of the radio resource
groups on the basis of the measurement indication.
41. A control unit as claimed in claim 33, wherein the control unit
is configured with radio resource groups that correspond with
defined ranges of measurement indication values; and is arranged to
allocate to the user equipment a radio resource unit from the radio
resource group that corresponds to a range within which a
measurement indication received from the user equipment falls.
42. A control unit as claimed in claim 33, wherein the control unit
is implemented as an integrated circuit.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to telecommunications and more
particularly to radio resource allocation in cellular communication
systems.
BACKGROUND OF THE INVENTION
[0002] A cellular network is a radio network made up of a number of
radio cells each served by a transceiver, known as a cell site or
base station. Cellular networks are inherently asymmetric such that
a set of fixed transceivers serve a cell and a set of distributed
mobile transceivers provide services to the users.
[0003] A cellular network is able to provide more transmission
capacity than a single transmitter network because a radio
frequency of a cell can be reused in another cell for different
transmission. Frequency reuse, however, causes interference between
cells that use the same and nearby frequencies.
[0004] This inter-cell interference has conventionally been solved
by co-ordination/planning based methods. An example of such methods
is frequency reuse where different groups of radio channels may be
assigned to adjacent cells, and the same groups are assigned to
cells separated by a certain distance (reuse distance) to reduce
co-channel interference. The method is relatively effective and
straightforward, but wastes channel resource.
[0005] Another alternative is provided by co-ordination/planning
based methods that comprise use of dynamic channels temporarily
assigned for use in cells for the duration of the call, returned
and kept in a central pool after the call is over. In some other
dynamic solutions the total number of channels is divided into two
groups, one of which is used for fixed allocation to the cells,
while the other is kept as a central poor to be shared by all
users. The reuse factor of these methods still remains low,
actually in heavy traffic load they may perform worse than the
above disclosed fixed channel assignment method.
[0006] In the new emerging systems, for example in the upcoming
evolution of 3rd Generation Partnership Project (3GPP) systems
(also called as Long Term Evolution (LTE) systems), the
requirements, according to the working assumptions, are
challenging. The planned frequency reuse factor is 1, and at the
same time significantly improved system performance, in terms or
average throughput and cell throughput is targeted. In order to
meet these challenges, mitigation of inter-cell interference is now
extensively studied.
[0007] The approaches considered in inter-cell interference
mitigation comprise inter-cell-interference
co-ordination/avoidance. The common theme of
inter-cell-interference co-ordination/avoidance is to apply
restrictions to the resource management (configuration for the
common channels and scheduling for the non common channels) in a
coordinated way between cells. Such restrictions in a cell will
provide the possibility for improvement in (Signal-to-Interference
Ratio) SIR, and cell-edge data-rates/coverage, on the corresponding
time/frequency resources in a neighbor cell.
[0008] The available inter-cell interference co-ordination methods
require certain inter-communication between different network nodes
in order to set and reconfigure the above mentioned restrictions.
However, links between cells are expensive and typically cause
delays. Thus, for the time being it seems that reconfiguration of
the restrictions will be done on a time scale corresponding to
days, and the inter-node communication is going to be very limited,
basically with a rate of in the order of days. In such scenarios
mechanisms that do not rely on inter-cell co-ordination are
critically needed.
SUMMARY OF THE INVENTION
[0009] An object of the present invention to provide a solution
that enables mitigation of inter-cell interference in a cellular
communication system where capacity and system performance
requirements are high, and inter-communication of physical layer
information between different network nodes is limited. The objects
of the invention are achieved by a radio resource allocation
method, a cellular communication system, user equipment, a control
unit, a network infrastructure element, a computer program product
and a computer program distribution medium, which are characterized
by what is stated in the independent claims. The preferred
embodiments of the invention are disclosed in the dependent
claims.
[0010] The invention is based on the idea that radio resource of
cells in the communication system are divided into more than one
radio resource groups. User equipment are then allocated a radio
resource from one of the radio resource groups on the basis of the
determined interference to be generated to the defined group of
neighbouring cells.
[0011] An advantage of the invention is that the inter-cell
interference decreases and the throughput of the cellular system
increases, but the exchange of physical layer information is not
increased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the following the invention will be described in greater
detail by means of preferred embodiments with reference to the
attached drawings, in which:
[0013] FIG. 1 illustrates a simplified example of a mobile
communications system;
[0014] FIG. 2 illustrates the central elements of the embodiment of
FIG. 1;
[0015] FIG. 3 illustrates the radio resource of a cell in the
embodiment of FIG. 2;
[0016] FIG. 4 illustrates the steps of the improved radio resource
allocation method;
[0017] FIG. 5 illustrates the step of determining the interference
from the point of view of the user equipment;
[0018] FIG. 6 illustrates the step of determining the interference
in the embodied radio resource allocation method from the point of
view of the network infrastructure element;
[0019] FIGS. 7A and 7B show a basic timeslot structure for uplink
data transmission;
[0020] FIG. 8 illustrates a schematic representation of a network
configuration in a cellular communication system;
[0021] FIG. 9 illustrates the steps of another embodied radio
resource allocation method;
[0022] FIG. 10 illustrates a procedure for implementing a step in
the embodied radio resource allocation method of FIG. 9; and
[0023] FIG. 11 illustrates a step 93 determining the interference
in the embodied radio resource allocation method.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The following embodiments are exemplary implementations of
the present invention. Although the specification may refer to
"an", "one", or "some" embodiment(s), reference is not necessarily
made to and/or a described feature does not apply to only one
particular embodiment only. Single features of different
embodiments of this specification may be combined to provide
further embodiments that are thus considered to belong to the scope
of protection.
[0025] FIG. 1 illustrates a simplified example of a cellular
communications system to which the present solution may be applied.
The system of FIG. 1 is a mobile communication system that
comprises a number of wireless access points through which users
may connect to the network and thus utilize the communication
services of the system. In the following, the invention is
described with base station cells of a mobile communications
system, where the access point may change when users are moving
within the service area of the systems. It should be noted,
however, that the solution may be applied in interference control
of any access point, notwithstanding whether part of the same or
different system as the potentially interfering access points.
[0026] A mobile network infrastructure may be logically divided
into core network (CN) 10 and radio access network (RAN) 11
infrastructures. The core network 10 is a combination of exchanges
and basic transmission equipment, which together provide the basis
for network services. The radio access network 11 provides mobile
access to a number of core networks of both mobile and fixed
origin.
[0027] Based on the cellular concept, in RAN a large area is
divided into a number of sub-areas called cells. Each cell has its
own base station 12, which is able to provide a radio link for a
number of simultaneous users by emitting a controlled low-level
transmitted signal. In present mobile communications systems RAN
typically comprises a separate controlling network element 13,
which manages the use and integrity of the radio resources of a
group of one or more base stations. However, the scope covers also
systems without such separate physical element, for example systems
where at least part of the radio network control functions are
implemented in the individual base stations.
[0028] A user accesses the services of the mobile communication
system with user equipment 14 that provides required functionality
to communicate over a radio interface defined for the radio access
network 11.
[0029] FIG. 2 illustrates in more detail the central elements used
in implementing the embodiment of FIG. 1. As described above, a
base station is in control of defined (static or dynamic) radio
resources, and users communicate with the network infrastructure
using a particular radio resource of at least one base station,
typically the base station in the coverage area of which the users
presently resides.
[0030] A mobile communication system utilizes a predefined channel
structure, according to the offered communication services. A
typical example of a channel structure is a three-tier channel
organization where topmost logical channels relate to the type of
information to be transmitted, transport channels relate to the way
the logical channels are to be transmitted, and the physical
channels provide the transmission media through which the
information is actually transferred. In this context the role of a
base station is to implement radio access physical channels and
transfer information from transport channels to the physical
channels according to predefined radio network control
functions.
[0031] Part of the physical channel resource of a cell is typically
reserved for some particular use, for example for transport
channels that are common for all user equipment in the cell, and
those used for initial access. Part of the physical channel
resource of a cell may, on the other hand, be allocated dynamically
for traffic. FIG. 2 shows elementary configurations for the system
elements involved in allocating physical channels for user
equipment.
[0032] User equipment 14 of the mobile communications system can be
a simplified terminal for speech only or a terminal for diverse
services. In the latter case the terminal acts as a service
platform and supports loading and execution of various functions
related to the services. User equipment typically comprises mobile
equipment and a subscriber identity module. The subscriber identity
module is typically a smart card, often a detachably connected
identification card, that holds the subscriber identity, performs
authentication algorithms, and stores authentication and encryption
keys and other subscription information that is needed at the
mobile station. The mobile equipment may be any equipment capable
of communicating in a mobile communication system or a combination
of several pieces of equipment, for instance a multimedia computer
to which a card phone has been connected to provide a mobile
connection. In this context, the user equipment thus refers to an
entity formed by the subscriber identity module and the actual
mobile equipment.
[0033] A network infrastructure element 216 of FIG. 2 is any entity
comprising the functions that control use of radio resources of at
least one cell in the mobile communication system. In the context
of the embodiment of FIG. 1, the network infrastructure element 212
may be a base station, or a separate base station control
element.
[0034] The network infrastructure element 216 comprises processing
unit 218, an element that comprises an arithmetic logic unit, a
number of special registers and control circuits. Connected to the
processing unit is a memory unit 220, a data medium where
computer-readable data or programs or user data can be stored. The
memory unit typically comprises memory units that allow both
reading and writing (RAM), and memory units whose contents can only
be read (ROM). The network infrastructure element also comprises an
interface unit 222 with input unit 224 for inputting data from
other network infrastructure elements, for internal processing in
the network infrastructure element, and output unit 226 for
outputting data from the internal processes of the network
infrastructure element to the other network infrastructure
elements. Examples of elements of said input unit comprise network
interfaces, generally known to a person skilled in the art.
[0035] The network infrastructure unit also comprises a transceiver
unit 228 configured with receiving unit 230 for receiving
information from the air interface and for inputting the received
information to the processing means 218, as well as with
transmitting unit 232 for receiving information from the processing
means 218, and processing it for sending via the air interface. The
implementation of such a transceiver unit is generally known to a
person skilled in the art. The processing unit 218, memory unit
220, the interface unit 222, and the transceiver unit 228 of the
network infrastructure element are electrically interconnected for
performing systematic execution of operations on the received
and/or stored data according to predefined, essentially programmed
processes of the unit. In systematic execution of the operations
the processing unit 218 acts a control unit that may be implemented
as a single integrated circuit, or a combination or two or more
functionally combined integrated circuits. In a solution according
to the invention, the operations comprise the functionality of the
network infrastructure element as described with FIGS. 4 and 6.
[0036] User equipment of FIG. 2 comprises a processing unit 200,
and a memory unit 202. The user equipment also comprises a user
interface unit 204 with input unit 206 for inputting data by the
user for internal processing in the unit, and output unit 208 for
outputting user data from the internal processes of the unit.
Examples of said input unit comprise a keypad, or a touch screen, a
microphone, or the like. Examples of said output unit comprise a
screen, a touch screen, a loudspeaker, or the like.
[0037] The user equipment also comprises a radio communication unit
210 configured with a receiver 212 for receiving information from
the radio access network 11 over the air interface and processing
it for inputting to the processing unit 200, as well as a
transmitter 214 for receiving information from the processing unit
200, for further processing and transmitting the information via
the air interface to the radio access network 11. The processing
unit 200, the memory unit 202, the user interface unit 204, and the
radio communication unit 210 are electrically interconnected for
performing systematic execution of operations on the received
and/or stored data according to predefined, essentially programmed
processes of the user equipment. In a solution according to the
invention, the operations comprise the functionality of the user
equipment as described with FIGS. 4 and 5.
[0038] In the embodiment of FIG. 2, the radio resource of each cell
exists in the form of frequency band, and is divided into radio
resource units in form of physical channels. A physical channel 234
is typically defined by its carrier frequency, and one or more
parameters according to the selected multiple access scheme. For
example, a physical channel of wideband code division multiple
access (WCDMA) scheme is defined by its carrier frequency,
channelisation code (CDMA) and relative phase for the uplink
connection. In time division multiple access (TDMA) a radio
frequency is divided into time slots and a physical channel
corresponds to one or more time slots. In frequency division
multiple access (FDMA) technique in which each user receives a
radio channel of its own on a common frequency band. In the
emerging systems, these basic forms of multiple access schemes are
combined into more and more sophisticated schemes to meet the key
performance and capability targets for rational long-term
evolution. For example, in the upcoming evolution of 3rd Generation
Partnership Project (3GPP) LTE systems, a potential candidate for
uplink is single carrier FDMA (SC-FDMA). During channel allocation
a dedicated channel in form of unique combination of transmission
parameters defining a radio resource is agreed between the network
infrastructure element and the user equipment so that information
streams to and from the user equipment can be differentiated in the
air interface.
[0039] For mobility management purposes, when the user moves within
the coverage area of the system, user equipment 14 continuously
receives and transmits signals using the undedicated physical
channels arranged into the system. When there is user data to be
transmitted to or from the user equipment, a dedicated radio
resource, as described above, needs to be allocated to the task.
Allocation is typically performed through a predefined signaling
procedure, which takes place between the user equipment 14, and the
network infrastructure element 216 that controls the radio resource
from which the allocation is to be made. Basic channel allocation
procedures are widely documented, and well known to a person
skilled in the art, and therefore not described in more detail
herein. As a result of the channel allocation, a unique radio
resource is allocated to the user equipment, and the network
infrastructure and the user equipment begin to transmit and receive
using the transmission parameters that define the allocated radio
resource.
[0040] FIG. 3 illustrates the radio resource of a cell in an
embodiment of FIG. 2. The radio resource corresponds to a
continuous set of frequencies F lying between two specified
limiting frequencies f.sub.min and f.sub.max. The set of
frequencies F forms a frequency band 30. The carrier frequency of
the frequency unit increases towards the limiting frequency
f.sub.max. According to the invention, the frequency band 30 is
divided into more than one frequency groups 32, 33, 34, 35, 36,
wherein each frequency group comprises one or more radio resource
units 31. As described above, a radio resource unit 31 may
correspond to a carrier frequency, timeslot, spread spectrum code,
or any other combination of transmission parameters that may be
separately allocated to users, depending on the selected multiple
access scheme. For simple graphical illustration, the exemplary
frequency groups 32, 33, 34, 35, 36 of FIG. 3 are shown as
comprised of one or more adjacent radio frequency carriers. It is
clear that the radio resource groups according to the invention may
comprise any logical combination of a number of related radio
resource units that for a purpose can be dealt with as an entity.
For example, a radio resource group can consist of a number of (for
example 2-4) physical radio resource units that may, or may not
reside next to each other in the frequency domain.
[0041] As will be described in the following, user equipment
requiring dedicated transmission capacity will be allocated a radio
resource from the radio resource group in the serving cell, and the
radio resource group will be selected on the basis of interference
to be generated by the user equipment to the surrounding cells.
[0042] FIG. 4 illustrates the steps of the embodied radio resource
allocation method according to the invention, applied to the
embodied system described in FIGS. 1, 2, and 3. As discussed above,
the radio resource of a plurality of cells is first divided (step
41) into more than one radio resource groups.
[0043] Radio resource allocation begins when the network
infrastructure element 216 detects (step 42) a need for dedicated
or shared radio resource of the cell 12 for the user equipment 14.
Such may happen, for example, when the user of user equipment 14
initiates a call or a session, at handover procedures, where the
user equipment moves from one cell to another, and at setup of user
equipment terminated call or session. In the following, the case of
radio resource request by the user equipment is described as an
example.
[0044] The radio resource request inherently or explicitly
specifies transmission characteristics of the required radio
resource. Advanced cellular communications systems may employ
several data modulation schemes (e.g. quadrature phase shift keying
(QPSK) and quadrature amplitude modulation (QAM)) to transfer data
with variable data rates. Additionally, several coding schemes may
also be implemented with different effective code rates (ECR). In
the radio resource request, the user equipment specifies the
required data modulation schemes and code rates it uses. These
transmission characteristics of the requested radio resource are
typically specific to the user equipment and vary, for example,
according to the supported data modulation and coding scheme
supported by the user equipment. However, if the user equipment can
support more than one data modulation and coding schemes, the
transmission characteristics of the requested radio resource may
even vary according to the communication instance, and the data
modulation and coding scheme combination chosen for the
instance.
[0045] When a radio resource request reaches the network
infrastructure element, the network infrastructure element analyses
from the request the relevant transmission characteristics, and if
possible allocates a radio resource that corresponds to the
transmission characteristics, rejects the request, or initiates a
signalling procedure to re-negotiate with the user equipment new,
achievable characteristics.
[0046] According to the invention, channel allocation is adjusted
to take into consideration the interference to be generated by the
requested radio resource to a defined group of neighbouring cells.
The interference is determined (step 43) in the network
infrastructure element on the basis of information on the
transmission paths to the defined group of neighbouring cells,
provided by the user equipment.
[0047] FIG. 5 illustrates the step 43 of determining the
interference in the embodied radio resource allocation method from
the point of view of the user equipment 14. In general terms, the
user equipment acquires the required information on the
transmission paths to the defined group of neighbouring cells, and
provides this information to the network infrastructure to be used
in channel allocation decisions. More specifically, for handover
purposes the user equipment continuously collects measurement data
m.sub.k, k=1, . . . , K, that provides basis for computing the
properties of the transmission paths to a selected group of
neighbouring cells (step 51). Here m denotes measurement data
element, k denotes the identity of a cell, and K the number of
cells in the selected group of cells.
[0048] Within the scope of protection, the selection of the group
can be implemented in various ways. For example, the handover
procedures utilize groups to which cells are classified according
to the pilot signal of the radio link. As an example, an active set
comprises cells that form a soft handover connection to the mobile
station, a candidate set comprises cells that are not presently
used in the soft handover connection, but whose pilot signals are
strong enough to be added to the active set, and a neighbour set or
monitored set is the list of cells that the user equipment
continuously measures, but whose pilot signals are not strong
enough to be added to the active set. The selection of the group
can thus be a dynamic decision based on signal levels, for example,
as in any of the above groups, or a static definition based on some
other criteria, for example, geometric locations of the user
equipment, etc.
[0049] The conventional measurement types comprise, for example,
intra-frequency measurements, inter-frequency measurements,
inter-system-measurements, traffic volume measurements, quality
measurements and internal measurements of the user equipment
transmission power and user equipment received signal level. In the
emerging systems, some new measurement types may also be applied.
The measurement events may be triggered based on several criteria,
for example at change of best cell, change in defined pilot channel
signal level, changes in the signal-to-noise (SIR) level,
periodically, etc. Through these measurement procedures, the user
equipment has a substantial basis for estimating the
characteristics of the transmission paths to the selected group of
surrounding cells.
[0050] According to the invention, the user equipment generates
(step 52) from the measurement data m.sub.k a plurality of
measurement indications M.sub.k that represent properties of the
transmission paths to the k=1, . . . , K cells of the selected
group, and thus serve as a basis for estimating interference to be
generated to the selected group of cells by a particular radio
resource of a user equipment. Depending on the complexity of the
computations, and the processing capacity of the user equipment,
the measurement indications M.sub.k may be simple measurement data
to be forwarded to the network side for further processing, or more
or less computed values directly applicable for further analysis.
In the embodied solution, the measurement indication M.sub.k by the
user equipment comprises advantageously values of measured path
loss to the cells in the active group.
[0051] The user equipment sends (step 53) the measurement
indications M.sub.k of all the cells in the selected group of K
cells to the controlling network infrastructure element such that
they are available in the network infrastructure element at least
at the time of the radio resource allocation. Transfer of
measurement indication events can be triggered in line with some
other measurement events, or be based on a separate scheme, for
example take place periodically or at the time of connection
setup.
[0052] Correspondingly, FIG. 6 illustrates the step 43 of
determining the interference in the embodied radio resource
allocation method from the point of view of the network
infrastructure element 216. In general terms, the network
infrastructure element receives the information on the transmission
paths to the defined group of neighbouring cells from the user
equipment, and uses this information to select an appropriate radio
resource group for the user equipment. More specifically, the
network infrastructure element NIE.sub.j receives (61) measurement
indication values M.sub.k from the user equipment. On the basis of
the measurement indication values M.sub.k, the network
infrastructure element computes (step 62) one or more interference
values I.sub.j,k that represent the effective interference to be
incurred by the requested radio resource to the selected group of
neighbouring cells. Effective interference relates herein to the
interference that is considered relevant for the radio resource
allocation and is associated with a particular computing method.
Several different measurement indications are applicable. In the
presently embodied example, the network infrastructure element
NIE.sub.j receives from the user equipment the computed path loss
values p.sub.k for the transmission path between the user equipment
and the cells in its active group, and computes effective
interference I.sub.j, K as total interference to the active group
by the equation
I j = k = 1 k .noteq. j K p k ##EQU00001##
[0053] where j is the index of the own cell, p.sub.k is the
measured path loss to the kth cell, and K is the number of cells in
the active set. Other computing methods, for example, weighted
averages or the like are possible within the scope of
protection.
[0054] In another embodiment of the invention, the network
infrastructure element NIE.sub.j computes the effective
interference I.sub.j, K on the basis of the Channel Quality
Indicator (CQI) values, received from the user equipment. The CQI
reporting concept is basically a concept for the downlink, and the
user equipment is configured to measure CQI to be able to provide
to the base station a metric, which indicates the current
experienced channel quality. User equipment may, for example,
suggest a radio resource transmission configuration that it needs
to support while observing a certain block error probability.
Different receiver implementations typically offer a different
mapping between SINR and sustained throughput. A good downlink
channel indicated by the CQI measurements of the user equipment
means lower path loss and transmission power, and accordingly
corresponds with lower interference to the selected group of
neighboring cells. The user equipment generates measurement
indications M.sub.k in form of CQI measurements, which in this
embodiment serve as a basis for estimating interference to be
generated to the selected group of cells by a particular radio
resource of user equipment. The effective interference I.sub.j, K
to be incurred by the radio resource associated with the user
equipment to the selected group of neighbouring cells can be
determined on the basis of the CQI values of the user equipment
directly or through simple correlation.
[0055] According to the invention, the users are arranged into
different radio resource groups by allocating their radio resources
according to a computed value that represent interference to be
generated to defined neighbouring cells. Users whose requested
radio resource is estimated to generate a similar interference to
the surrounding cells, will be allocated to the same radio resource
groups. Accordingly, based on the computed total interference
I.sub.j, K the embodied network infrastructure element selects
(step 44) a radio resource group f.sub.K from which the radio
resource is to be allocated. In the embodied case, each of the
frequency groups 32, 33, 34, 35, 36 of the frequency band 30
correspond to a defined range of total interference values. The
computation of the total interference provides a value I.sub.j, K,
for the interference. A corresponding frequency group may
determined by comparing the value I.sub.j, K, to the ranges, and
choosing the frequency group in the range of which the value exits.
The channel allocation may then be made from the determined
frequency group. Channel allocation within a frequency group may be
made using a selected multiple access scheme, for example, FDMA,
CDMA, TDMA, etc., and the channel may utilize one or more radio
resource units of the frequency group.
[0056] Through the invented mechanism, a plurality of user
equipment that cause similar interference to relevant neighbouring
cells becomes automatically arranged to the same frequency group.
The power control of the user equipment classified to frequency
groups as described above can then managed separately, which gives
rise to several advantages.
[0057] Cellular systems typically comprise a mechanism by which a
network infrastructure element, like a base station, can command
user equipment to increase or decrease the uplink transmission
power. The comparison involving the received power is based on a
predefined measurement parameter, for example,
signal-to-interference ratio (SIR), signal-to-noise ratio, signal
strength, Frame Error Ratio (FER) and Bit Error Ratio (BER). The
base station receives the user equipment signal, estimates a
pre-defined parameter, for example, signal-to-noise-power ratio
and/or signal-to-interference-power ratio, compares the estimated
value with a pre-defined threshold value and, when necessary, sends
a transmission power command to the user equipment to increase or
decrease its signal power.
[0058] When physical layer information of several cells is
available to a controlling network element, the network
infrastructure element is able to co-ordinate the allowed power
levels of the cells and target SIRs to be used by the base
stations. When exchange of physical layer information between base
stations is limited, only methods that apply pre-defined control
procedures and levels are practically possible. In addition, the
size of cells in mobile communications systems varies considerably,
which means that also the dynamic range for transmission path
measurements, for example path loss measurements varies
accordingly. With large and moderate cell sizes the dynamic range
is adequate, and measurements of the transmission path within the
own cell, and arranging users in frequency groups accordingly would
already be enough to provide the increased performance. However,
with smaller size cells the dynamic range for, for example, path
loss measurements becomes correspondingly smaller, and the
granularity of the path loss measurements within the own cell may
in some cases be deficient. The full effect of the information
received from the user equipment is achieved by utilizing
information on the plurality of transmission paths to the
neighbouring cells.
[0059] In a typical environment, signals transmitted from user
terminals located close to a base station are expected to induce a
smaller interference to the neighbouring cells and signals
transmitted from user terminals distant to a base station (i.e.
located at the edge of a cell) a more significant interference.
User terminals located at the edge of the cell are likely to be
allocated to the same subgroup and the user terminals located close
to the base station to the same subgroup, which means that the
negative effect of "near-far" problem is reduced.
[0060] In addition, the classification is based, not only on the
path loss in the own cell, but on information or estimates on a
comprehensive amount of radio links to the surrounding cells and is
therefore more accurate and thus effective, even with smaller cell
sizes. The reduced interference results in increased overall
performance and system capacity.
[0061] In the embodied example, the base station receives the user
equipment signal, estimates a pre-defined parameter, for example,
signal-to-noise-power ratio and/or signal-to-interference-power
ratio, compares the estimated value with a pre-defined threshold
value and, when necessary, sends a transmission power command to
the user equipment to increase or decrease its signal power.
According to the invention, the system may set (step 45) a
different target value for each radio resource group such that high
signal-to-noise-power ratio and/or signal-to-interference-power
ratio can be used in radio resource groups where user equipment
generate only moderate interference to the other cells.
Correspondingly, in the radio resource groups where interference to
the other cells is considerable, lower signal-to-noise-power ratio
and/or signal-to-interference-power ratio needs to be used. When
the power is adjusted (step 46) according to the improved method,
the user equipment that generates moderate interference may be
commanded to use higher transmission power and thus achieve higher
throughput, while the transmission power of the more interfering
user equipment can be effectively controlled at the same time. Use
of similar classification criteria in all the cells results in
increased throughput rates and higher overall performance of the
system.
[0062] In another exemplary embodiment, the radio resource unit
separately allocatable to a user corresponds to a resource block in
time and frequency domain, further divisioned by means of
block-level spreading codes. As an example of such code divisional
multiple (CDM) access scheme, block-wise spreading using Hadamard
codes is discussed in more detail.
[0063] The basic uplink transmission scheme of SC-FDMA is
single-carrier transmission with cyclic prefix to achieve uplink
inter-user orthogonality and to enable efficient frequency-domain
equalization at the receiver side. Frequency-domain generation of
the signal, sometimes known as DFT-spread OFDM (Discrete Fourier
Transform-spread Orthogonal Frequency Division Multiplexing), is
assumed. FIGS. 7A and 7B show a basic timeslot structure for uplink
data transmission.
[0064] FIG. 7A illustrates a basic structure of a timeslot 70 in
the time and frequency domain in the SC-FDMA basic transmission
scheme. The channel-coded, interleaved, and data-modulated
information is mapped onto SC-FDMA time/frequency symbols. The
overall SC-FDMA time/frequency resource symbols can be organized
into a number of resource units (RU). Each RU consists of a number
of consecutive or non-consecutive sub-carriers within one timeslot.
The timeslot 70 corresponds to a cyclic time interval that can be
recognized and defined uniquely.
[0065] FIG. 7B illustrates the concept of block-wise spreading,
applied on top of the SC-FDMA basic transmission scheme. In the
example of FIG. 7B, the basic timeslot comprises seven separate
blocks for control and/or data transmission. At least one of the
blocks is used as a reference signal. Three blocks (LB#1 and LB#4
and LB#7) are used for pilot transmission. This is due to the fact
that when spreading is applied, the operation point in terms of SNR
decreases. The arrangement aims to increase pilot energy and that
way optimize link performance in spreading. In addition, with
increased amount of pilot symbols it is possible to generate more
orthogonal pilot signals. It should be noted that the data
transmission may include either or both of scheduled data
transmission and contention based data transmission.
[0066] In block-wise spreading, the overall SC-FDMA time/frequency
symbols are organized into a number of radio resource units. Each
radio resource unit basically corresponds to a number of symbols
during a block LB# within one timeslot. In the present embodiment,
as shown in FIG. 7B, before entering the basic DFT-s-OFDM
transmission 72, the coded symbol sequences S.sub.1, S.sub.2, . . .
, S.sub.N undergo a block-wise spreading 71 using Hadamard codes of
length four.
[0067] Thus, for example, an allocation of a single physical
resource block provides four orthogonal resources in 180 kHz
frequency band, each with a symbol rate of 24 ks/s. Each radio
resource unit is capable to convey 24 information bits assuming
quadrature phase shift keying (QPSK) with effective coding rate of
1/2 and Transmission Time Interval (TTI) of 1 ms.
[0068] In TDM/FDM/CDM radio a resource unit is thus separable unit
in time and frequency domain, divisioned by a channelization code
that comprises one or more spreading codes of one or more type.
Separable in this context refers to the fact that two radio
resource units with different positions in the code domain are
different, even if other factors identifying the radio resource
units are the same. A position of a radio resource block in the
time or frequency domain does not need to be singular, for example
a radio resource unit may comprise a number of consecutive long
blocks or consecutive or non-consecutive subcarriers. In the
present embodiment a radio resource unit corresponds to a physical
resource block in a defined time and frequency divisioned by means
of Hadamard spreading code. The channelization code in this context
thus comprises a Hadamard spreading code applied block-wise to the
coded sequence of symbols.
[0069] In interference considerations, maintaining orthogonality of
the code channels is of importance. However, user equipment that
apply the same code channels in different cells are inherently
non-orthogonal. In order to control interference for the
transmissions, allocations of radio resource units need to be
implemented in a coordinated manner such that the effective
interference due to the user equipment in any of the neighboring
cells is minimized. Furthermore, as discussed above, there should
be an opportunity to enable this without relying on additional
signaling, or only on limited amount of additional signaling
between the base stations.
[0070] According to the invention, such coordination may be
implemented by means of grouping available radio resource units of
cells, associating each group with a spreading code and an
interference criterion, mapping the interference state of the
transmission path reported by user equipment to the interference
criterion, and allocating a radio resource unit from a group
associated with the interference criterion. As an example of such
arrangement, allocations of radio resource units whose
configuration was illustrated in FIG. 7 are described in more
detail.
[0071] As an exemplary embodiment, FIG. 8 illustrates a schematic
representation of a network configuration in a cellular
communication system. The system comprises 57 cells formed by base
station sectors BS.sub.n, n=1, . . . 57 in 19 base station sites
S.sub.m, m=1, . . . , 19. Each base station site comprises three
base station sectors, the transceivers of each of the base station
sectors co-locating in the central cross-point of the cellular
coverage areas. Base station sites S.sub.m, m=1, . . . , 19 are
divided into three classes of Type A, Type B, Type C in a following
way:
TABLE-US-00001 Sites, type A S1 BS1 BS2 BS3 S8 BS15 BS30 BS31 S10
BS17 BS34 BS35 S12 BS20 BS37 BS38 S14 BS22 BS41 BS42 S16 BS25 BS44
BS45 S18 BS27 BS28 BS48 Sites, type B S2 BS4 BS13 BS14 S4 BS7 BS9
BS19 S6 BS10 BS23 BS24 S9 BS32 BS33 BS51 S13 BS39 BS40 BS54 S17
BS46 BS47 BS57 Sites, type C S3 BS5 BS6 BS16 S5 BS8 BS9 BS21 S7
BS11 BS12 BS26 S11 BS36 BS52 BS53 S15 BS43 BS55 BS56 S19 BS29 BS49
BS50
[0072] According to the invention, each of the cells provides a
radio resource comprised of a number of separately allocatable
radio resource units. In the present embodiment, such radio
resource units correspond to a physical resource block allocation
divisioned by means of Hadamard spreading codes. In the example of
FIG. 8, order four Hadamard codes are used, such that each row of
matrix W corresponds with a spreading code C.sub.i.
W = [ 1 1 1 1 1 - 1 1 - 1 1 1 - 1 - 1 1 - 1 - 1 1 ] = [ C 1 C 2 C 3
C 4 ] ##EQU00002##
[0073] In any of the cells BS.sub.n, n=1, . . . 57, radio resource
units with the same spreading code form a radio resource group. In
the embodiment of FIG. 8, three different radio resource groups G1,
G2, G3 are used. This means that three spreading codes, for
example, [0074] C1:[1 1 1 1] [0075] C2:[1-1 1-1] [0076] C3:[1
1-1-1] from matrix W are utilized, and each of the group
corresponds with one radio resource group. For example in site S1
of type A, base station sector BS1 is configured with three radio
resource groups G1, G2, G3 and the radio resource groups correspond
with spreading codes as follows: [0077] C1:=:G1 [0078] C2:=:G2
[0079] C3:=:G3.
[0080] Each of the groups of base station sector BS1 is also
associated with a range of measurement indication values as follows
[0081] G1:=:{range1} [0082] G2:=:{range2} [0083] G3:=:{range3}.
[0084] In operation the transceiver of the base station sector BS1
receives measurement indication from user equipment UE1 80 located
in the edge of cell of base station sector BS1. BS1 checks to which
of the ranges {range1}, {range2}, {range3} the measurement
indication value falls, and selects the radio resource unit for
allocation from the corresponding group G1, G2, G3.
[0085] The measurement indication in this embodiment provides
information from the transmission path between the user equipment
that generated the measurement indication and the transceiver of
the current base station sector. Exemplary parameters applicable
for use as the measurement indication in this embodiment comprise
path loss, channel quality indicator (CQI), signal-to-noise ratio
(SNR), and signal-to-interference ratio (SINR). Other similar
parameters may naturally be applied without deviating from the
scope of protection.
[0086] Considering the current example utilizing path loss
determination, the base station derives from the received
measurement indication, either directly or through calculation, a
path loss value that corresponds with one of the ranges {range 1}
applied in the base station sector BS1. BS1 allocates radio
resource units to the user equipment according to this path loss
classification, which results in that user equipment in sectors of
equal distance from the transceiver of the base station site have
the same spreading code allocated.
[0087] According to the invention, in the current embodiment all
base station sectors BS1, BS2, BS3 within one base station site S1
apply the same set of codes, ranges and groups, and the
correspondence between groups and codes and between groups and
ranges is the same. The effective interference to be generated to
the neighbouring cells is determined by considering the
orthogonality between transmissions of the user equipment for which
the radio resource allocation is to be made and of user equipment
locating in any of the neighboring cells. The defined group of
neighboring cells used as a basis for interference considerations
in this embodiment may comprise all cells neighboring the cell that
is currently allocating the radio resource unit.
[0088] The orthogonality between user equipment that apply the same
block-level spreading code is improved by a coordinated allocation
scheme that aims to maximize the spatial distance between such user
equipment. In the present embodiment this is achieved by
configuring the cells such that in Type A sites S1, S8, S10, S12,
S14, S16, S18, in Type B sites 2, 4, 6, 9, 13, 17, and in Type C
sites S3, S5, S7, S11, S15, the same set of codes, ranges and
groups are applied, but the correspondence between groups and codes
and/or between groups and ranges in each of the Type A, B or C
sites is arranged to be different. This results in situation
illustrated in FIG. 8 by different sizes of circles over the cells.
The relative distance of user equipment using the same spreading
code is illustrated by the size of the circle. It may be seen that
by changing the mapping between the groups and ranges or between
the groups and spreading codes, the spatial distance between user
equipment that use the same spreading code in neighboring cells may
be maximized. This provides favorable interference conditions,
which is especially critical to the user equipment located at the
cell edges.
[0089] It is also appreciated that as far as timing of different
code channels is within cyclic prefix duration, different code
channels are substantially orthogonal. The orthogonality starts to
degrade gradually as the timing difference between the code
channels increases. Considering user equipment UE1 located in the
edge of cell of base station sector BS1, the dominant interferers
are also located at the cell edge and have similar propagation loss
values in respect of BS1 as user equipment UE1. While the grouping
in this embodiment is related to the propagation distance, in a
synchronized system the uplink timing is relatively similar for
user equipment UE1 and its dominant interferers. Also the physical
distance between user equipment UE1 and its dominant interferers is
relatively small. This means that timing differences between the
user equipment UE1 and its dominant interferers in relation to the
base station sector transceiver BS1 are typically within the cyclic
prefix duration and the code channels thus remain adequately
orthogonal.
[0090] For a person skilled in the art it is clear that the above
example may be varied in several ways without deviating from the
scope of protection. For example, the mapping between the ranges,
groups and codes may be arranged and changed in several ways. As an
example, any of the codes, the groups, and the ranges may be
arranged into a predefined order and mapped to the other
counterparts in that order, for example, by rotating the order to
begin from a different point for each of the base station site
classes. Furthermore, the principle may be implemented also when
the base station sites are not sectored; in such case the
application of same sets of ranges and groups is naturally
inherent.
[0091] FIG. 9 illustrates the steps of the presently embodied radio
resource allocation method according to the invention, applied to
the embodied system as described in FIGS. 1, 2, and 7. As discussed
above, the radio resource units in a cell is first divided (step
91) into more than one radio resource groups G1, G2, G3.
[0092] Radio resource allocation begins when the network
infrastructure element controlling the radio resource of the cell
detects (step 92) a need for dedicated or shared radio resource of
the cell for user equipment. When a request RR.sub.req for radio
resource reaches the network infrastructure element, the network
infrastructure element analyses relevant transmission
characteristics in the transmission path TP.sub.UE between the user
equipment and the transceiver of the cell. The transmission
characteristics may be determined, for example, from measurement
indications in the request or on the basis of earlier measurement
indications received from the user equipment. If possible the
network infrastructure element allocates a radio resource unit
rru.sub.i (step 94) according to a predefined allocation scheme,
rejects the request, or initiates a signalling procedure to
re-negotiate with the user equipment new, achievable
characteristics. In this embodiment the predefined allocation
scheme is adjusted to take into consideration the interference
between user equipment using the same channel code in neighbouring
cells. Thus in step 94, the radio resource unit rru.sub.i is
allocated from group G.sub.i that is selected on the basis of the
determined relevant transmission characteristics in the
transmission path TP.sub.UE between the user equipment and the
transceiver of the cell, as discussed in the context of FIG. 8.
[0093] FIG. 10 illustrates in more detail a procedure for
implementing step 93 in the embodied radio resource allocation
method of FIG. 9 from the point of view of the user equipment. In
general terms, the user equipment acquires the required information
on the transmission path in the current cell, and provides this
information to the network infrastructure to be used in channel
allocation decisions. More specifically, for handover purposes the
user equipment continuously collects measurement data s.sub.k, that
provides basis for computing the properties of the transmission
path in the current cell (step 101). According to the invention,
the user equipment generates (step 102) from the measurement data
s.sub.k a measurement indication S.sub.k that indicates properties
of the transmission paths to the current cell. Depending on the
complexity of the computations, and the processing capacity of the
user equipment, the measurement indication S.sub.k may be simple
measurement data to be forwarded to the network side for further
processing, or more or less computed values directly applicable for
further analysis. In the embodied solution, the measurement
indication S.sub.k by the user equipment comprises advantageously
values of measured path loss to the current cell.
[0094] The user equipment sends (step 103) the measurement
indications S.sub.k to the controlling network infrastructure
element such that it is available in the network infrastructure
element at least at the time of the radio resource allocation.
Transfer of measurement indication events can be triggered in line
with some other measurement events, or be based on a separate
scheme, for example take place periodically or at the time of
connection setup.
[0095] Correspondingly, FIG. 11 illustrates the step 93 of
determining the interference in the embodied radio resource
allocation method from the point of view of the network
infrastructure element. In general terms, the network
infrastructure element receives the information on the transmission
path to current cell, and uses this information to select an
appropriate radio resource group for the user equipment. More
specifically, the network infrastructure element NIE.sub.j receives
(111) a measurement indication value S.sub.k from the user
equipment. On the basis of the measurement indication value
S.sub.k, the network infrastructure element reads, derives or
computes (step 112) a comparison value CV.sub.k that represents the
propagation distance of the transmission path. The network
infrastructure element compares (step 113) the comparison value
CV.sub.k to a group of predefined ranges {range1}, {range2},
{range3} and checks within which range the comparison value falls.
On the basis of the range, the network infrastructure element
determines (step 114) the group G1, G2, G3 and allocates (step 115)
a radio resource unit for the transmissions from the user equipment
from that particular group.
[0096] In the above example, Hadarmard codes have been used to
illustrate the use of spreading codes and implementation of
block-level spreading. However, for a person skilled in the art it
is clear that also other types of the spreading codes may be
applied. For example, Hadamard codes may be used only when the
required length of the code is power of two. For other code
lengths, for example code length of three, for example
complex-valued GCL (Generalized Chirp Like) codes may be used.
[0097] Alternatively, a scheme using modulated Constant Amplitude
Zero AutoCorrelation (CAZAC) sequences enables multiplexing
different user equipment into a given time and frequency resource.
This is achieved by allocating different cyclic shifts of CAZAC
sequence for different user equipment. In sequence modulator a
CAZAC sequence is modulated using binary phase shift keying (BPSK),
quadrature phase shift keying (QPSK), or 8 phase shift keying
(8PSK). Each sequence carries 1 bit, 2 bits, or 3 bits, depending
on the applied modulation scheme. Here allocation of a physical
resource block provides at maximum 12 orthogonal resources in 180
kHz frequency band each having a symbol rate of 12 ks/s. This
assumes that 12 cyclic shifts of CAZAC codes are used by different
user equipment. The requirement for orthogonality between user
equipment is that the delay spread of the radio channel does not
exceed the length of the cyclic shifts.
[0098] It is cleat that other code types and related orthogonality
requirements may be applied without deviating from the scope of
protection.
[0099] An embodiment of the invention may be implemented as a
computer program comprising instructions for executing a computer
process for radio resource allocation of a cellular
telecommunication system. The computer program may be executed in
the processing unit 218 of the network infrastructure element 216.
The network infrastructure element 216 represents herein a logical
element the processes of which can be performed in the processing
unit of one network entity, or as a combination of processes
performed in the processing units of a base station, radio network
controller, or even some other elements (for example, servers,
router units, switches, etc) of the telecommunication unit.
[0100] The computer program may be stored on a computer program
distribution medium readable by a computer or a processor. The
computer program medium may be, for example but not limited to, an
electric, magnetic, optical, infrared or semiconductor system,
device or transmission medium. The medium may be a computer
readable medium, a program storage medium, a record medium, a
computer readable memory, a random access memory, an erasable
programmable read-only memory, a computer readable software
distribution package, a computer readable signal, a computer
readable telecommunications signal, and a computer readable
compressed software package.
[0101] Even though the invention has been described above with
reference to examples in conjunction with the accompanying
drawings, it is clear that the invention is not restricted thereto
but it can be modified in several ways within the scope of the
appended claims.
* * * * *