U.S. patent application number 14/574954 was filed with the patent office on 2015-04-16 for method and apparatus for triggering cell reselection based on a resource suspension.
The applicant listed for this patent is Broadcom Corporation. Invention is credited to Tao CHEN, Keiichi KUBOTA, Brian MARTIN.
Application Number | 20150105081 14/574954 |
Document ID | / |
Family ID | 47712999 |
Filed Date | 2015-04-16 |
United States Patent
Application |
20150105081 |
Kind Code |
A1 |
MARTIN; Brian ; et
al. |
April 16, 2015 |
Method And Apparatus For Triggering Cell Reselection Based On A
Resource Suspension
Abstract
A mobile communications device determines, while in a CELL_FACH
state, that uplink transmissions from the mobile communication
device are causing interference to a neighbor cell different from a
serving cell of the mobile communication device; and thereafter
modifies a network resource that may be causing the interference.
In specific non-limiting embodiments, the resource is an E-DCH and
the modifying is suspending or releasing the E-DCH; the
determination of interference is from received interference data
that indicates a level of the interference or from the device by
comparing one or more parameters against respective one or more
reselection criteria thresholds (e.g., transmit power and path
loss). In other non-limiting embodiments, when an amount of data
exceeds a predetermined threshold the E-DCH is suspended or
released, and the device reselects from the serving cell, prior to
transferring the data.
Inventors: |
MARTIN; Brian; (Surrey,
GB) ; KUBOTA; Keiichi; (Surrey, GB) ; CHEN;
Tao; (Salo, FI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Broadcom Corporation |
Irvine |
CA |
US |
|
|
Family ID: |
47712999 |
Appl. No.: |
14/574954 |
Filed: |
December 18, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13210201 |
Aug 15, 2011 |
8954074 |
|
|
14574954 |
|
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Current U.S.
Class: |
455/436 |
Current CPC
Class: |
H04W 36/20 20130101;
H04W 36/30 20130101 |
Class at
Publication: |
455/436 |
International
Class: |
H04W 36/30 20060101
H04W036/30 |
Claims
1. A method for operating a mobile communication device, the method
comprising: while the mobile communication device is operating in a
cell forward access channel (CELL_FACH) state, determining that
uplink transmissions from the mobile communication device are
causing interference to a neighbor cell different from a serving
cell of the mobile communication device; and modifying by the
mobile communication device a network resource that may be causing
the interference.
2. The method according to claim 1, wherein it is determined from
received interference data that the uplink transmissions are
causing interference to the neighbor cell, the received
interference data indicating a level of the interference.
3. The method according to claim 1, wherein the mobile
communication device determines that the uplink transmissions are
causing interference to the neighbor cell by comparing one or more
parameters against respective one or more reselection criteria
thresholds, the reselection criteria thresholds including at least
one of: transmit power of the uplink transmissions; and path loss
between the mobile communication device and the neighbor cell.
4. The method according to claim 1, wherein the network resource
comprises an enhanced dedicated channel (E-DCH) and the modifying
is selected from among suspending the E-DCH and releasing the
E-DCH.
5. The method according to claim 1, the method further comprising:
based on the suspended or released E-DCH, causing a reselection of
the mobile communication device from the serving cell.
6. The method according to claim 5, wherein: the E-DCH is suspended
or released based on, and the reselection of the mobile
communication device from the serving cell is based on, an amount
of data to be transmitted to and/or from the mobile communications
device exceeding an uplink buffer or other predetermined limit; and
the E-DCH is suspended or released, and the reselection of the
mobile communication device from the serving cell, occurs prior to
transmission of the data.
7. An apparatus for controlling a mobile communication device, the
apparatus comprising: at least one memory including computer
program code, and circuitry; where the at least one memory and the
computer program code is configured with the circuitry to cause the
mobile communication device at least to: while the mobile
communication device is operating in a cell forward access channel
(CELL_FACH) state, determine that uplink transmissions from the
mobile communication device are causing interference to a neighbor
cell different from a serving cell of the mobile communication
device; and modify by the mobile communication device a network
resource that may be causing the interference.
8. The apparatus according to claim 7, wherein it is determined
from received interference data that the uplink transmissions are
causing interference to the neighbor cell, the received
interference data indicating a level of the interference.
9. The apparatus according to claim 7, wherein the mobile
communication device determines that the uplink transmissions are
causing interference to the neighbor cell by comparing one or more
parameters against respective one or more reselection criteria
thresholds, the reselection criteria thresholds including at least
one of: transmit power of the uplink transmissions; and path loss
between the mobile communication device and the neighbor cell.
10. The apparatus according to claim 7, wherein the network
resource comprises an enhanced dedicated channel (E-DCH) and the
modifying is selected from among suspending the E-DCH and releasing
the E-DCH.
11. The apparatus according to claim 7, the method further
comprising: based on the suspended or released E-DCH, causing a
reselection of the mobile communication device from the serving
cell.
12. The apparatus according to claim 11, wherein the E-DCH is
suspended or released based on, and the reselection of the mobile
communication device from the serving cell is based on, an amount
of data to be transmitted to and/or from the mobile communications
device exceeding an uplink buffer or other predetermined limit.
13. The apparatus according to claim 12; wherein: the E-DCH is
suspended or released, and the reselection of the mobile
communication device from the serving cell, occurs prior to
transmission of the data.
14. A non-transitory computer readable memory on which is stored
computer readable program instructions which, when executed by a
mobile communication device, cause the mobile communication device
to at least: determine, while the mobile communication device is
operating in a cell forward access channel (CELL_FACH) state, that
uplink transmissions from the mobile communication device are
causing interference to a neighbor cell different from a serving
cell of the mobile communication device; and modify a network
resource that may be causing the interference.
15. The non-transitory computer readable memory according to claim
14, wherein the network resource comprises an enhanced dedicated
channel (E-DCH) and the modifying is selected from among suspending
the E-DCH and releasing the E-DCH.
16. The non-transitory computer readable memory according to claim
14, wherein it is determined from received interference data that
the uplink transmissions are causing interference to the neighbor
cell, the received interference data indicating a level of the
interference.
17. The non-transitory computer readable memory according to claim
14, wherein the mobile communication device determines that the
uplink transmissions are causing interference to the neighbor cell
by comparing one or more parameters against respective one or more
reselection criteria thresholds, the reselection criteria
thresholds including at least one of: transmit power of the uplink
transmissions; and path loss between the mobile communication
device and the neighbor cell.
18. The non-transitory computer readable memory according to claim
14, wherein the network resource comprises an enhanced dedicated
channel (E-DCH) and the modifying is selected from among suspending
the E-DCH and releasing the E-DCH.
19. The non-transitory computer readable memory according to claim
18, wherein the E-DCH is suspended or released based on an amount
of data to be transmitted to and/or from the mobile communications
device exceeding an uplink buffer or other predetermined limit.
20. The non-transitory computer readable memory according to claim
19, wherein the executed program instructions further cause the
mobile communication device to reselect the mobile communication
device from the serving cell after the E-DCH is suspended or
released but prior to transmission of the data.
Description
TECHNOLOGICAL FIELD
[0001] Embodiments of the present invention relate generally to
communications technology and, more particularly to suspension
and/or release of a network resource such as for example an E-DCH
while a mobile terminal is in the CELL_FACH state.
BACKGROUND
[0002] The communications between a mobile terminal and a serving
cell, such as the uplink communications from the mobile terminal to
the serving cell, may sometimes create interference with neighbor
cells. This interference may inhibit the operation of the neighbor
cells or may at least cause the mobile terminal and/or the neighbor
cells to operate less efficiently. In some operational states, such
as a cell dedicated channel (CELL_DCH) state, the mobile terminal
and the serving cell may monitor the neighbor cells in such a
manner that instances of neighbor cell interference may be
identified and the operation of the mobile terminal and/or the
serving cell may be modified in such a manner as to reduce the
potential for the neighbor cell interference. Indeed, in the
CELL_DCH state, the neighbor cells may be added to the active set
so as to be involved in uplink power control. In this regard, the
mobile terminal may receive signals from the serving cell as well
as the neighbor cells. As such, neighbor cells may identify
instances in which the mobile terminal is creating interference
such that the mobile terminal may reduce its uplink power in an
effort to correspondingly reduce the neighbor cell interference.
More particularly, for a mobile terminal operating in a CELL_DCH
state, the uplink power from the mobile terminal may be controlled
via relative grants from neighbor cells within the active set of
the mobile terminal.
[0003] In other operational states, however, the mobile terminal
may not communicate with the neighbor cells in the same manner and,
as such, may not be able to identify instances of potential
neighbor cell interference. For example, a mobile terminal in a
cell forward access channel (CELL_FACH) state may only receive
signals from the serving cell. As such, in instances in which the
mobile terminal is creating interference for the neighbor cells,
the neighbor cells are unable to communicate with the mobile
terminal in order to request that the power, such as the uplink
power, be reduced in an effort to correspondingly reduce the
neighbor cell interference. For example, in contrast to the
relative grants from neighbor cells to a mobile terminal in a
CELL_DCH state that serve to control the uplink power, a mobile
terminal operating in the CELL_FACH state may not have similar
control of its uplink power since the uplink power of the mobile
terminal may only be controlled by the serving cell using absolute
grants without consideration of possible neighbor cell
interference. As such, a mobile terminal that is creating neighbor
cell interference may impair the operation of the neighbor cells
and, in some instances, may suffer from radio link failure.
[0004] In Release 8 of the Third Generation Partnership Project
(3GPP) specification, an enhanced uplink for a mobile terminal in
the CELL_FACH state in the idle mode was introduced. This enhanced
uplink is termed a common enhanced dedicated channel (Common
E-DCH). As such, mobile terminals may utilize the E-DCH in other
radio resource control (RRC) states in addition to or other than
the CELL_DCH state. Notwithstanding the potential for the creation
of neighbor cell interference to be created by the uplink
transmissions of a mobile terminal in the CELL_FACH state, it is
anticipated that mobile terminals will frequently operate in the
CELL_FACH state, such as to perform infrequent or bursty data
transmissions, and that operation of mobile terminals in the
CELL_FACH state may increase as a result of the introduction of the
E-DCH. As such, the issues relating to potential neighbor cell
interference while a mobile terminal is operating in the CELL_FACH
state may also become more frequent and problematic.
[0005] A number of signaling based methods have been proposed in an
effort to provide some measure of interference control for the
neighbor cells in instances in which a mobile terminal is operating
in the CELL_FACH state. However the proposals have generally
suffered from various drawbacks including, for example, increased
complexity for the mobile terminal and/or the serving cell or the
failure to address all use cases or scenarios.
SUMMARY
[0006] A method, apparatus and computer program product are
therefore provided according to an example embodiment in order to
trigger a reselection of a serving cell in an instance in which a
mobile terminal may be creating interference with a neighbor cell.
Based upon received reselection data, the mobile terminal may
release and/or suspend a network resource, such as an enhanced
dedicated channel (E-DCH), in order to trigger a reselection of a
new serving cell. In one embodiment, the method, apparatus and
computer program product may trigger reselection of a new cell in
an instance in which neighbor cell interference has been
potentially created while the mobile terminal is in the CELL_FACH
state. As such, the method, apparatus and computer program product
of example embodiments of the present invention may reduce neighbor
cell interference, thereby improving overall system
performance.
[0007] In one embodiment, a method is provided that includes
determining the presence of a reselection condition based on
reselection data. In an instance in which the presence of the
reselection condition is determined, the method includes causing a
network resource to be modified. The method also includes causing a
reselection of a serving cell.
[0008] In another embodiment, an apparatus is provided that
includes at least one processor and at least one memory including
computer program code with the at least one memory and the computer
program code configured to, with the at least one processor, cause
the apparatus at least to determine the presence of a reselection
condition based on reselection data. The at least one memory and
the computer program code are also configured to, with the at least
one processor, cause the apparatus at least to cause a network
resource to be modified in an instance in which the presence of the
reselection condition is determined. The at least one memory and
the computer program code are also configured to, with the at least
one processor, cause the apparatus at least to cause a reselection
of a serving cell.
[0009] In a further embodiment, a computer program product is
provided that includes at least one non-transitory
computer-readable storage medium having computer-readable program
instructions stored therein, the computer-readable program
instructions including program instructions are configured to
determine the presence of a reselection condition based on
reselection data. The computer-readable program instructions of
this embodiment also include program instructions configured to
cause a network resource to be modified in an instance in which the
presence of the reselection condition is determined. The
computer-readable program instructions of this embodiment also
include program instructions configured to cause a reselection of a
serving cell.
[0010] In yet another embodiment, an apparatus is provided that
includes means for determining the presence of a reselection
condition based on reselection data. The apparatus of this
embodiment also includes, in an instance in which the presence of
the reselection condition is determined, means for causing a
network resource to be modified. The apparatus of this embodiment
also includes means for causing a reselection of a serving
cell.
[0011] In one embodiment, a method is provided that includes
determining the presence of uplink interference while a mobile
terminal is in a CELL_FACH state. The method of this embodiment
also causes an E-DCH to be modified in an instance in which the
presence of uplink interference is determined. The method of this
embodiment also includes causing a reselection of a serving
cell.
[0012] In another embodiment, an apparatus is provided that
includes at least one processor and at least one memory including
computer program code with the at least one memory and the computer
program code configured to, the at least one processor, cause the
apparatus at least to determine the presence of uplink interference
while a mobile terminal is in a CELL_FACH state. The at least one
memory and the computer program code are also configured to, with
the at least one processor, cause the apparatus of this embodiment
to cause an E-DCH to be modified in an instance in which the
presence of uplink interference is determined. The at least one
memory and the computer program code are also configured to, with
the at least one processor, cause the apparatus of this embodiment
to cause a reselection of a serving cell.
[0013] In a further embodiment, a computer program product is
provided that includes at least one non-transitory
computer-readable storage medium having computer-readable program
instructions stored therein, the computer-readable program
instructions including program instructions configured to determine
the presence of uplink interference while a mobile terminal is in a
CELL_FACH state. The computer-readable program instructions of this
embodiment also include program instructions configured to cause
the apparatus of this embodiment to cause an E-DCH to be modified
in an instance in which the presence of uplink interference is
determined. The computer-readable program instructions of this
embodiment also include program instructions configured to cause a
reselection of a serving cell.
[0014] In yet another embodiment, an apparatus is provided that
includes means for determining the presence of uplink interference
while a mobile terminal is in a CELL_FACH state. The apparatus of
this embodiment also includes means for causing an E-DCH to be
modified in an instance in which the presence of uplink
interference is determined. The apparatus of this embodiment also
includes means for causing a reselection of a serving cell.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Having thus described the example embodiments of the
invention in general terms, reference will now be made to the
accompanying drawings, which are not necessarily drawn to
scale.
[0016] FIG. 1 is a schematic representation of a system having a
serving cell and one or more neighbor cells that may experience
interference created by the mobile terminal and that may benefit
from an embodiment of the present invention.
[0017] FIG. 2 is a block diagram of an apparatus that may be
embodied by a mobile terminal in accordance with one embodiment of
the present invention.
[0018] FIG. 3 is a flow chart illustrating operations performed in
accordance with one embodiment of the present invention.
[0019] FIG. 4 illustrates the flow chart of operations performed in
accordance with another embodiment of the present invention.
DETAILED DESCRIPTION
[0020] The present invention now will be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all embodiments of the inventions are shown. Indeed,
these inventions may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout.
[0021] As used in this application, the term `circuitry` refers to
all of the following: (a) hardware-only circuit implementations
(such as implementations in only analog and/or digital circuitry)
and (b) to combinations of circuits and software (and/or firmware),
such as (as applicable): (i) to a combination of processor(s) or
(ii) to portions of processor(s)/software (including digital signal
processor(s)), software, and memory(ies) that work together to
cause an apparatus, such as a mobile phone or server, to perform
various functions) and (c) to circuits, such as a microprocessor(s)
or a portion of a microprocessor(s), that require software or
firmware for operation, even if the software or firmware is not
physically present.
[0022] This definition of `circuitry` applies to all uses of this
term in this application, including in any claims. As a further
example, as used in this application, the term "circuitry" would
also cover an implementation of merely a processor (or multiple
processors) or portion of a processor and its (or their)
accompanying software and/or firmware. The term "circuitry" would
also cover, for example and if applicable to the particular claim
element, a baseband integrated circuit or application specific
integrated circuit for a mobile phone or a similar integrated
circuit in server, a cellular network device, or other network
device.
[0023] A method, apparatus and computer program product of an
example embodiment of the present invention are configured to
determine instances in which a mobile terminal may be creating
neighbor cell interference, such as a result of interference
created by uplink transmissions from the mobile terminal to a
serving cell. In accordance with an example embodiment, a network
resource, such as an E-DCH, may be modified (e.g., suspended and/or
released) by the mobile terminal that may be creating neighbor cell
interference. Based upon the modified network resource, the mobile
terminal may select a new serving cell in an effort to reduce
neighbor cell interference. In one embodiment, the mobile terminal
identifies the potential for neighbor cell interference while in
the CELL_FACH state, thereby permitting neighbor cell interference
to be reduced or otherwise addressed even while the mobile terminal
is in the CELL_FACH state.
[0024] Although the method, apparatus and computer program product
may be implemented in a variety of different systems, one example
of such a system is shown in FIG. 1, which includes a first
communication device (e.g., mobile terminal 10) that is capable of
communication via a serving cell 12, such as a base station, a Node
B, an evolved Node B (eNB) or other access point, with a network 14
(e.g., a core network). While the network may be configured in
accordance with Long Term Evolution (LTE) or LTE-Advanced (LTE-A),
other networks may support the method, apparatus and computer
program product of embodiments of the present invention including
those configured in accordance with wideband code division multiple
access (W-CDMA), CDMA2000, global system for mobile communications
(GSM), general packet radio service (GPRS) and/or the like.
[0025] The network 14 may include a collection of various different
nodes, devices or functions that may be in communication with each
other via corresponding wired and/or wireless interfaces. For
example, the network may include one or more cells, including
serving cell 12 and one or more neighbor cells 16 (designated
neighbor cell 1, neighbor cell 2, . . . neighbor cell n in the
embodiment of FIG. 1), each of which may serve a respective
coverage area. The serving cell and the neighbor cells could be,
for example, part of one or more cellular or mobile networks or
public land mobile networks (PLMNs). In turn, other devices such as
processing devices (e.g., personal computers, server computers or
the like) may be coupled to the mobile terminal 10 and/or other
communication devices via the network.
[0026] A communication device, such as the mobile terminal 10 (also
known as user equipment (UE)), may be in communication with other
communication devices or other devices via the serving cell 12 and,
in turn, the network 14. In some cases, the communication device
may include an antenna for transmitting signals to and for
receiving signals from a serving cell.
[0027] In some example embodiments, the mobile terminal 10 may be a
mobile communication device such as, for example, a mobile
telephone, portable digital assistant (PDA), pager, laptop
computer, or any of numerous other hand held or portable
communication devices, computation devices, content generation
devices, content consumption devices, or combinations thereof. As
such, the mobile terminal 10 may include one or more processors
that may define processing circuitry either alone or in combination
with one or more memories. The processing circuitry may utilize
instructions stored in the memory to cause the mobile terminal 10
to operate in a particular way or execute specific functionality
when the instructions are executed by the one or more processors.
The mobile terminal 10 may also include communication circuitry and
corresponding hardware/software to enable communication with other
devices and/or the network 14.
[0028] In one embodiment, for example, the mobile terminal 10
and/or the serving cell 12 may be embodied as or otherwise include
an apparatus 20 as generically represented by the block diagram of
FIG. 2. While the apparatus 20 may be employed, for example, by a
mobile terminal 10 or a serving cell 12, it should be noted that
the components, devices or elements described below may not be
mandatory and thus some may be omitted in certain embodiments.
Additionally, some embodiments may include further or different
components, devices or elements beyond those shown and described
herein.
[0029] As shown in FIG. 2, the apparatus 20 may include or
otherwise be in communication with processing circuitry 22 that is
configurable to perform actions in accordance with example
embodiments described herein. The processing circuitry may be
configured to perform data processing, application execution and/or
other processing and management services according to an example
embodiment of the present invention. In some embodiments, the
apparatus or the processing circuitry may be embodied as a chip or
chip set. In other words, the apparatus or the processing circuitry
may comprise one or more physical packages (e.g., chips) including
materials, components and/or wires on a structural assembly (e.g.,
a baseboard). The structural assembly may provide physical
strength, conservation of size, and/or limitation of electrical
interaction for component circuitry included thereon. The apparatus
or the processing circuitry may therefore, in some cases, be
configured to implement an embodiment of the present invention on a
single chip or as a single "system on a chip." As such, in some
cases, a chip or chipset may constitute means for performing one or
more operations for providing the functionalities described
herein.
[0030] In an example embodiment, the processing circuitry 22 may
include a processor 24 and memory 28 that may be in communication
with or otherwise control a communication interface 26 and, in some
cases, a user interface 30. As such, the processing circuitry may
be embodied as a circuit chip (e.g., an integrated circuit chip)
configured (e.g., with hardware, software or a combination of
hardware and software) to perform operations described herein.
However, in some embodiments taken in the context of the mobile
terminal 10, the processing circuitry may be embodied as a portion
of a mobile computing device or other mobile terminal.
[0031] The user interface 30 (if implemented) may be in
communication with the processing circuitry 22 to receive an
indication of a user input at the user interface and/or to provide
an audible, visual, mechanical or other output to the user. As
such, the user interface may include, for example, a keyboard, a
mouse, a joystick, a display, a touch screen, a microphone, a
speaker, and/or other input/output mechanisms. The apparatus 20
need not always include a user interface. For example, in instances
in which the apparatus is embodied as a serving cell 12, the
apparatus may not include a user interface. As such, the user
interface is shown in dashed lines in FIG. 2.
[0032] The communication interface 26 may include one or more
interface mechanisms for enabling communication with other devices
and/or networks. In some cases, the communication interface may be
any means such as a device or circuitry embodied in either
hardware, or a combination of hardware and software that is
configured to receive and/or transmit data from/to a network 14
and/or any other device or module in communication with the
processing circuitry 22, such as between the mobile terminal 10 and
the serving cell 12. In this regard, the communication interface
may include, for example, an antenna (or multiple antennas) and
supporting hardware and/or software for enabling communications
with a wireless communication network and/or a communication modem
or other hardware/software for supporting communication via cable,
digital subscriber line (DSL), universal serial bus (USB), Ethernet
or other methods.
[0033] In an example embodiment, the memory 28 may include one or
more non-transitory memory devices such as, for example, volatile
and/or non-volatile memory that may be either fixed or removable.
The memory may be configured to store information, data,
applications, instructions or the like for enabling the apparatus
20 to carry out various functions in accordance with example
embodiments of the present invention. For example, the memory could
be configured to buffer input data for processing by the processor
24. Additionally or alternatively, the memory could be configured
to store instructions for execution by the processor. As yet
another alternative, the memory may include one of a plurality of
databases that may store a variety of files, contents or data sets.
Among the contents of the memory, applications may be stored for
execution by the processor in order to carry out the functionality
associated with each respective application. In some cases, the
memory may be in communication with the processor via a bus for
passing information among components of the apparatus.
[0034] The processor 24 may be embodied in a number of different
ways. For example, the processor may be embodied as various
processing means such as one or more of a microprocessor or other
processing element, a coprocessor, a controller or various other
computing or processing devices including integrated circuits such
as, for example, an ASIC (application specific integrated circuit),
an FPGA (field programmable gate array), or the like. In an example
embodiment, the processor may be configured to execute instructions
stored in the memory 28 or otherwise accessible to the processor.
As such, whether configured by hardware or by a combination of
hardware and software, the processor may represent an entity (e.g.,
physically embodied in circuitry--in the form of processing
circuitry 22) capable of performing operations according to
embodiments of the present invention while configured accordingly.
Thus, for example, when the processor is embodied as an ASIC, FPGA
or the like, the processor may be specifically configured hardware
for conducting the operations described herein. Alternatively, as
another example, when the processor is embodied as an executor of
software instructions, the instructions may specifically configure
the processor to perform the operations described herein.
[0035] Referring now to FIGS. 3 and 4, flowcharts illustrating the
operations performed by a method, apparatus and computer program
product, such as apparatus 20 of FIG. 2, from the perspective of a
mobile terminal 10 in accordance with one embodiment of the present
invention are illustrated. It will be understood that each block of
the flowcharts, and combinations of blocks in the flowcharts, may
be implemented by various means, such as hardware, firmware,
processor, circuitry and/or other device associated with execution
of software including one or more computer program instructions.
For example, one or more of the procedures described above may be
embodied by computer program instructions. In this regard, the
computer program instructions which embody the procedures described
above may be stored by a memory device 28 of an apparatus employing
an embodiment of the present invention and executed by a processor
24 in the apparatus. As will be appreciated, any such computer
program instructions may be loaded onto a computer or other
programmable apparatus (e.g., hardware) to produce a machine, such
that the resulting computer or other programmable apparatus
provides for implementation of the functions specified in the
flowcharts' block(s). These computer program instructions may also
be stored in a non-transitory computer-readable storage memory that
may direct a computer or other programmable apparatus to function
in a particular manner, such that the instructions stored in the
computer-readable storage memory produce an article of manufacture,
the execution of which implements the function specified in the
flowcharts' block(s). The computer program instructions may also be
loaded onto a computer or other programmable apparatus to cause a
series of operations to be performed on the computer or other
programmable apparatus to produce a computer-implemented process
such that the instructions which execute on the computer or other
programmable apparatus provide operations for implementing the
functions specified in the flowcharts' block(s). As such, the
operations of FIGS. 3 and 4, when executed, convert a computer or
processing circuitry into a particular machine configured to
perform an example embodiment of the present invention.
Accordingly, the operations of each of FIGS. 3 and 4 define an
algorithm for configuring a computer or processing circuitry 22,
e.g., processor, to perform an example embodiment. In some cases, a
general purpose computer may be provided with an instance of the
processor which performs the algorithm of a respective one of FIGS.
3 and 4 to transform the general purpose computer into a particular
machine configured to perform an example embodiment.
[0036] Accordingly, blocks of the flowcharts support combinations
of means for performing the specified functions and combinations of
operations for performing the specified functions. It will also be
understood that one or more blocks of the flowchart, and
combinations of blocks in the flowcharts, can be implemented by
special purpose hardware-based computer systems which perform the
specified functions, or combinations of special purpose hardware
and computer instructions.
[0037] In some embodiments, certain ones of the operations above
may be modified or further amplified as described below. Moreover,
in some embodiments additional optional operations may also be
included (some examples of which are shown in dashed lines in FIGS.
3 and 4). It should be appreciated that each of the modifications,
optional additions or amplifications below may be included with the
operations above either alone or in combination with any others
among the features described herein.
[0038] FIG. 3 is a flow chart illustrating serving cell reselection
performed in accordance with one embodiment of the present
invention. Referring now to FIG. 3, as shown in operation 30, the
apparatus 20 embodied, for example, by a mobile terminal 10, may
include means, such as the processing circuitry 22, the processor
24, the communications interface 26 or the like, for receiving
reselection data. In an embodiment, reselection data may include
interference data, reselection criteria, and/or a network command.
Reselection criteria, in one embodiment, is that criteria that
would generally cause an apparatus 20, such as mobile terminal 10,
to transition from a current serving cell, such as serving cell 12,
to another serving cell, such as neighbor cell 16 when a neighbor
cell 16 received power is determined to be higher than the serving
cell 12 received power. In an example embodiment, and as described
above, the received reselection data may also include interference
data. Interference data may indicate the level of interference
between a mobile terminal, such as mobile terminal 10, and one or
more neighbor cells, such as neighbor cell 16.
[0039] As shown in decision operation 32 of FIG. 3, the apparatus
20 may also include means, such as the processing circuitry 22, the
processor 24 or the like, for determining the presence of a
reselection condition. In an example embodiment, a reselection
condition may occur in an instance in which it is determined, such
as by the processor, that the reselection criteria have been met,
in an instance in which it is determined, again such as by the
processor, that interference exists between the mobile terminal and
one or more neighboring cells and/or in an instance in which a
network command is received, such as by the communications
interface, that indicates that the mobile terminal, for example, is
to release a network resource, such as the E-DCH. Potential
interference between the mobile terminal 10 and neighbor cells 16
may be identified in various manners including, for example, by
analyzing the transmission power of the mobile terminal, path loss
and/or neighbor cells uplink interference levels may be
analyzed.
[0040] In one embodiment, the apparatus 20, such as the processor
24, may determine the transmission power of the signals transmitted
via the uplink dedicated physical control channel (DPCCH) to the
serving cell 12. In an instance in which the transmission power for
signals transmitted via an uplink channel, such as the uplink
DPCCH, is relatively high, the mobile terminal 10 may be located
relatively far from the serving cell and/or the mobile terminal 10
may be suffering from uplink interference from other mobile
terminals served by the neighbor cells 16. In either instance, a
relatively high transmission power for signals transmitted via an
uplink channel of the mobile terminal 10 may create interference
with the neighbor cells 16.
[0041] Additionally or alternatively, the apparatus 20, such as the
processor 24, may determine, in one embodiment, the path loss may
be determined to be the difference between the value of the primary
common pilot channel (CPICH) transmission power as signaled by the
network and the CPICH received signal code power (RSCP) as measured
by the UE. The path loss of a neighbor cell 16 provides an
indication as to the distance between the mobile terminal 10 and
the neighbor cell 16. In an instance in which the path loss is
relatively small, the mobile terminal 10 may be relatively near the
neighbor cell 16, thereby increasing the likelihood that the signal
transmissions by the mobile terminal 10 may create interference for
the neighbor cell 16. Conversely, in an instance in which the path
loss is relatively large, the mobile terminal may be relatively far
away from the neighbor cell such that there is a lower likelihood
that the signal transmissions from the mobile terminal 10 will
create interference for the neighbor cell 16.
[0042] The apparatus 20 may additionally or alternatively include
means, such as the processing circuitry 22, the processor 24 or the
like, for determining other parameters or conditions associated
with the operation of the mobile terminal 10 that may be indicative
of neighbor cell interference. For example, the apparatus, such as
the processor, the communication interface 26 or the like, may
receive information provided by the neighbor cell 16, such as via a
system information block (SIB), e.g., SIB7, so as to obtain
information regarding the uplink interference level of the neighbor
cell. Based upon at least some of the foregoing parameters, such as
the transmission power, the path loss and/or the uplink
interference level, the apparatus 20, such as the processor 24, may
determine if the operation of the mobile terminal 10 is creating or
is likely to have created interference for the neighbor cells
16.
[0043] In one embodiment, the apparatus 20, such as the processor
24, may be configured to compare the transmission power to a first
threshold with the transmission power satisfying the first
threshold by exceeding the first threshold, to compare the path
loss to a second threshold with the path loss satisfying the second
threshold by being less than the second threshold and optionally
compare one or more other parameters, such as the uplink
interference level, to respective thresholds. The thresholds may be
pre-defined and stored by memory 28 of the apparatus 20.
Alternatively, a network element, such as the serving cell 12, a
radio network controller or the like, may notify the mobile
terminal of the respective thresholds, such as via an RRC
measurement control message or via system information, such as
SIB5, SIB11, SIB11bis and/or SIB12.
[0044] In an example embodiment and as described herein, the
apparatus 20, such as the processor 24, may determine that a
reselection condition may be present based on the above described
reselection criteria and interference data, alone or in
combination. However, the apparatus 20, such as the processor 24,
may alternatively or additionally determine that a reselection
condition is present based upon the existence of a predetermined
amount of data to be transmitted to/from the mobile terminal. For
example, when there is only a small amount of data to be
transmitted (e.g., a common control channel (CCCH) transmission)
then there is a lower probability of a reselection condition and
thus a lower chance that a network resource, such as the E-DCH,
needs to be suspended. However when there is a larger amount of
data, for example an amount of data that exceeds an uplink buffer
and/or another predetermined limit, then it is more likely that a
reselection condition will occur and a network resource, such as
the E-DCH, needs to be suspended. The network resource, such as the
E-DCH, may be released and or suspended in order to permit
reselection to occur prior to the transfer of the large amount of
data.
[0045] As shown in operation 34 of FIG. 3, the apparatus 20 may
also include means, such as the processing circuitry 22, the
processor 24, communications interface 26 or the like, for causing
a report to be transmitted. In an embodiment, in an instance in
which the apparatus determines the presence of a reselection
condition, as described with reference to decision operation 32,
then the apparatus may advise a serving cell, a network resource,
radio network controller and/or the like, that a network resource,
such as the E-DCH, has been released.
[0046] In one embodiment, the report that is caused to be
transmitted by the apparatus 20, such as the mobile terminal 10,
may provide a buffer status, such as an empty buffer status
regardless of the actual state of the buffer. For example, the
apparatus 20, embodied, for example by the mobile terminal 10, may
report an empty buffer status (e.g., Total E-DCH Buffer Status
(TEBS)=0 bytes) in the scheduling information (SI) even though the
buffer is not empty. Upon receipt of the empty buffer status, the
network, such as the serving cell 12, may release the network
resource, such as the E-DCH. Once the mobile terminal 10 recovers
(e.g. there is no longer interference with a neighbor cell) then
the resource, such as the E-DCH, may be resumed or allocated
again.
[0047] In another embodiment, the apparatus 20, such as the mobile
terminal 10, may add a new field to the SI that functions to
transmit a report to a network resource, radio network controller
and/or the like indicating that the network resource, such as the
E-DCH, may need to be suspended. Alternatively or additionally, the
new field may also take the form of a special value of TEBS.
Alternatively or additionally, the new field may also take the form
of a special value of Channel Quality Indication (CQI).
[0048] As shown in operation 36 of FIG. 3, the apparatus 20 may
also include means, such as the processing circuitry 22, the
processor 24, communications interface 26 or the like, for causing
a network resource, such as the E-DCH, to be modified in an
instance in which the presence of a reselection condition has been
identified and a report has provided to the network. In one
embodiment, the apparatus 20, such the mobile terminal 10,
autonomously releases or suspends the network resource, such as the
E-DCH. By autonomously acting, the mobile terminal 10 may reduce
latency. In other embodiments, the network resource, such as the
E-DCH, may be released while the apparatus 20, such as the mobile
terminal 10, is in the CELL-FACH state using an inactive absolute
grant. Alternatively or additionally, the use of an inactive
absolute grant and/or an autonomous action by the apparatus 20,
such as the mobile terminal 10, may also be accompanied by the
establishment of a timeout procedure, such as defined by a timer.
The timeout procedure defined by the timer may be configured to
prevent the requesting of another resource within the timeout
procedure or may prevent the mobile terminal from requesting a new
resource until the interference conditions are no longer
present.
[0049] Alternatively or additionally, the apparatus 20, embodied,
for example, by the mobile terminal 10, may receive a message using
means such as the processor 24 and the communications interface 26,
for receiving a message from a serving cell 12, a network resource,
radio network controller and/or the like that causes the
modification of the network resource, such as the E-DCH as is
described with respect to Operation 36 of FIG. 3. In an embodiment,
a command (e.g., absolute grant value, high speed shared control
channel order, and/or MAC header information) may be received that
instructs the mobile terminal to suspend or release the network
resource, such as the E-DCH. In another embodiment, the mobile
terminal 10 may receive an indication of a modified serving grant
(e.g., mobile terminal transmit power is reduced to avoid
interference) which causes the mobile terminal 10 to suspend or
release the resource.
[0050] Alternatively or additionally, a message may indicate that
the apparatus 20, embodied by, for example, the processor 24, may
apply a specific bias, offset and/or priority to a neighbor cell or
frequency when evaluating reselection as shown with respect to
Operation 38. For example, applying a specific bias, offset and/or
priority to a neighbor cell effectively allows for a fast trigger
for cell reselection. In this example, the use of RRC signaling to
release the RRC connection and perform redirection may be avoided.
The mobile terminal 10 may reselect and maintain the RRC signaling
and any packet data protocol (PDP) context to be re-established on
the other frequency.
[0051] Alternatively or additionally, an apparatus, embodied, by
for example, the serving cell 12 may trigger a reselection
condition. In some cases the serving cell 12 may trigger a
reselection condition without the mobile terminal 12 reporting an
interference condition and/or the presence of reselection criteria.
A serving cell 12, in an instance in which the network experiences
high load on a frequency, may for example, cause a network
transmission that indicates a reselection condition as described
with reference to FIG. 3 to cause the mobile terminal 10 to modify
a network resource, such as the E-DCH for purposes of load
balancing. In this example case, the release of the network
resource, such as the E-DCH would be triggered by the serving cell
12 (e.g. via High Speed Shared Control Channel order, or inactive
grant, etc.) and the network command would likely be accompanied by
a reselection offset. The reselection offset is configured to cause
the mobile terminal 10 to switch to another frequency.
[0052] Alternatively or additionally, the apparatus 20, embodied
by, for example, by the processor 24, may receive a specific
adjustment to for a reselection calculation. For example, a
reselection calculation may include applying a temporary bias (such
as offset and/or priority) for neighboring cells 16.
[0053] As shown in operation 38 of FIG. 3, the apparatus 20 may
also include means, such as the processing circuitry 22, the
processor 24, communications interface 26 or the like, for causing
the reselection of a serving cell. As described herein, the
apparatus 20, such as the mobile terminal 10 may perform
reselection of a new serving cell to avoid interference situations.
Alternatively or additionally, the reselection may include
activating a previous serving cell that was suspended or released,
by the mobile terminal 10. Alternatively or additionally, in one
embodiment, when the reselection criteria are met, the radio
resource control (RRC) layer may indicate to the medium access
control (MAC) that a network resource, such as an E-DCH resource,
should be suspended or released. The suspension or modification of
a network resource is further described with reference to operation
34.
[0054] As indicated above, the method, apparatus and computer
program product of one embodiment are configured to permit a mobile
terminal 10 operating in a CELL_FACH to determine the potential for
neighbor cell interference and to suspend and/or release a network
resource, such as the E-DCH, to trigger reselection of a cell even
while the mobile terminal is in the CELL_FACH state. In order to
provide further explanation of this embodiment, reference is made
to FIG. 4 in which the mobile terminal is initially operating in a
CELL_FACH state as shown in operation 40. The apparatus 20 of this
embodiment may include means, such as the processing circuitry 22,
the processor 24 or the like, for determining whether neighbor cell
interference is being caused by the mobile terminal while the
mobile terminal is in the CELL_FACH state. See, for example,
operation 42 of FIG. 4. As described above, the apparatus, such as
a processor, may determine whether neighbor cell interference is
being caused by determining whether one or more parameters satisfy
respective thresholds and/or whether a reselection criteria is
present. For example, to determine the presence of an interference
the apparatus, such as a processor, may determine whether the
transmission power for signals transmitted via an uplink channel
satisfies a respective threshold, whether a path loss for signals
received from the neighbor cell satisfies a respective threshold
and/or whether an uplink interference level at the neighbor cell
satisfies a respective threshold.
[0055] In an instance in which the apparatus 20, such as the
processor 24, does not determine that neighbor cell interference is
being created, the apparatus need not issue suspend and/or release
the network resource and, instead, the mobile terminal 10 may
continue to operate in the CELL_FACH state while the apparatus
continues to monitor the various parameters for an indication of
neighbor cell interference and/or the reselection criteria.
However, the apparatus may also include means, such as the
processing circuitry 22, the processor 24, the communication
interface 26 or the like, for causing a measurement report to be
provided to a network element, such as the serving cell 12, a radio
network controller or other network element, in an instance in
which it is determined that neighbor cell interference is being
caused. Based on the determined interference with the neighbor
cell, in one embodiment, the apparatus may include means, such as
the processing circuitry, the processor, the communication
interface or the like, for causing a network resource, such as an
E-DCH, to be modified. See operation 44 of FIG. 4. As described
with respect to operation 36 of FIG. 3, the apparatus may release
and/or suspend the E-DCH resource. As shown in operation 46 of FIG.
4, the apparatus 20 may also include means, such as the processing
circuitry 22, the processor 24, communications interface 26 or the
like, for causing the reselection of a serving cell.
[0056] Advantageously, the apparatus 20, method and computer
program product as described herein enables a mobile terminal 10 to
perform cell reselection when a network resource, such as an E-DCH,
is allocated. The apparatus, method and computer program product as
described herein further allows flexible conditions as to the
suitable conditions to perform reselection (e.g., large amount of
data may cause high interference thereby indicating reselection).
In some embodiments, the apparatus, method and computer program
product as described herein avoids causing interference to neighbor
cells 16, radio link failures and dropped calls, while avoiding
complex interference control algorithms. The apparatus, method and
computer program product as described herein further provides for
dynamic load balancing between frequencies with reduced latency and
reduced power consumption.
[0057] Many modifications and other embodiments of the inventions
set forth herein will come to mind to one skilled in the art to
which these inventions pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the inventions are
not to be limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Moreover, although the
foregoing descriptions and the associated drawings describe example
embodiments in the context of certain example combinations of
elements and/or functions, it should be appreciated that different
combinations of elements and/or functions may be provided by
alternative embodiments without departing from the scope of the
appended claims. In this regard, for example, different
combinations of elements and/or functions than those explicitly
described above are also contemplated as may be set forth in some
of the appended claims. Although specific terms are employed
herein, they are used in a generic and descriptive sense only and
not for purposes of limitation.
* * * * *