U.S. patent application number 14/324330 was filed with the patent office on 2014-10-30 for method and apparatus for dynamic adjustment of uplink transmission time.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Bibhu P Mohanty, Ozcan Ozturk, Sharad Deepak Sambhwani, Mehmet Yavuz.
Application Number | 20140321440 14/324330 |
Document ID | / |
Family ID | 39639118 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140321440 |
Kind Code |
A1 |
Yavuz; Mehmet ; et
al. |
October 30, 2014 |
METHOD AND APPARATUS FOR DYNAMIC ADJUSTMENT OF UPLINK TRANSMISSION
TIME
Abstract
Systems and methods for dynamically adjusting the transmission
time interval (TTI) for a communications system are presented. The
described aspects provide for dynamically adjusting the TTI in a
communication session between a base station or nodeB and a
wireless device or user equipment between a shorter TTI, which can
provide increased data throughput and lower power consumption, and
a longer TTI, which can provide more rugged communication link
connections. By dynamically adjusting the TTI, the communications
link can be optimized for the given communication channel
conditions. Determinations, based on indicia related to the
communications system conditions, can be employed in dynamic TTI
adjustment. These determinations can be formed centrally at the
Radio Network Controller (RNC), at the RNC supplemented with user
equipment (UE) available information, or formed in a distributed
manner between the RNC and UE across a communications system.
Inventors: |
Yavuz; Mehmet; (San Diego,
CA) ; Mohanty; Bibhu P; (San Diego, CA) ;
Ozturk; Ozcan; (San Diego, CA) ; Sambhwani; Sharad
Deepak; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
39639118 |
Appl. No.: |
14/324330 |
Filed: |
July 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12104795 |
Apr 17, 2008 |
8811335 |
|
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14324330 |
|
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60913262 |
Apr 20, 2007 |
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Current U.S.
Class: |
370/336 |
Current CPC
Class: |
H04L 1/0007 20130101;
Y02D 70/1262 20180101; H04W 52/367 20130101; H04W 52/0216 20130101;
Y02D 70/142 20180101; H04W 28/06 20130101; Y02D 70/1244 20180101;
H04W 52/0229 20130101; H04W 28/12 20130101; Y02D 70/25 20180101;
H04W 88/12 20130101; Y02D 30/70 20200801; Y02D 70/1246 20180101;
Y02D 70/1242 20180101; Y02D 70/1222 20180101; H04W 48/16 20130101;
Y02D 70/146 20180101; Y02D 70/23 20180101 |
Class at
Publication: |
370/336 |
International
Class: |
H04W 28/06 20060101
H04W028/06 |
Claims
1. A method for dynamically adjusting a transmission time interval
in a communications system, comprising: monitoring, at a radio
network controller, at least one indicator related to at least one
communication link condition; determining at the radio network
controller, based at least in part on the at least one indicator,
at least one transmission time interval to facilitate communication
over the at least one communication link; and communicating, from
the radio network controller, at least one instruction, for at
least one user equipment employing the at least one communication
link, to employ at least one determined transmission time interval
during at least one of an established communications event, a voice
call, a data call, a soft-handoff condition, or any combination
thereof
2. The method of claim 1, further comprising: receiving, at the
radio network controller, at least one other indicator that cannot
be directly monitored by the radio network controller, related to
at least one communication link condition, wherein determining at
least one transmission time interval to facilitate communication
over the at least one communication link is based at least in part
on the at least one received indicator.
3. The method of claim 1, wherein the at least one instruction
instructs the at least one user equipment in communication with the
radio network controller over the at least one communication link,
to dynamically adjust a transmission time interval used in the at
least one communication link.
4. The method of claim 3, wherein the dynamically adjusted
transmission time interval is different than an immediately prior
transmission time interval used in the at least one communication
link.
5. The method of claim 3, wherein the dynamically adjusted
transmission time interval is at least one of 2 ms or 10 ms.
6. The method of claim 1, wherein the at least one indicator
related to the at least one communication link condition comprises
at least one of a packet error rate, a pilot channel signal to
noise ratio, or a transmission power headroom indicator.
7. The method of claim 1, wherein the determination of the at least
one transmission time interval based at least in part on the at
least one indicator, is related to information about a metric of
the at least one communication link condition crossing a threshold
value.
8. The method of claim 7, wherein packet error rate is the metric
and the threshold value is between about 0.1% and about 5% for a
period between about one transmission time interval and about 1
second.
9. The method of claim 1, wherein the at least one indicator
further comprises information received relating to a plurality of
metrics further relating to a plurality of communication link
conditions corresponding to respective ones of a plurality of user
equipment, wherein the resulting determination of the at least one
transmission time interval comprises a plurality of transmission
time intervals, and wherein each of the plurality of user equipment
is instructed to employ a respective one of the plurality of
determined transmission time intervals based on the respective
communication link condition.
10. The method of claim 9, wherein at least a first of the
plurality of user equipment is instructed to employ a first
transmission time interval and at least a second of the plurality
of user equipment is instructed to employ a second transmission
time interval that is different than the first transmission time
interval.
11. The method of claim 1, wherein the determination of at least
one transmission time interval is related to optimizing data
throughput in relation to the at least one communication link
condition.
12. A computer-readable medium storing computer executable codes,
comprising: a first set of codes for causing a computer to monitor,
at a radio network controller, at least one indicator related to at
least one communication link condition; a second set of codes for
causing the computer to determine at the radio network controller,
based at least in part on the at least one indicator, at least one
transmission time interval to facilitate communication over the at
least one communication link; and a third set of codes for causing
the computer to communicate, from the radio network controller, at
least one instruction, for at least one user equipment employing
the at least one communication link, to employ at least one
determined transmission time interval during at least one of an
established communications event, a voice call, a data call, a
soft-handoff condition, or any combination thereof
13. The computer-readable medium of claim 12, further comprising a
fourth set of codes for causing a computer to receive, at the radio
network controller, at least one indicator that cannot be directly
monitored by the radio network controller, related to at least one
communication link condition, wherein determining at least one
transmission time interval to facilitate communication over the at
least one communication link is based at least in part on at least
one of the received indicators.
14. An apparatus, comprising: means for monitoring, at a radio
network controller, at least one indicator related to at least one
communication link condition; means for determining at the radio
network controller, based at least in part on the at least one
indicator, at least one transmission time interval to facilitate
communication over the at least one communication link; and means
for communicating, from the radio network controller, at least one
instruction, for at least one user equipment employing the at least
one communication link, to employ at least one determined
transmission time interval during at least one of an established
communications event, a voice call, a data call, a soft-handoff
condition, or any combination thereof.
15. The apparatus of claim 14, further comprising: means for
communicating to a radio network controller, at least one indicator
that cannot be directly monitored by the radio network controller,
related to at least one communication link condition, wherein
determining at least one transmission time interval to facilitate
communication over the at least one communication link is based at
least in part on at least one of the received indicators.
16. A radio network controller (RNC) comprising: a memory
comprising a TTI determination component module having a
communications condition analyzer component, a TTI selection logic
component, and an input/output component; a processor in
communication with the memory and operable to form a TTI window
instruction based at least in part on TTI window information;
wherein the communications condition analyzer component is operable
to analyze a communication condition between the RNC and at least
one UE; wherein the TTI selection logic component is operable to
determine at least one appropriate TTI window based at least in
part on the analysis of the communications condition; wherein the
input/output component can at least receive incoming information
related to communication conditions and communicate said
communication condition information to the communications condition
analyzer, and further can at least receive the determined TTI
window information from the TTI selection logic component and
communicate said TTI window information to the processor; a
communications module in communication with the memory and the
processor and operable to receive a transmission relating to
communications condition indicia; wherein the TTI determination
component module is operable to generate at least one instruction
relating to dynamically adjusting a TTI window between the RNC and
the at least one UE during at least one of an established
communications event, a voice call, a data call, a soft-handoff
condition, or any combination thereof; and wherein the
communications module is further operable to receive the
dynamically adjusted TTI window instruction and communicate said
instruction to the least one UE.
17. The RNC of claim 16, wherein the communications condition
analyzer component is operable to receive externally analyzed
information related to the communication condition between the RNC
and the at least one UE from the input/output component and the TTI
selection logic component is operable to determine the at least one
appropriate TTI window based at least in part on the received
communications condition information.
18. The RNC of claim 17, wherein the TTI window instruction
instructs a UE in communication with the RNC over a communication
link, to dynamically adjust the TTI used in the established
communication link.
19. The RNC of claim 18, wherein the dynamically adjusted TTI is
different than an immediately prior TTI used in the established
communication link.
20. The RNC of claim 18, wherein the dynamically adjusted TTI is at
least one of 2 ms or 10 ms.
21. The RNC of claim 17, wherein the information related to
communication condition between the RNC and at least one UE
comprises at least one of a packet error rate, a pilot channel
signal to noise ratio, or a transmission power headroom
indicator.
22. The RNC of claim 17, wherein the determination of at least one
appropriate TTI window based at least in part on the received
communications condition information, is related to information
about a metric of the communications condition crossing a threshold
value.
23. The RNC of claim 22, wherein packet error rate is the metric
and the threshold value is between about 0.1% and about 5% for a
period between about one transmission time interval and about 1
second.
24. The RNC of claim 22, wherein the received communications
condition information further comprises information received
relating to a plurality of metrics further relating to a plurality
of communication link conditions corresponding to respective ones
of a plurality of user equipment, wherein the resulting
determination of at least one appropriate TTI comprises a plurality
of TTIs, and wherein each of the plurality of user equipment is
instructed to employ a respective one of the plurality of
determined TTIs based on the respective communication link
condition.
25. The RNC of claim 24, wherein at least a first of the plurality
of user equipment is instructed to employ a first transmission time
interval and at least a second of the plurality of user equipment
is instructed to employ a second transmission time interval that is
different than the first transmission time interval.
26. The RNC of claim 13, wherein the determination of at least one
appropriate TTI window based at least in part on the received
communications condition information, is related to optimizing data
throughput in relation to the communication link condition.
Description
CLAIM OF PRIORITY UNDER 35 U.S.C. .sctn.119
[0001] The present Application for patent is a divisional of U.S.
application Ser. No. 12/104,795, "METHOD AND APPARATUS FOR DYNAMIC
ADJUSTMENT OF UPLINK TRANSMISSION TIME" filed Apr. 17, 2008, which
claims priority to Provisional Application No. 60/913,262, "Method
and Apparatus for Dynamic Adjustment of Uplink Transmission Time"
filed Apr. 20, 2007, and assigned to the assignee hereof and hereby
expressly incorporated by reference herein.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates generally to communication,
and more specifically to techniques for dynamically adjusting the
transmission timing interval (TTI) in a communication system.
[0004] 2. Background
[0005] Communication systems are widely deployed to provide various
communication services such as voice, packet data, and so on. These
systems can be multiple-access systems capable of supporting
communication with multiple users simultaneously by sharing the
available system resources. Examples of such multiple-access
systems include Code Division Multiple Access (CDMA) systems, Time
Division Multiple Access (TDMA) systems, Frequency Division
Multiple Access (FDMA) systems, and Orthogonal Frequency Division
Multiple Access (OFDMA) systems.
[0006] A communication system can employ a transmission time
interval (TTI) for transmission of data between communication
system components (e.g., between user equipment (UE) and a base
station (BS or NodeB)). For example, a NodeB may transmit one or
more data packets to a receiver in a given TTI, wherein the TTI can
be based on the transmission conditions, commonly referred to as
the link budget. Generally, the link budget refers to the gains and
losses in a signal transmitted between a transmitter and a receiver
in a communications system and therefore accounts for attenuated
signals, antenna gains, and other gains and losses. For example,
the received power is equal to the transmitted power minus losses
plus gains for that NodeB. As such, all transmissions within a
given NodeB can utilize a common TTI. Under current standards,
communications systems can select either a 2 millisecond (ms) or 10
ms TTI. Conventionally, communications systems select either the 2
ms or 10 ms TTI when establishing a communications event (e.g., a
voice call, data call, or combinations thereof, . . . ). Further
conventional systems typically employ the same TTI for all UE-NodeB
pairs in a given communications region (e.g., a cell).
[0007] There is therefore a need in the art to be able to
dynamically select TTI's within an established communication
session and further to be able to individually dynamically select
TTI's for a plurality of mobile devices within a transmission
region.
SUMMARY
[0008] The following presents a simplified summary of one or more
aspects in order to provide a basic understanding of such aspects.
This summary is not an extensive overview of all contemplated
aspects, and is intended to neither identify key or critical
elements of all aspects nor delineate the scope of any or all
aspects. Its sole purpose is to present some concepts of one or
more aspects in a simplified form as a prelude to the more detailed
description that is presented later.
[0009] The high speed packet access standard allows both 10
millisecond (ms) transmission time interval (TTI) and 2 ms TTI for
uplink transmission operations. High speed packet access (HSPA)
encompasses high speed downlink packet access (HSDPA) technology
and high speed uplink packet access (HSUPA) technology and also
includes HSPA+technology. HSDPA, HSUPA and HSPA+are part of the
Third Generation Partnership Project (3GPP) specifications Release
5, Release 6, and Release 7, respectively, which specifications are
expressly incorporated by reference herein. In HSUPA, the 2 ms TTI
can provide lower transmission delays and larger hybrid automatic
repeat request (HARQ) gains. Moreover, the 2 ms TTI can enable
longer battery life in a discontinuous transmission (DTX) mode for
mobile device operation. In contrast, the 10 ms TTI can provide
better link budgeting (e.g., more robust transmissions) and
therefore can be preferred for mobile devices located in regions of
a cell with poorer communication linking conditions.
[0010] The TTI can be shorter, for example, where transmission
conditions are good, and longer, for example, where transmission
conditions are poor. Two common TTI's are 2 ms and 10 ms, where,
for example, the 2 ms TTI can be employed for transmissions in good
conditions (e.g., a UE is close to a BS, there is little
interference, . . . ) and, also for example, the 10 ms TTI can be
employed where conditions are less optimal (e.g., a UE is located
at the NodeB cell edge, there is substantial interference, . . . ).
The transmitter can, for example, transmit more information over
the same total time by selecting the shorter TTI when the
conditions are germane to the use of the shorter TTI (e.g., there
will be more 2 ms TTI windows than 10 ms TTI windows in a given
total time window, such as, for example 200 ms). A transmitter can
also, for example, robustly transmit data (e.g., with a better link
budget) in less optimal conditions by selecting a longer TTI
window.
[0011] Conventional communications systems typically do not
dynamically select TTI windows (e.g., conventional systems do not
adjust TTI's during an established communication session). Further,
conventional communications systems generally do not designate TTIs
for each UE-BS pairing (e.g., one-to-one, many-to-one, or
one-to-many) within a transmission region (e.g., a cell) or for
UE-BS pairings transitioning between transmission regions (e.g., in
soft handoff or experiencing soft-handoff conditions). Rather,
conventional communications systems generally select a static TTI
when establishing a communication session and maintain that
selected TTI for the duration of the communication session. This
can occur where UE capabilities indicate a preferential TTI. Thus,
conventional systems may select a static TTI without deference to
actual communications link conditions. Moreover, this static TTI is
generally applied to every UE-BS pairing in a given region (e.g., a
cell).
[0012] Thus, for example all cell phones in a radio area network
(RAN) cell would be relegated to the same static TTI rate. This can
be detrimental to the overall quality, performance, and efficiency
of communications over the link(s) during an established
communications session. For example, where a cell phone call is
initiated in good conditions, a 2 ms TTI can be selected. As the
cell phone user, for example, drives away from the NodeB, the link
conditions can worsen, even sufficiently to cause, for example,
missed data packets, poor communications quality, or a dropped
call, all while continuing to maintain the 2 ms TTI.
[0013] As a second example, a cell phone call can be initiated
where link conditions are not optimal and a 10 ms TTI can be
selected. The transmission conditions over the link can also
improve, for example, as weather conditions improve. However, where
the TTI in the conventional system has already been selected as 10
ms, the communications link can continue to employ the 10 ms TTI,
inefficiently in light of the improved link conditions that could
support, for example, a 2 ms TTI (e.g., dynamically switching to a
2 ms TTI could provide higher quality and more efficient
communication or data transfer rates).
[0014] As a third example, assuming a plurality of cell phones in a
radio area network (RAN), where some cell phones are under good
conditions and others are under less optimal conditions, all cell
phones in a cell can be told to use 10 ms TTI rates (e.g., the
worst communications condition is used to set the TTI for all cell
phones in the RAN cell). While this can provide robust
communications for all UEs in the cell, where some of the UEs could
have used shorter TTI, they are not optimized and are performing
less efficiently than they could with, for example, a 2 ms TTI.
[0015] In contrast to conventional systems that can assign a
selected TTI to all UEs in a cell, the disclosed subject matter
facilitates dynamically assigning TTI rates to each UE in a cell.
By dynamically assigning TTI rates, it is meant that the TTI rate
for a communications link can be adjusted within an existing
communications event, for example, a cell phone can switch between
2 ms and 10 ms TTIs during a cell phone conversation to maintain
the most optimal performance. This can provide for improved
communications throughput where conditions permit and more rugged
communications where conditions are less optimal. Further, each UE
in the cell can be assigned the most appropriate TTI for that UE's
specific conditions. Under current HSPA standards, 2 ms and 10 ms
TTIs are contemplated and thus, for ease of understanding and
clarity, only these two TTI windows will be used for examples
within the disclosure. One of skill in the art will appreciate that
the disclosed subject matter is not so limited and that any TTI
window can be employed. Thus, where standards change and/or the use
of alternate TTI windows is desirable, these TTI windows are to be
considered within the scope and spirit of the herein disclosed
subject matter. Any specific example employing 2 ms and/or 10 ms
TTIs is not intended to be limiting and is disclosed only as an
example within the current standards.
[0016] In one specific embodiment, a radio network controller (RNC)
dynamically selects the TTI to be employed for communication with
UEs. Selection criteria used by the RNC can include, but are not
limited to, the signal to noise ratio of the pilot signal (Ecp/Nt)
and/or the packet error rate (PER) of one or more UEs. Thus, for
example, where the RNC determines that a UE is currently using a
first TTI and the Ecp/Nt has passed a predetermined threshold
and/or the PER, over a certain time interval, has transitioned a
predetermined limit, then the RNC can facilitate dynamic
reconfiguration of the UE to use an alternate TTI that can
facilitate a more optimal communications link.
[0017] In a second specific embodiment a UE employing a first TTI
can indicate communications link indicia (for example, the
available transmission (TX) power headroom) to a NodeB (for
example, by way of a scheduling information (SI) transmission). The
NodeB can relay this information to a RNC to facilitate a RNC
determination that the communications link is sub-optimal, for
example, that the UE can be TX power headroom limited. Where
non-optimal communications conditions exist (e.g., the UE has
limited TX power headroom), the RNC can facilitate dynamic
reconfiguration of the UE to use an alternate TTI that can
facilitate a more optimal communications link.
[0018] In a third specific embodiment, a UE employing a first TTI
can monitor communications link indicia. These communications link
indicia can include, but are not limited to, power headroom
limitations, change in TX power headroom over time (e.g., slope),
and/or HARQ early termination statistics. The UE can communicate a
UE request that the RNC dynamically reconfigure the UE to use an
alternate TTI that can facilitate a more optimal communications
link. As a non-limiting example, if the available TX power headroom
goes below a predetermined threshold, the UE can request to be
switched to a 10 ms TTI via a layer 3 message to the RNC.
[0019] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 illustrates a wireless communication system.
[0021] FIG. 2 illustrates a schematic diagram of one aspect of a
computer device implementation of one or more of the components of
FIG. 1.
[0022] FIGS. 3A-3C illustrate schematic diagrams of functional
modules in accordance with aspects of the disclosed subject
matter.
[0023] FIG. 4 illustrates a timing diagram for HSUPA compliant
multi-code transmission in accordance with an aspect of the
disclosed subject matter.
[0024] FIG. 5 illustrates a timing diagram for dynamic adjustment
of TTI in accordance with an aspect of the disclosed subject
matter.
[0025] FIG. 6 illustrates comparative timing diagrams for dynamic
TTI adjustment in accordance with aspects of the disclosed subject
matter.
[0026] FIG. 7 illustrates a depiction of elements in a
communications system in accordance with an aspect of the disclosed
subject matter.
[0027] FIG. 8 illustrates a comparative depiction of non-limiting
exemplary dynamic TTI adjustment techniques in accordance with an
aspect of the disclosed subject matter.
[0028] FIG. 9 illustrates a method to facilitate dynamic adjustment
of TTI in accordance with an aspect of the disclosed subject
matter.
[0029] FIG. 10 illustrates a method to facilitate dynamic
adjustment of TTI in accordance with an aspect of the disclosed
subject matter.
[0030] FIG. 11 illustrates a method to facilitate dynamic
adjustment of TTI in accordance with an aspect of the disclosed
subject matter.
[0031] FIG. 12 illustrates a method to facilitate dynamic
adjustment of TTI in accordance with an aspect of the disclosed
subject matter.
DETAILED DESCRIPTION
[0032] Various aspects are now described with reference to the
drawings. In the following description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of one or more aspects. It may be
evident, however, that such aspect(s) may be practiced without
these specific details.
[0033] As used in this application, the terms "component,"
"module," "system" and the like are intended to include a
computer-related entity, such as but not limited to hardware,
firmware, a combination of hardware and software, software, or
software in execution. For example, a component may be, but is not
limited to being, a process running on a processor, a processor, an
object, an executable, a thread of execution, a program, and/or a
computer. By way of illustration, both an application running on a
computing device and the computing device can be a component. One
or more components can reside within a process and/or thread of
execution and a component may be localized on one computer and/or
distributed between two or more computers. In addition, these
components can execute from various computer readable media having
various data structures stored thereon. The components may
communicate by way of local and/or remote processes such as in
accordance with a signal having one or more data packets, such as
data from one component interacting with another component in a
local system, distributed system, and/or across a network such as
the Internet with other systems by way of the signal.
[0034] Furthermore, various aspects are described herein in
connection with a terminal, which can be a wired terminal or a
wireless terminal. A terminal can also be called a system, device,
subscriber unit, subscriber station, mobile station, mobile, mobile
device, remote station, remote terminal, access terminal, user
terminal, terminal, communication device, user agent, user device,
or user equipment (UE). A wireless terminal may be a cellular
telephone, a satellite phone, a cordless telephone, a Session
Initiation Protocol (SIP) phone, a wireless local loop (WLL)
station, a personal digital assistant (PDA), a handheld device
having wireless connection capability, a computing device, or other
processing devices connected to a wireless modem. Moreover, various
aspects are described herein in connection with a base station. A
base station may be utilized for communicating with wireless
terminal(s) and may also be referred to as an access point, a
NodeB, or some other terminology.
[0035] The techniques described herein may be used for various
wireless communication systems such as Code Division Multiple
Access (CDMA), Time Division Multiple Access (TDMA), Frequency
Division Multiple Access (FDMA), Orthogonal Frequency Division
Multiple Access (OFDMA), Single Carrier Frequency Division Multiple
Access (SC-FDMA or SCFDMA) and other systems. The terms "system"
and "network" are often used interchangeably. A CDMA system may
implement a radio technology such as Universal Terrestrial Radio
Access (UTRA), Code Division Multiple Access 2000 (CDMA2000 or
cdma2000.RTM.), etc. UTRA includes Wideband-CDMA (W-CDMA) and other
variants of CDMA. CDMA2000 covers IS-2000, IS-95 and IS-856
standards. A TDMA system may implement a radio technology such as
Global System for Mobile Communications (GSM). An OFDMA system may
implement a radio technology such as Evolved UTRA (E-UTRA), Ultra
Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),
IEEE 802.20 (Mobile Broadband Wireless Access (MBWA)), Fast
Low-latency Access with Seamless Handoff Orthogonal Multiplexing
(FOFDM or Flash-OFDM.RTM.), etc. UTRA and E-UTRA are part of
Universal Mobile Telecommunication System (UMTS). 3rd Generation
Partnership Project (3GPP) Long Term Evolution (LTE) is an upcoming
release of UMTS that uses E-UTRA, which employs OFDMA on the
downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE and GSM
are described in documents from an organization named "3rd
Generation Partnership Project" (3GPP). CDMA2000 and UMB are
described in documents from an organization named "3rd Generation
Partnership Project 2" (3GPP2).
[0036] Moreover, the term "or" is intended to mean an inclusive
"or" rather than an exclusive "or." That is, unless specified
otherwise, or clear from the context, the phrase "X employs A or B"
is intended to mean any of the natural inclusive permutations. That
is, the phrase "X employs A or B" is satisfied by any of the
following instances: X employs A; X employs B; or X employs both A
and B. In addition, the articles "a" and "an" as used in this
application and the appended claims should generally be construed
to mean "one or more" unless specified otherwise or clear from the
context to be directed to a singular form.
[0037] Turning to FIG. 1, illustrated is a wireless communication
system 100 with a number of base stations 110 that support
communication for a number of wireless terminals 120. A base
station is a fixed station used for communicating with the
terminals and can also be called an access point, a base
transceiver station (BTS), a NodeB, or some other terminology. A
terminal may be fixed or mobile and may also be called a mobile
station (MS), a mobile equipment (ME), a user equipment (UE), a
wireless device, a subscriber unit, or some other terminology. The
terminals may be dispersed throughout the system. Each base station
may communicate with any number of terminals at any given moment
depending on various factors such as, for example, the number of
terminals within the coverage (e.g., cell) of the base station, the
available system resources, the data requirements of the terminals,
and so on. A system controller 130 provides coordination and
control for the base stations. The system controller may comprise a
radio network controller (RNC) (not illustrated). Transmission
protocols between the terminals and base station can include TTI
widows as part of the protocol, for example, as described in the
3GPP specification releases 5, 6 and/or 7, among other
specifications.
[0038] Typically, the 3GPP release 6 (and release 7) standard
allows 10 ms transmission time interval (TTI) or 2 ms TTI for
uplink operation, as herein described. Generally, the 2 ms TTI
provides lower transmission delay, larger HARQ gain, longer UE
battery life, or combinations thereof Further, as disclosed herein,
the 10 ms TTI can provide more robust communications over, for
example, less optimal communications links and may therefore be
preferred for UEs at a cell edge, experiencing soft-handoff
conditions, or in soft handoff.
[0039] Specifically, the 3GPP release 6 (HSUPA) standard designates
an enhanced uplink dedicated channel (EDCH), one or more EDCH
dedicated physical channels (EDPDCH) (up to 4 EDPDCH channels
currently allowed), and an EDCH dedicated physical control channel
(EDPCCH), each of which can communicate information within a single
TTI, wherein the TTI can be 2 ms or 10 ms in HSUPA. The EDCH
carries a single transport block per TTI. The EDCH is mapped to the
one or more (up to 4) EDPDCH. The EDPDCH uplink channels can
include a header, a payload, and scheduling information with the
TTI. The EDCH is associated with the EDPCCH. The EDPCCH uplink
channel can include control information (e.g., a sequence
identification number and an indicator of the transport format) and
a resource status indicator (e.g., indicates to the NodeB that the
UE granted data rate is, or is not, satisfactory). The EDCH can
include data in a single transport block set (TBS). Employing these
uplink channels (among others), data can be uploaded from the UE to
the NodeB in either 2 ms or 10 ms TTIs in compliance with the 3GPP
specification (e.g., release 6 and/or 7).
[0040] Conventional HSUPA (and HSUPA+) networks typically employ
either the 10 ms TTI or 2 ms TTI for a communication link with the
UE. The TTI is assigned to UEs by way of a reconfiguration message
sent to the UE from a RNC. The RNC can assign a TTI for all UEs in
a cell. For example, in large cells which can have link budget
problems with a 2 ms TTI, a 10 ms TTI can be assigned to all UE in
the cell, which can improve cell performance but also can reduce
transmission capacity and battery life. In any given period of
time, more short TTI windows can occur than long TTI windows. Thus,
short TTIs (e.g., 2 ms TTIs) generally can be employed to carry
information more efficiently by sending the information in more
individual transport block sets (TBS) per given time period, for
example five 2 ms TTI can be sent in the same time as one 10 ms
TTI. Generally it can be preferential to employ shorter TTI (e.g.,
2 ms TTI), where germane to the communications system, over longer
TTI (e.g., 10 ms TTI) because of the possibility of improved
performance (e.g., transmitting more information in less total
time). However, where the communications system cannot support the
shorter TTI because of system conditions, (e.g., Ecp/Nt ratio
cannot be increased due to limited TX power headspace, the packet
error rate (PER) is excessively high for the shorter TTI, . . . )
the longer TTI (e.g., 10 ms TTI) can be preferential.
[0041] Referring to FIG. 2, the components of system 100 (FIG. 1)
may be embodied in a computer device 200 that includes a memory 210
in communication with a processor 220. Memory 210 is operable for
storing applications for execution by processor 220. Memory 210 can
include random access memory (RAM), read only memory (ROM), and a
combination thereof. In particular, each component of system 100
(FIG. 1) may include one or more functional modules, applications,
or programs 230 operable to perform the component-specific actions
described herein. Further, processor 220 is operable for carrying
out processing functions associated with one or more of the
components described herein. Processor 220 can include a single
processor or multiple sets of processors or multi-core processors.
Moreover, processor 220 can be implemented as an integrated
processing system and/or a distributed processing system.
[0042] Additionally, computer device 200 includes user interface
240 operable to receive inputs from a user of a UE 120, and to
generate outputs for presentation to the user. User interface 240
can include one or more input devices, including but not limited to
a keyboard, a number pad, a mouse, a touch-sensitive display, a
navigation key, a function key, a microphone, a voice recognition
component, any other mechanism capable of receiving an input from a
user, or any combination thereof. Further, user interface 240 can
include one or more output devices, including but not limited to a
display, a speaker, a haptic feedback mechanism, a printer, any
other mechanism capable of presenting an output to a user, or any
combination thereof
[0043] Further, computer device 200 includes a communications
component 250 that provides for establishing and maintaining
communications with one or more other components utilizing
hardware, software, and services. Communications component 250 can
carry communications between components on computer device 200, as
well as between computer device 200 and external devices, such as
access point system controller 130 or NodeB 110 (FIG. 1), other
network-side or infrastructure elements, or other devices serially
or locally connected to computer device 200. Communications
component 250 includes a receiver to receive communications and a
transmitter to transmit communications. Further, communications
component 250 includes the corresponding receive chain components
and transmit chain components to enable exchanging messages
according to one or more respective protocols. Additionally,
computer device 200 can further include database 260, which can be
any suitable combination of hardware and/or software, that provides
for mass storage of data/information, data relationships, and
software programs/applications employed in connection with aspects
described herein when not in use in active memory 210.
Additionally, database 260 can store one or more functional
modules/programs/applications 230 when the respective applications
are not in active memory 210.
[0044] Referring to FIG. 3, illustrated are schematic diagrams of
functional modules in accordance with aspects of the disclosed
subject matter. Specifically with regard to FIG. 3A, depicted is a
schematic diagram of a functional module in one embodiment of a
dynamic TTI adjustment communications system in accordance with
aspects of the disclosed subject matter. In an embodiment, the TTI
determination component 300 can be located in an RNC (e.g., in the
system controller 130 (see FIG. 1), or in the RNC of FIGS. 7 and
8). In alternative embodiments, the TTI determination component 300
can be located in a NodeB, in other portions of a system controller
(e.g., 130 of FIG. 1), or in similar computer implemented portion
of a communications system germane to determining an optimal TTI
and communicating an instruction to the UE to dynamically adjust
the TTI window. The TTI determination component 300 can be a single
component or can be formed in a distributed manner. Further, the
components of the TTI determination component 300 can be embodied
in shared components, for example, the communication module 250
(see FIG. 2) can function as the I/O component 315 of TTI
determination component 300. Further, TTI determination component
300 can include a communications condition analyzer component 305
that can analyze the communications condition (e.g., the link
budget) of a communications link between, for example, a UE and a
NodeB. The analysis can be based on indicia of communications link
conditions including, among others, the Packet Error Rate (PER),
transmission (TX) power level, and/or the Pilot channel signal to
noise ratio (Ecp/Nt).
[0045] The communications condition analyzer component 305 can be
communicatively coupled to a TTI selection logic component 310. The
TTI selection logic component 310 can determine a most optimal TTI
window for the communications link between, for example, the UE and
NodeB. The determination can be based, at least in part, on the
analysis of the communications condition from component 310.
Further, the determination can be based on additional factors
including, for example, business goals, inferences about future
communications system conditions (e.g., determined by an artificial
intelligence component (not illustrated)), or a predetermined logic
pattern, among other factors related to improving communications
system performance by selecting an appropriate TTI.
[0046] TTI Determination component 300 can further include an
input/output (I/O) component 315. The I/O component 315 can be
employed to receive information into, or send information from, the
TTI determination component 300. For example, the I/O component 315
can receive indicia related to the communications condition for
analysis in the communications condition analyzer component 305.
Similarly, for example, the I/O component 315 can communicate the
selected TTI from TTI selection logic component 310 to, for example
a transmitter (not illustrated) to be sent to a UE.
[0047] Turning to FIG. 3B, depicted is a schematic diagram of a
functional module in one embodiment of a dynamic TTI adjustment
communications system in accordance with aspects of the disclosed
subject matter. In an embodiment, the TTI determination component
330 can be located in an RNC (e.g., in the system controller 130
(see FIG. 1), or in the RNC of FIGS. 7 and 8). In alternative
embodiments, the TTI determination component 300 can be located in
a NodeB, in other portions of a system controller (e.g., 130 of
FIG. 1), or in similar computer implemented portion of a
communications system germane to determining an optimal TTI and
communicating an instruction to the UE to dynamically adjust the
TTI window. The TTI determination component 300 can be a single
component or can be formed in a distributed manner. Further, the
components of the TTI determination component 300 can be embodied
in shared components, for example, the communication module 250
(see FIG. 2) can function as the I/O component 315 of TTI
determination component 300. TTI determination component 330 can
include a communications condition input component 335 that can
receive indicia related to an external analysis of a communications
condition (e.g., the link budget) of a communications link between,
for example, a UE and a NodeB. The external analysis can be based
on indicia of communications link conditions including, among
others, the Packet Error Rate (PER), TX power level, UE TX power
headroom and/or the Pilot channel signal to noise ratio (Ecp/Nt).
By receiving an externally analyzed communications condition, this
information can be directly acted upon with or without further
processing.
[0048] The communications condition input component 335 can be
communicatively coupled to a TTI selection logic component 340. TTI
selection logic component 340 can be the same as, or similar to,
TTI selection logic component 310. The TTI selection logic
component 340 can determine a most optimal TTI window for the
communications link between, for example, the UE and NodeB. The
determination can be based, at least in part, on the analysis of
the communications condition from component 340. Further, the
determination can be based on additional factors including, for
example, business goals, inferences about future communications
system conditions (e.g., determined by an artificial intelligence
component (not illustrated)), or a predetermined logic pattern,
among other factors related to improving communications system
performance by selecting an appropriate TTI.
[0049] TTI Determination component 330 can further include an
input/output (I/O) component 345. The I/O component 345 can be
employed to receive information into, or send information from, the
TTI determination component 330. For example, the I/O component 345
can receive externally analyzed communications condition
information and pass this to the communications condition input
component 335. Similarly, for example, the I/O component 345 can
communicate the selected TTI from TTI selection logic component 340
to, for example a transmitter (not illustrated) to be sent to a
UE.
[0050] Turning to FIG. 3C, depicted is a schematic diagram of a
functional module in one embodiment of a dynamic TTI adjustment
communications system in accordance with aspects of the disclosed
subject matter. . In an embodiment, the UE based TTI request
component 360 can be located in a UE (e.g., in a UE 120 (see FIG.
1), in a cell phone, a PDA, a laptop computer, or other UE as
herein described). In alternative embodiments, the UE based TTI
request component 360 can be located in a NodeB. The UE based TTI
request component 360 can be a single component or can be formed in
a distributed manner, for example between the UE and a NodeB.
Further, the components of the UE based TTI request component 360
can be embodied in shared components, for example, the
transmitter/receiver of a UE 120 (see FIG. 1) can function as the
local TTI request generator component 375 of the UE based TTI
request component 360.
[0051] The UE based TTI request component 360 can include a
communications condition analyzer component 365 that can be the
same as, or similar to, communications condition analyzer component
305. The communications condition analyzer component 365 can
analyze the communications condition (e.g., the link budget) of a
communications link between, for example, a UE and a NodeB, based
at least in part on communications indicia that can be monitored by
a UE. The analysis can be based on indicia of communications link
conditions including, among others, the TX power headroom, the rate
of change over time of the TX power headroom, actual TX power
level, and/or the Pilot channel signal to noise ratio (Ecp/Nt).
[0052] The communications condition analyzer component 365 can be
communicatively coupled to a local TTI selection logic component
370. Local TTI selection logic component 370 can determine a most
optimal TTI window for the communications link between, for
example, the UE and NodeB. This determination can be based, at
least in part, on the analysis of the communications condition from
component 365. Thus, the local TTI determination is in general
based on an analysis of the communication condition from the UE
perspective.
[0053] UE based TTI request component 360 can further include a
local TTI request generator component 375 (which can be similar to
I/O component 315). The local TTI request generator component 375
can be employed to receive information into, or send information
from, the UE based TTI request component 360. For example, the
local TTI request generator component 375 can receive
communications condition information available to the UE and pass
this to the communications condition analyzer component 365.
Similarly, for example, the local TTI request generator component
375 can communicate the selected local TTI from local TTI selection
logic component 370 to, for example a transmitter (not illustrated)
to be sent to the RNC.
[0054] The local TTI request generator component 375 also
specifically can be employed to generate a TTI request that can be
communicated to the RNC. The TTI request can be based at least in
part on the local TTI selection logic component 370 determination.
Thus, where the local communications conditions (e.g., the link
budget indicia perceivable by the UE) are analyzed, a local TTI
determination based at least in part thereon can be formed. This
local TTI determination can then be employed in forming a TTI
request that can be sent to, for example, the RNC. The RNC can then
make further determinations (not illustrated) relating to
fulfilling the local TTI request and can, based on these additional
determinations (not illustrated) send instructions to the UE to
adjust the TTI based at least in part on the local TTI request.
[0055] Referring now to FIG. 4, illustrated is a timing diagram 400
for HSUPA transmissions. Information can be transmitted within each
TTI 410. As discussed herein, the EDCH 410 can be extended by
mapping onto as many as four EDPDCH 420 under current 3GPP
specifications (rel. 6). In this example (e.g., in accord with rel.
6 of the 3GPP specification), the TTI can be 2 ms or 10 ms. The
3GPP specification typically can facilitate data rates of several
Mbit/s over HSPA (e.g., 3GPP rel. 6) by increasing capacity of
existing mobile radio networks. This can be particularly useful for
systems requiring high data throughput, for example, voice over
internet protocol (VoIP), video conferencing, and mobile office
applications. Further improvements are possible under HSPA+ (e.g.,
3GPP rel. 7).
[0056] In contrast to conventional systems where a static TTI is
assigned for a communications session with a UE, in accordance with
the disclosed subject matter, a TTI can be dynamically assigned to
each UE within a communications system depending on the
communication conditions specific to the respective UE. Thus, where
communications systems conditions change, the TTI can be changed
within the continuing communications session events. For example, a
determination can be made based in part on a UE's link budget
requirements that a transition from a first TTI to a second TTI can
facilitate improved communications system performance. The
disclosed subject matter is not limited to selecting between a
specific set of TTIs, however, for simplicity and ease of
understanding under current communications system industry
specifications, the examples and discussion herein are generally
described with respect to examples of 2 ms and 10 ms TTIs. It is
noted, however, that other temporal windows for TTIs can be
employed where they conform to industry or application standards,
and that all such TTIs are considered within the scope and spirit
of the disclosure.
[0057] Referring now to FIG. 5, a diagram 500 for dynamic
adjustment of TTIs in accordance with the disclosed subject matter
is illustrated. A plot of a determining factor (DF) against time is
given illustrating a threshold level (Threshold 502) and a
determining factor level (DF Level 504) changing with time. Where a
communications system can be employing 2ms TTIs for communicating
data at 510, this can continue until the DF Level 504 exceeds the
threshold level 502 at 520. Where the DF Level 504 exceeds the
Threshold 502 at 520, the communications system (e.g., the RNC) can
dynamically adjust the TTI from a 2 ms TTI at 530 to a 10 ms TTI at
540 to facilitate continued communications over the established
communications link. For example, a reconfiguration message from
the RNC can be transmitted to the UE to instruct the UE to employ
the new TTI. Similarly, where the DF Level 504 drops below the
Threshold 502 at 550, the communications system can dynamically
adjust the TTI from a 10 ms TTI at 560 to a 2 ms TTI at 570 to
facilitate continued communications over the established
communications link. As stated herein, the disclosed subject matter
is not limited to 2 ms and/or 10 ms TTIs and these specific TTI
windows are used only as non-limiting examples because they comply
with current industry standards (e.g., 3GPP rel. 6 and 7). Where
other TTI windows comport with relevant industry or applications
standards, these TTI windows are to be considered within the scope
of the disclosed subject matter.
[0058] As an example based on the transitions illustrated in FIG. 5
(and relevant under current standards as herein disclosed), where a
cell phone call begins near a NodeB, the transmission conditions
can be sufficiently good (e.g., the conditions are able to sustain
a communications link at a predetermined HARQ residual error rate,
packet error rate (for example, 0% to 2%, among others), TX power
headroom, . . . , or combinations thereof). This will prove very
valuable in overcoming possible USPTO Examiner rejections against
prior art that may be raised.] to support a 2 ms TTI (e.g., 510)
which can be preferred over a longer TTI (for example, the 2 ms TTI
can be more efficient than the 10 ms TTI because of higher
information throughput, . . . ). Then, as the phone call continues,
the cell phone user can enter an elevator where the communications
conditions are impaired (e.g., DF Level 504 exceeds Threshold 502
at 520). Where the communications system was using 2 ms TTI windows
for data transmission (e.g., 530), the RNC can designate that a 10
ms TTI should be used to maintain the telephone call (e.g., RNC can
instruct a transition from 2 ms TTI 530 to 10 ms TTI 540). The
longer TTI can be used while the cell phone call continues in the
elevator by employing conventional cell phone methods to maintain
the best connection with 10 ms TTI windows (e.g., increasing TX
power levels to maintain the link where there is interference
caused by the elevator shaft, . . . ). While using the longer TTI,
the transmissions can be, for example, less efficient (e.g., more
power used with higher TX power levels, less information transfer
over a given total time interval, . . . ), but this can be
preferable to, for example, not being able to close the
communications link. The cell phone user can then leave the
elevator upon reaching their desired floor, at which time the DF
Level 504 can decrease to below the Threshold 502 level (e.g., at
550). In response, the RNC can designate that the efficiency of the
communication link can be improved by again transitioning the TTI
(e.g., more information transferred in a given total time window, .
. . ), this time from a 10 ms TTI (e.g., 560) to a 2 ms TTI (e.g.,
570). It is to be appreciated that the disclosed subject matter can
facilitate dynamically adjusting between at least two TTIs based at
least in part on the communications condition (e.g., link budget)
of the respective UE-NodeB pairs.
[0059] Referring now to FIG. 6, in another aspect, where a
plurality of UEs are present within a communication system 600,
each UE can be instructed by the RNC to employ an appropriate TTI
for each of the respective communications links. In contrast to
conventional systems where a single TTI is generally assigned to
all UEs in a cell, based upon the worst communications link
conditions, the disclosed subject matter facilitates dynamic TTI
transitioning over time for each individual UE in the cell. Thus, a
first UE 610 can employ a 10 ms TTI and, over time, transition to a
2 ms TTI based on changing communications conditions specific to
first UE 610, while a second UE 620 employs only a 10 ms TTI, a
third UE 630 employs only a 2 ms TTI, and a fourth UE 640 employs a
10 ms TTI and transitions to a 2 ms TTI then to a 10 ms TTI and
back to a 2 ms TTI. Thus, dynamic adjustment of the TTI can
facilitate more optimal and efficient communications systems as
compared to relegating all UEs in a cell to the "lowest common
denominator" TTI.
[0060] In accordance with an aspect of the disclosed subject
matter, dynamic adjustment of TTIs can be determined based at least
in part on a determining factor (DF) transitioning a threshold
level (e.g., 504), as herein disclosed. The DF can be a single
indicium, a combination of different indicia, or an inference based
at least in part on an indicium. The indicium or indicia are
typically related to the communications link conditions, such that
the dynamic adjustment of the TTI can facilitate more optimum data
communications between a BS and a UE. Thus, while good
communication link conditions can allow use of both a 2 ms and 10
ms TTI, the more optimal TTI of the communication link can be the 2
ms TTI where this facilitates faster communication of data between
the UE and the BS. However, other factors or indicia can be
included in a determination for dynamically adjusting the TTI. For
example, where the link conditions are good and both a 2 ms and 10
ms TTI can be employed, the 10 ms TTI can be selected where the
data transmission rate is sufficiently low so as not to need the 2
ms TTI.
[0061] Similarly, where the link conditions are good enough to
support both the 2 ms and 10 ms TTI, the 10 ms TTI can be selected
because it is determined that the UE is in soft handoff to another
BS where the 10 ms TTI is preferable, or because it is determined
that the UE is experiencing soft-handoff conditions wherein the 10
ms TTI would provide a better communication link. In a specific
example, the packet error rate (PER) can be employed as a DF such
that, for example, as the PER exceeds 1% the RNC can dynamically
transition to the 10 ms TTI to facilitate maintaining the
communications link without excessive packet errors. As a second
specific example, the Pilot channel signal to noise ratio (Ecp/Nt)
can be employed as a DF such that, for example, where the Ecp/Nt
has reached a threshold through being increased to compensate for
increasing error rates, the RNC can dynamically adjust to a 10 ms
TTI to allow a lower Ecp/Nt to be employed (e.g., a TX power
headroom limited state can be an indicator of a need to dynamically
transition between TTIs). Similarly, where PER and/or Ecp/Nt are
used as indicia, they can also indicate that a transition to a
shorter TTI is appropriate, for example, where the PER is below a
threshold (for example below 1%), the RNC can initiate a dynamic
transition to a 2 ms TTI to facilitate more efficient data
transmissions across the communications link. Where the
communication condition (e.g., link budget) can be affected by a
nearly limitless number of factors, a similarly large number of
other indicia related to the link budget can be employed to
facilitate determining when to dynamically adjust the TTI, and all
such communication condition indicia (e.g., link budget indicia)
are considered within the scope of the disclosed subject
matter.
[0062] Referring now to FIG. 7, illustrated is a diagram of a
system 700 facilitating dynamic adjustment of TTI in accordance
with an aspect of the disclosed subject matter. System 700 can
comprise multiple base stations (NodeB). Each NodeB can be
communicatively coupled to an RNC (in FIG. 7 the two NodeB are
connected to a single RNC for simplicity of illustration, however
the disclosed subject matter is not so limited). The RNC can
dynamically adjust the TTI of each UE in system 700 independently.
For example, cell phone 710 can be instructed to employ a 2 ms TTI
when it is located near a NodeB and has good communications link
conditions. Further, for example, cell phone 720 can be instructed
to employ a 10 ms TTI because it can have poor communications link
conditions due to being located near to the cell edge. Moreover,
PDA 730 can be directed to transition from a 2 ms TTI to a 10 ms
TTI as the PDA 730 approaches the cell edge, or when PDA 730
experiences soft-handoff conditions or is in a soft-handoff. As
such, depending on the communications conditions experienced by
PDA, the RNC can instruct the PDA 703 to dynamically adjust its TTI
to maintain a satisfactory closed link. As discussed at length
herein, the disclosed subject matter is not limited to TTIs of 2 ms
and 10 ms, but rather can employ TTIs of any duration where germane
to the communications system.
[0063] Referring now to FIG. 8, illustrated are diagrams of syste
ms 800, 820, 850 to facilitate dynamic adjustment of TTI in
accordance with aspects of the disclosed subject matter. System 800
can comprise one or more UEs 802, one or more NodeBs 804, and one
or more RNCs 806. The UEs 802 can be communicatively coupled to the
NodeBs 804 by a wireless connection. Information can be
communicated from the UEs 802 to the RNCs 806 by way of the NodeBs
804. In one embodiment of the disclosed subject matter, this
information can include both communication information/data (e.g.,
an information payload, VoIP packets, voice information,
application data, . . . ) and communication link information (e.g.,
Ecp/Nt, PER, quality of service data, . . . ).
[0064] The RNCs 806 can monitor 810 the information communicated to
it by way of the NodeBs 804. Monitoring by the RNCs 806 can be done
in a continuous, synchronous, or asynchronous manner. Where the
monitoring is done in a continuous manner, the monitored
information can be continually updated to facilitate forming a
determination 810 related to indicia relating to dynamically
adjusting TTI. Similarly, in synchronous monitoring 810, the
indicia can be monitored on a predetermined regular schedule such
that the monitored information is updated at regular intervals to
facilitate forming a determination 810 related to indicia relating
to dynamically adjusting TTI. Additionally, asynchronous monitoring
810 can be employed to update monitoring information at irregular
intervals, such as, but not limited to, when a call is initiated,
when a soft handoff occurs, when a particular level of data
throughput occurs, when total traffic through the RNC 806 from
multiple UEs 802 occurs, during specific periods of the day (e.g.,
high call volume periods, . . . ), or combinations thereof among
others.
[0065] The indicia monitored at 810 can be employed in determining
when dynamic adjustment of TTI is appropriate. Generally speaking,
system 800 employs the RNC 806 to monitor and determine 810 when a
dynamic adjustment of TTI should occur without placing substantial
additional burden on either the NodeB 804 or the UEs 802 in the
system 800. Where a determination is made at 810 that a dynamic TTI
adjustment is appropriate, the RNC 806 can initiate the dynamic TTI
adjustment by instructing the UE 802 to change from a first TTI to
a second TTI.
[0066] System 800 further supports assigning a TTI to each UE 802
depending on communications link conditions. Thus, system 800 can
monitor indicia and determine 810 employing an initial TTI (e.g.,
when a communication link is formed, the RNC 806 of system 800 can
instruct UE 802 to begin with the most appropriate TTI, such as a 2
ms TTI or a 10 ms TTI). For example, the link budget requirements
of each UE 802 in system 800 can be employed in monitoring and
determining 810 assignment of a TTI. Thus UEs 802 at the cell edge,
for example, having insufficient transmit power can be assigned 10
ms TTI by the RNC 806. Moreover, other UEs 802 can be assigned 2 ms
TTI where the respective communications link conditions are
sufficient to support 2 ms TTI. This can result in a fully
supported mixed TTI system, as herein disclosed.
[0067] In one example in accordance with the disclosed subject
matter, system 800 can facilitate the RNC 806 monitoring indicia,
such as, the Ecp/Nt setpoint and packet error rate (PER) of each UE
802. In this example, if RNC 806 detects that a UE 802 is currently
using 2 ms TTI and the Ecp/Nt setpoint has passed a certain
threshold and/or the communication link PER over a certain time
interval is beyond acceptable limit, then the RNC 806 can determine
that UE 802 can have limited TX power headroom and can be unable to
maintain closing the communications uplink (e.g., the call is in
danger of being dropped). In response, the RNC 806 can send a
reconfiguration message to UE 802 (by way of NodeB 804) instructing
the UE 802 to transition to a 10 ms TTI from the 2 ms TTI to
facilitate continued communication (e.g., a dynamic adjustment of
the TTI). This non-limiting exemplary system 800 would not require
any standards change under the 3GPP rel. 6 or rel. 7 standards
(HSUPA or HSPA+respectively).
[0068] The RNC 806 can determine an optimum TTI for each UE 802 of
system 800. Optimum TTIs can be based on numerous system factors
including, but not limited to, overall system 800 performance,
highest data transfer rates, lowest overall power consumption,
alignment of system 800 usage with business goals, etc. Being able
to dynamically adjust the TTI can empower system administrators to
base the dynamic TTI adjustments on a nearly limitless number of
predetermined optimum operating conditions, and all such conditions
are to be considered within the scope of the disclosed subject
matter. For example, RNC 806 can monitor the Ecp/Nt setpoint and
packet error rate (PER) of each UE 802. Where the RNC 806 detects
that a UE 802 is currently using 10 ms TTI and its Ecp/Nt setpoint
is below a certain threshold and its PER is within an acceptable
limit, the RNC can send a reconfiguration message to the UE 802,
requesting the UE 802 to transition from the 10 ms TTI to a 2 ms
TTI to facilitate more efficient use of system 800 resources during
the continued communication link.
[0069] Returning to FIG. 8, system 820 can comprise one or more UEs
822, one or more NodeBs 824, and one or more RNCs 826. The UEs 822
can be communicatively coupled to the NodeBs 824 by a wireless
connection. Information can be communicated from the UEs 822 to the
RNCs 826 by way of the NodeBs 824. In an embodiment of the
disclosed subject matter, this information can include both
communication information/data (e.g., an information payload, VoIP
packets, voice information, application data, . . . ). Further, the
UEs 822 can collect and send specific indicia 830 through the
communication channel to RNC 826 by way of NodeB 824. These indicia
can comprise communication link information (e.g., Ecp/Nt, PER,
quality of service data, TX power headroom information, . . . ).
RNC 826 can receive the indicia and form a determination 840
relating to dynamically adjusting TTI. Thus, system 820 can
function similar to system 800 except that system 820 can include
communicating link information available to the UE 822 (e.g., link
information not directly available to the RNC 826) to improve the
determinations formed at 840 over the determination formed at 810.
In general, system 820 can provide more information into a
determination process relating to dynamically adjusting TTI.
[0070] Thus, where an RNC 826 does not have direct access to select
communications link information (e.g., a UE's 822 TX power
headroom, . . . ), the RNC 826 can be required to determine these
indicia based on other indicia (e.g., similar to system 800).
However, by communicating this information (e.g., sending indicia
830) to the RNC 826 from UE 822, the indicia can be directly relied
on rather than inferred or determined. The additional indicia can
be sent 830, for example, in scheduled transmission operations by
way of scheduling information (SI) messages passed to the
[0071] RNC 826 through NodeB 824. Information passed to RNC 826 can
facilitate determinations 840 made by the RNC 826. System 820
therefore can improve the reliability of the determinations
relating to dynamic adjustment of TTI (indicia accessible to the UE
822 but not directly available to the RNC 826 can be specifically
communicated to RNC 826). However, system 820 can require a change
in current standards to incorporate gathering and communicating
these additional indicia rather than relying on the RNC 826 to
infer these indicia based on other monitored indicia already
available to the RNC 826.
[0072] Again returning to FIG. 8, system 850 can comprise one or
more UEs 852, one or more NodeBs 854, and one or more RNCs 856. The
UEs 852 can be communicatively coupled to the NodeBs 854 by a
wireless connection. Information can be communicated from the UEs
852 to the RNCs 856 by way of the NodeBs 854. In an embodiment of
the disclosed subject matter, this information can include both
communication information/data (e.g., an information payload, VoIP
packets, voice information, application data, . . . ). Further, the
UEs 822 can monitor and determine when a dynamic adjustment of TTI
would be beneficial and can send a request 860 to the RNC 856 to
initiate the dynamic TTI adjustment. RNC 856 can receive the
request and form a determination 870 relating to dynamically
adjusting TTI. Thus, system 870 can function similar to system 800
except that system 850 can shift monitoring indicia and aspects of
determining the appropriateness of dynamic TTI adjustment to the
UEs 852. In general, system 820 can preprocess communications link
information at the UE 852 and determine the need to dynamically
adjust TTI (e.g., from the perspective of the UE 852), such that a
request to dynamically adjust the TTI for UE 852 can be provided to
the RNC 856 where the request can be included in a determination of
the appropriateness of dynamically adjusting the TTI for the
requesting UE 852.
[0073] UE 852 can have knowledge of indicia relative to the UE 852
that can be employed in forming a determination relating to dynamic
adjustment of the TTI for UE 852. For example, the indicia can be
UE 852 TX power headroom limitation and UE 852 HARQ early
termination statistics. Based on these locally relevant indicia, UE
852 can send a request to the RNC 856 to dynamically adjust the UE
852 TTI. The request can be processed by the RNC 856 in light of
other indicia not local to UE 852 (e.g., system resources, business
goals, complex analytics, . . . ) and form a determination at 870
relating to dynamically adjusting the UE 852 TTI in response to the
request. For example, if the available TX power headroom for UE 852
goes below a certain threshold, UE 852 can request, for example by
sending a layer 3 message, that RNC 856 switch UE 852 from a 2 ms
TTI to a 10 ms TTI. Monitoring 860 indicia at the UE 852 can
further facilitate monitoring indicia in real time, for example,
monitoring the change (i.e., slope) in the remaining UE 852 TX
power headroom which can facilitate proactively generating a
request for dynamic TTI adjustment (e.g., requesting dynamic TTI
adjustment before UE 852 actually runs out of TX power headroom).
The RNC can then combine this request UE 852 with additional
indicia (e.g., Ecp/Nt setpoint, PER, . . . ) and can make the final
decision to initiate dynamically adjusting UE 852 TTI, if deemed
appropriate. System 850 can give the best performance (as compared
to system 800 and 820) however it can require standards changes
(e.g., the specific UE 852 algorithms would need to be specified
and new layer 3 messaging would need to be identified between UE
852 and RNC 856 by way of NodeB 854).
[0074] Referring now to FIG. 9, illustrated is a methodology 900
facilitating dynamic adjustment of TTI in accordance with an aspect
of the disclosed subject matter. At 910, information can be
received relating to a communication link condition. This
information can include indicia relating to the uplink portion of
the communication link. Indicia can include, for example, the
packet error rate, pilot channel signal to noise ratio, TX power
headroom information, or combinations thereof among other indicia
related to the communication link. These indicia can correlate to
the quality of the communications link. For example, where there is
a higher than acceptable packet error rate, there can be
insufficient power to transmit data packets from a UE to a NodeB.
As a second example, where the pilot channel signal to noise ratio
is above a threshold, there can be an excessive number of UEs
transmitting at a sufficiently high TX power to cause substantial
interference. One of skill in the art will appreciate that numerous
other indicia can be related to the condition of the communications
link and that all such indicia are within the scope of the
disclosed subject matter as they relate to determining the
appropriateness of dynamic adjustment of TTI windows.
[0075] At 920, the received information can be included in forming
a determination of the appropriateness of dynamically adjusting TTI
with a communications system. By dynamically adjusting TTI, the TTI
can be changed within an established communication link to maintain
or improve the performance of that communications link. For
example, where a 2 ms TTI is being employed, and received indicia
indicate an excessively high PER, a determination can be formed
that changing to a 10 ms TTI can improve the performance of the
communications link and therefore is appropriate.
[0076] At 930, the TTI can be dynamically adjusted in accordance
with the determination of appropriateness. Where for example, it is
determined that switching form a 2 ms TTI to a 10 ms TTI is
appropriate to maintain the established communications link, a RNC
can instruct a UE to adjust the TTI from 2 ms to 10 ms. At this
point, methodology 900 can end.
[0077] In addition to dynamically adjusting TTI within an
established communications link, methodology 900 can also
facilitate dynamically adjusting TTI when a communications link is
established. For example, when a cell phone call is initiated, an
RNC can receive information relating to the condition of the
potential communications link (910) such that a determination of
the most appropriate TTI can be formed (920) and the UE can be
instructed to close the link with the appropriate TTI (930). Thus,
for example, where a cell phone at the cell edge initiates call, a
low Ecp/Nt can indicate that a 10 ms TTI can be the most
appropriate TTI to employ and the UE can be instructed to establish
the call with the 10 ms TTI. Similarly, other UEs in the cell can
individually be instructed to employ appropriate TTIs (e.g., a
mixed TTI cell can be established).
[0078] Moreover, TTI can be dynamically adjusted based on
additional criteria in combination with the communication link
condition indicia. For example, where a UE has a sufficiently good
communications link condition to maintain a 2 ms TTI but is
entering a soft handoff to a second NodeB, the RNC can, for
example, instruct the UE to default to a 10 ms TTI to facilitate
the soft handoff. Alternatively, where the second NodeB
communications link conditions indicia indicates that the soft
handoff can be completed with a 2 ms TTI, the UE can be instructed
by the RNC to maintain the 2 ms TTI throughout the soft handoff. As
disclosed herein, dynamic adjustment of the TTI is not limited to 2
ms and 10 ms TTI, and one of skill in the art will appreciate that
all TTI times are within the scope of the disclosed subject matter
where those TTI comport with established standards or specific
applications.
[0079] Referring now to FIG. 10, illustrated is a methodology 1000
facilitating dynamic adjustment of TTI in accordance with an aspect
of the disclosed subject matter. At 1010, information related to a
communication link condition can be monitored at an RNC. The
indicia available to the RNC for monitoring can be combined to form
determinations about likely communications link conditions. For
example, where the PER rises above a threshold and elevating the
Ecp/Nt does not correct the rising PER, a determination can be made
that it is likely the UE has limited TX power headroom and the
communications link is not likely to improve. One of skill in the
art will appreciate that a nearly limitless number of other
determinations can be made about communications system
characteristics based on the indicia monitored by the RNC and that
all such indicia and determinations related thereto are within the
scope of the disclosed subject matter.
[0080] At 1020, the RNC can determine the appropriateness of
dynamically adjusting the TTI based at least in part on the
information monitored. Where, for example, it has been determined
that the communications link is not likely to improve based on the
monitored Ecp/Nt and PER, the RNC can determine that it can be
appropriate to dynamically adjust the TTI to improve and maintain
the established communication link. At 1030, the RNC can initiate
dynamic TTI adjustment in accord with the determination. For
example, where it has been determined that it is likely that a UE
is TX power headroom limited and a 2 ms TTI is employed, the RNC
can instruct the UE to dynamically adjust to a 10 ms TTI to
facilitate improved communication over the link. At this point
methodology 1000 can end. Methodology 1000 can comply with current
industry standards (e.g., 3GPP rel. 6&7).
[0081] Referring now to FIG. 11, illustrated is a methodology 1100
facilitating dynamic adjustment of TTI in accordance with an aspect
of the disclosed subject matter. At 1110, communication link
condition information available to a UE can be received. This
information can be information not directly available for
monitoring by an RNC. For example, an RNC can infer the available
TX power headroom available for UE based on other indicia as herein
disclosed, however this same information can be directly available
to the UE itself Thus, the UE can communicate these indicia, for
example, to a NodeB which can forward the information on to the
RNC.
[0082] At 1120, the RNC can determine the appropriateness of
dynamically adjusting the TTI based at least in part on the UE
information received. For example, where the available UE TX power
headroom information is received by the RNC, indicating that there
is insufficient headroom remaining, he RNC can determine that
dynamically adjusting the TTI is appropriate. At 1130, the RNC can
initiate dynamic adjustment of the TTI where appropriate. Thus, for
example, where the determination has been made that it is
appropriate to adjust the TTI, the RNC can instruct the UE to
adjust the TTI. At his point methodology 1100 can end.
[0083] In general, methodology 1100 allows additional information
to be communicated to the RNC to facilitate improved determinations
related to dynamically adjusting TTI. As compared to methodology
800, where the RNC can be required to form determinations on the
likelihood of a condition existing (e.g., inferences) where the RNC
cannot directly monitor indicia of the condition, methodology 1100
permits gathering of these additional indicia and communication of
them to the RNC for improved dynamic adjustment of TTI. Methodology
1100 may not comply with current industry standards (e.g., 3GPP
rel. 6&7), though the additional benefits can be an impetus for
modification of the standards to incorporate the additional
messaging capacity to communicate the UE available information to
the RNC to facilitate improved determinations relating to dynamic
TTI adjustment.
[0084] Referring now to FIG. 12, illustrated is a methodology 1200
facilitating dynamic adjustment of TTI in accordance with an aspect
of the disclosed subject matter. At 1210, a UE can receive
information related to communication link conditions. At 1220 the
UE can determine the appropriateness of dynamically adjusting the
TTI for that UE based at least in part on the information received
by the UE. At 1230, the localized determination of appropriateness
can cause a request for dynamic TTI adjustment to be sent to the
RNC. Thus, each UE in a communications system can self monitor,
determine when a TTI adjustment is needed, and initiate a request
for dynamic TTI adjustment based on the local communications link
conditions. For example, where a UE is self monitoring an
increasing Ecp/Nt setpoint (e.g., 1210), the UE can determine that
it will soon need to adjust the TTI to maintain the established
link (e.g., 1220), and in response to this determination can
request that the RNC dynamically adjust the TTI (e.g., 1230).
[0085] At 1240, the RNC can initiate a dynamic TTI adjustment based
at least in part on the UE request. Thus, while each UE can request
TTI adjustment, the RNC can make a final determination, based on
other factors in addition to the request, as to the appropriateness
of dynamically adjusting the TTI. Where for example, a UE requests
a TTI adjustment, the RNC can determine that the TTI adjustment is
not appropriate where the overall communications system performance
could be negatively affected by the dynamic TTI adjustment and in
response can refuse to initiate the dynamic TTI adjustment. At this
point Methodology 1200 can end.
[0086] Methodology 1200, in general, distributes aspects of
determining the appropriateness of dynamic TTI adjustment among the
different elements of a communications network. This can allow UEs
in a communications system to form local determinations based on
communications link conditions that are locally relevant and
available to the UE. This further takes computational loading off
of the RNC and can reduce messaging and information traffic volume,
related to passing the indicia used in forming the determinations,
sent across the communications network from the UE to the RNC by
way of the NodeBs. Where the determinations are formed local to the
UEs only a request needs to be sent to the RNC as part of the RNC's
determinations as to the appropriateness of the dynamic TTI
adjustment. By centralizing the final determinations related to TTI
adjustment, additional factors not local to the UEs can be
considered with the final determination. After a final
determination has been formed, a simple message back to the UE can
instruct the UE to dynamically adjust the TTI. Methodology 1200 can
be incompatible with current industry standards (e.g., 3GPP rel.
6&7), however, methodology 1200 can provide significant benefit
in regard to dynamic TTI adjustment. One of skill in the art will
appreciate that any future standards development can incorporate
this distributed dynamic TTI adjustment methodology but that such
features would be considered within the scope of the disclosed
subject matter.
[0087] Further, those skilled in the art will understand that
information and signals may be represented using any of a variety
of different technologies and techniques. For example, data,
instructions, commands, information, signals, bits, symbols, and
chips that may be referenced throughout the above description may
be represented by voltages, currents, electromagnetic waves,
magnetic fields or particles, optical fields or particles, or any
combination thereof
[0088] The various illustrative logics, logical blocks, modules,
and circuits described in connection with the embodiments disclosed
herein may be implemented or performed with a general purpose
processor, a digital signal processor (DSP), an application
specific integrated circuit (ASIC), a field programmable gate array
(FPGA) or other programmable logic device, discrete gate or
transistor logic, discrete hardware components, or any combination
thereof designed to perform the functions described herein. A
general-purpose processor may be a microprocessor, but, in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A processor may also
be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration. Additionally, at least
one processor may comprise one or more modules operable to perform
one or more of the steps and/or actions described above.
[0089] Further, the steps and/or actions of a method or algorithm
described in connection with the aspects disclosed herein may be
embodied directly in hardware, in a software module executed by a
processor, or in a combination of the two. A software module may
reside in RAM memory, flash memory, ROM memory, EPROM memory,
EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM,
or any other form of storage medium known in the art. An exemplary
storage medium may be coupled to the processor, such that the
processor can read information from, and write information to, the
storage medium. In the alternative, the storage medium may be
integral to the processor. The processor and the storage medium may
reside in an ASIC.
[0090] Further, in some aspects, the processor and the storage
medium may reside in an ASIC. Additionally, the ASIC may reside in
a user terminal In the alternative, the processor and the storage
medium may reside as discrete components in a user terminal
Additionally, in some aspects, the steps and/or actions of a method
or algorithm may reside as one or any combination or set of codes
and/or instructions on a machine readable medium and/or computer
readable medium, which may be incorporated into a computer program
product. The various illustrative logical blocks, modules, and
circuits described in connection with the examples disclosed herein
may be implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0091] In one or more aspects, the functions described may be
implemented in hardware, software, firmware, or any combination
thereof. If implemented in software, the functions may be stored or
transmitted as one or more instructions or code on a
computer-readable medium. Computer-readable media includes both
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A storage medium may be any available media that can be
accessed by a computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. Also, any
connection may be termed a computer-readable medium. For example,
if software is transmitted from a website, server, or other remote
source using a coaxial cable, fiber optic cable, twisted pair,
digital subscriber line (DSL), or wireless technologies such as
infrared, radio, and microwave, then the coaxial cable, fiber optic
cable, twisted pair, DSL, or wireless technologies such as
infrared, radio, and microwave are included in the definition of
medium. Disk and disc, as used herein, includes compact disc (CD),
laser disc, optical disc, digital versatile disc (DVD), floppy disk
and blu-ray disc where disks usually reproduce data magnetically,
while discs usually reproduce data optically with lasers.
Combinations of the above should also be included within the scope
of computer-readable media.
[0092] While the foregoing disclosure discusses illustrative
aspects and/or embodiments, it should be noted that various changes
and modifications could be made herein without departing from the
scope of the described aspects and/or embodiments as defined by the
appended claims. Furthermore, although elements of the described
aspects and/or embodiments may be described or claimed in the
singular, the plural is contemplated unless limitation to the
singular is explicitly stated. Additionally, all or a portion of
any aspect and/or embodiment may be utilized with all or a portion
of any other aspect and/or embodiment, unless stated otherwise. The
previous description of the disclosed examples is provided to
enable any person skilled in the art to make or use the present
invention. Various modifications to these examples will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other examples without departing
from the spirit or scope of the invention. Thus, the present
invention is not intended to be limited to the examples shown
herein but is to be accorded the widest scope consistent with the
principles and novel features disclosed herein.
* * * * *