U.S. patent application number 13/041373 was filed with the patent office on 2011-09-08 for seamless cell reconfiguration in broadband wireless networks.
Invention is credited to Muthaiah Venkatachalam, Xiangying Yang.
Application Number | 20110216741 13/041373 |
Document ID | / |
Family ID | 44531272 |
Filed Date | 2011-09-08 |
United States Patent
Application |
20110216741 |
Kind Code |
A1 |
Yang; Xiangying ; et
al. |
September 8, 2011 |
SEAMLESS CELL RECONFIGURATION IN BROADBAND WIRELESS NETWORKS
Abstract
Embodiments of a system and method for wireless communication
are provided. In certain embodiments, systems and methods for
providing seamless reconfiguration of a network which incorporate
known features of the network. In some embodiments, the mobile
station implements a hand over from one physical base station to
the same physical base station, so as to allow that base station to
reconfigure and update configuration parameters.
Inventors: |
Yang; Xiangying; (Portland,
OR) ; Venkatachalam; Muthaiah; (Beaverton,
OR) |
Family ID: |
44531272 |
Appl. No.: |
13/041373 |
Filed: |
March 5, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61311174 |
Mar 5, 2010 |
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Current U.S.
Class: |
370/331 ;
370/328 |
Current CPC
Class: |
H04L 2463/061 20130101;
H04W 28/04 20130101; H04W 12/062 20210101; H04L 2001/125 20130101;
H04L 1/0073 20130101; H04L 63/0876 20130101; H04W 74/0833 20130101;
Y02D 30/70 20200801; H04L 1/0041 20130101; H04L 1/0061 20130101;
H03M 13/29 20130101; H04W 36/0038 20130101; H03M 13/09 20130101;
H04W 72/0413 20130101 |
Class at
Publication: |
370/331 ;
370/328 |
International
Class: |
H04W 36/06 20090101
H04W036/06; H04W 76/04 20090101 H04W076/04 |
Claims
1. A method for wireless communication performed by a mobile
station, the method comprising: receiving a message from a base
station with which the mobile station has a current connection,
wherein the message includes information regarding a configuration
change of the base station; halting the current connection with the
base station; updating parameters corresponding to the
configuration change based on the message; and resuming a
connection with the base station using the updated parameters.
2. The method of claim 1, wherein the information regarding a
configuration change includes a physical layer update for the base
station.
3. The method of claim 2, wherein the physical layer update
includes an updated cell-ID for the base station.
4. The method of claim 1, wherein the information regarding
configuration change includes an unavailable start time indicating
a time in which the base station will stop communicating for
reconfiguration.
5. The method of claim 1, wherein the information regarding a
configuration change includes an available start time indicating a
time in which the base station will resume communication after
reconfiguration.
6. A method for wireless communication performed by a base station,
the method comprising: determining that the base station is to
perform reconfiguration, wherein the reconfiguration includes
changing a physical layer parameter, such that the base station is
to operate according to an updated physical layer parameter after
the reconfiguration; transmitting a handover request to a mobile
station communicating with the base station, the handover request
requesting that the mobile station handover to a base station
having the updated physical layer parameter, such that the mobile
station performs a handover from the base station having a
non-updated physical layer parameter prior to reconfiguration to
the base station after reconfiguration having the updated physical
layer parameter.
7. The method of claim 6, wherein the reconfiguration is based on a
self-optimization of the base station with respect to other
adjacent base stations.
8. The method of claim 6, wherein the updated physical layer
parameter includes an updated cell-ID for the base station.
9. The method of claim 6, wherein the handover request includes an
unavailable start time indicating a time by which the mobile
station should initiate disconnection for the handover.
10. The method of claim 6, wherein the handover request includes an
available start time indicating a time after which the mobile
station can initiate re-connections for the handover.
11. A method for wireless communication performed by a base
station, the method comprising: determining that the base station
is to perform reconfiguration, wherein the reconfiguration includes
changing a physical layer parameter, such that the base station is
to operate according to an updated physical layer parameter after
the reconfiguration; transmitting a reconfiguration notification to
a mobile station communicating with the base station, the
reconfiguration notification providing the mobile station with
information regarding the updated physical layer parameter;
disconnecting with the mobile station; performing reconfiguration;
and reconnection with the mobile station after reconfiguration
using the updated physical layer parameter.
12. The method of claim 11, wherein transmitting a reconfiguration
notification includes broadcasting the reconfiguration notification
to all mobile stations connected to the base station.
13. The method of claim 11, wherein transmitting a reconfiguration
notification includes unicasting a reconfiguration notification to
each of the mobile stations connected to the base station; and
receiving an acknowledgement from each of the mobile stations
regarding successful reception of the reconfiguration
notification.
14. The method of claim 11, wherein the updated physical layer
parameter includes an updated cell-ID for the base station.
15. The method of claim 11, wherein the reconfiguration
notification includes an unavailable start time indicating a time
in which the base station will stop communicating for
reconfiguration.
16. The method of claim 11, wherein the reconfiguration
notification includes an available start time indicating a time in
which the base station will resume communication after
reconfiguration.
17. A wireless device comprising: an RF transceiver for
transmitting and receiving signals from a base station; processing
circuitry communicatively coupled to the RF transceiver and
configured to: receive a message from a base station with which the
mobile station has a current connection, wherein the message
includes information regarding a configuration change of the base
station; halt the current connection with the base station; update
parameters corresponding to the configuration change based on the
message; and resume a connection with the base station using the
updated parameters.
18. The device of claim 1, wherein the information regarding a
configuration change includes a physical layer update for the base
station.
19. The device of claim 2, wherein the physical layer update
includes an updated cell-ID for the base station.
20. A base station for providing wireless communication with a
plurality of mobile stations, the base station comprising: an RF
transceiver for transmitting to and receiving signals from a
plurality of mobile stations; and processing circuitry
communicatively coupled to the base station, the processing
circuitry configured to: determine that the base station is to
perform reconfiguration, wherein the reconfiguration includes
changing a physical layer parameter, such that the base station is
to operate according to an updated physical layer parameter after
the reconfiguration; transmit a reconfiguration notification to a
mobile station communicating with the base station, the
reconfiguration notification providing the mobile station with
information regarding the updated physical layer parameter;
disconnect with the mobile station; perform reconfiguration; and
reconnect with the mobile station after reconfiguration using the
updated physical layer parameter.
21. The base station of claim 20, wherein transmit a
reconfiguration notification includes broadcast the reconfiguration
notification to all mobile stations connected to the base
station.
22. The base station of claim 20, wherein transmit a
reconfiguration notification includes unicast a reconfiguration
notification to each of the mobile stations connected to the base
station; and receive an acknowledgement from each of the mobile
stations regarding successful reception of the reconfiguration
notification.
23. The base station of claim 20, wherein the updated physical
layer parameter includes an updated cell-ID for the base station.
Description
PRIORITY CLAIM
[0001] This application claims the benefit of priority under 35
U.S.C. 119(e) to U.S. Application Ser. No. 61/311,174 filed on Mar.
5, 2010, which is incorporated herein by reference in its
entirety.
TECHNICAL FIELD
[0002] The present invention pertains to wireless communications
and wireless networks, and reconfiguration of network elements.
BACKGROUND
[0003] The quality of operation and efficiency of a wireless
communication network is subject to a variety of complexities.
Mobile users expect high quality services, and mobile operators
seek to optimize operation to allow increased user base with
decreased costs. Reducing operational expenditures in a Radio
Access Network (RAN) involves consideration of these complexities
and solutions that may be implemented without interruption to the
users.
[0004] Improvements to a wireless network are implemented as new
features and solutions to problems are implemented in the network
as updates and configurations. Often such updates and
configurations are done through human intervention, either
physically or remotely modifying network elements, such as the
transmitter, or Base Station (BS), and various nodes within the
transmission network. In this way, these updates and configuration
changes are not automatic, but rather have an administrator or
technician implement the change incurring time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates a wireless network in accordance with
some example embodiments;
[0006] FIG. 2 is a flow diagram illustrating a method for seamless
reconfiguration of operating parameters in a wireless communication
network, in accordance with some example embodiments;
[0007] FIG. 3 illustrates an example of one method for seamless
reconfiguration in a signal flow diagram, according to example
embodiments.
[0008] FIG. 4 illustrates a method to implement an intra-BS
handover to allow seamless relay link re-establishment, according
to example embodiments.
[0009] FIG. 5 is a wireless communication system supporting
reconfiguration, according to example embodiments.
DETAILED DESCRIPTION
[0010] The following description and the drawings illustrate
specific embodiments of the invention sufficiently to enable those
skilled in the art to practice them. Other embodiments may
incorporate structural, logical, electrical, process, and other
changes. Examples merely typify possible variations. Individual
components and functions are optional unless explicitly required,
the sequence of operations may vary, and features of some
embodiments may be included in or substituted for those of others.
Embodiments of the invention set forth in the claims encompass all
available equivalents of those claims. Embodiments of the invention
may be referred to herein, individually or collectively, by the
term "invention" merely for convenience and without intending to
limit the scope of this application to any single invention or
inventive concept if more than one is in fact disclosed.
[0011] Various embodiments are described herein relating to methods
to a variety of wireless communication over-the-air protocols in
accordance with specific communication standards, such as the
Institute of Electrical and Electronics Engineers (IEEE) standards
including IEEE 802.16m standards, although the scope of the
invention is not limited in this respect as they may also be
suitable to transmit and/or receive communications in accordance
with other techniques and standards.
[0012] In some embodiments, network components may communicate in
accordance with the IEEE 802.16-2004 and the IEEE 802.16(e)
standards for wireless metropolitan area networks (WMANs) including
variations and evolutions thereof, although the scope of the
invention is not limited in this respect as they may also be
suitable to transmit and/or receive communications in accordance
with other techniques and standards. For more information with
respect to the IEEE 802.11 and IEEE 802.16 standards, please refer
to "IEEE Standards for Information Technology--Telecommunications
and Information Exchange between Systems"--Local Area
Networks--Specific Requirements--Part 11 "Wireless LAN Medium
Access Control (MAC) and Physical Layer (PHY), ISO/IEC 8802-11:
1999," and Metropolitan Area Networks--Specific Requirements--Part
16: "Air Interface for Fixed Broadband Wireless Access Systems,"
May 2005 and related amendments/versions.
[0013] In 4G broadband wireless network such as IEEE802.16m or 3GPP
LTE(A), Self-Organizing/Optimizing Network (SON) feature is very
desirable to achieve automatic network configuration optimization
which minimal human intervention, particularly in a dense
deployment such as Femtocell or Picocells with many base stations
(BS) in an given area. A Self-Organizing Optimizing Network (SON)
is a network wherein newly added base stations are designed to be
self-configured similar to a `plug-and-play` paradigm, while
operational BSs will regularly self-optimize parameters and
algorithmic behavior in response to observed network performance
and radio conditions. Various self-healing mechanisms may be
triggered to temporarily compensate for a detected equipment
outage, while awaiting a more permanent solution. There are a
variety of SON implementations, wherein SON networks are commonly
divided into three subareas: i) self-configuration; ii)
self-optimization; and iii) self-healing.
[0014] Self-configuration enables the network to add a new base
station, or make modifications to an existing BS by enabling the BS
for automatic configuration and integration into the network. This
may involve establishing sufficient connectivity in the network,
download of configuration parameters, download of software and
updates, reconfiguration of the operation code in the BS, and so
forth.
[0015] Self-optimization enables a BS to regularly adjust, update
or in some embodiments add, parameters can be regularly adjusted,
based on BS and/or Mobile Station (MS) observations. In one
example, a SON feature enables establishment of automatic neighbor
relationships, referred to as Neighbor Relations Automatically
(NAR). Other examples may optimize random access parameters or
mobility robustness in terms of Hand Over (HA), also referred to as
Hand Off, oscillations.
[0016] Under operating conditions, an existing active node may
encounter a problem and become inoperable or may have impaired
operation, wherein the node, such as a BS, may perform self-healing
operations to reduce the impacts of such failures. In one example,
self-healing may act to adjust parameters and algorithms in
adjacent cells such that other nodes are able to support those
users associated with the failing node.
[0017] SON networks features are currently incorporated in, and
under discussion in, various communication standard organizations.
More are expected to be introduced gradually with the arrival of
new 4G systems in RANs.
[0018] SON features allow a network to automatically change
operational parameters, operating code, features, and so forth,
which act to extend, change, configure, and optimize the network
coverage, capacity, cell size, topology, and frequency allocation
and bandwidth, based on changes in interference, signal strength,
location, traffic pattern, and other environment criteria. SON
features work to remove human intervention from these operations.
Presented herein are methods of reusing known features, such as
hand off procedures, to achieve automatic and/or seamless
reconfiguration and updates to a transceiver. In some embodiments,
a hand off procedure is initiated at the MS wherein the hand off is
from one base station to the same base station. By implementing the
hand off procedure, the BS is able to terminate communications
which use the first configuration set of information and begin
communication which use a second configuration set of information.
Operation of the MS is not interrupted, but proceeds as usual,
wherein such operation includes a hand off. The MS does not need a
special or new message or process to perform this hand off, but
rather may implement the known procedures. In some embodiments, an
indication may be sent to the MS, or the MS may be aware of the
reconfiguration or update, however, the process is seamless from
the perspective of the MS. Such techniques may be applied in a
variety of systems and for a variety of information change
situations.
[0019] When implemented in a wireless network, the SON network
minimizes the operation costs of running a network, as SON features
reduce and/or eliminate manual configuration of network operational
parameters at the time of network planning, network deployment,
network operations, and network optimization while fitting into the
existing operational processes and procedures that are currently in
place today. For example, current systems rely on multiple human
interventions for such maintenance, which impacts network
operations. Many of the telecommunication standards bodies are
currently discussing these concepts, including of 3GPP (3rd
Generation Partnership Project) and the NGMN (Next Generation
Mobile Networks) group.
[0020] In an example embodiment, a method for wireless
communication performed by a mobile station includes receiving a
message from a base station with which the mobile station has a
current connection, wherein the message includes information
regarding a configuration change of the base station. The method
then continues to halt the current connection with the base
station, update parameters corresponding to the configuration
change based on the message, and then resume a connection with the
base station using the updated parameters. According to one
embodiment of this method, the information regarding a
configuration change includes a physical layer update for the base
station. The physical layer update may include an updated cell-ID
for the base station. The information regarding configuration
change may include an unavailable start time indicating a time in
which the base station will stop communicating for reconfiguration.
The information regarding a configuration change may include an
available start time indicating a time in which the base station
will resume communication after reconfiguration.
[0021] In another example, a method for wireless communication
performed by a base station, begins by determining that the base
station is to perform reconfiguration, wherein the reconfiguration
includes changing a physical layer parameter, such that the base
station is to operate according to an updated physical layer
parameter after the reconfiguration. The method then continues by
transmitting a handover request to a mobile station communicating
with the base station, the handover request requesting that the
mobile station handover to a base station having the updated
physical layer parameter, such that the mobile station performs a
handover from the base station having a non-updated physical layer
parameter prior to reconfiguration to the base station after
reconfiguration having the updated physical layer parameter. The
reconfiguration may be based on a self-optimization of the base
station with respect to other adjacent base stations. The updated
physical layer parameter may include an updated cell-ID for the
base station. The handover request may include an unavailable start
time indicating a time by which the mobile station should initiate
disconnection for the handover. The handover request may include an
available start time indicating a time after which the mobile
station can initiate re-connections for the handover.
[0022] In still another embodiment, a method for wireless
communication performed by a base station, begins by determining
that the base station is to perform reconfiguration, wherein the
reconfiguration includes changing a physical layer parameter, such
that the base station is to operate according to an updated
physical layer parameter after the reconfiguration. Next, the
process continues by transmitting a reconfiguration notification to
a mobile station communicating with the base station, the
reconfiguration notification providing the mobile station with
information regarding the updated physical layer parameter. The BS
then disconnects with the MS, performs reconfiguration and then
reconnects with the MS using an updated physical layer parameter.
In some embodiment, the method of transmitting a reconfiguration
notification may include broadcasting the reconfiguration
notification to all mobile stations connected to the base station.
In some embodiments, a reconfiguration notification may include
unicasting a reconfiguration notification to each of the mobile
stations connected to the base station, and receiving an
acknowledgement from each of the mobile stations regarding
successful reception of the reconfiguration notification. The
updated physical layer parameter may include an updated cell-ID for
the base station. The reconfiguration notification may include an
unavailable start time indicating a time in which the base station
will stop communicating for reconfiguration. The reconfiguration
notification may include an available start time indicating a time
in which the base station will resume communication after
reconfiguration.
[0023] According to one embodiment, a wireless device includes an
RF transceiver, a processing circuitry and a memory storage device.
The RF transceiver for transmitting and receiving signals from a
base station. The processing circuitry communicatively coupled to
the RF transceiver; the processing circuitry is configured to
receive a message from a base station with which the mobile station
has a current connection, wherein the message includes information
regarding a configuration change of the base station. The
processing circuitry is further to halt the current connection with
the base station, and update parameters corresponding to the
configuration change based on the message. Finally, the processing
circuitry is to resume a connection with the base station using the
updated parameters. The information regarding a configuration
change may include a physical layer update for the base station.
The physical layer update may include an updated cell-ID for the
base station.
[0024] In still another embodiment, a base station for providing
wireless communication with a plurality of mobile stations, the
base station includes an RF transceiver, processing circuitry and a
memory storage device. The RF transceiver is for transmitting to
and receiving signals from a plurality of mobile stations. The
processing circuitry is communicatively coupled to the base
station, and is configured to determine that the base station is to
perform reconfiguration, wherein the reconfiguration includes
changing a physical layer parameter, such that the base station is
to operate according to an updated physical layer parameter after
the reconfiguration. The processing circuitry is further to
transmit a reconfiguration notification to a mobile station
communicating with the base station, the reconfiguration
notification providing the mobile station with information
regarding the updated physical layer parameter. The processing
circuitry is further to disconnect with the mobile station, perform
reconfiguration, and reconnect with the mobile station after
reconfiguration using the updated physical layer parameter. In one
embodiment the base station transmits the reconfiguration
notification by a broadcast transmission, including the
reconfiguration notification, wherein the base station transmits to
all mobile stations connected to the base station. In another
embodiment, the base station transmits a reconfiguration
notification such as to unicast a reconfiguration notification to
each of the mobile stations connected to the base station; and then
the base station receives an acknowledgement from each of the
mobile stations regarding successful reception of the
reconfiguration notification. The updated physical layer parameter
may include an updated cell-ID for the base station.
[0025] FIG. 1 illustrates a wireless network 100, according to some
embodiments, having multiple nodes or Base Stations (BS) 102, 104,
106, and 108, for communication over-the-air with various wireless
communications devices including cellular devices, laptop
computers, tablet devices, e-Reader devices, and other devices
having wireless capabilities, and such as cellular devices 108,
109. The network 100 may also include a Wireless Local Area Network
(WLAN) or other network having a router for processing
transmissions within the WLAN, and may include processing through
other networks, such as having an Internet connection, such as
Internet 120 by way of gateway 150.
[0026] In some embodiments, the BSs may be Relay Nodes (RN), as
illustrated in FIG. 1, wherein BSs 102, 106, and 108 act as RNs,
while BS 104 acts as a BS. The configuration of network 100 is
discussed in more detail hereinbelow. A variety of network
configurations are considered in this description.
[0027] In some embodiments, wireless network 100 may be a broadband
wireless multiple access communication network, in which uplink and
downlink time-slots are determined by network base station and
provided to one or more of network nodes for communicating with
network BS 102, 104, 106 and/or 108 in a multiple access manner.
The various mobile users 110, 112, 114, 116, 118 are located
throughout the network.
[0028] In some embodiments, network 100 may communicate using
Orthogonal Frequency Division Multiplexing (OFDM). In some of these
embodiments, network 100 may be a Wireless Fidelity (Wi-Fi) network
implementing a multicarrier communication technique, such as OFDM,
and/or by implementing spread spectrum communications. In some
embodiments, the frequency spectrum used by network 100 may
comprise either a 5 GHz frequency spectrum or a 2.4 GHz frequency
spectrum.
[0029] In some embodiments where network 100 communicates using
OFDM, the communication signals may comprise a plurality of
orthogonal subcarriers. Each subcarrier of the communication
signals may have a null at substantially a center frequency of the
other subcarriers and/or each subcarrier may have an integer number
of cycles within a symbol period, although the scope of the
invention is not limited in this respect.
[0030] In some embodiments, network 100 may communicate in
accordance with specific communication standards, such as the
Institute of Electrical and Electronics Engineers (IEEE) standards
including IEEE 802.16m standards, although the scope of the
invention is not limited in this respect as they may also be
suitable to transmit and/or receive communications in accordance
with other techniques and standards.
[0031] As described herein, methods to automate changes in a
network, such as network 100 of FIG. 1, supporting an 802.16m
standard in a system may include applying SON features which allow
updates and changes without interruption of operation. Ideally,
such modifications are made in seamless manner which is invisible
to the mobile users, such MSs 110, 112, 114, 116, 118, and 119. The
network 100 may support any number of users, each having a variety
of capabilities.
[0032] The network 100 of FIG. 1 further includes various radio
cells, 130 and 140. In operation, the BSs 102, 104, 106, and 108
may hand over calls to each other or other nodes (not shown). As
mentioned above, in 4G broadband wireless network, such as
IEEE802.16m or 3GPP LTE(A), SON features allow the network to
optimize automatic network configuration and reduce/eliminate human
intervention, particularly in a dense deployment. Some network
configurations have many BSs in a small area.
[0033] One such network is a femtocell network having a small
cellular BS or Access Point (AP), which may be for use in a home or
small business. The BS connects to a network through a broadband
connection. Current designs typically support 2 to 4 active mobile
phones in a residential setting, and 8 to 16 active mobile phones
in enterprise settings. A femtocell allows service providers to
extend service coverage indoors, especially where access would
otherwise be limited or unavailable. Although much attention is
focused on WCDMA, the concept is applicable to all standards,
including GSM, CDMA2000, TD-SCDMA, WiMAX and LTE solutions.
[0034] Another type network incorporates Picocells, where a small
cellular BS or AP covers a small area, such as in a building,
office, shopping mall, transit station, aircraft, and so forth. In
cellular networks, picocells are typically used to extend coverage
to indoor areas where outdoor signals do not reach well, or to add
network capacity in areas with very dense phone usage, such as
train stations. Picocells provide coverage and capacity in areas
difficult or expensive to reach using the more traditional
approaches. In cellular wireless networks, such as in a Global
System for Mobile communications (GSM) system, a picocell base
station is typically a low cost, small, reasonably simple unit that
connects to a Base Station Controller (BSC). Multiple picocell
`heads` connect to each BSC: the BSC performs radio resource
management and hand-over functions, and aggregates data to be
passed to a Mobile Switching Centre (MSC) and/or a Gateway GPRS
Support Node (GGSN).
[0035] Some embodiments discussed herein include networks that
support IEEE 802.16 standards, such as IEEE 802.16m. To provide
some basics for understanding the concepts developed in this
description, the 802.16 standard has two basic aspects of the air
interface: i) the physical layer (PHY); and ii) the Media Access
Control layer (MAC). For example, in systems supporting IEEE
802.16e, communications incorporate a Scalable OFDMA to carry data,
supporting channel bandwidths of between 1.25 MHz and 20 MHz, with
up to 2048 sub-carriers. The system supports adaptive modulation
and coding, so that in conditions of good signal, a highly
efficient 64 QAM coding scheme is used, whereas when the signal is
poorer, a more robust BPSK coding mechanism is used. In
intermediate conditions, 16 QAM and QPSK can also be employed.
Other PHY features include support for Multiple-in Multiple-out
(MIMO) antennas in order to provide good Non-Line-Of-Sight (NLOS)
characteristics, such as higher bandwidth, and Hybrid Automatic
Repeat reQuest (HARQ) for good error correction performance.
[0036] According to the IEEE 802.16 family of standards, the MAC
describes a number of convergence sub-layers describing how
wireline technologies, such as Ethernet, ATM and IP, are
encapsulated on the air interface, and how data is classified, and
so forth. It also describes how secure communications are
delivered, such as by using secure key exchange during the
authentication process, and encryption during data transfer.
Further features of the MAC layer include power saving mechanisms,
such as using Sleep Mode and Idle Mode, and handover
mechanisms.
[0037] A feature of IEEE 802.16 systems is the connection oriented
technology. The Subscriber Station (SS), or MS, cannot transmit
data until it has been allocated a channel by the BS. This allows
802.16e to provide strong support for Quality of Service (QoS). The
evolved RAN for LTE has a single node, referred to as the eNodeB
(eNB), wherein NodeB refers to a BS. The eNB, such as BS 104 of
FIG. 1 interfaces with the MS, also referred to as User Equipment
(UE), such as UE 110, 112, 114, 116, 118, or 119. The eNB hosts the
physical layer, PHY, the MAC, the Radio Link Control (RLC), and
Packet Data Control Protocol (PDCP) layers that include the
functionality of user-plane header-compression and encryption. It
also offers Radio Resource Control (RRC) functionality
corresponding to the control plane. It performs many functions
including radio resource management, admission control, scheduling,
enforcement of negotiated UL QoS, cell information broadcast,
ciphering/deciphering of user and control plane data, and
compression/decompression of Down Link (DL)/Up Link (UL) user plane
packet headers.
[0038] In one embodiment, a SON feature enables a BS to
automatically obtain an optimal PHY configuration, including but
not limited to Cell-ID selection so as to minimize inter-cell
interference. In IEEE 802.16m systems. The Cell-ID (also referred
to as CID, or C-ID) is a generally unique number used to identify
each BS or sector of a BS within a Location Area Code (LAC) or in
the network. Cell-ID is the basis for other control/data channel
configurations, including, frequency segment allocation for the
Advanced MAP (A-MAP) and ranging channel. The A-MAP is part of the
DL control channel and includes the Assignment A-MAP (A-A-MAP) to
contain resource assignment information, the HARQ Feedback A-MAP
(HF-A-MAP) to carry HARQ ACK/NACK information for UL data
transmission, and Power Control A-MAP (PC-A-MAP) to carry fast
power control command to AMS. MS operation, however, assumes a
static Cell-ID. Change of Cell-ID, for example via SON function,
may confuse operation and performance of the MS, particularly with
respect to PHY and/or MAC operations.
[0039] Similar issues may arise in other scenarios. For example, in
a system supporting 3GPP LTE-A, a Relay Node (RN) may share the
same identification for an eNB-ID as its donor eNB (the
corresponding BS). If in the future mobile relay is used, RN may
need to switch its eNB-ID after switching to a different donor eNB,
which may cause issues with its associated UEs (MSs).
[0040] One method to enable Cell-ID change without
interrupting/confusing MS data communications is implemented to
improve quality and may be used in a power saving state, the BS
will not know and reconfiguration will likely cause service drop
for these MS.
[0041] In some embodiments, a SON technique is implemented for
reconfiguration of information in a unicast communication. In a
case of a small cell, the BS may serve a small number of MSs, which
makes a unicast solution a reasonable alternative as overhead will
not be too large. The BS may unicast the reconfiguration
information to each MS, and waits for an acknowledgement to ensure
reliability. The unicast message may be protected for integrity,
thus reducing the risk of a safety concern. In addition to a
traditional unicast message, some embodiments implement a new
procedure at the MS, which begins by a signal from the BS
identifying a configuration change. This message may be unicast or
broadcast. The MS obtains the configuration change, and applies new
configuration parameters at Action Time.
[0042] FIGS. 2 and 3 illustrate examples of one method for seamless
reconfiguration in a signal flow diagram. This example illustrates
explicit signaling of configuration change when an upgrade is to be
implemented at the MS.
[0043] As in FIG. 2, the method starts with the BS signals send to
the MS for confirmation change, operation 202. The MS then receives
the configuration change, operation 204. The MS then applies the
received new configuration parameters at Action Time, operation
206.
[0044] The signal flow diagram of FIG. 3 illustrates communications
between a MS and a BS to perform the method of FIG. 2. The
signaling initiates when the BS sends an HO-CMD message to the MS;
the HO-CMD is basically a hand off command identifying a new
Cell-ID, a current BSID (BS identifier), a Disconnect Time and an
Action Time. The MS and the BS then maintain data communication
until Disconnection Time.
[0045] For an intra-BS handover, a method according to one
embodiment of seamless BS reconfiguration, without introducing a
totally new procedure at the MS. The method sends a request to the
MS to perform handover from current serving BS to the same BS.
According to current IEEE802.16m standard, an HO procedure defines
Disconnection Time (DT) and Action Time (AT), which can be mapped
to an Unavailable Start Time (UST) and AT defined in Table-1.
TABLE-US-00001 TABLE 1 Self-Configuration fields in SON-ADV
Unavailable Start Time The time (frame #) that BS stop
communication for its own reconfiguration Action time The time
(frame #) from which change takes effect, and BS restart
communication after reconfiguration New Cell-ID The new Cell-ID to
be used after Action Time Other PHY Variable length field
configurations
[0046] In one example method, the MS may simply perform an
optimized intra-BS HO using an existing procedure, and align the MS
time to stop or restart communications with the BS according to the
BS defined reconfiguration start or finish time.
[0047] The method 400 illustrated in FIG. 4 describes intra-cell HO
to allow seamless BS reconfiguration. The method 400 allows for
reduced MS behavior, such as a software or firmware upgrades, to
implement at the MS compared to a regular handover. Since
IEEE802.16m systems apply HO framework which allows seamless HO.
The data communications may resume after the Action Time without
waiting for network reentry signaling to complete. In one
embodiment an AAI_RNG-REQ/RSP transaction may happen in parallel,
as long as it is before a specified deadline after the Action Time,
wherein the service interruption may impact the BS reconfiguration
interval without impacting the MS timing and operations, thus a
seamless HO for the MS.
[0048] An HO procedure may automatically update the security keys
used for authentication and integrity protection, such as where
consistent with a 3GPP LTE security architecture. The preamble
index (cell-ID or PCI) is included in the key hierarchy. Such
method may be applied to LTE technology in a variety of
embodiments. In one group mobility example, a mobile relay scheme,
such as an LTE-A rel-10 relay architecture, may require a RN and
its corresponding donor eNB to share the same eNB ID. This is used
when D-eNB applies a proxy function between RN and MME, so that the
network signaling knows which routing to apply to the network and
RN. Then, if the RN re-establishes its relay link with another eNB,
such as due to mobility, line failure or load balancing
requirement, the RN may use a new eNB ID. This may cause an
associated UE to reset its MAC and declare a link failure. Using
the intra-BS handover framework, such failure recovery may be
avoided and thus UE experiences a smooth transition.
[0049] As illustrated in FIG. 4, the method 400 starts when the RN
determines to re-establish its relay link, operations 402. The RN
determines a re-establishment time, t, at operation 404. The RN
then issues a handover command to at least some of the connected
UEs, wherein the Disconnect Time=T1, the Action Time=T1+t, and the
new configurations are provided to the UEs, operation 406. The RN
finishes the relay link re-establishment at time T0+t, operation
408. Then the UE hands over the connection back to RN at T1+t,
operation 410.
[0050] The various embodiments described herein provide seamless
reconfiguration in a wireless network in contrast to methods in
which configuration parameters, such as BSID, are changed, and the
MS may treat it as a link loss, repeat a network reentry and cause
a data drop or service interruption. The methods described herein,
one method involves making the MS aware of a change and effectively
acts to "skip" the change period and automatically uses the new
configuration after a change period.
[0051] Other methods may use intra-BS handover procedure to ask the
MS to perform a hand over operation without changing BS connection,
but effectively handing off to the same BS. This reconfigures the
connection back to the same physical BS after a predetermined or
specified time period and thus does not require MS update. This is
in contrast to LTE specifications where "intra-eNB" handover allows
a UE to handover from one cell of the eNB to another cell of the
same eNB. Note also, that "cell" in an LTE system is similar to a
BS in an IEEE 802.16m system. Therefore, from the MAC point of
view, an LTE "intra-eNB" handover UE is not in communication with
the same MAC function entity before/after handover. The use of the
HO techniques to achieve seamless reconfiguration may be used in a
variety of systems and is not limited to the specific wireless
communication systems described herein. The unique combination of
components and techniques in such embodiments provides an
improvement over previously known structures and techniques.
[0052] FIG. 7 illustrates a wireless communication device 500
performing the sleep mode optimizations described hereinabove.
Central Processing Unit (CPU) 512 is coupled to bus 510 for control
of device 500. Transceiver 506 communicates with a network
wirelessly, and is coupled to the bus 510, which may be any of a
variety of mechanisms for communication within device 600.
Operation of device 500 to support a wireless protocol standard,
including IEEE 802.16. Device 500 may include a plurality of
controllers (not shown) which may be implemented as instructions
stored on a computer-readable storage medium, circuitry, or a
combination thereof. The device 500 further includes configuration
module 504 which controls configuration, reconfiguration, update
and changes within the device 500. The device 500 further includes
a memory storage unit 502, which may store code to implement the
operations to implement seamless reconfiguration, and so forth.
Other embodiments may have alternate configurations to implement
the methods described herein.
[0053] Unless specifically stated otherwise, terms such as
processing, computing, calculating, determining, displaying, or the
like, may refer to an action and/or process of one or more
processing or computing systems or similar devices that may
manipulate and transform data represented as physical (e.g.,
electronic) quantities within a processing system's registers and
memory into other data similarly represented as physical quantities
within the processing system's registers or memories, or other such
information storage, transmission or display devices. Furthermore,
as used herein, a computing device includes one or more processing
elements coupled with computer-readable memory that may be volatile
or non-volatile memory or a combination thereof.
[0054] Embodiments of the invention may be implemented in one or a
combination of hardware, firmware and software. Embodiments of the
invention may also be implemented as instructions stored on a
machine-readable medium, which may be read and executed by at least
one processor to perform the operations described herein. A
machine-readable medium may include any mechanism for storing or
transmitting information in a form readable by a machine (e.g., a
computer). For example, a machine-readable medium may include
read-only memory (ROM), random-access memory (RAM), magnetic disk
storage media, optical storage media, flash-memory devices,
electrical, optical, acoustical or other form of propagated signals
(e.g., carrier waves, infrared signals, digital signals, etc.), and
others.
[0055] The Abstract is provided to comply with 37 C.F.R. Section
1.72(b) requiring an abstract that will allow the reader to
ascertain the nature and gist of the technical disclosure. It is
submitted with the understanding that it will not be used to limit
or interpret the scope or meaning of the claims.
[0056] In the foregoing detailed description, various features are
occasionally grouped together in a single embodiment for the
purpose of streamlining the disclosure. This method of disclosure
is not to be interpreted as reflecting an intention that the
claimed embodiments of the subject matter require more features
than are expressly recited in each claim. Rather, as the following
claims reflect, invention may lie in less than all features of a
single disclosed embodiment. Thus the following claims are hereby
incorporated into the detailed description, with each claim
standing on its own as a separate preferred embodiment.
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