U.S. patent number 9,271,260 [Application Number 14/061,991] was granted by the patent office on 2016-02-23 for enabling receive diversity during paging channel timeline operation.
This patent grant is currently assigned to Apple Inc.. The grantee listed for this patent is Apple Inc.. Invention is credited to Swaminathan Balakrishnan, Wael S. Barakat, Chandra S. Chetty, Raghuveer Mallikarjunan, Johnson O. Sebeni, Tahir Shamim.
United States Patent |
9,271,260 |
Barakat , et al. |
February 23, 2016 |
Enabling receive diversity during paging channel timeline
operation
Abstract
Enabling receive diversity based on detecting incorrect paging
message length. A paging channel may be monitored. An indication of
a paging message may be received on the paging channel. The paging
message may include a message length field indicating a message
length of the paging message. The message length field of the
paging message may be received on the paging channel and decoded.
It may be determined that the message length indicated in the
message length field is incorrect. Receive diversity may be enabled
for at least one subsequent paging occasion in response to
determining that the message length indicated in the message length
field is incorrect.
Inventors: |
Barakat; Wael S. (San Jose,
CA), Chetty; Chandra S. (Sunnyvale, CA), Sebeni; Johnson
O. (Fremont, CA), Mallikarjunan; Raghuveer (Sunnyvale,
CA), Balakrishnan; Swaminathan (Santa Clara, CA), Shamim;
Tahir (San Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Assignee: |
Apple Inc. (Cupertino,
CA)
|
Family
ID: |
51165541 |
Appl.
No.: |
14/061,991 |
Filed: |
October 24, 2013 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140200040 A1 |
Jul 17, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61753181 |
Jan 16, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
68/02 (20130101) |
Current International
Class: |
H04W
68/00 (20090101); H04W 68/02 (20090101) |
Field of
Search: |
;455/458,574 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mitchell; Nathan
Assistant Examiner: Lam; Dung
Attorney, Agent or Firm: Meyertons Hood Kivlin Kowert &
Goetzel, P.C. Hood; Jeffrey C.
Parent Case Text
PRIORITY CLAIM
The present application claims benefit of priority to U.S.
Provisional Application No. 61/753,181 titled "Enabling Receive
Diversity During Paging Channel Timeline Operation" and filed on
Jan. 16, 2013, whose inventors are Wael S Barakat, Chandra S
Chetty, Johnson O Sebeni, Raghuveer Mallikarjunan, Swaminathan
Balakrishnan, and Tahir Shamim, which is hereby incorporated by
reference in its entirety as though fully and completely set forth
herein.
Claims
What is claimed is:
1. A method for operating a wireless user equipment (UE) device,
the method comprising: monitoring a paging channel; detecting an
indication of a first paging message on the paging channel, wherein
the first paging message comprises a message length field
indicating a message length of the first paging message; receiving
and decoding the message length field of the first paging message
on the paging channel; determining that the message length
indicated in the message length field is incorrect; enabling
receive diversity for at least one subsequent paging occasion in
response to determining that the message length indicated in the
message length field is incorrect; and determining that the message
length indicated in the message length field of the first paging
message is incorrect comprises one or more of: determining that the
message length field indicates a message length which is longer
than a specified maximum paging message length; or detecting an
indication of a second paging message on the paging channel while
decoding the first paging message.
2. The method of claim 1, the method further comprising: ceasing to
decode the first paging message after determining that the message
length indicated in the message length field is incorrect, based on
determining that the message length indicated in the message length
field is incorrect.
3. The method of claim 1, wherein determining that the message
length indicated in the message length field is incorrect
comprises: determining that the message length field indicates a
message length which is longer than a specified maximum paging
message length.
4. The method of claim 1, wherein determining that the message
length indicated in the message length field is incorrect
comprises: detecting an indication of a second paging message on
the paging channel while decoding the first paging message
according to the message length indicated in the message length
field.
5. The method of claim 1, wherein the UE operates according to a
3GPP2 cellular communication standard.
6. The method of claim 1, wherein enabling receive diversity
comprises utilizing multiple antennas of the UE to monitor the
paging channel for the at least one subsequent paging occasion.
7. The method of claim 1, the method further comprising: disabling
receive diversity after the at least one subsequent paging occasion
if no further errors are detected while attempting to receive and
decode paging messages on the at least one subsequent paging
occasion.
8. A wireless user equipment (UE) device, comprising: a radio,
comprising at least two antennas configured for wireless
communication; a processing element operably coupled to the radio;
wherein the radio and the processing element are configured to:
monitor a paging channel; detect an indication of a first paging
message on the paging channel, wherein the first paging message
comprises a message length field indicating a message length of the
first paging message; receive and decoding the message length field
of the first paging message on the paging channel; determine that
the message length indicated in the message length field is
incorrect; enable receive diversity for at least one subsequent
paging occasion in response to determining that the message length
indicated in the message length field is incorrect; and determine
that the message length indicated in the message length field of
the first paging message is incorrect comprises one or more of:
determining that the message length field indicates a message
length which is longer than a specified maximum paging message
length; or detecting an indication of a second paging message on
the paging channel while decoding the first paging message.
9. The UE of claim 8, wherein enabling receive diversity comprises
utilizing at least two antennas of the radio to monitor the paging
channel for the at least one subsequent paging occasion.
10. The UE of claim 8, wherein the radio and the processing element
are configured to monitor the paging channel, detect the indication
of the first paging message, and receive and decode the message
length field of the paging message with receive diversity disabled,
wherein enabling receive diversity for the at least one subsequent
paging occasion in response to determining that the message length
indicated in the message length field is incorrect configures the
radio and the processing element to monitor the paging channel,
detect indications of paging messages, and receive and decode
message length fields of paging messages with receive diversity
enabled for the at least one subsequent paging occasion.
11. The UE of claim 10, wherein monitoring the paging channel,
detecting the indication of the first paging message, and receiving
and decoding the message length field of the paging message with
receive diversity disabled comprises using only one antenna of the
radio to monitor the paging channel, detect the indication of the
first paging message, and receive and decode the message length
field of the paging message.
12. The UE of claim 8, wherein the radio and the processing element
are configured to monitor the paging channel, detect the indication
of the first paging message, and receive and decode the message
length field of the paging message with receive diversity enabled,
wherein enabling receive diversity for the at least one subsequent
paging occasion in response to determining that the message length
indicated in the message length field is incorrect comprises
extending the use of receive diversity for the at least one
subsequent paging occasion.
13. The UE of claim 8, wherein, in response to determining that the
message length indicated in the message length field is incorrect,
the radio and the processing element are configured to enable
receive diversity for one of: a predetermined amount of time; or a
predetermined number of paging occasions, wherein the radio and the
processing element are configured to disable receive diversity
after the predetermined amount of time or predetermined number of
paging occasions if no further errors are detected while attempting
to receive and decode paging messages during the predetermined
amount of time or predetermined number of paging occasions.
14. The UE of claim 8, wherein the UE is configured to communicate
using at least a first radio access technology and a second radio
access technology, wherein when receive diversity is disabled, the
UE is capable of utilizing the at least two antennas of the radio
to communicate using each of the first and second radio access
technologies simultaneously, wherein when receive diversity is
enabled, the UE is able to communicate using only one of the first
or second radio access technology at a time.
15. A non-transitory computer accessible memory medium comprising
program instructions for a wireless user equipment (UE) device,
wherein when executed, the program instructions cause the UE to:
monitor a paging channel at a first paging occasion, wherein a
first antenna is used to monitor the paging channel at the first
paging occasion; detect an indication of a first paging message on
the paging channel using the first antenna during the first paging
occasion, wherein the first paging message comprises a message
length field indicating a message length of the first paging
message; receive and decoding the message length field of the first
paging message on the paging channel using the first antenna during
the first paging occasion; determine that the message length
indicated in the message length field of the first paging message
is incorrect; monitor the paging channel for at least one
subsequent paging occasion, wherein the first antenna and a second
antenna are used to monitor the paging channel at the at least one
subsequent paging occasion in response to determining that the
message length indicated in the message length field of the first
paging message is incorrect; and determining that the message
length indicated in the message length field of the first paging
message is incorrect comprises one or more of: determining that the
message length field indicates a message length which is longer
than a specified maximum paging message length; or detecting an
indication of a second paging message on the paging channel while
decoding the first paging message.
16. The memory medium of claim 15, wherein the at least one
subsequent paging occasion comprises a plurality of subsequent
paging occasions, wherein the program instructions further cause
the UE to monitor the paging channel using only the first antenna
after the plurality of subsequent paging occasions if no further
errors are detected while attempting to receive and decode paging
messages during the plurality of subsequent paging occasions,
wherein the program instructions further cause the UE to monitor
the paging channel using the first antenna and the second antenna
for at least one additional paging occasion after the plurality of
subsequent paging occasions one or more further errors are detected
while attempting to receive and decode paging messages during the
plurality of subsequent paging occasions.
17. The memory medium of claim 15, wherein the program instructions
further cause the UE to: cease decoding the first paging message
after determining that the message length indicated in the message
length field of the first paging message is incorrect, based on
determining that the message length indicated in the message length
field of the first paging message is incorrect.
18. The memory medium of claim 15, wherein monitoring the paging
channel, detecting the indication of the first paging message, and
receiving and decoding the message length field of the first paging
message are performed in accordance with a 3GPP2 radio access
technology, wherein the indication of the first paging message
comprises a synchronized capsule indicator (SCI) having a value of
1.
19. The memory medium of claim 15, wherein monitoring the paging
channel for the first paging occasion and the at least one
subsequent paging occasion are performed as part of discontinuous
reception operation of the UE.
Description
FIELD
The present application relates to wireless devices, and more
particularly to a system and method for enabling receive diversity
during paging channel timeline operation by a wireless device.
DESCRIPTION OF THE RELATED ART
Wireless communication systems are rapidly growing in usage. Many
wireless communication technologies utilize a paging channel, often
in combination with discontinuous reception (DRX) techniques, as a
way of implementing an energy efficient idle mode of operation. In
such systems, a wireless device may be able to "sleep" (operate in
a low-power state) for significant blocks of time, while
periodically "waking up" (operating in an active state) to monitor
the paging channel and potentially performing various other
activities.
SUMMARY OF THE INVENTION
Embodiments are presented herein of various methods for operating
wireless devices in conjunction with paging channel timelines, and
of wireless devices configured to implement the various
methods.
In particular, techniques are described providing features for
detecting and responding to incorrectly decoded paging message
lengths. Among other features, the techniques may provide features
enabling a wireless device to cease attempting to decode paging
messages which (due to the incorrectly decoded paging message
length) are known to be invalid. Additionally, or alternatively,
the techniques may provide features for improving the chances of
correctly receiving subsequent paging messages in response to
detecting an incorrectly decoded paging message length, such as
receive diversity.
The techniques described herein may be implemented in and/or used
with a number of different types of devices, including but not
limited to, cellular phones, portable media players, portable
gaming devices, tablet computers, and/or any of various other types
of computing devices.
This Summary is intended to provide a brief overview of some of the
subject matter described in this document. Accordingly, it will be
appreciated that the above-described features are merely examples
and should not be construed to narrow the scope or spirit of the
subject matter described herein in any way. Other features,
aspects, and advantages of the subject matter described herein will
become apparent from the following Detailed Description, Figures,
and Claims.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present subject matter can be
obtained when the following detailed description of the embodiments
is considered in conjunction with the following drawings, in
which:
FIG. 1 illustrates an exemplary (and simplified) wireless
communication system;
FIG. 2 illustrates a base station (BS) in communication with user
equipment (UE);
FIG. 3 illustrates an exemplary block diagram of a UE;
FIG. 4 illustrates an exemplary block diagram of a BS; and
FIG. 5 is a flowchart diagram illustrating an exemplary method for
a UE to enable receive diversity during paging channel timeline
operation.
While the features described herein may be susceptible to various
modifications and alternative forms, specific embodiments thereof
are shown by way of example in the drawings and are herein
described in detail. It should be understood, however, that the
drawings and detailed description thereto are not intended to be
limiting to the particular form disclosed, but on the contrary, the
intention is to cover all modifications, equivalents and
alternatives falling within the spirit and scope of the subject
matter as defined by the appended claims.
DETAILED DESCRIPTION
Acronyms
The following acronyms are used in this disclosure:
UE: User Equipment
BS: Base Station
3GPP: Third Generation Partnership Program
3GPP2: Third Generation Partnership Program 2
RAT: Radio Access Technology
GSM: Global System for Mobile Communication
UMTS: Universal Mobile Telecommunication System
LTE: Long Term Evolution
TERMS
The following is a glossary of terms used in this disclosure:
Memory Medium--Any of various types of non-transitory memory
devices or storage devices. The term "memory medium" is intended to
include an installation medium, e.g., a CD-ROM, floppy disks, or
tape device; a computer system memory or random access memory such
as DRAM, DDR RAM, SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile
memory such as a Flash, magnetic media, e.g., a hard drive, or
optical storage; registers, or other similar types of memory
elements, etc. The memory medium may include other types of
non-transitory memory as well or combinations thereof. In addition,
the memory medium may be located in a first computer system in
which the programs are executed, or may be located in a second
different computer system which connects to the first computer
system over a network, such as the Internet. In the latter
instance, the second computer system may provide program
instructions to the first computer for execution. The term "memory
medium" may include two or more memory mediums which may reside in
different locations, e.g., in different computer systems that are
connected over a network. The memory medium may store program
instructions (e.g., embodied as computer programs) that may be
executed by one or more processors.
Carrier Medium--a memory medium as described above, as well as a
physical transmission medium, such as a bus, network, and/or other
physical transmission medium that conveys signals such as
electrical, electromagnetic, or digital signals.
Programmable Hardware Element--includes various hardware devices
comprising multiple programmable function blocks connected via a
programmable interconnect. Examples include FPGAs (Field
Programmable Gate Arrays), PLDs (Programmable Logic Devices), FPOAs
(Field Programmable Object Arrays), and CPLDs (Complex PLDs). The
programmable function blocks may range from fine grained
(combinatorial logic or look up tables) to coarse grained
(arithmetic logic units or processor cores). A programmable
hardware element may also be referred to as "reconfigurable
logic".
Computer System--any of various types of computing or processing
systems, including a personal computer system (PC), mainframe
computer system, workstation, network appliance, Internet
appliance, personal digital assistant (PDA), television system,
grid computing system, or other device or combinations of devices.
In general, the term "computer system" can be broadly defined to
encompass any device (or combination of devices) having at least
one processor that executes instructions from a memory medium.
User Equipment (UE) (or "UE Device")--any of various types of
computer systems devices which are mobile or portable and which
performs wireless communications. Examples of UE devices include
mobile telephones or smart phones (e.g., iPhone.TM.,
Android.TM.-based phones), portable gaming devices (e.g., Nintendo
DS.TM., PlayStation Portable.TM., Gameboy Advance.TM., iPhone.TM.),
laptops, PDAs, portable Internet devices, music players, data
storage devices, or other handheld devices, etc. In general, the
term "UE" or "UE device" can be broadly defined to encompass any
electronic, computing, and/or telecommunications device (or
combination of devices) which is easily transported by a user and
capable of wireless communication.
Base Station--The term "Base Station" has the full breadth of its
ordinary meaning, and at least includes a wireless communication
station installed at a fixed location and used to communicate as
part of a wireless telephone system or radio system.
Processing Element--refers to various elements or combinations of
elements. Processing elements include, for example, circuits such
as an ASIC (Application Specific Integrated Circuit), portions or
circuits of individual processor cores, entire processor cores,
individual processors, programmable hardware devices such as a
field programmable gate array (FPGA), and/or larger portions of
systems that include multiple processors.
Channel--a medium used to convey information from a sender
(transmitter) to a receiver. It should be noted that since
characteristics of the term "channel" may differ according to
different wireless protocols, the term "channel" as used herein may
be considered as being used in a manner that is consistent with the
standard of the type of device with reference to which the term is
used. In some standards, channel widths may be variable (e.g.,
depending on device capability, band conditions, etc.). For
example, LTE may support scalable channel bandwidths from 1.4 MHz
to 20 MHz. In contrast, WLAN channels may be 22 MHz wide while
Bluetooth channels may be 1 Mhz wide. Other protocols and standards
may include different definitions of channels. Furthermore, some
standards may define and use multiple types of channels, e.g.,
different channels for uplink or downlink and/or different channels
for different uses such as data, control information, etc.
Automatically--refers to an action or operation performed by a
computer system (e.g., software executed by the computer system) or
device (e.g., circuitry, programmable hardware elements, ASICs,
etc.), without user input directly specifying or performing the
action or operation. Thus the term "automatically" is in contrast
to an operation being manually performed or specified by the user,
where the user provides input to directly perform the operation. An
automatic procedure may be initiated by input provided by the user,
but the subsequent actions that are performed "automatically" are
not specified by the user, i.e., are not performed "manually",
where the user specifies each action to perform. For example, a
user filling out an electronic form by selecting each field and
providing input specifying information (e.g., by typing
information, selecting check boxes, radio selections, etc.) is
filling out the form manually, even though the computer system must
update the form in response to the user actions. The form may be
automatically filled out by the computer system where the computer
system (e.g., software executing on the computer system) analyzes
the fields of the form and fills in the form without any user input
specifying the answers to the fields. As indicated above, the user
may invoke the automatic filling of the form, but is not involved
in the actual filling of the form (e.g., the user is not manually
specifying answers to fields but rather they are being
automatically completed). The present specification provides
various examples of operations being automatically performed in
response to actions the user has taken.
FIGS. 1 and 2--Communication System
FIG. 1 illustrates an exemplary (and simplified) wireless
communication system. It is noted that the system of FIG. 1 is
merely one example of a possible system, and features of this
disclosure may be implemented in any of various systems, as
desired.
As shown, the exemplary wireless communication system includes a
base station 102 which communicates over a transmission medium with
one or more user devices 106A, 106B, etc., through 106N. Each of
the user devices may be referred to herein as a "user equipment"
(UE). Thus, the user devices 106 are referred to as UEs or UE
devices.
The base station 102 may be a base transceiver station (BTS) or
cell site, and may include hardware that enables wireless
communication with the UEs 106A through 106N. The base station 102
may also be equipped to communicate with a network 100 (e.g., a
core network of a cellular service provider, a telecommunication
network such as a public switched telephone network (PSTN), and/or
the Internet, among various possibilities). Thus, the base station
102 may facilitate communication between the user devices and/or
between the user devices and the network 100.
The communication area (or coverage area) of the base station may
be referred to as a "cell." The base station 102 and the UEs 106
may be configured to communicate over the transmission medium using
any of various radio access technologies (RATs), also referred to
as wireless communication technologies, or telecommunication
standards, such as GSM, UMTS (WCDMA), LTE, LTE-Advanced (LTE-A),
3GPP2 CDMA2000 (e.g., 1.times.RTT, 1.times.EV-DO, HRPD, eHRPD),
Wi-Fi, WiMAX etc. Base station 102 and other similar base stations
operating according to the same or a different cellular
communication standard may thus be provided as a network of cells,
which may provide continuous or nearly continuous overlapping
service to UE 106 and similar devices over a wide geographic area
via one or more cellular communication standards.
A UE 106 may be capable of communicating using multiple wireless
communication standards. For example, a UE 106 might be configured
to communicate using two or more of GSM, UMTS, CDMA2000, WiMAX,
LTE, WLAN, Bluetooth, one or more global navigational satellite
systems (GNSS, e.g., GPS or GLONASS), one and/or more mobile
television broadcasting standards (e.g., ATSC-M/H or DVB-H), etc.
Other combinations of wireless communication standards (including
more than two wireless communication standards) are also
possible.
FIG. 2 illustrates user equipment 106 (e.g., one of the devices
106A through 106N) in communication with the base station 102. The
UE 106 may be a device with wireless network connectivity such as a
mobile phone, a hand-held device, a computer or a tablet, or
virtually any type of wireless device.
The UE 106 may include a processor that is configured to execute
program instructions stored in memory. The UE 106 may perform any
of the method embodiments described herein by executing such stored
instructions. Alternatively, or in addition, the UE 106 may include
a programmable hardware element such as an FPGA (field-programmable
gate array) that is configured to perform any of the method
embodiments described herein, or any portion of any of the method
embodiments described herein.
In some embodiments, the UE 106 may be configured to communicate
using any of multiple radio access technologies/wireless
communication protocols. For example, the UE 106 may be configured
to communicate using two or more of CDMA2000, LTE, LTE-A, WLAN, or
GNSS. Other combinations of wireless communication technologies are
also possible.
The UE 106 may include one or more antennas for communicating using
one or more wireless communication protocols. In some embodiments,
the UE 106 may share one or more parts of a receive and/or transmit
chain between multiple wireless communication standards. The shared
radio may include a single antenna, or may include multiple
antennas (e.g., for MIMO) for performing wireless communications.
In other embodiments, the UE 106 may include separate transmit
and/or receive chains (e.g., including separate antennas and other
radio components) for each wireless communication protocol with
which it is configured to communicate. In still other embodiments,
the UE 106 may include one or more radios which are shared between
multiple wireless communication protocols, and one or more radios
which are used exclusively by a single wireless communication
protocol. For example, in one set of embodiments, the UE 106 may
include a shared radio for communicating using either of LTE or
CDMA2000 1.times.RTT, and separate radios for communicating using
each of Wi-Fi and Bluetooth. Other configurations are also
possible.
FIG. 3--Exemplary Block Diagram of a UE
FIG. 3 illustrates an exemplary block diagram of a UE 106. As
shown, the UE 106 may include a system on chip (SOC) 300, which may
include portions for various purposes. For example, as shown, the
SOC 300 may include processor(s) 302 which may execute program
instructions for the UE 106 and display circuitry 304 which may
perform graphics processing and provide display signals to the
display 360. The processor(s) 302 may also be coupled to memory
management unit (MMU) 340, which may be configured to receive
addresses from the processor(s) 302 and translate those addresses
to locations in memory (e.g., memory 306, read only memory (ROM)
350, NAND flash memory 310) and/or to other circuits or devices,
such as the display circuitry 304, radio 330, connector I/F 320,
and/or display 360. The MMU 340 may be configured to perform memory
protection and page table translation or set up. In some
embodiments, the MMU 340 may be included as a portion of the
processor(s) 302.
As shown, the SOC 300 may be coupled to various other circuits of
the UE 106. For example, the UE 106 may include various types of
memory (e.g., including NAND flash 310), a connector interface 320
(e.g., for coupling to a computer system, dock, charging station,
etc.), the display 360, and wireless communication circuitry (e.g.,
for UMTS, LTE, CDMA2000, Wi-Fi, GPS, etc.).
The UE device 106 may include at least one antenna, and in some
embodiments multiple antennas, for performing wireless
communication with base stations and/or other devices. For example,
the UE device 106 may use antennas 335 and 337 to perform the
wireless communication.
The UE 106 may be provided with multiple antennas for any of a
number of reasons. As one possibility, the UE 106 may be provided
with multiple antennas in order that the UE 106 may enable transmit
and/or receive diversity some or all of the time. For example,
utilizing multiple antennas to receive wireless signals may provide
more robust reception capabilities, such that the wireless device
may be able to successfully (e.g., accurately) receive and decode
wireless signals in poorer channel conditions (e.g., decreased
signal strength and/or quality, due to distance, interference,
etc.) than utilizing a single antenna. However, utilizing multiple
antennas may also consume more power than utilizing a single
antenna, so it may not be desirable to do so in all circumstances,
such as for example if channel conditions are sufficiently good to
support successful reception using a single antenna.
Furthermore, as noted above, the UE 106 may be configured to
communicate wirelessly using multiple wireless communication
standards/radio access technologies (RATs) in some embodiments. If
configured in such a way, the UE 106 may multiplex radio resources
between the multiple RATs, such that it may be desirable to deploy
one (or more) antennas according to one RAT at some times, and to
deploy one (or more) antennas according to a different RAT at other
times.
As described further herein, the UE 106 may include hardware and
software components for implementing features for enabling receive
diversity while monitoring and decoding the paging channel based on
detecting an incorrectly decoded paging message length, such as
those described herein with reference to, inter alia, FIG. 5. The
processor 302 of the UE device 106 may be configured to implement
part or all of the methods described herein, e.g., by executing
program instructions stored on a memory medium (e.g., a
non-transitory computer-readable memory medium). In other
embodiments, processor 302 may be configured as a programmable
hardware element, such as an FPGA (Field Programmable Gate Array),
or as an ASIC (Application Specific Integrated Circuit).
Alternatively (or in addition) the processor 302 of the UE device
106, in conjunction with one or more of the other components 300,
304, 306, 310, 320, 330, 335, 337, 340, 350, 360 may be configured
to implement part or all of the features described herein, such as
the features described herein with reference to, inter alia, FIG.
5.
FIG. 4--Exemplary Block Diagram of a Base Station
FIG. 4 illustrates an exemplary block diagram of a base station
102. It is noted that the base station of FIG. 4 is merely one
example of a possible base station. As shown, the base station 102
may include processor(s) 404 which may execute program instructions
for the base station 102. The processor(s) 404 may also be coupled
to memory management unit (MMU) 440, which may be configured to
receive addresses from the processor(s) 404 and translate those
addresses to locations in memory (e.g., memory 460 and read only
memory (ROM) 450) or to other circuits or devices.
The base station 102 may include at least one network port 470. The
network port 470 may be configured to couple to a telephone network
and provide a plurality of devices, such as UE devices 106, access
to the telephone network as described above in FIGS. 1 and 2.
The network port 470 (or an additional network port) may also or
alternatively be configured to communicatively couple to a cellular
network, e.g., a core network of a cellular service provider. The
core network may provide mobility related services and/or other
services to a plurality of devices, such as UE devices 106. In some
cases, the network port 470 may couple to a telephone network via
the core network, and/or the core network may provide a telephone
network (e.g., among other UE devices serviced by the cellular
service provider).
The base station 102 may include at least one antenna 434, and
possibly multiple antennas. The at least one antenna 434 may be
configured to operate as a wireless transceiver and may be further
configured to communicate with UE devices 106 via radio 430. The
antenna 434 communicates with the radio 430 via communication chain
432. Communication chain 432 may be a receive chain, a transmit
chain or both. The radio 430 may be configured to communicate via
various wireless telecommunication standards, including, but not
limited to, LTE, LTE-A, TD-SCDMA, WCDMA, CDMA2000, etc.
The processor 404 of the base station 102 may be configured to
implement part or all of the methods described herein, e.g., by
executing program instructions stored on a memory medium (e.g., a
non-transitory computer-readable memory medium). Alternatively, the
processor 404 may be configured as a programmable hardware element,
such as an FPGA (Field Programmable Gate Array), or as an ASIC
(Application Specific Integrated Circuit), or a combination
thereof. Alternatively (or in addition) the processor 404 of the
base station 102, in conjunction with one or more of the other
components 430, 432, 434, 440, 450, 460, 470 may be configured to
implement part or all of the features described herein, such as the
features described herein with reference to, inter alia, FIG.
5.
FIG. 5--Flowchart
FIG. 5 is a flowchart diagram illustrating a method for a wireless
UE device 106 to enable receive diversity based on detecting paging
channel message errors. The method shown in FIG. 5 may be used in
conjunction with any of the computer systems or devices shown in
the above Figures, among other devices. In various embodiments,
some of the method elements shown may be performed concurrently, in
a different order than shown, or may be omitted. Additional method
elements may also be performed as desired. As shown, this method
may operate as follows.
In 502, the UE 106 may monitor a paging channel. In particular, the
UE 106 may monitor the paging channel for indications of incoming
paging messages from a cellular network which operates according to
a cellular technology supported by the UE 106. The cellular network
may include a network of cells provided by base stations (such as
base station 102) as well as a core network, among various possible
components. The UE 106 may in particular be camped on a particular
cell (a "first cell") in the network, provided by a particular base
station (a "first base station"), which may provide the UE 106 with
a wireless link to the cellular network.
The cellular technology (or "radio access technology", or "RAT")
according to which the cellular network operates and which is
supported by the UE 106, may be any of various cellular
technologies, such as a 3GPP or 3GPP2 cellular communication
standard, including but not limited to GSM, cdmaOne, UMTS, CDMA2000
(1.times.RTT, 1.times.EV-DO, etc.), LTE, LTE-A, etc. Note that it
is also possible (as previously noted, and further described
subsequently herein) that the UE 106 may be configured to support
multiple cellular communication technologies/standards.
Monitoring the paging channel may be part of idle-mode operation
for the UE 106. In other words, the UE 106 may camp on the first
cell in an idle-mode. The first cell may serve the UE 106 and
provide a connection (e.g., a passive connection, in the idle-mode)
to the core network. For example, to camp on the first cell in the
idle-mode the UE 106 may establish a radio resource control (RRC)
entity, which may operate in an RRC-idle state while the UE 106 is
in the idle-mode. The nature of idle-mode operation for a UE 106
may vary according to different wireless communication
technologies. Generally, the idle-mode operation may be appropriate
when a UE 106 is not actively exchanging data (e.g., as part of a
call or a networking application such as a web browser) with the
network. In some cases the idle-mode may include a discontinuous
reception or "DRX" mode. In a DRX mode, a UE 106 may generally be
inactive (e.g., with one or more components, such as radio and/or
baseband components, powered down or sleeping) except for a window
of activity during each DRX cycle. The active portion of a DRX
cycle may be scheduled in a regular periodic manner; for example,
many networks schedule the active portion of DRX cycles to occur at
1.28 s intervals, or at some multiple of 1.28 s (e.g., 2.56 s, 5.12
s, etc). Other values for DRX periodicity may be used as
desired.
During the active portion of a DRX cycle, the UE 106 may perform
certain actions (e.g., according to the configuration of the UE 106
and/or according to configuration information received from the
network). For example, the UE 106 may monitor the paging channel
for paging messages, which may provide indications of incoming
voice calls or data, among various possibilities. The cellular
network may be configured to transmit any paging messages for the
UE 106 on the paging channel at specific scheduled (typically in a
regular periodic manner) occasions. The UE 106 may thus configure
its DRX operation such that the active portion of each DRX cycle
corresponds to these "paging occasions", in order that the UE 106
may monitor the paging channel at the times when paging messages
might be directed to the UE 106. The UE 106 may also check
for/update system configuration settings, perform mobility related
functions (e.g., serving and/or neighboring cell search and/or
measurement, cell re-selection if necessary) and/or perform any of
various other actions during the active portion of the DRX cycle.
The UE 106 may then sleep in between those paging occasions, once
any such other configured activities and operations are
completed.
In 504, while monitoring the paging channel (e.g., as part of
idle-mode DRX operation according to a radio access technology, as
described above), an indication of an incoming paging message (a
"first paging message") may be detected. Various RATs may provide
paging channels with different configurations, including different
means of indicating to a UE 106 that an upcoming paging message is
directed to the UE 106. As one possibility, the paging channel may
be arranged in such a manner that certain periodically occurring
indicator bits may be used to indicate the presence of an upcoming
paging message.
Again depending on the particular RAT according to which the UE 106
is operating, the structure of a paging message may be variable.
For at least some such RATs, however, a paging message may be
structured to include a message length field, which may indicate a
message length of that paging message. Thus, in 506, based on
detecting the indication of the incoming first paging message, the
UE 106 may receive (e.g., on the paging channel) and decode a
message length field of the first paging message.
In 508, it may be determined that the message length indicated in
the message length field of the first paging message is incorrect.
Any of a variety of techniques may be used to determine that the
message length indicated in the message length field of the first
paging message is incorrect.
As one example, in some instances it may be determined directly
from decoding the message length field of the first paging message
that the message length indicated in the message length field of
the first paging message is incorrect. For example, it may be
possible that the message length indicated in the message length
field may be longer than a specified maximum paging message length.
In particular, although the message length field may theoretically
indicate any message length up a maximum possible value of the
message length field (e.g., 255 bytes for an 8 bit field, or 127
bytes for a 7 bit field, 511 bytes for a 9 bit field, etc.), it may
be possible that the specification of the RAT standard according to
which the UE 106 may be operating may specify a maximum possible
paging message length which is less than the maximum possible value
of the message length field. In other words, it may be possible for
the combined maximum possible length of all possible fields of a
paging message may be less than the maximum possible value of the
message length field. For example, if the message length field is
an 8 bit field (thus having a maximum value of 255 bytes), but the
maximum possible length of a paging message according to the
appropriate specification is 148 bytes, any value of the paging
message length field greater than 148 may be erroneous. Note that
the above example is not intended to be limiting, and that
alternate examples for any of various other message length fields
and/or maximum specified paging message lengths are also
possible.
Accordingly, if the UE 106 determines that the message length field
indicates a message length which is longer than a specified maximum
paging message length, the UE 106 may determine that the message
length indicated in the message length field is incorrect.
Note that it may also be possible to determine that the message
length indicated in the message length field of the first paging
message is incorrect based on other considerations, even if the
message length indicated by the message length field is less than
the specified maximum possible paging message length.
For example, after receiving and decoding the message length field
of the first paging message, if the message length initially
appears to be valid (e.g., less than or equal to the specified
maximum possible paging message length), the UE 106 may continue to
decode signals received on the paging channel according to the
message length indicated by the message length field. However, if
an indication of a new incoming paging message (a "second paging
message") is detected while decoding the first paging message
according to the message length indicated in the message length
field of the first paging message, this may be an indication of an
error in decoding the first paging message. In particular, this may
be an indication of an error either in the message length field of
the first paging message, or the indication of the second paging
message may be an error, e.g., if the cellular network does not
normally interrupt a paging message to initiate a new paging
message.
Thus, multiple means of determining that the message length
indicated in the message length field is incorrect may be possible,
including those described hereinabove and any of various other
techniques. In at least some instances, the UE 106 may cease
decoding the first paging message after determining that the
message length indicated in the message length field is incorrect,
based on determining that the message length indicated in the
message length field is incorrect. For example, if the message
length indicated in the message length field is larger than the
specified maximum paging message length, the CRC check would fail
and the message would not be successfully received, so power may be
conserved by not attempting to decode the paging message in this
case, potentially with little or no downside. Similarly, if an
indication of a second paging message is detected on the paging
channel while decoding the first paging message, in this case too
it would be expected that the CRC check would fail and the message
would not be successfully received, and so it may be beneficial (at
least under some circumstances) to cease attempting to decode the
first paging message. It may also be desirable in this scenario for
the UE 106 to attempt to decode the second paging message.
Furthermore, in 510, the UE 106 may enable receive diversity for at
least one subsequent paging occasion in response to determining
that the message length indicated in the message length field of
the first paging message is incorrect. Enabling receive diversity
for a paging occasion may include using multiple antennas of the UE
106 to monitor the paging channel during that paging occasion.
The message length indicated in the message length field may be
incorrect for any of a variety of reasons. One such reason may
include poor channel conditions over the wireless link between the
UE 106 and the first cell. Poor channel conditions, which might
include poor signal strength and/or quality (e.g., due to distance
between the UE 106 and the first base station; interference with
other cells, other wireless devices, and/or natural features;
movement of the UE 106; and/or any of various other reasons), among
various possibilities, might, for example, cause the UE 106 to
erroneously decode and thus misinterpret signals received on the
paging channel. Enabling receive diversity, in particular by
utilizing multiple antennas to monitor the paging channel, may thus
(at least in some circumstances) improve the ability of the UE 106
to successfully (i.e., correctly) decode signals received in poor
channel conditions.
Thus, given the potentially more robust reception capability of a
UE 106 while utilizing receive diversity compared to not utilizing
receive diversity, it may be desirable to at least temporarily
enable receive diversity when the UE 106 determines that it has
incorrectly decoded at least a portion of an incoming paging
message (e.g., the paging message length field), in order to
increase the likelihood of successfully/correctly decoding
subsequent paging messages. Note that at least in some instances,
receive diversity may be enabled under such conditions on a
temporary basis, and may eventually be disabled for any of a
variety of reasons. For example, there may be disadvantages to
enabling receive diversity (e.g., relative to disabling receive
diversity) such that it may not be desirable to permanently enable
receive diversity.
For example, utilizing multiple antennas (e.g., with corresponding
receivers/receive chains) may consume more power than utilizing a
single antenna. Accordingly, enabling receive diversity may more
rapidly deplete the battery reserves of the UE 106, which may have
a negative affect on battery life of the UE 106. Alternatively, or
possibly in addition, the UE 106 might be configured to operate
according to (e.g., to support) multiple RATs using at least some
shared communication circuitry, as previously noted. If the shared
communication circuitry includes one or both of the antennas which
might be used to enable receive diversity, enabling receive
diversity might preclude the other RAT from communicating while the
UE 106 is monitoring the paging channel. Thus, if desired, receive
diversity may be enabled while monitoring the paging channel only
at selected times when it may be expected to have a significant
impact on user experience, such as if the UE 106 is experiencing
difficulty decoding paging messages using a single antenna.
Accordingly, in some instances receive diversity may be enabled for
a specific (e.g., predetermined) period of time and/or number of
subsequent paging occasions in response to determining that the
message length indicated in the message length field is incorrect.
For example, receive diversity might be enabled for five (or four,
three, two, or any other number of) subsequent paging occasions
after determining that the message length indicated in the message
length field is incorrect. If desired, receive diversity might also
or alternatively be enabled for the remainder of the current paging
occasion upon determining that the message length indicated in the
message length field is incorrect.
If no further errors are detected while attempting to receive and
decode paging messages during the period of time for which receive
diversity is enabled, receive diversity may again be disabled, such
that on one or more paging occasions subsequent to receive
diversity being disabled only one antenna may be used to monitor
the paging channel and perform any other activities on those one or
more paging occasions. However, if errors continue to be detected
(e.g., if a subsequent paging message length field is determined to
be incorrect, or a subsequent paging message fails a CRC check,
among various possibilities), the period of time for which receive
diversity is enabled may be extended. For example, if a subsequent
error is detected, the length of time and/or number of subsequent
paging occasions for which receive diversity is enabled may be
renewed/extended.
It is worth noting that initially, while monitoring the paging
channel, detecting the indication of the first paging message,
receiving and decoding the message length field, and determining
that the message length indicated in the message length field is
incorrect (e.g., as described hereinabove with respect to steps
502, 504, 506, and 508 of FIG. 5), receive diversity may not have
been enabled. For example, steps 502, 504, 506, and 508 may have
been performed using a single antenna.
However, it is also possible that receive diversity may have
already been enabled. For example, if the message length indicated
in the message length field of a recently (e.g., in the same paging
occasion or a recent paging occasion) detected paging message was
incorrect, receive diversity might have already been enabled for
the current paging occasion. In this case, enabling receive
diversity in response to determining that the message length
indicated in the message length field of the first paging message
is incorrect may more particularly include renewing or extending
receive diversity for the at least one subsequent paging
occasion.
Thus, by utilizing the method of FIG. 5 as provided above according
to various embodiments, a UE 106 may be able to at least
temporarily enable receive diversity in response to detecting
paging message errors, and in particular in response to detecting
an incorrectly decoded paging message length. This may allow the UE
106 to improve the chances of correctly decoding subsequent paging
messages in difficult reception conditions, without requiring
receive diversity to be permanently enabled. Furthermore, by
detecting an incorrectly decoded paging message length, a UE 106
may be able to cease attempting to decode a paging message which is
expected to be unsuccessfully decoded, which may reduce power
consumption by the UE 106.
Additional Information
The following description provides certain exemplary details of one
scenario in conjunction with which the method of FIG. 5 may be
used. Note that while the following information is provided for
illustrative purposes of certain exemplary details which may be
used in some implementations, this information is provided by way
of example only, and is not intended to be limiting to the
disclosure as a whole.
In particular, the exemplary scenario described may relate to the
3GPP2 radio access technology CDMA 2000. CDMA 2000, like many radio
access technologies, may provide the possibility of performing
discontinuous reception (DRX) in certain states or modes of
operation. DRX operation may include monitoring a paging channel
for paging messages (among other possible activities) during an
active portion of each periodic DRX cycle, and sleeping between
those active portions of each DRX cycle.
In CDMA 2000, the paging channel (PCH) may be slotted with one 80
ms PCH slot, which may be divided into four 20 ms PCH frames. Each
frame may in turn be divided into two 10 ms half frames. Depending
on the Paging Channel Rate (PRAT), which may be indicated in the
SYNC channel to be either 4.8 kbps or 9.6 kbps, each half frame may
therefore fit 48 or 96 bits respectively.
Each half-frame may include a 1-bit synchronized capsule indicator
(SCI) field and a 47 or 95 bit body field. An SCI of 1 may indicate
the start of a new PCH message capsule in the current half-frame
and an SCI of 0 may indicate otherwise. A message capsule on the
PCH may occupy more than one PCH half-frame.
A wireless device which is monitoring the PCH may accordingly
detect whether the SCI at the beginning of each half-frame is 1 or
0. If it detects a 1, the wireless device may proceed to decode the
paging channel message indicated by the SCI. Note that the SCI in
this exemplary scenario may function as an indicator bit of the
presence or absence of an upcoming paging message; thus, when set
to 1, an SCI might function as an indication of an incoming paging
message (such as the "first paging message" described with respect
to step 504 of FIG. 5).
The paging channel message capsule may be structured with a message
length ("MSG_LEN") field, a body field, a cyclic redundancy check
(CRC) field, and possibly padding. The message length field may
indicate the length of the paging channel message capsule in bytes,
and may be 8 bits long. Based on the message length field, the
wireless device may then be able to decode and construct the
complete paging message from the current and subsequent
half-frames. When all bits have been collected, a 30-bit CRC check
(e.g., using the data decoded from the CRC field) may be performed
to determine whether the decoded message is good (e.g., if the CRC
check confirms the accuracy of the message) or not.
While the 8-bit length of the MSG_LEN field in this exemplary
scenario implies that the length of the body could be up to 255
bytes (2040 bits) long, there may be other limits to the actual
message body. For example, per 3GPP2 specifications, the multiple
messages that can be encapsulated in a paging channel message body
may have a maximum size of 1146 bits, e.g., according to C.S0005
section 3.7, C.S0004 sections 3.1.2.1 and 3.1.2.2, and C.S0003
2.2.1.1.1.3. Since the MSG_LEN is the sum of the MSG_LEN field (8
bits), body field (variable up to 1146 bits) and CRC field (30
bits), the maximum transmittable paging channel message by the
network in this exemplary case may be 1184 bits (148 bytes).
If the wireless device incorrectly decodes the MSG_LEN field (e.g.,
due to poor channel conditions), the device might attempt to
collect the corresponding message bits, but fail to correctly
decode the paging message. Two possible failure scenarios
include:
If an SCI of 1 is detected, the wireless device may interrupt the
process and start decoding a new PCH message, thus aborting
decoding the current message, or
If all bits corresponding to the (incorrect) message length are
collected, the CRC check will fail.
In both these cases, the wireless device may not only fail to
successfully decode a paging message intended for the wireless
device (which may negatively affect user experience, e.g., as a
result of a missed or at least delayed call), but may also
needlessly expend energy (and thus drain the battery of the
wireless device) by attempting to collect and decode (at least part
of) an incorrect message.
However, if techniques such as those described with respect to,
inter alia, FIG. 5 are implemented, it may be possible for a
wireless device to detect and respond to incorrectly decoded paging
message lengths in a manner that avoids expending energy attempting
to decode paging messages which (due to the incorrectly decoded
paging message length) are known to be invalid, and/or improves the
chances of correctly receiving subsequent paging messages.
For example, a wireless device configured to implement the features
described with respect to, inter alia, FIG. 5 may be able to detect
and respond to certain error conditions indicative of an
incorrectly decoded paging message length. Thus, if the MSG_LEN
field of a paging message indicates that the length of the paging
message is longer than the maximum transmittable paging message
(i.e., longer than 1184 bits, in this exemplary scenario), this may
be an error condition indicative of an incorrectly decoded paging
message length. Another such error condition could include decoding
a `1` in the SCI field of a half-frame which is in the process of
being decoded as specified by the paging message length field of a
previous paging message. Detecting an SCI of 1 in any such
half-frames might be taken as an indication of a newly incoming
paging message, which might indicate that the message length of the
previous paging message may have been incorrectly decoded (e.g.,
the actual paging message length may have been less than the
decoded paging message length). Both such conditions may at least
be indicative of incorrect decoding of the information being
received on the paging channel, and may in particular be indicative
of an incorrectly decoded paging message length.
In such cases, the wireless device may cease attempting to decode
the current paging message, since it may be highly likely to
contain errors. Furthermore, the wireless device may at least
temporarily enable receive diversity for monitoring and decoding
the paging channel in response to detecting such conditions. This
may improve the likelihood of correctly decoding subsequent paging
messages, in particular since such conditions may often be caused
by difficult channel conditions which may at least in some cases be
countered by utilizing multiple antennas for receive diversity.
Embodiments of the present disclosure may be realized in any of
various forms. For example some embodiments may be realized as a
computer-implemented method, a computer-readable memory medium, or
a computer system. Other embodiments may be realized using one or
more custom-designed hardware devices such as ASICs. Still other
embodiments may be realized using one or more programmable hardware
elements such as FPGAs.
In some embodiments, a non-transitory computer-readable memory
medium may be configured so that it stores program instructions
and/or data, where the program instructions, if executed by a
computer system, cause the computer system to perform a method,
e.g., any of a method embodiments described herein, or, any
combination of the method embodiments described herein, or, any
subset of any of the method embodiments described herein, or, any
combination of such subsets.
In some embodiments, a device (e.g., a UE 106) may be configured to
include a processor (or a set of processors) and a memory medium,
where the memory medium stores program instructions, where the
processor is configured to read and execute the program
instructions from the memory medium, where the program instructions
are executable to implement any of the various method embodiments
described herein (or, any combination of the method embodiments
described herein, or, any subset of any of the method embodiments
described herein, or, any combination of such subsets). The device
may be realized in any of various forms.
Although the embodiments above have been described in considerable
detail, numerous variations and modifications will become apparent
to those skilled in the art once the above disclosure is fully
appreciated. It is intended that the following claims be
interpreted to embrace all such variations and modifications.
* * * * *