U.S. patent application number 14/258982 was filed with the patent office on 2014-08-14 for multiple input multiple output (mimo) based concurrent scan of neighbor cells.
This patent application is currently assigned to Qualcomm Incorporated. The applicant listed for this patent is Qualcomm Incorporated. Invention is credited to Steven D. Cheng, Tom Chin, Remi J. Gurski, Kuo-Chun Lee, Guangming Shi.
Application Number | 20140228028 14/258982 |
Document ID | / |
Family ID | 46934704 |
Filed Date | 2014-08-14 |
United States Patent
Application |
20140228028 |
Kind Code |
A1 |
Cheng; Steven D. ; et
al. |
August 14, 2014 |
Multiple Input Multiple Output (MIMO) Based Concurrent Scan of
Neighbor Cells
Abstract
Methods, systems, and devices are described for concurrently
performing handoff-related measurements for neighbor cells using
multiple input multiple output (MIMO) antenna resources. In one
example, a mobile device is in communication with a serving cell.
Handoff-related measurements of first wireless signals from a first
neighbor cell are performed. The first wireless signals are
received at first MIMO antenna resources of a device.
Handoff-related measurements of second wireless signals from a
second neighbor cell are performed, as well. The second wireless
signals are received at second MIMO antenna resources concurrently
with the first wireless signals received at the first MIMO antenna
resources. The first handoff-related measurements and the second
handoff-related measurements may be performed during a scan
interval. A type of handoff-related measurement to perform may be
determined based on a determined length of the scan interval.
Inventors: |
Cheng; Steven D.; (San
Diego, CA) ; Gurski; Remi J.; (San Deigo, CA)
; Lee; Kuo-Chun; (San Diego, CA) ; Chin; Tom;
(San Diego, CA) ; Shi; Guangming; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Qualcomm Incorporated |
San Diego |
CA |
US |
|
|
Assignee: |
Qualcomm Incorporated
San Diego
CA
|
Family ID: |
46934704 |
Appl. No.: |
14/258982 |
Filed: |
April 22, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13237675 |
Sep 20, 2011 |
8730915 |
|
|
14258982 |
|
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Current U.S.
Class: |
455/436 |
Current CPC
Class: |
H04N 21/42676 20130101;
H04W 36/00837 20180801; H04B 17/318 20150115; H04L 5/0023 20130101;
H04W 36/0094 20130101; H04W 36/0083 20130101; H04J 11/003 20130101;
H04B 7/0413 20130101; H04B 1/713 20130101; H04W 36/14 20130101;
H04B 7/0452 20130101; H04W 88/06 20130101; H04B 3/38 20130101; H04B
17/382 20150115; H04B 7/12 20130101 |
Class at
Publication: |
455/436 |
International
Class: |
H04W 36/00 20060101
H04W036/00 |
Claims
1. A method, comprising: tuning second multiple input multiple
output (MIMO) antenna resources of a device from a serving
frequency band of a serving cell to a second frequency band of a
second neighbor cell during a scan interval; performing first
handoff-related measurements of first wireless signals received
over a first frequency band from a first neighbor cell at first
MIMO antenna resources of the device, wherein the device is in
communication with the serving cell; performing second
handoff-related measurements of second wireless signals received
over the second frequency band from the second neighbor cell at the
second MIMO antenna resources of the device, wherein the second
wireless signals are received at the second MIMO antenna resources
concurrently with the first wireless signals being received at the
first MIMO antenna resources; and determine whether to handoff to
the first neighbor cell or the second neighbor cell based at least
in part on the first handoff-related measurements and the second
handoff-related measurements.
2. The method of claim 1, wherein the first frequency band is the
serving frequency band.
3. The method of claim 1, further comprising tuning the first MIMO
antenna resources of the device from the serving frequency band to
the first frequency band of the first neighbor cell during the scan
interval, wherein the first frequency band is different from the
serving frequency band.
4. The method of claim 3, further comprising tuning the first MIMO
antenna resources of the device from the first frequency band to
the serving frequency band following the scan interval or following
performing the first handoff-related measurements.
5. The method of claim 1, further comprising tuning the second MIMO
antenna resources of the device from the second frequency band to
the serving frequency band following the scan interval or following
performing the second handoff-related measurements.
6. The method of claim 1, further comprising performing the first
handoff-related measurements and the second handoff-related
measurements during the scan interval.
7. The method of claim 1, further comprising: determining a length
of the scan interval; and determining whether the first
handoff-related measurements and the second handoff-related
measurements are power measurements or signal quality measurements
based at least in part on the length of the scan interval.
8. The method of claim 1, wherein the first handoff-related
measurements and the second handoff related measurements comprise a
signal quality measurement including a signal-to-noise ratio (SNR),
a carrier to interference-plus-noise-ratio (CINR), a bit error
ratio (BER), an energy per bit to noise power spectral density
ratio (Eb/NO), or an energy per symbol per noise power spectral
density ratio (ES/NO).
9. The method of claim 1, wherein the first neighbor cell
implements a first radio access technology (RAT), and the second
neighbor cell implements the first RAT.
10. The method of claim 9, wherein the serving cell implements the
first RAT.
11. The method of claim 9, wherein the serving cell implements a
second RAT different from the first RAT.
12. The method of claim 1, wherein the first neighbor cell
implements a first radio access technology (RAT), and the second
neighbor cell implements a second RAT different from the first
RAT.
13. The method of claim 12, wherein the serving cell implements the
first RAT.
14. The method of claim 12, wherein the serving cell implements a
third RAT different from the first RAT and the second RAT.
15. A device comprising: a plurality of multiple input multiple
output (MIMO) antenna resources; a transceiver coupled with the
plurality of MIMO antenna resources; a tuning module coupled with
the transceiver and configured to: tune second MIMO antenna
resources of a device from a serving frequency band of a serving
cell to a second frequency band of a second neighbor cell during a
scan interval; and a measurement module coupled with the
transceiver and configured to: perform first handoff-related
measurements of first wireless signals received over a first
frequency band from a first neighbor cell at first MIMO antenna
resources of the device, wherein the device is in communication
with the serving cell; perform second handoff-related measurements
of second wireless signals received over the second frequency band
from the second neighbor cell at the second MIMO antenna resources
of the device, wherein the second wireless signals are received at
the second MIMO antenna resources concurrently with the first
wireless signals being received at the first MIMO antenna
resources; and determine whether to handoff to the first neighbor
cell or the second neighbor cell based at least in part on the
first handoff-related measurements and the second handoff-related
measurements.
16. The device of claim 15, wherein the first frequency band is the
serving frequency band.
17. The device of claim 15, wherein the tuning module is further
configured to tune the first MIMO antenna resources of the device
from the serving frequency band to the first frequency band of the
first neighbor cell during the scan interval, wherein the first
frequency band is different from the serving frequency band.
18. The device of claim 17, wherein the tuning module is further
configured to tune the first MIMO antenna resources of the device
from the first frequency band to the serving frequency band
following the scan interval or following performing the first
handoff-related measurements.
19. The device of claim 15, wherein the tuning module is further
configured to tune the second MIMO antenna resources of the device
from the second frequency band to the serving frequency band
following the scan interval or following performing the second
handoff-related measurements.
20. The device of claim 15, wherein the measurement module is
further configured to perform the first handoff-related
measurements and the second handoff-related measurements during the
scan interval.
21. The device of claim 15, wherein the first neighbor cell
implements a first radio access technology (RAT), and the second
neighbor cell implements the first RAT.
22. The device of claim 15, wherein the first neighbor cell
implements a first radio access technology (RAT), and the second
neighbor cell implements the second RAT different from the first
RAT.
23. An apparatus comprising: means for tuning second multiple input
multiple output (MIMO) antenna resources of a device from a serving
frequency band of a serving cell to a second frequency band of a
second neighbor cell during a scan interval; means for performing
first handoff-related measurements of first wireless signals
received over a first frequency band from a first neighbor cell at
first MIMO antenna resources of the device, wherein the device is
in communication with the serving cell; means for performing second
handoff-related measurements of second wireless signals received
over the second frequency band from the second neighbor cell at the
second MIMO antenna resources of the device, wherein the second
wireless signals are received at the second MIMO antenna resources
concurrently with the first wireless signals being received at the
first MIMO antenna resources; and means for determining whether to
handoff to the first neighbor cell or the second neighbor cell
based at least in part on the first handoff-related measurements
and the second handoff-related measurements.
24. The apparatus of claim 23, wherein the first frequency band is
the serving frequency band.
25. The apparatus of claim 23, wherein the means for tuning is
further configured to tune the first MIMO antenna resources of the
device from the serving frequency band to the first frequency band
of the first neighbor cell during the scan interval, wherein the
first frequency band is different from the serving frequency
band.
26. The apparatus of claim 25, wherein the means for tuning is
further configured to tune the first MIMO antenna resources of the
device from the first frequency band to the serving frequency band
following the scan interval or following performing the first
handoff-related measurements.
27. The apparatus of claim 23, wherein the means for tuning is
further configured to tune the second MIMO antenna resources of the
device from the second frequency band to the serving frequency band
following the scan interval or following performing the second
handoff-related measurements.
28. A computer program product comprising a non-transitory
computer-readable medium, the computer-readable medium comprising:
code for causing at least one computer to tune second multiple
input multiple output (MIMO) antenna resources of a device from a
serving frequency band of a serving cell to a second frequency band
of a second neighbor cell during a scan interval; code for causing
the at least one computer to perform first handoff-related
measurements of first wireless signals received over a first
frequency band from a first neighbor cell at first MIMO antenna
resources of the device, wherein the device is in communication
with the serving cell; code for causing the at least one computer
to perform second handoff-related measurements of second wireless
signals received over the second frequency band from the second
neighbor cell at the second MIMO antenna resources of the device,
wherein the second wireless signals are received at the second MIMO
antenna resources concurrently with the first wireless signals
being received at the first MIMO antenna resources; and code for
causing the at least one computer to determine whether to handoff
to the first neighbor cell or the second neighbor cell based at
least in part on the first handoff-related measurements and the
second handoff-related measurements.
29. The computer program product of claim 28, wherein the first
frequency band is the serving frequency band.
30. The computer program product of claim 28, wherein the
computer-readable medium further comprises code for causing the at
least one computer to tune the first MIMO antenna resources of the
device from the serving frequency band to the first frequency band
of the first neighbor cell during the scan interval, wherein the
first frequency band is different from the serving frequency band.
Description
CLAIM OF PRIORITY
[0001] The present application for patent is a Continuation
application of U.S. Ser. No. 13/237,675, filed Sep. 20, 2011,
entitled "Multiple Input Multiple Output (MIMO) Based Concurrent
Scan of Neighbor Cells, and assigned to the assignee hereof and
hereby expressly incorporated by reference herein.
BACKGROUND
[0002] Wireless communication systems are widely deployed to
provide various types of communication content such as voice, data,
and so on. These systems may be multiple-access systems capable of
supporting communication with multiple users by sharing the
available system resources (e.g., bandwidth and transmit power).
Examples of such multiple-access systems include code division
multiple access (CDMA) systems, time division multiple access
(TDMA) systems, frequency division multiple access (FDMA) systems,
3GPP Long Term Evolution (LTE) systems, and orthogonal frequency
division multiple access (OFDMA) systems.
[0003] Generally, a wireless multiple-access communications system
may include a number of base stations, each simultaneously
supporting communication for multiple mobile devices. Base stations
may communicate with mobile devices on downstream and upstream
links. Each base station has a coverage range, which may be
referred to as the coverage area of the cell. Mobile devices
desiring to enter the coverage area of a base station may initiate
contact to establish communications with the base station. For
example, when a mobile device desires to enter the coverage area of
a target base station, the mobile device may initiate handoff
procedures to terminate communication with a base station the
device is currently communicating with and establish a new
communications link with the target base station. The handoff
procedure includes sending an initial transmission to the target
base station. When the target base station receives the initial
transmission, it may communicate a response to the mobile device
with transmission-related information that enables the mobile
device and the target base station to establish a communications
channel.
[0004] A handoff procedure may result in the mobile device being
handed off from a base station that used a particular radio access
technology (RAT) to a base station that uses a different RAT.
Before the handoff procedure is initiated, the mobile device may
measure the quality of the signals received from potential target
base stations. These measurements may be executed during a specific
time period. Often, the time period is relatively short and this
may impact the ability of the mobile device to measure signals of
potential target base stations that use a different RAT or
different frequency.
SUMMARY
[0005] Systems, methods, device, and computer-readable products are
described for concurrently scanning neighbor cells using MIMO based
antenna resources. In one example, neighbor cells are identified
for scanning. A length of a scan interval may be detected. A first
set of handoff-related measurements are performed on wireless
signals received from a first neighbor cell at first MIMO antenna
resources. A second set of handoff-related measurements are
concurrently performed on wireless signals received at second MIMO
antenna resources from a second neighbor cell. For example, the
first and/or second handoff-related measurements may be power
measurements or signal quality measurements. In one configuration,
the type of handoff-related measurement to be performed may be
based on the determined length of the scan interval. In one
example, the first handoff-related measurements and the second
handoff-related measurements may be performed during the scan
interval. In addition, a determination may be made as to whether
the device is in a connect mode or an idle mode. The type of
handoff-related measurement to be performed may also be based on
the determined mode of the device.
[0006] In one configuration, the first handoff-related measurements
may be a power measurement and the second handoff-related
measurements may be a signal quality measurement. In one example,
the signal quality measurements may include a signal-to-noise ratio
(SNR), a carrier to interference-plus-noise-ratio (CINR), a bit
error ratio (BER), an energy per bit to noise power spectral
density ratio (E.sub.b/N.sub.O), or an energy per symbol per noise
power spectral density ratio (E.sub.S/N.sub.O).
[0007] In one example, a first downlink message received at the
first MIMO antenna resources from the first neighbor cell may be
decoded. Further, a second downlink message received at the second
MIMO antenna resources from the second neighbor cell may also be
decoded. In one configuration, the messages may be decoded when the
device is in an idle mode.
[0008] The first neighbor cell may be in a different frequency band
from the serving cell. In addition, the second neighbor cell may be
in a different frequency band from the serving cell. A receiver
associated with the first MIMO antenna resources may be tuned
during a first period of the scan interval to the frequency band of
the first neighbor cell. Further, a receiver associated with the
second MIMO antenna resources may be tuned during the first period
of the scan interval to the frequency band of the second neighbor
cell. In one configuration, the receiver associated with the first
MIMO antenna resources and the receiver associated with the second
MIMO antenna resources may be tuned to the frequency band of the
serving cell during a second period of the scan interval.
[0009] In one example, the first neighbor cell may include a first
radio access technology (RAT) and the second neighbor cell may also
include the first RAT. In one configuration, the serving cell may
also include the first RAT. In another example, the second neighbor
cell may include a second RAT that is different from the first RAT.
The second neighbor cell may also operate in a different frequency
band than the serving cell.
[0010] A device to concurrently scan neighbor cells using MIMO
based antenna resources is also described. The device may include a
plurality of multiple input multiple output (MIMO) antenna
resources, and a transceiver coupled with the plurality of MIMO
antenna resources. The device may also include a detection module
in communication with the transceiver. The detection module may
determine a length of a scan interval. The device may further
include a measurement module coupled with the transceiver. The
measurement module may determine a type of handoff-related
measurement to perform based on the determined length of the scan
interval. The measurement module may perform first handoff-related
measurements of first wireless signals from a first neighbor cell
received at first MIMO antenna resources of the plurality of MIMO
antenna resources. The device may be in communication with a
serving cell. The measurement module may also perform second
handoff-related measurements of second wireless signals from a
second neighbor cell received at second MIMO antenna resources of
the plurality of MIMO antenna resources. The second wireless
signals may be received at the second MIMO antenna resources
concurrently with the first wireless signals being received at the
first MIMO antenna resources.
[0011] An apparatus to concurrently scan neighbor cells using MIMO
based antenna resources is also described. The apparatus may
include means for determining a type of handoff-related measurement
to perform based on a determined length of a scan interval. The
apparatus may include means for performing first handoff-related
measurements of first wireless signals from a first neighbor cell
received at first multiple input multiple output (MIMO) antenna
resources of a device. The device may be in communication with a
serving cell. The apparatus may further include means for
performing second handoff-related measurements of second wireless
signals from a second neighbor cell received at second MIMO antenna
resources of the device. The second wireless signals may be
received at the second MIMO antenna resources concurrently with the
first wireless signals being received at the first MIMO antenna
resources.
[0012] A computer program product to concurrently scan neighbor
cells using MIMO based antenna resources is also described. The
product may include a non-transitory computer-readable medium. The
medium may include code for determining a type of handoff-related
measurement to perform based on a determined length of a scan
interval. The medium may include code for performing first
handoff-related measurements of first wireless signals from a first
neighbor cell received at first multiple input multiple output
(MIMO) antenna resources of a device. The device may be in
communication with a serving cell. The computer-readable medium may
further include code for performing second handoff-related
measurements of second wireless signals from a second neighbor cell
received at second MIMO antenna resources of the device. In one
example, the second wireless signals may be received at the second
MIMO antenna resources concurrently with the first wireless signals
being received at the first MIMO antenna resources.
[0013] The foregoing has outlined rather broadly the features and
technical aspects of examples according to disclosure. Additional
features will be described hereinafter. The conception and specific
examples disclosed may be readily utilized as a basis for modifying
or designing other structures for carrying out the same purposes of
the present disclosure. Such equivalent constructions do not depart
from the spirit and scope of the appended claims. Features which
are believed to be characteristic of the concepts disclosed herein,
both as to their organization and method of operation will be
better understood from the following description when considered in
connection with the accompanying figures. Each of the figures is
provided for the purpose of illustration and description only and
not as a definition of the limits of the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A further understanding of the nature of the present
invention may be realized by reference to the following drawings.
In the appended figures, similar components or features may have
the same reference label. Further, various components of the same
type may be distinguished by following the reference label by a
dash and a second label that distinguishes among the similar
components. If only the first reference label is used in the
specification, the description is applicable to any one of the
similar components having the same first reference label
irrespective of the second reference label.
[0015] FIG. 1 is a block diagram of a wireless communications
system;
[0016] FIG. 2 is a block diagram of a system including a base
station and a mobile device;
[0017] FIG. 3 is a block diagram illustrating one configuration of
the mobile device;
[0018] FIG. 4A shows one example of the mobile device;
[0019] FIG. 4B illustrates a further example of the mobile
device;
[0020] FIG. 5 is a flow chart illustrating one example of a method
to concurrently perform a scan procedure of multiple neighbor cells
using MIMO based antenna resources;
[0021] FIG. 6 shows a method to concurrently scan neighbor cells
that operate in the same frequency band as the serving cell during
the same scan interval using MIMO based antenna resources;
[0022] FIG. 7, shown a method of scanning multiple neighbor cells
in parallel with at least one neighbor cell operating in a
different frequency band and/or RAT than the serving cell and at
least one neighbor cell sharing the same frequency and RAT as the
serving cell;
[0023] FIG. 8, shows a method to determine the type of measurement
to calculate based on a determined length of a scan interval while
the device is in a connect mode; and
[0024] FIG. 9 shows a method to determine the type of measurement
to calculate based on the mode of the device and a determined
length of a scan interval.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Concurrent scanning of wireless signals using multiple input
multiple output (MIMO) antenna resources on a multi-mode device is
described. The scan procedure performed by the MIMO antenna
resources may be implemented to measure certain characteristics of
signals received from neighbor cells. The measured characteristics
may be related to procedures to handoff the mobile device from one
base station to another. For example, the device may be in
communication with a serving cell. While in communication with the
serving cell, the device may receive first wireless signals from a
first neighbor cell during a scan interval and perform first
handoff-related measurements of the first wireless signals using a
first set of MIMO antenna resources. In addition, the device may
receive second wireless signals from a second neighbor cell during
the scan interval. The device may perform second handoff-related
measurements of the second wireless signals using a second set of
MIMO antenna resources. The device may receive and measure the
first wireless signals concurrently with the receipt and
measurement of the second wireless signals. In one example, the
results of the scan procedure may be used by either the serving
cell or the device to determine whether to perform a handoff
procedure.
[0026] As used herein the term "serving cell" may be used
interchangeably with the term "serving base station". Similarly,
the term "neighbor cell" may be used interchangeably with the term
"neighbor base station".
[0027] The device may be a multi-mode device that is capable of
supporting various wireless communications systems such as CDMA,
TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system"
and "network" are often used interchangeably. A CDMA system may
implement a radio access technology (RAT) such as CDMA2000,
Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers
IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and A are
commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is
commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data
(HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants
of CDMA. A TDMA system may implement a RAT such as Global System
for Mobile Communications (GSM). An OFDMA system may implement a
RAT such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA),
IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM,
etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication
System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced
(LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA,
UMTS, LTE, LTE-A, and GSM are described in documents from an
organization named "3rd Generation Partnership Project" (3GPP).
CDMA2000 and UMB are described in documents from an organization
named "3rd Generation Partnership Project 2" (3GPP2). Currently,
neighbor cell measurements obtained during a scan interval are
limited to neighbor cells using a frequency band or radio access
technology (RAT) associated with the serving cell. For example, if
the serving cell is within a WiMAX network, current standards limit
the neighbor cell measurements to neighbor cells using WiMAX-based
RATs and operating in a frequency band within the WiMAX network.
The architecture of the device described herein allows the device
to continue to obtain measurements of neighbor cells using a
frequency band and RAT associated with the serving cell, while,
during the same scan interval, obtain measurements of neighbor
cells that use frequency bands or RATs that are different than
those used by the serving cell.
[0028] The techniques described herein may be used for the systems
and RATs mentioned above as well as other systems and RATs. Thus,
the following description provides examples, and is not limiting of
the scope, applicability, or configuration set forth in the claims.
Changes may be made in the function and arrangement of elements
discussed without departing from the spirit and scope of the
disclosure. Various embodiments may omit, substitute, or add
various procedures or components as appropriate. For instance, the
methods described may be performed in an order different from that
described, and various steps may be added, omitted, or combined.
Also, features described with respect to certain embodiments may be
combined in other embodiments.
[0029] Referring first to FIG. 1, a block diagram illustrates an
example of a wireless communications system 100. The system 100
includes base stations 105 (or cells), mobile devices 115, a base
station controller 120, and a core network 125 (the controller 120
may be integrated into the core network 125). The system 100 may
support operation on multiple carriers (waveform signals of
different frequencies).
[0030] The base stations 105 may wirelessly communicate with the
mobile devices 115 via a base station antenna (not shown). The base
stations 105 may communicate with the mobile devices 115 under the
control of the base station controller 120 via multiple carriers.
Each of the base station 105 sites may provide communication
coverage for a respective geographic area. The coverage area for
each base station 105 here is identified as 110-a, 110-b, or 110-c.
The coverage area for a base station may be divided into sectors
(not shown, but making up only a portion of the coverage area). The
system 100 may include base stations 105 of different types (e.g.,
macro, micro, and/or pico base stations). There may be overlapping
coverage areas for different technologies.
[0031] The mobile devices 115 may be dispersed throughout the
coverage areas 110. The mobile devices 115 may be referred to as
mobile stations, mobile devices, access terminals (ATs), user
equipments (UEs), subscriber stations (SSs), or subscriber units.
The mobile devices 115 may include cellular phones and wireless
communications devices, but may also include personal digital
assistants (PDAs), other handheld devices, netbooks, notebook
computers, etc.
[0032] The base stations 105 may provide different RATs. For
example, one base station may provide WiMAX based RATs while
another base station may provide CDMA based RATs. In one
configuration, the mobile devices 115 may be multi-mode devices,
thereby allowing them to use both WiMAX based RATs and CDMA based
RATs, for example. In order to transition from a serving cell
providing WiMAX based RATs to a neighbor cell providing CDMA based
RATs, the mobile devices 115 may calculate handoff-related
measurements for the neighbor cell before handoff procedures are
initiated. The mobile devices 115 described herein include an
architecture that allows them to perform concurrent scanning
procedures (i.e., handoff-related measurements) of multiple base
stations providing different RATs during a single scan interval.
For example, the mobile devices 115 may include an architecture
that allows them to perform measurements of the wireless signals
received from neighbor base stations that provide the same RATs as
provided by the serving base station (e.g., WiMAX based RATs)
while, in parallel, performing measurements of the wireless signals
received from neighbor base stations that provide different RATs
(e.g., CDMA based RATs).
[0033] FIG. 2 is a block diagram of a system 200 including a base
station 105-a and a mobile device 115-a. This system 200 may be an
example of the system 100 of FIG. 1. The base station 105-a may be
equipped with antennas 234-a through 234-x, and the mobile device
115-a may be equipped with antennas 252-a through 252-n. At the
base station 105-a, a transmit processor 220 may receive data from
a data source.
[0034] The transmit processor 220 may process the data. The
transmit processor 220 may also generate reference symbols, and a
cell-specific reference signal. A transmit (TX) MIMO processor 230
may perform spatial processing (e.g., precoding) on data symbols,
control symbols, and/or reference symbols, if applicable, and may
provide output symbol streams to the transmit modulators 232-a
through 232-x. Each modulator 232 may process a respective output
symbol stream (e.g., for OFDM, etc.) to obtain an output sample
stream. Each modulator 232 may further process (e.g., convert to
analog, amplify, filter, and upconvert) the output sample stream to
obtain a downlink (DL) signal. In one example, DL signals from
modulators 232-a through 232-x may be transmitted via the antennas
234-a through 234-x, respectively.
[0035] At the mobile device 115-a, the mobile device antennas 252-a
through 252-n may receive the DL signals from the base station
105-a and may provide the received signals to the demodulators
254-a through 254-n, respectively. Each demodulator 254 may
condition (e.g., filter, amplify, downconvert, and digitize) a
respective received signal to obtain input samples. Each
demodulator 254 may further process the input samples (e.g., for
OFDM, etc.) to obtain received symbols. A MIMO detector 256 may
obtain received symbols from all the demodulators 254-a through
254-n, perform MIMO detection on the received symbols if
applicable, and provide detected symbols. A receive processor 258
may process (e.g., demodulate, deinterleave, and decode) the
detected symbols, providing decoded data for the mobile device
115-a to a data output, and provide decoded control information to
a processor 280, or memory 282.
[0036] The mobile device 115-a may include a transceiver controller
284 that may determine which antennas 252 receive signals from
certain base stations 110. For example, the transceiver controller
284 may activate a first antenna 252-a to receive DL signals from
the base station 105-a, wherein the base station 105-a may be
currently serving the mobile device 115-a. The base station 105-a
and mobile device 115-a may, therefore, be using the same frequency
band and/or the same RAT. While the first antenna 252-a is
receiving signals from the base station 105-a, the transceiver
controller 284 may also activate another antenna 252-n to receive
DL signals from another base station servicing a different
geographical area than where the mobile device 115-a is currently
located. As a result, the other base station and the mobile device
115-a may not be using the same frequency band and/or the same RAT.
In various examples, the transceiver controller 284 may activate
both sets of antennas during the same scan interval so that the
antennas receive the signals from different base stations during
the same time interval.
[0037] On the uplink (UL), at the mobile device 115-a, a transmit
processor 264 may receive and process data from a data source. The
transmit processor 264 may also generate reference symbols for a
reference signal. The symbols from the transmit processor 264 may
be precoded by a transmit MIMO processor 266 if applicable, further
processed by the demodulators 254-a through 254-n (e.g., for
SC-FDMA, etc.), and be transmitted to the base station 105-a in
accordance with the transmission parameters received from the base
station 105-a. At the base station 105-a, the UL signals from the
mobile device 115-a may be received by the antennas 234, processed
by the demodulators 232, detected by a MIMO detector 236 if
applicable, and further processed by a receive processor. The
receive processor 238 may provide decoded data to a data output and
to the processor 240.
[0038] Referring now to FIG. 3, a block diagram illustrates one
configuration of a mobile device 115-b. The mobile device 115-b may
be an example of the mobile device 115 of FIG. 1 or 2. The device
115-b may include a number of antennas 315 coupled to a transceiver
305. The number of antennas 315 may be MIMO based antennas that
receive/transmit signals from/to base stations. The antennas 315
may receive signals from different base stations concurrently. For
example, a first MIMO antenna 315-a-1 may receive signals a from
first base station simultaneously with a second MIMO antenna
315-a-2 receiving different signals from a second base station. In
another example, the first MIMO antenna 315-a-1 may begin to
receive signals and the second MIMO antenna 315-a-2 may begin to
receive signals at a later time, during which the first MIMO
antenna 315-a-1 is still receiving the signals. As a result, the
terms "concurrently" and "in parallel" as used herein and in
connection with other Figures may mean simultaneously and/or
overlapping.
[0039] The base stations may be operating in a frequency band that
is the same or different than the frequency band used by the base
station currently serving the mobile device 115-b. In another
example, the base stations may provide a RAT that is different than
the RAT currently being to the mobile device 115-b from the serving
base station.
[0040] The signals received by the antennas 315 may be analyzed by
a measurement module 310. The measurement module 310 may determine
various characteristics of the received signals. The mobile device
115-b may use the determined characteristics to determine whether
to engage in a handoff to a neighbor base station. For example, the
mobile device 115-b may be in communication with a serving base
station. The antennas 315 may receive signals from a number of
neighbor base stations during a scan interval. The scan interval
represents a time period where there is a break in communication
between the mobile device 115-b and the serving base station. The
measurement module 310 may analyze the signals received from the
neighbor base stations, and the mobile device 115-b may determine
whether to cease communications with the serving base station and
establish communications with one of the neighbor base stations
based on the characteristics of the signals analyzed by the
measurement module 310.
[0041] FIG. 4A, is a block diagram illustrating one example of the
mobile device 115-c. The mobile device 115-c may be an example of
the mobile device 115 of FIG. 1, 2, or 3. In one configuration, the
mobile device 115-c may include a detection module 405, a
transceiver 305, a number of antennas 315, a decoding module 410, a
measurement module 310-a, and a transceiver controller 284-a. The
measurement module 310-a may be an example of the measurement
module 310 of FIG. 3. The transceiver controller 284-a may be an
example of the transceiver controller 284 of FIG. 2.
[0042] In one example, the detection module 405 may analyze certain
information relating to scanning procedures initiated by the mobile
device 115-c. The detection module 405 may also detect
characteristics of neighbor base stations and the serving base
station. Information detected by the detection module 405 may be
communicated to the transceiver controller 284-a. The controller
284-a may control or regulate the transceiver 305 and the antennas
315. For example, the controller 284-a may determine which
antenna(s) 315 should receive signals from the serving base station
and which antenna(s) 315 should receive and process signals from
the neighbor base stations. The controller 284-a may determine
which antenna(s) 315 should receive and process signals on
different frequencies. The controller 284-a may determine which
antenna(s) should perform power measurements or signal quality
measurements based on the length of the scan interval, and on
whether (and how much) tuning is required. The measurement module
310-a and the decoding module 410 may analyze the signals received
by the antennas 315-a.
[0043] In one example, the measurement module 310-a may identify
properties of the neighbor base stations based on an analysis of
the signal received from each base station. For example, the
measurement module 310-a may measure the strength of the signals
received from the neighbor base stations. The decoding module 410
may decode data that may be encoded in a signal received from a
neighbor base station. For example, data identifying a neighbor
base station may be encoded in the signal. In addition, timing
information, power characteristics, offset information, etc. for
the neighbor cell may also be encoded in the signal. Performing
measurements or decoding signals from various neighbor base
stations may occur in parallel during a scan interval. For example,
the measurement module 310-a may perform measurements of signals
received from one neighbor base station during a scan interval
while the decoding module 410 decodes signals received from another
neighbor base station during the same scan interval.
[0044] Referring now to FIG. 4B, a block diagram illustrates mobile
device 115-d. The mobile device 115-d may be an example of the
mobile device 115 of FIG. 1, 2, 3, or 4A. The device 115-d may
include a detection module 405-a, a transceiver controller 284-b, a
tuning module 425, a transceiver 305, a number of MIMO based
antennas 315, a number of receivers 430 associated with each of the
antennas 315, a measurement module 310-b, and a decoding module
410-a.
[0045] The detection module 405-a may include a scan interval
detection module 415 and a neighbor cell detection module 420. In
one example, the device 115-d may have an established
communications channel with a serving base station. The neighbor
cell detection module 420 may identify neighbor base stations
(e.g., serving different geographical areas than the serving cell).
The neighbor cell detection module 420 may identify whether the
neighbor base stations are operating in the same frequency band as
the serving base station. The neighbor cell detection module 420
may further detect whether the neighbor base stations are
functioning with the same RAT as the serving base station.
[0046] The device 115-d may perform a scan procedure to determine
whether a handoff procedure should be initiated. The scan
procedure, which includes performing handoff-related measurements
of signals received from neighbor base stations, may be performed
during a scan interval. The scan interval detection module 415 may
detect the commencement of the scan interval as well as the length
of the scan interval.
[0047] Information detected by the detection module 405-a may be
communicated to the transceiver controller 284-b. The controller
284-b may determine which MIMO antennas 315 receive signals from
neighbor base stations sharing the same frequency and RAT as the
serving base station, and which MIMO antennas 315 receive signals
from neighbor base stations that operate in a different frequency
band and RAT. The controller 284-b may also determine the type of
measurements to perform on the received signals. The transceiver
controller 284-b may base this determination on the length of the
scan interval. For example, the scan interval may be determined to
be a very short time period. The controller 284-b may determine
that signals received from some or all of the neighbor base
stations should be analyzed to determine a power measurement of the
signals. The power measurement may be determined by a power
measurement module 435 within the measurement module 310-b. An
example of the power measurement of the received signal may be a
received signal strength indicator (RSSI).
[0048] In another example, the scan interval detection module 415
may determine that the scan interval has a longer time period. The
transceiver controller 284-b may provide instructions that signals
received from some or all of the neighbor base stations should be
analyzed to calculate a signal quality measurement. The signal
quality measurement may be calculated by a signal quality
measurement module 440. Examples of the a signal quality
measurement may include signal-to-noise ratio (SNR), carrier to
interference-plus-noise ratio (CINR), a bit error ratio (BER), an
energy per bit to noise power spectral density ratio
(E.sub.b/N.sub.O), an energy per symbol per noise power spectral
density ratio (E.sub.S/N.sub.O), a carrier-to-receiver noise
density ratio (C/kT), or a modulation error ratio (MER).
[0049] In one configuration, the scan interval may be an even
longer time period. Signals received from neighbor base stations
may include a DL encoded message that includes information
regarding the neighbor base station. During a long scan interval,
these encoded messages may be decoded by the decoding module 410-a
to extract the information from the message about a neighbor base
station. The extracted information may include identification
information for the neighbor base station. The information may also
provide power characteristics, timing parameters, etc. for the
neighbor base station. The mobile device 115-d may use the decoded
information to successfully handoff from the serving base station
to the selected neighbor base station.
[0050] In one example, a neighbor station may operate in a
different frequency band or RAT than the serving base station.
Before signals are received at an antenna 315 from the neighbor
base station, the tuning module 425 may tune a receiver 430
associated with the antenna 315. The receiver may be tuned to the
frequency band of the neighbor base station. In one configuration,
the tuning module 425 may perform the tuning during a portion of
the scan interval. After the receiver 430 is tuned to the neighbor
base station operating in the different frequency band, the antenna
315 may receive the signals from the neighbor base station and the
measurement module 310-b may proceed to perform a handoff-related
measurement of the received signals. Upon completing the
handoff-related measurements of the signals, the tuning module 425
may tune the receiver 430 back to the frequency band of the serving
base station.
[0051] In one configuration, the tuning module 425 may not tune
receivers associated with antennas 315 that receive signals during
the scan interval from neighbor base stations that operate in the
same frequency or RAT as the serving base station As a result,
during the scan interval, the antennas 315 may concurrently receive
signals from neighbor base stations that operate in the same or
different frequency band as the serving station and provide the
same or different RAT as the serving base station.
[0052] FIG. 5 is a flow chart illustrating one example of a method
500 to concurrently perform a scan procedure of multiple neighbor
cells using MIMO based antenna resources. The method 500 may be
implemented by a mobile device, such as the mobile device 115 of
FIG. 1, 2, 3, 4A, or 4B. In the example, the method 500 may be
implemented by the transceiver 305 and the measurement module 310
of FIG. 3.
[0053] At block 505, a type of handoff-related measurement to
perform may be determined based on a determined length of a scan
interval. The detection module 405 may determine the length of the
scan interval. The measurement module 310 may determine the type of
measurement to perform based on the scan interval length. At block
510, first handoff-related measurements of first wireless signals
may be performed. The first wireless signals may be received at
first MIMO antenna resources of the device 115, such as a first
antenna 315-a-1 of FIG. 3. The first wireless signals may be
transmitted from a first neighbor cell to the first MIMO antenna
315-a-1. In one configuration, the device 115 may be in
communication with a serving cell.
[0054] At block 515, second handoff-related measurements of second
wireless signals may be performed. In one example, the second
wireless signals may be received at second MIMO antenna resources
of the device, such as a second antenna 315-a-2 of FIG. 3. The
second wireless signals may be transmitted from a second neighbor
cell. In one configuration, the second MIMO antenna resource
315-a-2 may receive the second wireless signals concurrently with
the first wireless signals being received at the first MIMO antenna
resource 315-a-1. As previously explained, "concurrently" may be
interpreted to mean that first signals and second signals are
received during overlapping time periods at the respective MIMO
antennas. Thus, "concurrently" may mean that the first MIMO antenna
resources 315-a-1 may begin to receive the first wireless signals
and at a later time, while the first MIMO antenna resources 315-a-1
are still receiving the first wireless signals, the second MIMO
antenna resources 315-a-2 may begin to receive the second wireless
signals. As a result, the receipt of the signals at their
respective antennas may overlap.
[0055] Therefore, the method 500 may provide for scanning signals
in parallel from multiple neighbor base stations using MIMO based
antenna resources 315 of a mobile device 115. It should be noted
that the method 500 is just one implementation and that operations
of the method 500 may be rearranged or otherwise modified such that
other implementations are possible.
[0056] FIG. 6 shows an example of a method 600 to concurrently scan
neighbor cells that operate in the same frequency band as the
serving cell during the same scan interval using MIMO based antenna
resources. In one configuration, the method 600 may be implemented
by the mobile device, such as the mobile device 115 of FIG. 1, 2,
3, 4A, or 4B. In the example, the method 600 may be implemented by
the detection module 405, the transceiver controller 284, and the
measurement module 310 of the device 115 of FIG. 4A or 4B.
[0057] At block 605, neighbor cells that are in the same frequency
band as the serving cell may be identified. This may further
include identifying neighbor cells that provide the same RAT as the
serving cell. At block 610, the beginning of a scan interval may be
identified. At block 615, the identified neighbor cells may be
divided into two or more subsets of cells. In one example, at block
620, first handoff-related measurements of first wireless signals
may be performed during the scan interval. The first wireless
signals may be from a first subset of neighbor cells and received
at first MIMO antenna resources 315-a-1. In addition, at block 625,
second handoff-related measurements of second wireless signals may
be performed in parallel with the first handoff-related
measurements. The second wireless signals may be from a second
subset of neighbor cells and received at second MIMO antenna
resources 315-a-2. In one example, the first and second
handoff-related measurements may be power measurements, such as
RSSI measurements, of the received signals. In another example, the
handoff-related measurements may be signal quality measurements,
such as, but not limited to, CINR, SNR, and the like.
[0058] Thus, the method 600 may provide for concurrently scanning
neighbor cells that operate in the same frequency band or RAT as
the serving cell during the same scan interval. It should be noted
that the method 600 is just one implementation and that operations
of the method 600 may be rearranged or otherwise modified such that
other implementations are possible.
[0059] Referring now to FIG. 7, an exemplary method 700 of scanning
multiple neighbor cells in parallel with at least one neighbor cell
operating in a different frequency band and/or RAT than the serving
cell and at least one neighbor cell sharing the same frequency and
RAT as the serving cell. In one example, the method 700 may be
implemented by the mobile device 115 of FIG. 1, 2, 3, 4A, or
4B.
[0060] In one configuration, at block 705, at least one neighbor
cell may be identified that is operating in the same frequency or
with the same RAT as the serving cell. In addition, at least one
neighbor cell operating in a different frequency band or with a
different RAT as the serving cell is also identified. At block 710,
a length of a scan interval is determined. At block 715, the
beginning the scan interval is identified. For a first neighbor
cell that is operating in the same frequency band or same RAT as
the serving cell, first handoff-related measurements of first
wireless signals are performed at block 720 during the scan
interval. The first wireless signals may be received at first MIMO
antenna resources 315-a-1 of the device 115.
[0061] For a second neighbor cell identified as operating in a
different frequency band or different RAT than the serving cell,
the steps described in blocks 725, 730, and 735 may be performed.
For example, at block 725, at the beginning of the scan interval, a
receiver associated with second MIMO antenna resources 315-a-2 of
the device 115 may be tuned to the frequency band of the second
neighbor cell. At block 730, the second MIMO antenna resources
315-a-2 may receive wireless signals from the second neighbor cell
and second handoff-related measurements may be performed on the
received signals. At block 735, after the measurements have been
obtained and at the conclusion of the scan interval, the receiver
associated with the second MIMO antenna resources 315-a-2 may be
tuned to the frequency band of the serving cell.
[0062] Therefore, the method 700 may allow the mobile device 115 to
scan, in parallel, neighbor cells that operate in the same
frequency band or RAT as the serving cell and neighbor cells that
provide different RATs and/or operate in different frequency bands.
In some examples, a scan procedure of multiple neighbor cells may
occur during the same scan interval regardless of the RAT or
frequency band associated with each neighbor cell. It should be
noted that the method 700 is just one implementation and that
operations of the method 700 may be rearranged or otherwise
modified such that other implementations are possible. Various
examples of concurrent handoff-related measurements of cells
operating in different frequency bands and RATs than the serving
cell are now described. These various examples may be implemented
through the method 700 described above and the architecture of the
device 115.
Concurrent Power Measurement
[0063] In one configuration, during the scan interval (including
future scan intervals and the period between adjacent scan
intervals), the device 115 may dedicate the first MIMO antenna
resources 315-a-1 to the serving cell. In other words the first
MIMO antenna resource 315-a-1 may be dedicated to neighbor cells
sharing the same frequency band or RAT as the serving cell. The
second MIMO antenna resources 315-a-2 may be assigned to neighbor
cells in a different frequency band or providing a different RAT
than the serving cell. In one example, during the scan interval,
the first MIMO antenna resources 315-a-1 may receive wireless
signals from the neighbor cells and power measurements for these
signals may be calculated. Further, during the same scan interval,
the receiver associated with the second MIMO antennas 315-a-2 may
be tuned to the different frequency band during a portion of the
scan interval. After the tuning of the receiver is completed, power
measurements of the signals received from the neighbor cells in a
different frequency band are calculated. In one example, at the
conclusion of the scan interval, the receiver may be tuned to the
frequency band of the serving cell.
Concurrent Signal Quality Measurement
[0064] In one example, during each scan interval, the device 115
may use the MIMO antenna resources 315 to receive signals from
neighbor cells and measure the signal quality measurement of each
signal. In one configuration, the device 115 may calculate the
signal quality measurement of each neighbor cell in a mutually
exclusive manner. At the beginning of the scan interval, the first
MIMO antenna resources 315-a-1 may begin to receive signals from
neighbor cells sharing the same frequency and/or RAT as the serving
cell, while a receiver associated with the second MIMO antenna
resources 315-a-2 may be tuned to the frequency band of the
neighbor cell providing the different RAT. After the tuning, the
second MIMO antenna resources 315-a-2 may begin to receive the
signals from the neighbor cells and the measurement module 310 may
calculate a signal quality measurement for the signals received
from the various neighbor cells. At the end of the scan interval,
the receiver may be tuned to the frequency band of the serving
cell. As a result, signal quality measurements of neighbor cells
having similarities with the serving cell may be obtained in
parallel with measurements of neighbor cells that are different
than the serving cell using the architecture of the device 115.
Concurrent Power Measurement and Signal Quality Measurement
[0065] In one example, the device 115 may perform the power
measurement on the neighbor cells sharing the same frequency and
RAT as the serving cell and perform the signal quality measurement
on the neighbor cells on a different frequency band and RAT. Under
this scenario, the device 115 may use the concurrent power
measurement approach described above to speed-up the measurements
on the neighbor cells sharing the same frequency band with the
serving cell (i.e., dividing the neighbor cells into subsets of
cells). The device 115 may use the signal quality measurement
approach described above to measure the neighbor cells on the
different frequency. As a result, the power measurements and signal
quality measurements may be calculated concurrently for different
neighbor cells during the same scan interval.
[0066] In another example, the device 115 may perform the signal
quality measurements on neighbor cells sharing the same frequency
and RAT as the serving cell and perform the power measurements on
neighbor cells belonging to different RAT and/or operating on a
different frequency band. This example may provide two different
options.
[0067] In the first option, the signal quality measurements and the
power measurements may be mutually exclusive. For example, a scan
interval may be dedicated to either calculating the signal quality
measurement or the power measurement. If the scan interval is
dedicated to obtaining the signal quality measurement, the
concurrent signal quality measurement approach described above may
be implemented. If, power measurements are to be calculated during
the scan interval, the neighbor cells operating on the different
frequency or belonging to a different RAT may be divided into a
number of subsets, for example two subsets. The transceiver
controller 284-b may dedicate the first MIMO antenna resources
315-a-1 to the first subset and the second MIMO antenna resources
315-a-2 to the second subset. At the beginning of the scan
interval, the receivers of the two MIMO antennas may be tuned to
the frequencies of the neighbor cells. After the tunings are
completed, power measurements of the neighbor cells may be
calculated in a concurrent way. At the end of the scan interval,
the receivers of both MIMO antennas are tuned to the serving
cell.
[0068] In the second option, the signal quality measurements and
the power measurements may be performed concurrently. During each
scan interval, for example, the transceiver controller 284-b may
dedicate the first MIMO antenna resources 315-a-1 to the serving
cell and the neighbor cells sharing the same frequency band as the
serving BS, and the second MIMO antenna resources 315-a-2 to the
neighbor cells having a different frequency band or RAT. During
each scan interval, the device 115 may use a single input single
output (SISO) approach to perform the signal quality measurements
and the SISO approach to perform the power measurements. When power
measurements are performed on the neighbor cells with different
frequency bands, the receiver associated with the second MIMO
antenna resources 315-a-2 may be tuned to the frequency band of the
neighbor cell. After the tuning is completed, the measurement
module 310-b may start to calculate power measurements of signals
received from the neighbor cells on the different frequency band or
RAT. At the end of the scan interval, the receiver may be tuned to
the serving cell.
[0069] Referring now to FIG. 8, an example of a method 800 is
provided to determine the type of measurement to calculate based on
a determined length of a scan interval while the device 115 is in a
connect mode. In one configuration, the method 800 may be
implemented by the device 115 of FIG. 1, 2, 3, 4A, or 4B.
[0070] At block 805, a determination may be made that the device
115 is in a connected mode. For example, the device may be in
active communications with a serving base station. At block 810, at
least one neighbor cell in a different frequency band or RAT may be
identified. At block 815, the length of the scan interval may be
determined. At block 820, the beginning of the scan interval may be
identified.
[0071] In one configuration, if the length of the scan interval is
short, power measurements may be performed on neighbor cells
operating in a different frequency band. At block 825, a receiver
associated with MIMO antenna resources 315 may be tuned to the
frequency of the different frequency band. At block 830, power
measurements may be performed on wireless signals received from the
neighbor cells. In addition, at block 835, the receiver may be
tuned back to the frequency band of the serving cell. At block 855,
the conclusion of the scan interval may be identified.
[0072] In one configuration, if the length of the scan interval is
longer, signal quality measurements may be performed on neighbor
cells operating in a different frequency. At block 840, a receiver
associated with MIMO antenna resources 315 may be tuned to the
frequency of the different frequency band. At block 845, signal
quality measurements may be performed on wireless signals received
from the neighbor cells. At block 850, the receiver may be tuned to
the frequency band of the serving cell. At block 855, the scan
interval may conclude.
[0073] In one configuration, while the power measurements or signal
quality measurements (depending on the length of the scan interval)
are being performed on the neighbor cells operating in a different
frequency band or RAT than the serving cell, the device 115 may
concurrently perform other types of measurements on neighbor cells
sharing the same frequency or RAT as the serving cell. The type of
measurement to perform may be based on the amount of tuning needed,
as well (as more tuning may further reduce the actual amount of
time for scanning within the scan interval). As a result, during a
scan interval when the device 115 is in a connected mode, the
device 115 may perform power measurements or signal quality
measurements on neighbor cells with a different frequency band in
parallel with performing other types of measurements (e.g., power
measurements, signal quality measurements, etc.) on neighbor cells
with the same frequency band, as provided above with the various
examples. It should be noted that the method 800 is just one
implementation and that operations of the method 800 may be
rearranged or otherwise modified such that other implementations
are possible.
[0074] Referring now to FIG. 9, an example of a method 900 is
provided to determine the type of measurement to calculate based on
the mode of the device 115 and a determined length of a scan
interval. In one configuration, the method 900 may be implemented
by the device 115 of FIG. 1, 2, 3, 4A, or 4B.
[0075] At block 905, a determination may be made that the device
115 is in an idle mode. For example, the device may not be in
active communications with a serving base station. At block 910, at
least one neighbor cell in the same frequency band or RAT as the
serving cell and at least one neighbor cell in a different
frequency band or RAT may be identified. At block 915, the length
of the scan interval may be determined. For example, it may be
determined that the length of the scan interval is a long interval.
At block 920, the beginning of the scan interval may be
identified.
[0076] In one configuration, at block 925, handoff-related
measurements of first wireless signals may be calculated. The
signals may be received from the neighbor cells sharing the same
frequency band or RAT as the serving cell. At block 930, a receiver
associated with second MIMO antennas 315-a-2 may be tuned to the
different frequency band of the neighbor cells. Signals may be
received from these neighbor cells after the tuning in completed.
In one configuration, a DL encoded message may be received. At
block 945, the DL message may be decoded to provide information
regarding the neighbor cells. For example, timing information,
power characteristics, offset information, etc. for the neighbor
cell may be included in the DL message. At block 950, the receiver
may be tuned back to the serving cell. At block 955, the conclusion
of the scan interval is identified.
[0077] Thus, the method 900 allows the device 115, while in idle
mode, to use MIMO antenna resources to concurrently decode DL
messages received from neighbor cells operating in a different
frequency band or RAT and perform handoff-related measurements for
cells that operate in the same or different frequency band than the
serving cell. It should be noted that the method 900 is just one
implementation and that operations of the method 900 may be
rearranged or otherwise modified such that other implementations
are possible.
[0078] As provided by the description above, scan intervals may be
used to perform handoff-related measurements and other types of
measurements on neighbor cells in a different frequency or
different RAT than a serving cell in parallel with existing scan
procedures (i.e., performing measurements for neighbor cells in the
same frequency band). The scan procedure described above allows the
mobile device 115 to concurrently perform measurements of neighbor
cells with the same frequency band or RAT as the serving cell with
neighbor cells operating in a different frequency band or RAT
during the same scan interval.
[0079] The detailed description set forth above in connection with
the appended drawings describes exemplary embodiments and does not
represent the only embodiments that may be implemented or that are
within the scope of the claims. The term "exemplary" used
throughout this description means "serving as an example, instance,
or illustration," and not "preferred" or "advantageous over other
embodiments." The detailed description includes specific details
for the purpose of providing an understanding of the described
techniques. These techniques, however, may be practiced without
these specific details. In some instances, well-known structures
and devices are shown in block diagram form in order to avoid
obscuring the concepts of the described embodiments.
[0080] Information and signals may be represented using any of a
variety of different technologies and techniques. For example,
data, instructions, commands, information, signals, bits, symbols,
and chips that may be referenced throughout the above description
may be represented by voltages, currents, electromagnetic waves,
magnetic fields or particles, optical fields or particles, or any
combination thereof.
[0081] The various illustrative blocks and modules described in
connection with the disclosure herein may be implemented or
performed with a general-purpose processor, a digital signal
processor (DSP), an application specific integrated circuit (ASIC),
a field programmable gate array (FPGA) or other programmable logic
device, discrete gate or transistor logic, discrete hardware
components, or any combination thereof designed to perform the
functions described herein. A general-purpose processor may be a
microprocessor, but in the alternative, the processor may be any
conventional processor, controller, microcontroller, or state
machine. A processor may also be implemented as a combination of
computing devices, e.g., a combination of a DSP and a
microprocessor, multiple microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration.
[0082] The functions described herein may be implemented in
hardware, software executed by a processor, firmware, or any
combination thereof. If implemented in software executed by a
processor, the functions may be stored on or transmitted over as
one or more instructions or code on a computer-readable medium.
Other examples and implementations are within the scope and spirit
of the disclosure and appended claims. For example, due to the
nature of software, functions described above can be implemented
using software executed by a processor, hardware, firmware,
hardwiring, or combinations of any of these. Features implementing
functions may also be physically located at various positions,
including being distributed such that portions of functions are
implemented at different physical locations. Also, as used herein,
including in the claims, "or" as used in a list of items prefaced
by "at least one of" indicates a disjunctive list such that, for
example, a list of "at least one of A, B, or C" means A or B or C
or AB or AC or BC or ABC (i.e., A and B and C).
[0083] Computer-readable media includes both computer storage media
and communication media including any medium that facilitates
transfer of a computer program from one place to another. A storage
medium may be any available medium that can be accessed by a
general purpose or special purpose computer. By way of example, and
not limitation, computer-readable media can comprise RAM, ROM,
EEPROM, CD-ROM or other optical disk storage, magnetic disk storage
or other magnetic storage devices, or any other medium that can be
used to carry or store desired program code means in the form of
instructions or data structures and that can be accessed by a
general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of medium. Disk and disc,
as used herein, include compact disc (CD), laser disc, optical
disc, digital versatile disc (DVD), floppy disk and blu-ray disc
where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above are
also included within the scope of computer-readable media.
[0084] The previous description of the disclosure is provided to
enable a person skilled in the art to make or use the disclosure.
Various modifications to the disclosure will be readily apparent to
those skilled in the art, and the generic principles defined herein
may be applied to other variations without departing from the
spirit or scope of the disclosure. Throughout this disclosure the
term "example" or "exemplary" indicates an example or instance and
does not imply or require any preference for the noted example.
Thus, the disclosure is not to be limited to the examples and
designs described herein but is to be accorded the widest scope
consistent with the principles and novel features disclosed
herein.
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