U.S. patent application number 13/615279 was filed with the patent office on 2013-01-03 for test loading in ofdma wireless networks.
This patent application is currently assigned to Research In Motion. Invention is credited to Jeffrey Goff, Jeffrey Scott, Michael Woodley.
Application Number | 20130003687 13/615279 |
Document ID | / |
Family ID | 42026762 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130003687 |
Kind Code |
A1 |
Woodley; Michael ; et
al. |
January 3, 2013 |
Test Loading in OFDMA Wireless Networks
Abstract
A radio frequency radio (RF) transceiver that defines scheduling
logic for generating transmission schedules for orthogonal
frequency-division multiple access (OFDMA) RF transmissions from
the RF transceiver, wherein the scheduling logic specifies at least
one of a modulation type, a code rate, a sub-channel, and a
sub-carrier for a plurality of symbols to be transmitted in a
communication signal sub-frame. A processor generates outgoing data
bits and outgoing test data bits for transmission from the RF
transceiver as OFDMA transmission signals and OFDMA test data
transmission signals, respectively, according to the transmission
schedules to create loading within at least a portion of a cellular
service area that corresponds with a test-loading value. The amount
of the additional required loading is the difference between the
test-loading value and an actual loading value.
Inventors: |
Woodley; Michael; (McKinney,
TX) ; Scott; Jeffrey; (Murphy, TX) ; Goff;
Jeffrey; (Melbourne, AU) |
Assignee: |
Research In Motion
Waterloo
CA
|
Family ID: |
42026762 |
Appl. No.: |
13/615279 |
Filed: |
September 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12341790 |
Dec 22, 2008 |
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13615279 |
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Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04L 5/0091 20130101;
H04W 88/02 20130101; H04L 5/003 20130101; H04W 24/06 20130101; H04L
5/0062 20130101; H04L 5/0094 20130101; H04L 5/0007 20130101; H04L
5/0046 20130101; H04L 5/0037 20130101; H04W 72/044 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04W 72/12 20090101
H04W072/12; H04W 24/08 20090101 H04W024/08; H04W 72/08 20090101
H04W072/08 |
Claims
1-20. (canceled)
21. A base station transceiver system for testing communication
devices in a wireless network, the base station transceiver system
configured to: determine an actual loading value within a cellular
service area; determine an additional loading that is based on a
difference between the actual loading value and a test-loading
value; and transmit an OFDMA test data transmission signal to a
device under test within the cellular service area, the OFDMA test
data transmission signal being an equivalent of transmitting actual
user data using OFDMA radio technology and formats, to create
loading within the cellular service area that corresponds with the
test-loading value such that the device under test can be tested in
conditions that accurately simulate a network loading having an
increase in system noise level resulting from a plurality of active
users in a wireless network.
22. The base station transceiver system of claim 21, wherein the
base station transceiver system is further configured to update
transmission schedules to correspond with the test-loading value
and transmits OFDMA test data transmission signals based upon the
updated transmission schedules in a plurality of adjacent cell
sectors of the cellular service area as the device under test moves
from a first cell sector within the cellular service area to a
second cell sector within the cellular service area.
23. The base station transceiver system of claim 21, wherein the
base station transceiver system is further configured to update
transmission schedules to correspond to changes in actual loading
within the cellular service area.
24. The base station transceiver system of claim 23, wherein the
base station transceiver system is configured to transmit both (a)
OFDMA transmission signals comprising actual user data, and (b)
OFDMA test data transmission signals comprising the additional
loading in a common sub-frame as one OFDMA transmission.
25. The base station transceiver system of claim 21, wherein the
base station transceiver system employs a scheduling table having a
geometric pattern that is not sequential or linear in
construction.
26. The base station transceiver system of claim 21, wherein the
base station transceiver system receives a signal quality
indication from a remote wireless transceiver, the signal quality
indication corresponding to a forward link transmission of OFDMA
transmission signals.
27. The base station transceiver system of claim 21, wherein the
base station transceiver system varies at least one of the code
rate and the modulation type for transmission schedules for
outgoing OFDMA test data transmission signals.
28. The base station transceiver system of claim 21, wherein the
base station transceiver system generates transmission schedules
for outgoing OFDMA test data transmission signals and transmits
corresponding OFDMA test data transmission signals in a plurality
of adjacent cell sectors of the cellular service area to account
for movement of the device under test between adjacent cell
sectors.
29. The base station transceiver system of claim 21, wherein the
base station transceiver system specifies a communication signal
sub-frame scheduling table starting burst location.
30. The base station transceiver system of claim 21, wherein the
base station transceiver system defines a specific geometric
pattern in a sub-frame scheduling table for an outgoing OFDMA
transmission.
31. A method for testing communication devices in a wireless
network, the method comprising: determining an actual loading value
within a cellular service area or portion thereof; determining an
additional loading that is based on a difference between the actual
loading value and a test-loading value; and transmitting an OFDMA
test data transmission signal to a device under test within the
cellular service area or portion thereof, the OFDMA test data
transmission signal being an equivalent of transmitting actual user
data using OFDMA radio technology and formats, to create loading
within the cellular service area or portion thereof that
corresponds with the test-loading value such that the device under
test can be tested in conditions that accurately simulate a network
loading having an increase in system noise level resulting from a
plurality of active users in a wireless network.
32. The method of claim 31, the method further comprising: updating
transmission schedules to correspond with the test-loading value;
and transmitting OFDMA test data transmission signals based upon
the updated transmission schedules to a plurality of adjacent cell
sectors of the cellular service area as the device under test moves
from a first cell sector within the cellular service area to a
second cell sector within the cellular service area.
33. The method of claim 31, the method further comprising updating
transmission schedules to correspond to changes in loading within
the cellular service area.
34. The method of claim 31, the method further comprising
transmitting both (a) OFDMA transmission signals comprising actual
user data, and (b) OFDMA test data transmission signals comprising
the additional loading in a common sub-frame as one OFDMA
transmission.
35. The method of claim 31, the method further comprising varying
at least one of the code rate and the modulation type for
transmission schedules for outgoing OFDMA test data transmission
signals.
36. The method of claim 31, the method further comprising:
generating transmission schedules for outgoing OFDMA test data
transmission signals; and transmitting corresponding OFDMA test
data transmission signals in a plurality of adjacent cell sectors
of the cellular service area to account for movement of the device
under test between adjacent cell sectors.
37. The method of claim 31, the method further comprising
specifying a sub-frame scheduling table starting burst
location.
38. The method of claim 31, the method further comprising defining
a specific geometric pattern in a sub-frame scheduling table for an
outgoing OFDMA transmission.
39. A method for testing communication devices in a wireless
network, the method comprising: determining an actual loading value
within a cellular service area or portion thereof; determining an
additional loading, the additional loading being a difference
between the actual loading value and a test-loading value; and
transmitting an OFDMA transmission signal that includes test data
in addition to actual user data to a device under test within the
cellular service area to create loading within the cellular service
area or portion thereof that corresponds with the test-loading
value such that the device under test can be tested in conditions
that accurately simulate a network loading having an increase in
system noise level resulting from a plurality of active users in a
wireless network.
40. The method of claim 39, the method further comprising: updating
transmission schedules to correspond with the test-loading value;
and transmitting OFDMA transmission signals based upon the updated
transmission schedules to a plurality of adjacent cell sectors of
the cellular service area as the device under test moves between
cell sectors within the cellular service area.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates generally to wireless communication
systems and, more particularly, to testing communication devices in
a wireless network that supports orthogonal frequency-division
multiple access (OFDMA) transmissions.
DESCRIPTION OF RELATED ART
[0002] Wireless communication service providers, as well as
Internet service providers, face some difficult challenges as
communication networks are developed to work together to provide
seamless end-to-end call connectivity across the various platforms.
As such, small and large, as well as private and public, wireless
data networks are being created to seamlessly interact with large
wire line networks to enable users to establish point-to-point
connections independent of terminal type and location.
Traditionally, however, voice networks have paved the way for the
creation of data networks as users loaded the voice networks trying
to transmit data, including streaming data (video and voice).
Initially, traditional Public Switched Telephone Networks (PSTNs)
were used for data transmissions. The PSTNs, however, have been
largely supplanted by packet data networks, including various
versions of the "Internet".
[0003] Initial wireless voice networks, including AMPS, Time
Division Multiple Access (TDMA) including North American TDMA, Code
Division Multiple Access (CDMA) and Global System for Mobile
Communications (GSM), were used to transmit data in a limited
capacity. These networks are being replaced, however, by newer
wireless data-only networks, as well as data and voice networks
that increasingly have greater capacity.
[0004] The structure and operation of wireless communication
systems are generally known. Examples of such wireless
communication systems include cellular systems and wireless local
area networks, among others. Equipment that is deployed in these
communication systems is typically built to support standardized
operations, i.e., operating standards. These operating standards
prescribe particular carrier frequencies, modulation types, baud
rates, physical layer frame structures, MAC layer operations, link
layer operations, etc. By complying with these operating standards,
equipment interoperability is achieved.
[0005] In a cellular system, a regulatory body typically licenses a
frequency spectrum for a corresponding geographic area (service
area) that is used by a licensed system operator to provide
wireless service within the service area. Based upon the licensed
spectrum and the operating standards employed for the service area,
the system operator deploys a plurality of carrier frequencies
(channels) within the frequency spectrum that support the
subscriber units within the service area. Typically, these channels
are equally spaced across the licensed spectrum. The separation
between adjacent carriers is defined by the operating standards and
is selected to maximize the capacity supported within the licensed
spectrum without excessive interference. In most cases, limitations
are placed upon the amount of co-channel and adjacent channel
interference that may be caused by transmissions on a particular
channel. These limitations must therefore be tested to verify
operation in accordance with requirements, regulations and/or
standards.
[0006] In cellular systems, a plurality of base stations is
distributed across the service area. Each base station services
wireless communications within a respective cellular service area
(cell). Each cell may be further subdivided into a plurality of
sectors. In many cellular systems, each base station supports
forward link communications (from the base station to subscriber
units) on a first set of carrier frequencies, and reverse link
communications (from subscriber units to the base station) on a
second set of carrier frequencies. The first set and second set of
carrier frequencies supported by the base station are a subset of
all of the carriers within the licensed frequency spectrum. In
most, if not all, cellular systems, carrier frequencies are reused
so that interference between base stations using the same carrier
frequencies is minimized and system capacity is increased.
Typically, base stations using the same carrier frequencies are
geographically separated so that minimal interference results.
[0007] A new generation of cellular networks, systems and devices
are being developed to enable mobile stations to receive and
transmit data with increased throughput rates and capacity. For
example, many new mobile stations, often referred to as mobile
terminals or access terminals, are being developed to enable a user
to search the Internet or to send and receive e-mail messages
through the wireless mobile terminal, as well as to be able to
receive continuous bit rate data, including so called "streaming
data". Accordingly, different systems, devices and networks are
being developed to expand such capabilities and to improve their
operational characteristics. As the popularity of these devices
continues to increase, the devices and networks are tested to
determine satisfactory operation even during high network
loading.
[0008] When new cellular communication devices, including BTSs and
cell phones (mobile terminals), are developed, there often is a
need, therefore, to test the new cellular communication device
and/or to test the overall network operation. As mentioned before,
specific operational requirements need to be satisfied as a part of
introducing the new networks and/or cellular communication devices.
Such operational requirements include, for example, satisfying one
or more signal quality requirements notwithstanding network or
channel conditions. To establish such requirements are satisfied,
however, the network or communication devices need to be tested
under adverse conditions that interfere with signal transmission.
Such conditions typically do not exist on a continual basis and
thus a delay may be realized before the required testing can take
place. Accordingly, a need exists to avoid delaying test operations
until the desired conditions exist testing the device or
network.
BRIEF SUMMARY OF THE INVENTION
[0009] Operators and device manufacturers typically seek networks
and devices that meet performance metrics (e.g., throughput,
connection success, required power levels, bit error rates, etc.)
for a given level of loading. Operators of networks in particular,
have a need to prove their networks satisfy performance criteria
under loaded traffic conditions. Thus, the embodiments of the
invention provide a practical method and system for enabling an
operator to prove operation of their networks without requiring the
operators to deploy a plurality of mobile stations within the
network to create the loading that is necessary to prove successful
network operation. Generally, however, the embodiments and aspects
of the present embodiments of the invention may be applied to
cellular networks including packet data networks, local area
networks, wide area networks, and even to mobile terminals and
handsets.
[0010] A wireless communication device and method therefore
includes a radio frequency (RF) transceiver that defines scheduling
logic for generating transmission schedules for orthogonal
frequency-division multiple access (OFDMA) RF transmissions from
the RF transceiver. The scheduling logic specifies at least one of
a modulation type, a code rate, a sub-channel, and a sub-carrier
for a plurality of symbols across a plurality of slots of a
scheduling table to be transmitted in a communication signal
sub-frame. A processor generates outgoing data bits and outgoing
test data bits for transmission from the RF transceiver as OFDMA
transmission signals and OFDMA test data transmission signals,
respectively, according to the transmission schedules.
[0011] The transmission of OFDMA test data transmission signal,
which is the equivalent of transmitting actual user data using
OFDMA radio technology and formats, creates loading within at least
a portion of a cellular service area that corresponds with a
test-loading value. Thus, a device under test can be tested in
conditions that accurately simulate network loading such that the
result is an increase in the system noise level generally resulting
from a plurality of active users in the network in contrast to
conditions that merely have high levels of interference from noise.
Stated differently, data is generated and transmitted using OFDMA
protocols/formats to create loading to test a network and/or
device.
[0012] The wireless communication device also updates the
transmission schedules to correspond with the test loading value
and transmits the OFDMA test data transmission signals based on the
updated transmission schedules in a plurality of adjacent cell
sectors of a cellular service area as a device under test or other
mobile station moves to various locations within the cellular
service area. For example, a device under test or other mobile
device that migrates from a first cell sector of a cell service
area to a second cell sector would affect loading in both cell
sectors. Accordingly, the transmission schedules are updated to
correspond with changes in loading. The scheduling logic specifies,
in the transmission schedules of a sub-frame scheduling table, at
least one of a communication signal starting burst location and a
geometric pattern of the communication signal sub-frame scheduling
table for at least one of the OFDMA transmission signals and the
OFDMA test data transmission signals.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0013] A better understanding of the present invention can be
obtained when the following detailed description of the preferred
embodiment is considered with the following drawings, in which:
[0014] FIG. 1 is a functional block diagram of a communications
network formed in accordance with the present invention.
[0015] FIG. 2 is a network diagram that illustrates operation
according to one embodiment of the invention.
[0016] FIG. 3 is a diagram that illustrates operation according to
one embodiment of the invention for a mobile station that migrates
from one cell sector to another.
[0017] FIG. 4 is a functional block diagram of a wireless
communication device according to one embodiment of the
invention.
[0018] FIG. 5 is an exemplary scheduling table according to one
embodiment of the invention.
[0019] FIG. 6 is an exemplary scheduling table according to one
embodiment of the invention having a geometric pattern that is not
sequential.
[0020] FIG. 7 is an exemplary scheduling table according to one
embodiment of the invention having a geometric pattern that
demonstrates a distributed but symmetric pattern.
[0021] FIG. 8 is an exemplary scheduling table according to one
embodiment of the invention having a geometric pattern that
demonstrates a geometric pattern for transmission of test data that
conflicts with transmission of actual user data
[0022] FIG. 9 is a flow chart that illustrates a method according
to one embodiment of the invention.
[0023] FIG. 10 is a scheduling parameters table that illustrates
exemplary parameters that may be specified for use by scheduling
logic or a processor when completing a scheduling table according
to one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIG. 1 is a functional block diagram of a communications
network formed in accordance with the present invention. As may be
seen, communication network 10 includes mobile stations and mobile
terminals that communicate over cellular network elements in a
wireless network 12 and over network access nodes and wireless
network nodes of a wireless packet data network 14. Generally,
communication network 10 is a "cellular" network that supports
voice and data calls by a plurality of handsets and mobile
terminals using an orthogonal frequency division multiple access
(OFDMA) radio technology. OFDMA radio technology is a multi-carrier
transmission format that defines a plurality of orthogonal slightly
overlapping sub-carriers to transmit multiple simultaneous signals
across a wired or wireless medium. Because sub-carriers are
selected to be orthogonal relative to each other, interference is
eliminated even though the sub-carriers slightly overlap. The
sub-carriers may be used to carry data, nulls, and pilot signals.
Additionally, the sub-carriers may be used to carry binary data
using binary phase shift keying modulation. The sub-carriers may
also be used to carry multi-bit words using multi-bit encoding
schemes, such as phase shift keying (PSK) and quadrature amplitude
modulation (QAM), that substantially increase data throughput. One
particular benefit of OFDMA is that digital error correction
techniques such as bit interleaving may be used to distribute data
across multiple sub-carrier frequencies to reduce the effects of
interference.
[0025] To the extent that there are differences between orthogonal
frequency division multiplexing (OFDM) and OFDMA protocols and
radio technologies, the aspects and embodiments of the present
invention apply to both types of protocols, radio technologies, and
approaches. It should be understood that references herein to OFDMA
could include OFDM where applicable or relevant. In an OFDMA
communication system, data is communicated in a series of time
domain bursts that carry a group of frequency domain symbols in an
analog form at a specified carrier frequency prior to final
amplification and propagation across a transmission medium. A
receiver pre-amplifies a received RF signal (here, an OFDM/OFDMA
signal), down-converts the received signal, and applies a Fast
Fourier Transform (FFT) to recover the original frequency domain
signals/symbols.
[0026] Wireless packet data network 14 is intended to represent
newer Internet Protocol (IP) based OFDMA cellular networks that are
designed to support wireless data packet transmissions for packet
data sessions or data calls as well wireless local area networks
that do not have the signaling infrastructure of more traditional
cellular networks that support voice calls. These data calls
specifically include the ability to support voice calls wherein
voice information is transmitted in data packets through the packet
data network 14. The wireless packet data networks 14 can comprise
any type of packet data protocol network including wireless
networks that utilize OFDMA radio technology such as, for example,
IEEE 802.16e networks (including "WiMAX" and other variant
networks), Flash-OFDM networks, 3GPP Long Term Evolution (LTE)
networks, wireless broadband (WiBro) networks (South Korean telecom
networks), and High Performance Radio Metropolitan Area Network
(HIPERMAN) networks (European alternative to WiMAX).
[0027] At least some of these packet data networks may be deployed
with overlapping wireless networks 12 to facilitate deployment of
handset devices that utilize multiple communication protocols to
support data packet sessions as well as voice calls. Moreover, data
packet sessions are not necessarily precluded from being supported
and carried over traditional wireless networks 12 that support
voice calls. In general, wireless networks have evolved from merely
carrying voice to being able to support communications with
wireless handsets that carry both voice and data. For either
application (voice or data), communication network 10 includes
circuitry and logic for supporting the various aspects and/or
embodiments of the present invention for creating network loading
for test purposes using OFDMA radio technology.
[0028] Referring back to FIG. 1, mobile station (MS) 18 is engaged
in a voice call using OFDMA radio technology over a wireless
communication link with a Base Transceiver Station (BTS) 20. BTS 20
is coupled to a base station controller (BSC) 22, which in turn is
coupled to a mobile switching center (MSC) 24. A mobile station 26
is engaged in a voice call with BTS 28. BTS 28 is further coupled
to BSC 30 that is further coupled to MSC 24.
[0029] A mobile terminal 32 is engaged in a packet data session
over a wireless communication link with a wireless network node 34,
which in turn is coupled to a network access node 36. Network
access node 36 is also coupled to MSC 24. Network access node 36,
among other functions, acts as an interface device between wireless
network node 34 and MSC 24 and performs data protocol conversions
as is required. Mobile stations 18 and 26 may also engage in data
sessions using any of a plurality of protocols through their
corresponding BTSs 20 and 28, respectively, according to network
and device capability. Thus, MS 18 may establish a packet data
session with mobile terminal 32 because of the network connectivity
and because of data protocol conversions supported by one or more
devices including network access node 36.
[0030] MSC 24 controls calls (voice and data) routed through either
BSC 22 or BSC 30 that operatively connect MS 18 or MS 26 to a call
with another device in wireless network 12, or in packet data
network 14 or to a landline based public switched telephone network
(PSTN) telephone or data terminal. The basic operation of BTSs,
BSCs, and MSCs and the other network elements and PSTNs are well
known by one of average skill in the art and will not be described
further here.
[0031] Generally, the link quality communications with MSs 18 and
26 and mobile terminal 32 and other similar devices in a
communication network 10 may be characterized by parameters that
reflect signal quality including, for example, signal-to-noise
ratio (S/N), carrier-to-interference ratio (C/I),
carrier-to-interference plus noise ratio (C/I+N), and signal-to-
interference and noise ratio (SINR). Typically, a mobile device
transmits a signal quality indication to a network access device or
point in a reverse link communication (e.g., in a specified control
channel signal). Network loading generally results in a limitation
in RF performance or capacity due to C/I+N degradation in an OFDMA
communication channel due to the impact of co-channel and adjacent
channel sources of interference from forward link transmissions in
other cellular service areas (e.g., adjacent cell sectors).
[0032] Network loading is often inferred, therefore, by evaluating
such parameters that describe link performance in the presence of
inter-cell and intra-cell interference in a cellular network or
more generally, for all networks. Such interference, namely
co-channel and adjacent channel interference, increase with
increases in network loading. For example, the signal received by a
specified mobile station or mobile terminal over the forward link
from the BTS or wireless network node may contain interference from
forward link transmissions in neighboring cells, in adjacent cell
sectors, and in the same cell sector or local area under non-ideal
operational conditions (e.g., out-of-band signals spurs). Even
though the quality of a signal network signal link correlates,
generally, with an amount of network loading, network loading
refers, here, to a percentage of OFDMA wireless resources that are
used in a sub-frame burst for a specified service area (e.g., a
cell sector). Drive tests and other testing may then occur in
relation to specified network loading values. Link performance is
evaluated by comparing a signal quality parameter received in a
reverse link communication at the base station receiver or access
point or from samples of forward link signal quality collected from
a device under test (DUT) in relation to the network loading.
[0033] Referring back to FIG. 1, therefore, the aggregate of
forward link communications to MSs 18 and 26 and mobile terminal 32
and other similar devices will create interference for various
portions of cellular service areas (cells). More specifically,
forward link transmissions 40 to the MSs 18/26 or mobile terminals
32 and forward link transmissions 42 to DUTs 44/46 create network
loading and associated interference that affects the forward link
transmissions 42 to devices under test (DUTs) 44/46. Generally, all
of the forward link communications add to loading which may create
adjacent channel or co-channel interference for any one device. One
aspect of the embodiments of the present invention is that an
actual loading value in a cellular network utilizing OFDMA
communications is determined for an area (e.g., cell sector or
other service area) surrounding a device under test such as DUT 44
or 46. For example, if twenty percent of OFDMA resources of an
OFDMA Resource Block (scheduling table) are used for forward link
transmissions to carry user data for delivery to one or more
devices during a sub-frame burst, an actual loading value is equal
to twenty percent.
[0034] In an embodiment of the invention, the network loading
refers to loading within a cell sector though other areas may
readily be defined for such purposes. A BTS 20 or a wireless
network node 34 increases the network loading to correspond with a
test loading value for the service area (cell sector or other
defined area) of the corresponding DUT 44 or 46 as well as adjacent
or proximate areas to create the desired loading for DUTs 44 and
46. BTS 20 or wireless network node 34 determines a required
additional loading based on a difference between the actual loading
value and the test loading value for the service areas of DUTs 44
and 46, respectively, to create network loading that corresponds to
the test loading value.
[0035] The required additional loading is created by BTS 20 or
wireless network node 34 by generating and transmitting OFDMA test
data transmission signals 48 based on test data bits to supplement
actual user data bits that are transmitted as OFDMA transmission
signals 40 and 42. Thus, BTS 20 schedules OFDMA transmissions of
OFDMA transmission signals 40 and 42 that are based on actual data
bits and OFDMA test data transmission signals 48 that are based on
test data bits. The OFDMA test data transmission signals 48, when
combined with the OFDMA transmission signals 40 and 42, create
network loading for DUT 44 service area that corresponds with the
test loading value. It should be understood that the OFDMA
transmission signals 40 and 42 and the OFDMA test data transmission
signals 48 are transmitted in a common sub-frame as one OFDMA
transmission even though they are based on actual data bits and
test data bits, respectively.
[0036] While not shown explicitly herein, DUT 44 service area may
be a cell sector, a cell, or other defined service area in which
DUT 44 is presently located. Similarly, wireless network node 34
generates test data transmission signals 48 to create network
loading for DUT 46 service area that corresponds with the test
loading value. As such, DUTs 44 and 46 may be tested under desired
loading conditions.
[0037] The required additional loading for a service area (e.g.,
cell sector) adjacent to the service area for DUT 44 may be
different from a service area adjacent to the service area for DUT
46 based in part on the amount of interference from forward link
wireless transmissions occurring in the service areas that are
adjacent (or proximate) to the service areas of DUTs 44 and 46.
Accordingly, the number of test data bits transmitted as OFDMA test
data transmission signals 48 from BTS 20 may be different than from
wireless network node 34 even though the test loading values being
used for the service areas of DUTs 44 and 46 are equal. In the
described embodiment, these "service areas" are cell sectors though
the loading may be determined for a differently defined area.
Additionally, even if the service areas for DUTs 44 and 46 have
equal amounts of loading, the link quality for the communications
with DUTs 44 and 46 may vary based on interference from other
operations, multi-path interference, as well as other forms of
interference.
[0038] FIG. 2 is a network diagram that illustrates operation
according to one embodiment of the invention. A communication
network 50 includes cellular service areas 52 and 54 (cells 52 and
54, respectively). Cell 52 includes cell sectors 52a, 52b and 52c.
Cell 54 includes cell sectors 54a, 54b and 54c. BTS 56 supports
forward and reverse link transmissions for cell 52 within cell
sectors 52a-c while BTS 58 supports forward and reverse link
transmissions for cell 54 within cell sectors 54a-c.
[0039] BTS 56 transmits OFDMA transmission signals 60 to MS 62 and
OFDMA test data transmission signals 64 to create the required
additional loading within cell sector 52a to correspond to the test
loading value. BTS 58 transmits OFDMA transmission signals 66 to MS
68, OFDMA transmission signals 70 to DUT 72, and OFDMA test data
transmission signals 74 to create the required additional loading
within cell sector 54a to correspond to the test loading value. BTS
58 transmits OFDMA transmission signals 76 to MS 78, OFDMA
transmission signals 80 to MS 82, and OFDMA test data transmission
signals 84 to create the required additional loading within cell
sector 54b to correspond to the test loading value. BTS 58
transmits OFDMA test data transmission signals 86 to create the
required additional loading within cell sector 54c to correspond to
the test loading value.
[0040] Here, the additional required loading within cell sector 54c
is approximately equal to the test loading value since there are
not any devices communicating within cell sector 54c. Similarly,
within cell sectors 52b and 52c, BTS 56 transmits OFDMA test data
transmission signals 88 and 90, respectively, for the required
additional loading to approximately correspond to the test loading
value. Alternatively, for unused cell sectors such as cell sectors
52b-c and 54c, a standard level of transmission of OFDMA test data
transmission signals may be transmitted. In one embodiment, for
example, a specified percentage of available OFDMA resources are
allocated for cell sectors that do not have MSs or DUTs actively
communicating with the cell sector.
[0041] As may also be seen, test logic 92 is coupled to transmit a
test loading data 94 to each of BTSs 56 and 58. Test loading data
includes at least one scheduling parameter stored in scheduling
parameters table 98. Each of BTSs 56 and 58 use the test loading
data 94 to determine the required additional loading, or in other
embodiments, supplemental loading based on test data bits for each
cell sector 52a-c and 54a-c, respectively. Required additional
loading is based on actual loading within the cell sectors. Test
loading data 94 may carry a test loading value, for example, or it
may also carry other scheduling parameters 98 that are stored in
association with test logic 92. Test logic 92 comprises, in one
embodiment, circuitry that receives a user input that specifies a
desired test loading value (or other test loading parameters) for a
variety of tests. For example, test logic 92 consists of a central
user operated test control module. As such, test logic 92
distributes the user-selected test loading data 94 to each BTS 56
or 58 that may affect testing with a specified DUT 72.
[0042] Alternately, test logic 92 may comprise logic disposed
within each of BTSs 56 and 58 that specifies the test loading data
94. For this embodiment, for example, test logic 92 comprises
circuitry associated with a specified BTS of BTSs 56 and 58 that
receives a user specified test loading data 94 for use. The test
loading data 94 may be specified for each cell or cell sector
either remotely or at the cell (BSC or BTS). The test loading data
94 then is used by the transceiver system (here a BTS) to calculate
the required additional loading or supplemental loading based on
loading calculated in a manner defined within the BTS. Generally,
the loading is created by forward link transmissions in adjacent or
other cell sectors that cause interference within the cell sector
that is being used to service a particular device. More
specifically, inter-cell interference 96 from proximate or adjacent
cells of other cells, or from intra-cell interference 99 from
adjacent cell sectors within the same cell increase with increases
in loading. Thus, the test loading data 94 defines OFDMA
transmission scheduling parameters that create desired levels of
loading and associated interference to enable link quality to be
evaluated for operations under such loading conditions.
[0043] In operation, BTS 56 generates OFDMA test data transmission
signals 64 to create loading that corresponds to the test loading
value based on actual loading values determined for communications
with one or more MSs 62 in cell sector 52a. BTS 56 generates OFDMA
test data transmission signals 88 and 90 to create a standard level
of loading for unused cell sectors. BTS 58 generates OFDMA test
data transmission signals 74 for the required additional loading to
correspond to the test loading value based on loading for cell
sector 54a. The actual interference 96, 98 and 99 in cell sector
54a is due to forward link transmissions to one or more MSs 78, 82
and 62 as well as the OFDMA test data transmission signals 84, 86
and 64 transmitted in adjacent or proximate cell sectors. Each of
these MSs 78, 82 and 62 is operating in cell sectors within cell 52
or cell 54 that are adjacent or proximate to cell sector 52a.
[0044] BTS 58 generates OFDMA test data transmission signals 84 for
the required additional loading to correspond with the test loading
value based on actual loading within cell sector 54b. The actual
interference 98 and 99 in cell sector 54b is due to forward link
communications to one or more MSs/DUTs 68 and 72 (devices in
adjacent cell sectors of cell 54), respectively, as well as OFDMA
test data transmission signals 74 and 86, respectively. BTS 56
generates OFDMA test data transmission signals 64 for the required
additional loading to correspond to the test loading value for cell
sector 52a. The actual interference 96 and 97 in cell sector 52a is
due to forward link communications to one or more MSs/DUTs 68 and
72 (devices in adjacent cell sectors of cell 54) and to OFDMA test
data transmission signals 88 and 90 in cell sectors 52b and 52c,
respectively.
[0045] FIG. 3 is a diagram that illustrates operation according to
one embodiment of the invention for a mobile station that
transitions or migrates from one cell sector to another. Cell 52
includes cell sectors 52a, 52b and 52c and an MS 62 that is
traveling from cell sector 52a to cell sector 52b. While MS 62 is
within cell sector 52a, the required additional loading for cell
sectors 52a and 52b is determined to create loading that
corresponds with the test loading value. To maintain loading that
corresponds with the test loading value, however, BTS 56 determines
new required additional loading values for cell sectors 52a and
52b. BTS 56 then generates test data bits, schedules and then
transmits new OFDMA test data transmission signals 88 to correspond
with the required additional loading to create loading that
corresponds with the test loading value for each cell sector 52a
and 52b. Generally, the OFDMA test data transmission signals 88
will be increased in cell sector 52a as they are decreased in cell
sector 52b.
[0046] FIG. 4 is a functional block diagram of a wireless
communication device according to one embodiment of the invention.
Wireless communication system 100 includes a processing module 102.
Processing module 102 is coupled to produce outgoing digital
signals 104 to a transmitter front end 106. Transmitter front end
106 produces OFDMA transmission signals 108 and OFDMA test data
transmission signals 110, based on the outgoing digital signals 104
to a power amplifier 112 that produces amplified radio frequency
signals to a transmit/receive switch 114 for transmission from at
least one antenna operably coupled to switch 114. It should be
understood that the OFDMA transmission signals 108 and the OFDMA
test data transmission signals 110 are based on the outgoing
digital signals 104 are transmitted in a common sub-frame as one
OFDMA transmission even though outgoing digital signals 104 are
based on data signals and test data signals, respectively.
[0047] Incoming RF signals received by at least one antenna coupled
to switch 114 are directed to a low noise amplifier 116. Low noise
amplifier 116 produces amplified incoming RF signals to a receiver
front end 118 that produces incoming digital signals to processing
module 102. The incoming digital signals can periodically include a
signal quality indication shown here as C/I 136. Generally, C/I 136
reflects the link quality of a prior forward link transmission. Any
known signal quality indication parameter may be used herein.
[0048] Processing module 102 includes a data processing module that
processes ingoing digital signals and data and produces outgoing
digital data that is eventually transmitted as OFDMA transmission
signals 108. Test data generation module 122 produces test data
that is eventually transmitted as OFDMA test data transmission
signals 110. The test data either may be a random or pseudo-random
bit stream, a bit stream of logic "0" bits, a bit stream of logic
"1" bits, or a repeating defined bit pattern.
[0049] Processing module 102 further includes scheduling logic 124
that schedules the OFDMA transmission signals 108 and OFDMA test
data transmission signals 110. Modulation logic 126, and a
frequency control module 128 perform modulation processing and
frequency control and processing to correspond with modulation and
frequency based parameters specified by the scheduling logic 124.
The modulation processing includes generating data and digital
signals to correspond with any known type of quadrature amplitude
modulation (QAM) including binary phase shift-keying (BPSK),
quadrature phase shift-keyed modulation (QPSK) and other quadrature
amplitude modulation types including 8-QAM, 16-QAM, 32-QAM, 64-QAM,
128-QAM and 256-QAM. The frequency control module performs channel
selection and controls sample rate modifications of the digital
data, etc. in accordance with the parameters specified by the
scheduling logic. Frequency control module 128, in one embodiment,
also generates radio frequency front-end (RFFE) control signals 138
to control frequency operations within the transmitter front end.
For example, RFFE control signals 138 may specify local oscillation
frequencies and/or phase-locked loop operational parameters to
control an output frequency of an outgoing transmission signal.
Alternatively, frequency control module 128 may specify
interpolation and decimation values within the digital signal
processing of processing module 102 to affect digital data sample
rates and, therefore, a frequency of outgoing digital signals.
[0050] A digital signal-processing module 130 performs additional
digital signal processing to improve data robustness including
error correction coding and bit interleaving across various OFDMA
sub-carriers. A scheduling table is filled by the scheduling logic
124 to define a map of signal transmissions characterized by OFDMA
symbol identity and sub-channel indexes. The scheduling table
lists, for each symbol, what sub-channel indexes and what type of
modulation and a code rate for the OFDMA transmission signals and
for the OFDMA test data transmission signals in one embodiment of
the invention. Any parameter that affects an outgoing RF
transmission signal characteristics may be included within the
various embodiments of operation of the scheduling logic 124.
[0051] Accordingly, one aspect of the embodiment of FIG. 4 is that
the wireless communication system 100 is operable to generate
outgoing RF signals and to receive a C/I 136 from a remote
transceiver to which the outgoing RF signals are being sent.
Thereafter, as wireless communication system 100 increases the
amount of OFDMA test data transmission signals, C/I parameters in
C/I 136 will reflect a degradation in link quality that corresponds
to the increase in loading as loading is increased (especially in
adjacent cell sectors) to correspond with a test loading value.
Typically, therefore, a specified percentage of OFDMA resources are
allocated to forward link transmissions and the received C/I 136 is
evaluated to gauge network and or device performance.
[0052] Wireless communication system 100 may be a transceiver
system having the listed components co-located within one device or
distributed over two or more separate devices. Thus, wireless
communication system 100 may include the modules as shown within
processing module 102 with the exception of a few modules that are
placed in a separate device. As shown, for example, a scheduling
logic 140 (shown in dashed lines to represent an alternate
embodiment) and/or a scheduling table 142 may be formed within a
remote device in place of or instead of having a module 124
disposed within processor 102. As is shown here, scheduling logic
140 transmits scheduling data 144 to processing module 102. Thus,
wireless communication system 100 may be implemented within a
single BTS, partially within a BTS and a BSC, within a BTS that
works in conjunction with another remote device, within an access
point (singularly or with a remote device), etc. In one alternate
embodiment, wireless communication system 100 can comprise a mobile
terminal that generates OFDMA transmission signals as well as OFDMA
test data transmission signals to increase loading. It should also
be noted that the structure of FIG. 4 is exemplary. The structure
may readily be modified to include multiple-in multiple-out (MIMO)
architectures that comprise a plurality of Tx front ends 106 and Rx
front ends 118. Wireless communication devices 100 represents,
therefore, any type of handheld, mobile, fixed wireless terminal,
access point, wireless network node or BTS that utilizes OFDMA
radio technology and performs OFDMA transmissions.
[0053] FIG. 5 is an exemplary scheduling table according to one
embodiment of the invention. Scheduling table 150 of FIG. 5
represents what is also known as a Resource Block. Scheduling table
150 defines m.times.n slots such as slot 152. The rows of
scheduling table 150 represent sub-channel index numbers (0 to m)
while the columns of scheduling table 150 represent symbol numbers
(0 to n) of an OFDMA sub-frame burst. In the described embodiment,
for a specified number of symbols k . . . k+n, shown in the
leftmost column, a plurality of slots are defined within a
sub-frame that may be identified by the various sub-channel indexes
in relation to the symbols. Each slot further defines whether data,
test data or control channel signaling (or nothing) is to be
transmitted. For the data and the test data that is to be
transmitted, a plurality of transmission parameters including, for
example, a modulation type and a code rate are specified. In one
embodiment of the invention, the periodicity of the data,
especially for test data, may also be specified. Periodicity refers
to a frequency of repetition (i.e., a repetition schedule such as
every fourth sub-frame). Additionally, for the test data, a number
of times that the data is transmitted may also be specified. FIG. 9
below discuss parameters that a processor or scheduling logic may
use to complete a scheduling table such as scheduling table
150.
[0054] More generally, according to one embodiment, scheduling
table 150 is filled according to scheduling logic (e.g., scheduling
logic 124 of FIG. 4). The scheduling logic 124 may also specify a
specific loading pattern for scheduling table 150. As a part of the
specific loading pattern, scheduling logic 124 specifies a starting
location defined by a symbol number and a sub-channel index number.
For example, a starting location may be any of the slots of
scheduling table 150 including slot 152. Slot 152 is identified in
FIG. 5 as symbol k, sub-channel index 0. Generally, any of the
m.times.n slots of scheduling table 150, however, may be the
starting location that is specified by scheduling logic 124.
[0055] Continuing to refer to FIG. 5, scheduling table 150 defines
four regions that represent outgoing OFDMA transmission scheduling.
A first region that encompasses k and k+1 symbols and sub-channel
indexes 0-5, labeled as data 154, reflects scheduling (transmission
parameters) for OFDMA transmission signals that are to be
transmitted to a first remote device. A second region that
encompasses k and k+1 symbols and sub-channel indexes 6-9, labeled
as data 156, reflects scheduling (transmission parameters) for
OFDMA transmission signals that are to be transmitted to a second
remote device. A third region that encompasses k+2 through k+5
symbols and sub-channel indexes 0-9, labeled as test data 158,
reflects scheduling (transmission parameters) for OFDMA test data
transmission signals that are to be transmitted within a cell or
cell area (e.g., a cell sector). Finally, a fourth region that
encompasses k+6 through k+9 symbols and sub-channel indexes 0-9,
labeled as unused slots 160, reflects scheduling of unallocated or
unused slots for a given sub-frame.
[0056] The resources allocated for these transmissions of data 154
and 156 are twenty percent of resources that can be allocated in
scheduling table 150. It should be understood that a scheduling
table 150 is likely to be much larger than scheduling table 150.
For convenience, however, a 10.times.10 scheduling table 150 is
shown. For the functional example of FIG. 5, and if one assumes
that scheduling twenty percent of the resources defined in
scheduling table 150 results in a loading value of twenty percent,
and if a test loading value is equal to sixty percent, then
additional required loading is equal to forty percent to create
loading that corresponds to the test loading value of sixty
percent. Accordingly, symbols k+2-k+5 are scheduled to transmit
OFDMA test data transmission signals in all ten sub-channel indexes
(0-9) shown here in FIG. 5 to create loading (total) of sixty
percent.
[0057] Here, the scheduling of sub-frame resources (slots) can be
said to be linear or flat. As may be seen, the transmission
schedules for outgoing the OFDMA test data transmission signals
sequentially follow the transmission schedules for outgoing the
OFDMA transmission signals. The unused slots 160 follow the slots
for data 154, 156 and test data 158. Based on the transmission
schedules defined within scheduling table 150, a processing module
such as processing module 102 of FIG. 4, will generate
corresponding digital data that comprises actual data bits and test
data bits and that are digitally processed to create outgoing
digital signals. The outgoing digital signals are produced to a
transmitter front end that generates outgoing transmission signals
based upon the outgoing digital signals and upon RFFE control
signals such as RFFE control signals 138 produced by processing
module 102 for a transmission burst.
[0058] FIG. 6 is an exemplary scheduling table according to one
embodiment of the invention having a geometric pattern that is not
sequential or linear in construction as described in another
embodiment of this invention. Scheduling table 170, like scheduling
table 150, defines loading to correspond to a sixty percent test
loading value and that defines transmission schedules for the same
data 154, data 156, and test data 158. The loading here for data
154 and data 156 also is twenty percent leaving a required
additional loading value of forty percent that is created with the
OFDMA test data transmission signals that are generated based upon
test data 158. One key difference between scheduling table 170 and
scheduling table 150 is the geometric pattern of the resource
allocation for the transmission burst. As may be seen, data 154 and
data 156 are allocated to symbols k+4 and k+5. The sub-channel
index number assignments are the same. Test data 158 are allocated
to symbols k+1, k+2, k+7 and k+8. Unused slots 160 are allocated to
symbols k, k+3, k+6 and k+9. Thus, the different allocations are
not sequential as shown for scheduling table 150.
[0059] FIG. 7 is an exemplary scheduling table according to one
embodiment of the invention having a geometric pattern that
demonstrates a distributed but symmetric pattern. Scheduling table
180, like scheduling table 150, defines loading to correspond to a
sixty percent test loading value and that defines transmission
schedules for the same data 154, data 156, and test data 158. The
loading here for data 154 and data 156 also is twenty percent
leaving a required additional loading value of forty percent that
is established with the OFDMA test data transmission signals that
are generated based upon test data 158. According to this
embodiment, test data is generated and scheduled to create loading
that is equal to the difference between loading for actual data for
a sub-frame and a test loading value.
[0060] In an alternate embodiment, as will be discussed below in
relation to an exemplary embodiment shown in FIG. 8, a specific
amount of loading may be specified for transmission of test data
instead of the loading for test data transmissions being a
calculated value. Referring again to FIG. 7, one key difference
between scheduling table 180, scheduling table 170 and scheduling
table 150, is the geometric pattern of the resource allocation for
the transmission burst. As may be seen, data 154 is allocated to
symbols k+1, k+2, k+4, k+5, k+7 and k+8 and sub-channel indexes 6
and 7. Data 156 is allocated to symbols k+1, k+2, k+7 and k+8 and
sub-channel indexes 4 and 5. Unused slots 160 are allocated to
symbols k through k+9 and sub-channel indexes 0-3. Test data 158
are allocated to the remaining slots not allocated by data 154,
data 156, or that are unused (unallocated slots). As may be seen, a
very specific pattern is specified in scheduling table 180. One
purpose of scheduling characterized by a geometric pattern similar
to that shown here is to, for a specified test load value, to
maximize the interference to the DUT corresponding to the test load
value.
[0061] It should be noted that the geometric patterns shown above
in relation to FIGS. 5, 6 and 7 are also based upon the
transmission protocols that are being used for the OFDMA
transmissions. More specifically, some protocols have specific
requirements for allocations of the slots, for example, for
supporting control channel and other overhead signaling. Such
requirements may preclude the use of certain slots in a geometric
pattern of a scheduling table.
[0062] FIG. 8 is an exemplary scheduling table according to one
embodiment of the invention having a geometric pattern that
demonstrates a geometric pattern for transmission of test data that
conflicts with transmission of actual user data. Scheduling table
190, like scheduling tables 150, 170 and 180, defines loading to
correspond to a sixty percent test loading value and that defines
transmission schedules for data 154 and test data 158. The loading
here for data 154 and data 156, if both could be scheduled, also is
twenty percent. One difference, however, is that loading for the
test data is performed first and loading for data is performed
second. In this example, therefore, test data is given 1.sup.st
priority and actual data is given 2.sup.nd priority. Table 300
shown in relation to FIG. 10 below shows a field for specifying the
priority of test data in relation to actual data. Additionally,
loading for test data is set to a value greater than 40 percent (44
percent) here in FIG. 8 for exemplary purposes. Thus, for a test
loading value of 60 percent, or more generally, for a specified
total loading value of 60 percent, no more than 60 percent loading
will be allowed to occur. Accordingly, there are not enough
resources to schedule all of data 156. In this example, only
one-half of data 156 may be allocated to available resources.
Accordingly, FIG. 8 illustrates that the scheduling logic is
operable, according to one embodiment, to schedule a defined
geometric pattern (or loading amount) for scheduling test data in a
scheduling table prior to completing the scheduling table according
to other parameters.
[0063] This specific amount of loading due to the scheduling of
test data may be specified either numerically or implicitly. For
example, the loading may be specified implicitly based on a
specific geometric pattern of OFDM resources in a sub-frame
geometric table being specified or selected. For example, a
plurality of geometric patterns may be defined for test data
resource scheduling in a scheduling table. A selection or
specification of any one of the plurality of geometric patterns for
test data scheduling would have a corresponding loading effect or
implicit loading value.
[0064] Scheduling logic that operates according to the example of
FIG. 8 supports network and/or device operation testing in specific
conditions. Having one or more defined geometric patterns that
define scheduling patterns in a loading table may be beneficial for
testing system operation in situations where resources cannot
satisfy demand for resources for a particular sub-frame. For
example, BTS operation and scheduling logic operation within a BTS
or other transceiver system may be tested to demonstrate operation
in specific resource limited situations. The scheduling logic is
thus operable to perform scheduling to support testing that may be
specified by test parameters stored in test logic.
[0065] In many of the embodiments of the invention, a test loading
value is used to determine how much additional loading is to be
generated based on actual loading. In the alternate embodiment in
the example of FIG. 8, specified additional loading based on test
data is specified implicitly by selection of a defined geometric
pattern. Here, the pattern is a rectangle that consumes all
resources for the first four symbols of the sub-frame and a portion
of the fifth and sixth symbols. The scheduling logic schedules
actual data based on remaining available resources after scheduling
the specified additional loading for test data. Moreover, in this
embodiment, a test loading value of 60 percent is specified, as a
test parameter, in addition to the defined geometric pattern of
additional loading based on test data (which is also a test
parameter). Thus, an operator may evaluate scheduler performance in
scheduling actual data since there are not enough resources to
transmit all of data 156 in one sub-frame burst. Test parameters,
for example, may be stored and specified by test logic such as test
logic 92 of FIG. 2.
[0066] FIG. 9 is a flow chart that illustrates a method according
to one embodiment of the invention. The method initially comprises
transmitting to a mobile station or device under test (DUT) and
determining or receiving a signal quality indication (step 200).
More specifically, this step includes transmitting outgoing
orthogonal frequency-division multiple access (OFDMA) transmission
signals from an orthogonal frequency-division multiplexing capable
radio transceiver. The signal quality indicator can be any known
signal quality metric including but not limited to C/I, C/I+N, S/N,
BER, etc.
[0067] Thereafter, the method includes determining an actual
loading for a specified service area (step 204). The specified
service area is, in one embodiment, a cell sector. Subsequently,
the method includes generating outgoing data bits for transmission
from the radio frequency (RF) transceiver as outgoing OFDMA
transmission signals (step 208) and scheduling the OFDMA
transmission signals for transmission from the RF transceiver (step
212). Scheduling the OFDMA transmission signals includes specifying
at least one of a modulation type, a code rate, a sub-channel
index, and sub-carriers for a plurality of symbols to be
transmitted in a sub-frame scheduling table for a transmission
burst.
[0068] The method further includes determining required additional
loading to comply with a test loading value based on a difference
between the actual loading value and the test loading value (step
216) and generating outgoing test data bits for transmission as
OFDMA test data transmission signals (step 220). In one embodiment,
scheduling logic within the RF transceiver generates the
transmission schedule for data as well as test data. To transmit
the test data bits, the method includes generating transmission
schedules for the OFDMA test data transmission signals to
correspond with the required additional loading wherein (step 224).
Generating the transmission schedules for the OFDMA test data
transmission signals includes specifying at least one of a
modulation type, a code rate, a sub-channel, and a sub-carrier for
a plurality of symbols to be transmitted in the communication
signal sub-frame. Generating the transmission schedules for the
OFDMA test data transmission signals may further include specifying
a periodicity, a data type and a repetition number for transmission
of the OFDMA test data transmission signals.
[0069] For example, a random data stream may be specified for use
for the OFDMA test data transmission signals as specified by the
data type. Alternately, a data stream of logic zero bits or logic
one bits or a defined bit pattern may be specified. Additionally, a
number of times that such OFDMA test data transmission signals are
transmitted may be specified. Thus, for example, scheduling logic
may specify that a transmission schedule for one or more (or even
all) of the OFDMA test data transmission signals (or even specified
slots) occurs a number of times (e.g., 500 times). Thus, the
scheduling logic would generate a corresponding transmission
signals.
[0070] Thereafter, the method includes generating and transmitting
the OFDMA transmission signals based on the transmission schedules
for the OFDMA transmission signals (step 228). The method further
includes generating the OFDMA test data transmission signals based
on the transmission schedules for the OFDMA test data transmission
signals to create loading that corresponds with the test-loading
value (step 232).
[0071] In addition to generating OFDMA test data transmission
signals to create loading that corresponds with the test-loading
value for a cell sector of a DUT, the method also includes
scheduling and transmitting OFDMA test data transmission signals in
a plurality of adjacent cell sectors of at least one cellular
service area to satisfy the test-loading value (step 236). The
adjacent cell sectors may include cell sectors of one or more cell
sectors of other cell service areas. Finally, the method includes
updating the schedules for the test data transmission signals in a
plurality of adjacent cell sectors as a DUT or other mobile station
moves (transitions) from one location to another (step 240) to
maintain loading in each cell sector that corresponds with the test
loading value.
[0072] It should be understood that the OFDMA test data
transmission signals are orthogonal to the OFDMA transmission
signals. Orthogonality of signals can include either frequency or
time orthogonality, meaning that the signals are generated to not
conflict with each other within a specified cell area such as a
cell sector. Here, the frequencies of the signals are selected to
avoid interference (e.g., frequency overlap from co-channel or
adjacent channel interference).
[0073] In one embodiment of the invention, the method includes the
RF transceiver or processing module of the radio transceiver
varying at least one of a code rate and modulation type of the
OFDMA test data transmission signals scheduled within the
communication signal sub-frame. More specifically, this includes
the RF transceiver or processing module (or associated scheduling
logic) scheduling OFDMA test data transmissions in which the slots
of scheduling table 150, scheduling table 170 or scheduling table
180, for example, have at least one transmission parameter (e.g.,
modulation type, code rate, power level) that varies relative to
each other for a sub-frame transmission burst.
[0074] FIG. 10 is a scheduling parameters table that illustrates
exemplary parameters that may be specified for use by scheduling
logic or a processor when completing a scheduling table according
to one embodiment of the invention. In one embodiment, scheduling
parameters table 300 defines scheduling parameters that may be
stored in a central device that distributes one of test loading
values such as test loading data 94 in FIG. 2 or that distributes
loading parameters to one or more RF transceivers (e.g., BTSs
56-58). Alternatively, scheduling parameters table 300 may be
stored separately in association with each RF transceiver. Here,
the parameters may be entered on site or remotely through a
controlled communication link.
[0075] Referring to FIG. 10, it may be seen that typical parameters
include a starting position, a geometric pattern (previously
defined), number of slots of a sub-frame to be used as OFDMA test
data transmission signals, a periodicity factor, a data type (e.g.,
random data), a count, a test loading value, and a test data
priority. The starting positions may be any of the slots of a
scheduling table, for example, scheduling table 150. Here, an
exemplary starting position is symbol k+1, sub-channel index 2. The
geometric pattern may be one of a plurality of previously defined
patterns in one embodiment. Here, the geometric pattern is pattern
A that is one of a plurality of defined geometric patterns. The
periodicity refers to a frequency of repetition (e.g., every fourth
sub-frame). The data type refers a data stream pattern of test
data. For example, a data type can be a stream of random bits,
logic one bits, logic zero bits, or even a defined repeating bit
stream pattern. The data type thus defines the test data bit stream
that is generated for transmissions as the OFDMA test data
transmission signals. The count specifies how many times the OFDMA
test data transmission signals will be transmitted as it relates to
sub-frames and the periodicity. The test loading value is as
described previously. Finally, the test data priority refers to a
scheduling priority for the test data in relation to the actual
user data. For some tests, it may be desirable to fill a scheduling
table with OFDMA test data transmission signal transmission
parameters prior to filling the scheduling table with OFDMA
transmission signal transmission parameters. Here in table 300, the
test data is given 2.sup.nd priority relative to the priority given
for the user data. Thus, as is described throughout the
application, the user data is given first priority for scheduling
and the amount of loading that is based on the test data is a
function of how much actual data exists in the scheduling table for
transmission.
[0076] It should be understood that table 300 is exemplary and that
not all of these parameters need to be specified. Additionally,
other parameters may also be used. In addition, some parameters may
be mutually exclusive with others. For example, if a test loading
value is specified, it may not be necessary to specify any of the
patterns that relate to specific geometric patterns. Thus, table
300 can include the test loading value and not include any of burst
location, geometric pattern, starting position and number of slots.
Alternatively, if one or more of these parameters are included in
table 300, there may not be a need for specifying the test loading
value. For example, if table 300 includes a geometric pattern that
has an implicit loading factor based on the geometric design, it
may not be necessary to specify the test loading value if the
defined geometric pattern defines resource allocations for data as
well as test data. Other parameters that may be included are, for
example, number of slots for a given burst, a burst number,
preferred positioning of a single burst within a sub-frame. In
general, table 300 reflects logic that specifies how a scheduling
table is to be filled to specify transmission parameters for the
transmission of OFDMA data transmission signals and OFDMA test data
transmission signals.
[0077] The invention disclosed herein is susceptible to various
modifications and alternative forms. Specific embodiments therefore
have been shown by way of example in the drawings and detailed
description. It should be understood that the drawings and detailed
description thereto are not intended to limit the invention to the
particular form disclosed, but on the contrary, the invention is to
cover all modifications, equivalents and alternatives falling
within the spirit and scope of the present invention as defined by
the claims.
[0078] The present invention has also been described above with the
aid of method steps illustrating the performance of specified
functions and relationships thereof. The boundaries and sequence of
these functional building blocks and method steps have been
arbitrarily defined herein for convenience of description.
Alternate boundaries and sequences can be defined so long as the
specified functions and relationships are appropriately performed.
Any such alternate boundaries or sequences are thus within the
scope and spirit of the claimed invention.
[0079] The present invention has been described above with the aid
of functional building blocks illustrating the performance of
certain significant functions. The boundaries of these functional
building blocks have been arbitrarily defined for convenience of
description. Alternate boundaries may be defined as long as the
certain significant functions are appropriately performed.
Similarly, flow diagram blocks also have been defined herein to
illustrate certain significant functionality. To the extent used,
the flow diagram block boundaries and sequence could have been
defined otherwise and still perform the certain significant
functionality. Such alternate definitions of both functional
building blocks and flow diagram blocks and sequences are thus
within the scope and spirit of the claimed invention. One of
average skill in the art will also recognize that the functional
building blocks, and other illustrative blocks, modules and
components herein, can be implemented as illustrated or by discrete
components, application specific integrated circuits, processors
executing appropriate software and the like or any combination
thereof. For example, each device, server or system described in
relation to the Figures in the present specification may include,
in one or more embodiments, one or more of the structural elements
in a configuration similar to that of device 130 of FIG. 4 to
support associated operations and communications as described in
relation to the various figures.
[0080] As may be used herein, the terms "substantially" and
"approximately" provides an industry-accepted tolerance for its
corresponding term and/or relativity between items. Such an
industry-accepted tolerance ranges from less than one percent to
fifty percent and corresponds to, but is not limited to, component
values, integrated circuit process variations, temperature
variations, rise and fall times, and/or thermal noise. Such
relativity between items ranges from a difference of a few percent
to magnitude differences. As may also be used herein, the term(s)
"coupled to" and/or "coupling" and/or includes direct coupling
between items and/or indirect coupling between items via an
intervening item (e.g., an item includes, but is not limited to, a
component, an element, a circuit, and/or a module) where, for
indirect coupling, the intervening item does not modify the
information of a message but may adjust its current level, voltage
level, and/or power level.
[0081] As may further be used herein, inferred coupling (i.e.,
where one element is coupled to another element by inference)
includes direct and indirect coupling between two items in the same
manner as "coupled to." As may even further be used herein, the
term "operable to" indicates that an item includes one or more of
power connections, input(s), output(s), etc., to perform one or
more its corresponding functions and may further include inferred
coupling to one or more other items. As may still further be used
herein, the term "associated with," includes direct and/or indirect
coupling of separate items and/or one item being embedded within
another item. As may be used herein, the term "compares favorably,"
indicates that a comparison between two or more items, messages,
etc., provides a desired relationship. For example, when the
desired relationship is that signal 1 has a greater magnitude than
signal 2, a favorable comparison may be achieved when the magnitude
of signal 1 is greater than that of signal 2 or when the magnitude
of signal 2 is less than that of signal 1.
* * * * *