U.S. patent number RE42,225 [Application Number 11/429,637] was granted by the patent office on 2011-03-15 for system and method for timing detector measurements in a wireless communication system.
This patent grant is currently assigned to Harington Valve, LLC. Invention is credited to Jacques Behar, David Gazelle, Moti Kabelly, Yossi Keren, Stephen C. Pollmann, Kenneth L. Stanwood.
United States Patent |
RE42,225 |
Stanwood , et al. |
March 15, 2011 |
**Please see images for:
( Certificate of Correction ) ** |
System and method for timing detector measurements in a wireless
communication system
Abstract
A system that provides a wireless broadband connection between
base stations and customer sites is described. The system includes
indoor units within the base stations and customer sites and
communicate across cables to outdoor units. The indoor units link
to routers, switches and other devices and services. The outdoor
units transmit and receive wireless data and send it to the indoor
units. The indoor units control the timing of detector measurements
in the outdoor unit by transmitting a regular, repeating control
message at a predetermined time. Once the outdoor unit receives the
control message, it samples its detectors and reports measurements
back to the indoor unit.
Inventors: |
Stanwood; Kenneth L. (Vista,
CA), Kabelly; Moti (Hod Hasharon, IL), Behar;
Jacques (San Diego, CA), Keren; Yossi (Caesara,
IL), Pollmann; Stephen C. (Santee, CA), Gazelle;
David (Kfar Netter, IL) |
Assignee: |
Harington Valve, LLC (Los
Altos, CA)
|
Family
ID: |
32177015 |
Appl.
No.: |
11/429,637 |
Filed: |
May 4, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
09721416 |
Nov 22, 2000 |
06731946 |
May 4, 2004 |
|
|
Current U.S.
Class: |
455/517;
455/554.1; 455/3.01; 370/338; 455/452.1; 455/554.2; 370/280;
455/67.11; 375/222; 370/328; 455/426.2 |
Current CPC
Class: |
H04W
84/14 (20130101) |
Current International
Class: |
H04W
88/00 (20060101); H04W 4/00 (20060101); H04M
1/00 (20060101) |
Field of
Search: |
;455/3.01-3.06,423,424,561,562.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Ulm, et al., ,"Data-Over-Cable Interface Specifications, Radio
Frequency Interface Specification", Hewlett Packard Interim
Specification, Doc. Control No. SP-RF1101-970321, published Mar.
21, 1997 by MCNS Holdings, L.P., Section 6, pp. 43-85. cited by
other .
Wolf, et al., "On the Weight Distribution of Linear Block Codes
Formed From Convolutional Codes", IEEE, IEEE Transactions on
Communications, vol. 44:9, Sep. 1996. cited by other .
"Asynchronous Transfer Mode (ATM) Technical Overview", 2nd Edition,
Prentice Hall, Oct. 1995, Chapter 3, pp. 21-25. cited by other
.
Lin, et al., "Error Control Coding, Fundamentals and Applications",
Prentice-Hall Computer Applications in Electrical Engineering
Series, 1993, pp. 315-349. cited by other .
L.H. Charles Lee, "Convolutional Coding, Fundamentals and
Applications", Artech House, Inc., 1997, pp. 11-51. cited by other
.
Redl, et al., "An Introduction to GSM", Artech House, Inc., 1995;
pp. 84, 85 and 95. cited by other .
C.E. Shannon, ,"A Mathematical Theory of Communication", Bell
System Technical Journal, pp. 379-423 (Part 1), 623-656 (Part II),
Jul. 1948. cited by other .
Notice of Allowance mailed Dec. 24, 2003, for U.S. Appl. No.
09/721,416. cited by other.
|
Primary Examiner: Sobutka; Philip J
Attorney, Agent or Firm: Schwabe, Williamson & Wyatt,
P.C.
Claims
What is claimed is:
1. A wireless communication system having a plurality of base
stations and customer sites, wherein data is transferred between
.[.said.]. .Iadd.the .Iaddend.base stations and .[.said.].
.Iadd.the .Iaddend.customer sites, and wherein .[.said.]. .Iadd.the
.Iaddend.system .[.comprises.]. .Iadd.uses .Iaddend.preset downlink
time segments for transmitting .[.said.]. .Iadd.the .Iaddend.data
between the base stations and the customer sites, .Iadd.the system
.Iaddend.comprising: an indoor unit comprising a first modem
configured to modulate/demodulate data transmitted between the base
stations and the customer sites, wherein the indoor unit is adapted
to transmit a control message at a predetermined time with respect
to .[.said.]. .Iadd.one of the .Iaddend.preset downlink time
segments; an outdoor unit comprising a micro controller and a
signal detector, .[.said.]. .Iadd.the .Iaddend.outdoor unit being
adapted to receive the control message and, in response to
receiving .[.said.]. .Iadd.the .Iaddend.control message, read
.[.said.]. .Iadd.the .Iaddend.signal detector .Iadd.during the one
of the preset downlink time segments.Iaddend.; and a broadband
cable linking the indoor unit to the outdoor unit.
2. The system of claim 1, wherein the outdoor unit comprises a
buffer that stores .[.said.]. .Iadd.the .Iaddend.control message as
it is being transmitted from .[.said.]. .Iadd.the .Iaddend.indoor
unit.
3. The system of claim 2, wherein .[.said.]. .Iadd.the
.Iaddend.micro controller polls .[.said.]. .Iadd.the
.Iaddend.buffer to determine when a first byte of the control
message has been received.
4. The system of claim 3, wherein the micro controller is
configured to instruct the signal detector to take a signal
measurement in response to a determination that the buffer has
received the first byte of the control message.
5. The system of claim 1, wherein the .Iadd.one of the
.Iaddend.preset downlink time .[.segment.]. .Iadd.segments
.Iaddend.is within a time division duplex (TDD) frame.
6. The system of claim 5, wherein the .Iadd.one of the
.Iaddend.preset downlink time .[.segment.]. .Iadd.segments
.Iaddend.comprises at least 16 microseconds of time.
7. The system of claim 5, wherein the TDD frame comprises a
transition gap time adjacent .[.said.]. .Iadd.to the one of
.Iaddend.preset downlink time .[.segment.].
.Iadd.segments.Iaddend..
8. The system of claim 7, wherein .[.said.]. .Iadd.the
.Iaddend.transition gap time is approximately 6 microseconds.
9. The system of claim 1, wherein .[.said.]. .Iadd.the
.Iaddend.outdoor unit is configured to transmit a response message
to the indoor unit.
10. The system of claim 9, wherein .[.said.]. .Iadd.the
.Iaddend.response message comprises a value derived from reading
.[.said.]. .Iadd.the .Iaddend.signal detector.
11. A wireless communication system having a plurality of base
stations and customer sites, wherein data is transferred between
.[.said.]. .Iadd.the .Iaddend.base stations and .[.said.].
.Iadd.the .Iaddend.customer sites, and wherein .[.said.]. .Iadd.the
.Iaddend.system .[.comprises.]. .Iadd.uses .Iaddend.preset downlink
time segments for transmitting .[.said.]. .Iadd.the .Iaddend.data
between the base stations and the customer sites, .Iadd.the system
.Iaddend.comprising: an indoor unit comprising a first modem
configured to modulate/demodulate data transmitted between the base
stations and the customer sites, .[.said.]. .Iadd.the
.Iaddend.indoor unit further comprising a programmable memory
adapted to transmit a control message at a predetermined time with
respect to .[.said.]. .Iadd.one of .Iaddend.preset downlink time
segments; an outdoor unit comprising a micro controller and a
signal detector, .[.said.]. .Iadd.the .Iaddend.outdoor unit being
adapted to receive the control message and, in response to
receiving .[.said.]. .Iadd.the .Iaddend.control message, read
.[.said.]. .Iadd.the .Iaddend.signal detector .Iadd.during the one
of the preset downlink time segments.Iaddend.; and a broadband
cable linking the indoor unit to the outdoor unit.
12. The system of claim 11, wherein the outdoor unit comprises a
buffer that stores .[.said.]. .Iadd.the .Iaddend.control message as
it is being transmitted from .[.said.]. .Iadd.the .Iaddend.indoor
unit.
13. The system of claim 12, wherein .[.said.]. .Iadd.the
.Iaddend.micro controller polls .[.said.]. .Iadd.the
.Iaddend.buffer to determine when a first byte of the control
message has been received.
14. The system of claim 13, wherein the micro controller is
configured to instruct the signal detector to take a signal
measurement in response to a determination that the buffer has
received the first byte of the control message.
15. The system of claim 11, wherein the .Iadd.one of the
.Iaddend.preset downlink time .[.segment.]. .Iadd.segments
.Iaddend.is within a time division duplex (TDD) frame.
16. The system of claim 11, wherein the programmable memory is a
field programmable gate array (FPGA).
17. The system of claim 11, wherein .[.said.]. .Iadd.the
.Iaddend.outdoor unit is configured to transmit a response message
to the indoor unit.
18. A method for measuring .[.the.]. .Iadd.a .Iaddend.strength of a
signal transmitted from a base station to a customer site in a
wireless communication system, wherein .[.said.]. .Iadd.the
.Iaddend.wireless communication system .[.has.]. .Iadd.uses
.Iaddend.preset downlink time segments for transmitting data from
the base station to the customer site, and wherein .[.said.].
.Iadd.the .Iaddend.customer site comprises an indoor unit and an
outdoor unit, .[.said.]. .Iadd.the .Iaddend.method comprising:
transmitting a message from .[.said.]. .Iadd.the .Iaddend.indoor
unit to .[.said.]. .Iadd.the .Iaddend.outdoor unit, wherein
.[.said.]. .Iadd.the .Iaddend.message is timed to arrive at
.[.said.]. .Iadd.the .Iaddend.outdoor unit at a predetermined time
relative to .[.said.]. .Iadd.one of the .Iaddend.preset downlink
time .[.segment.]. .Iadd.segments.Iaddend.; and reading a detector
in .[.said.]. .Iadd.the .Iaddend.outdoor unit in response to
receipt of .[.said.]. .Iadd.the .Iaddend.message so that .[.said.].
.Iadd.the .Iaddend.detector is read during .[.said.]. .Iadd.the one
of the .Iaddend.preset downlink time .[.segment.].
.Iadd.segments.Iaddend..
19. The method of claim 18, wherein .[.said.]. .Iadd.the
.Iaddend.predetermined time is a time just prior to the .Iadd.one
of the .Iaddend.preset downlink time .[.segment.].
.Iadd.segments.Iaddend..
20. The method of claim 18, wherein reading .[.said.]. .Iadd.the
.Iaddend.detector comprises resetting .[.said.]. .Iadd.the
.Iaddend.detector, measuring .[.said.]. .Iadd.the .Iaddend.detector
for a predetermined time, and thereafter taking a power reading of
.[.said.]. .Iadd.the .Iaddend.detector.
21. The method of claim 18, wherein .[.said.]. .Iadd.the
.Iaddend.message is transmitted as a frequency shift key modulated
message.
22. The method of claim 18, wherein transmitting .[.said.].
.Iadd.the .Iaddend.message comprises transmitting .[.said.].
.Iadd.the .Iaddend.message to a buffer in .[.said.]. .Iadd.the
.Iaddend.outdoor unit.
23. The method of claim 18, comprising transmitting a response
message comprising values read from .[.said.]. .Iadd.the
.Iaddend.detector from .[.said.]. .Iadd.the .Iaddend.outdoor unit
to .[.said.]. .Iadd.the .Iaddend.indoor unit.
24. A method for tuning a wireless communication system, wherein
.[.said.]. .Iadd.the .Iaddend.wireless communication system
.[.has.]. .Iadd.uses .Iaddend.preset downlink time segments for
transmitting data from a base station to a customer site, and
wherein .[.said.]. .Iadd.the .Iaddend.customer site comprises an
indoor unit having a processor and an outdoor unit having tunable
attenuators, .[.said.]. .Iadd.the .Iaddend.method comprising:
transmitting a control message from .[.said.]. .Iadd.the
.Iaddend.indoor unit to .[.said.]. .Iadd.the .Iaddend.outdoor unit,
wherein .[.said.]. .Iadd.the .Iaddend.message is timed to arrive at
.[.said.]. .Iadd.the .Iaddend.outdoor unit at a predetermined time
relative to .[.said.]. .Iadd.one of the .Iaddend.preset downlink
time .[.segment.]. .Iadd.segments.Iaddend.; reading a detector in
.[.said.]. .Iadd.the .Iaddend.outdoor unit in response to receipt
of .[.said.]. .Iadd.the .Iaddend.message so that .[.said.].
.Iadd.the .Iaddend.detector will be read during .[.said
predetermined.]. .Iadd.the one of the preset .Iaddend.downlink time
.[.segment.]. .Iadd.segments.Iaddend.; transmitting a response
message comprising values from .[.said.]. .Iadd.the
.Iaddend.detector to .[.said.]. .Iadd.the .Iaddend.indoor unit;
determining the appropriate settings .[.said.]. .Iadd.for the
.Iaddend.attenuators in said outdoor unit; transmitting a second
control message comprising updated attenuator settings to
.[.said.]. .Iadd.the .Iaddend.outdoor unit; and tuning .[.said.].
.Iadd.the .Iaddend.outdoor unit based on .[.said.]. .Iadd.the
.Iaddend.updated attenuator settings.
25. The method of claim 18, wherein .[.said.]. .Iadd.the
.Iaddend.predetermined time is a time just prior to the .Iadd.one
of the .Iaddend.preset downlink time .[.segment.].
.Iadd.segments.Iaddend..
26. The method of claim 18, wherein reading .[.said.]. .Iadd.the
.Iaddend.detector comprises resetting .[.said.]. .Iadd.the
.Iaddend.detector, measuring .[.said.]. .Iadd.the .Iaddend.detector
for a predetermined time, and thereafter taking a power reading of
.[.said.]. .Iadd.the .Iaddend.detector.
27. The method of claim 18, wherein .[.said.]. .Iadd.the
.Iaddend.message is transmitted as a frequency shift key modulated
message.
28. The method of claim 18, wherein transmitting .[.said.].
.Iadd.the .Iaddend.message comprises transmitting .[.said.].
.Iadd.the .Iaddend.message to a buffer in .[.said.]. .Iadd.the
.Iaddend.outdoor unit.
.Iadd.29. A communication node, comprising: a first modem
configured to modulate and demodulate signals to be transmitted to
and from a base station via an outdoor unit; and a second modem
configured to transmit a control message to the outdoor unit at a
predetermined time prior to a preset downlink time segment, the
control message instructing the outdoor unit to read a signal
detector during the preset downlink time segment..Iaddend.
.Iadd.30. The communication node of claim 29, further comprising
the outdoor unit, and wherein the outdoor unit comprises a buffer
adapted to store at least a portion of the control message as it is
being transmitted from an indoor unit linked to the outdoor
unit..Iaddend.
.Iadd.31. The communication of node of claim 30, wherein the
outdoor unit is further adapted to poll the buffer to detect
receipt of a first byte of the control message..Iaddend.
.Iadd.32. The communication node of claim 31, wherein the outdoor
unit is further adapted to instruct the signal detector to take a
signal measurement in response to detection of receipt of the first
byte in the buffer..Iaddend.
.Iadd.33. The communication node of claim 29, wherein the preset
downlink time segment is within a time division duplex (TDD)
frame..Iaddend.
.Iadd.34. The communication node of claim 33, wherein a duration of
the preset downlink time segment comprises at least 16 microseconds
of time..Iaddend.
.Iadd.35. The communication node of claim 33, wherein the TDD frame
comprises a transition gap time adjacent to the preset downlink
time segment..Iaddend.
.Iadd.36. The communication node of claim 35, wherein the
transition gap time is approximately 6 microseconds..Iaddend.
.Iadd.37. The communication node of claim 30, wherein the outdoor
unit is adapted to transmit a response message to an indoor unit
linked to the outdoor unit..Iaddend.
.Iadd.38. The communication node of claim 37, wherein the response
message comprises a value derived from the signal
detector..Iaddend.
.Iadd.39. A wireless communication system, comprising: an indoor
unit comprising a modem configured to modulate and demodulate
signals transmitted between the wireless system and a remote
wireless device, wherein the indoor unit is configured to transmit
a control message at a predetermined time with respect to a preset
downlink time segment; and an outdoor unit comprising a signal
detector, the outdoor unit being configured to read the signal
detector during the present downlink time segment in response to
receipt of the control message..Iaddend.
.Iadd.40. The system of claim 39, further comprising a video server
configured to provide a video service to the remote wireless
device..Iaddend.
.Iadd.41. The system of claim 39, further comprising at least one
ATM switch configured to provide at least one ATM service to the
remote wireless device..Iaddend.
.Iadd.42. The system of claim 41, wherein the ATM switch is
configured to provide at least one service to the remote wireless
device, the at least one service selected from a group of services
consisting of a video service, a voice service and a data
service..Iaddend.
.Iadd.43. The system of claim 39, further comprising a sectored
active antenna array..Iaddend.
.Iadd.44. The system of claim 39 wherein the predetermined time to
transmit the control message by the indoor unit is before the
preset downlink time segment such that the outdoor unit receives a
bit of the control message at a start of the preset downlink time
segment..Iaddend.
.Iadd.45. A method to operate a communication node, the method
comprising: modulating and demodulating, by a first modem, signals
to be transmitted to and from a base station via an outdoor unit;
and transmitting, by a second modem, a control message to the
outdoor unit at a predetermined time prior to a preset downlink
time segment, the control message instructing the outdoor unit to
read a signal detector during the preset downlink time
segment..Iaddend.
.Iadd.46. The method of claim 45 wherein said transmitting the
control message includes: transmitting, at the predetermined time,
the control message by an indoor unit linked to the outdoor
unit..Iaddend.
.Iadd.47. The method of claim 46 wherein the predetermined time to
transmit the control message by the indoor unit is before the
preset downlink time segment such that the outdoor unit receives a
bit of the control message at a start of the preset downlink time
segment..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to wireless communication systems, and more
particularly to a wireless communication system that provides
telephone, data and Internet connectivity to a plurality of
users.
2. Description of Related Art
Several systems are currently in place for connecting computer
users to one another and to the Internet. For example, many
companies such as Cisco Systems, provide data routers that route
data from personal computers and computer networks to the Internet
along conventional twisted pair wires and fiber optic lines. These
same systems are also used to connect separate offices together in
a wide area data network.
However, these systems suffer significant disadvantages because of
the time and expense required to lay high capacity communications
cables between each office. This process is time consuming and
expensive. What is needed in the art is a high capacity system that
provides data links between offices, but does not require expensive
communication cables to be installed.
Many types of current wireless communication systems facilitate
two-way communication between a plurality of subscriber radio
stations or subscriber units (either fixed or portable) and a fixed
network infrastructure. Exemplary systems include mobile cellular
telephone systems, personal communication systems (PCS), and
cordless telephones. The objective of these wireless communication
systems is to provide communication channels on demand between the
subscriber units and the base station in order to connect the
subscriber unit user with the fixed network infrastructure (usually
a wired-line system). Several types of systems currently exist for
wirelessly transferring data between two sites.
In wireless systems using multiple access schemes, frames of time
are the basic transmission unit. Each frame is divided into a
plurality of slots of time. Some time slots are used for control
purposes and some time slots are used for information transfer.
Information is typically transmitted during time slots in the frame
where the time slots are assigned to a specific subscriber unit.
Subscriber units typically communicate with the base station using
a "duplexing" scheme which allows for the exchange of information
in both directions of connection.
Transmissions from the base station to the subscriber unit are
commonly referred to as "downlink" transmissions. Transmissions
from the subscriber unit to the base station are commonly referred
to as "uplink" transmissions. Depending upon the design criteria of
a given system, the prior art wireless communication systems have
typically used either time division duplexing (TDD) or frequency
division duplexing (FDD) methods to facilitate the exchange of
information between the base station and the subscriber units. Both
the TDD and FDD duplexing schemes are well known in the art.
In TDD systems, duplexing of transmissions between a base station
and its subscriber units is performed in the time domain. A
selected subscriber unit typically communicates with a selected
base station using a specific pre-defined radio frequency. The
channel is time-divided into repetitive time periods or time
"slots" which are employed for uplink and downlink transmissions.
In contrast to FDD systems, frequency allocation or frequency reuse
patterns are simplified because there is no requirement of
frequency separation between the uplink and downlink
transmissions.
Both the uplink and downlink transmissions occur during different
pre-determined time slots using the identical radio frequency. In
some current wireless communication systems, there are base
stations that act as central points for receiving and transmitting
data to a plurality of customer sites. These base stations
typically connect to other data systems such as the Internet, the
phone system or other systems that provide user data to the
customer's sites. As can be imagined, it is important to maintain a
strong signal between the base station and the customer sites.
Thus, in conventional systems, power detectors within the base
station and customer sites continually monitor wireless
transmissions in order to tune the system to receive the strongest
possible signal.
Unfortunately, prior customer sites relied on complicated control
signals to measure transmission power levels. These control signals
were implemented because in TDD systems the transmit and receive
paths use the same frequency. Thus, it was possible that when the
customer site equipment took a power measurement, it was actually
measuring a transmission signal from a nearby customer site that
was transmitting on the same frequency. The addition of the control
signals ensured that power measurements were taken from the base
station, and not a nearby customer site.
Moreover, in some prior systems, the customer site equipment was
separated into indoor units and outdoor units. The indoor units
typically included the modem and electronics for connected with the
customer's equipment. The outdoor unit was installed on the
exterior of the building and included the antenna for receiving and
transmitting wireless user data. However, in these systems, the
outdoor unit did not independently know when the base station was
transmitting.
Some prior systems attempted to solve this problem by including a
gating signal between the indoor unit and the outdoor unit. The
gating signal could be used to instruct the outdoor unit to sample
its receive detectors at a particular time, thus ensuring that the
receive detectors would measure signals from the base station.
Unfortunately, adding this signal to the transmission cable between
the outdoor unit and the indoor unit requires costly hardware
changes. In addition, transmitting the extra gating signal across
the transmission cable increases spurs and other undesirable
effects in the data transmission pathway.
This problem is compounded by the fact that the outdoor unit does
not contain a modem. A modem could serve as a conduit for the
outdoor unit to receive additional commands. Thus, the outdoor
unit, by itself, cannot determine the proper time to sample the
receive detectors.
Thus, what is needed in the art is a convenient system at the
customer site for accurately measuring the power of transmission
signals from the base station. Such a system is described
below.
SUMMARY OF THE INVENTION
One embodiment of the invention is a wireless communication system
having a plurality of base stations and customer sites, wherein
data is transferred between said base stations and said customer
sites, and wherein said system comprises preset downlink time
segments for transmitting said data between the base stations and
the customer sites. This embodiment includes: an indoor unit
comprising a first modem configured to modulate/demodulate data
transmitted between the base stations and the customer sites,
wherein the indoor unit is adapted to transmit a control message at
a predetermined time with respect to said preset downlink time
segments; an outdoor unit comprising a micro controller and a
signal detector, said outdoor unit being adapted to receive the
control message and, in response to receiving said control message,
read said signal detector; and a broadband cable linking the indoor
unit to the outdoor unit.
Another embodiment of the invention is a wireless communication
system having a plurality of base stations and customer sites,
wherein data is transferred between said base stations and said
customer sites, and wherein said system comprises preset downlink
time segments for transmitting said data between the base stations
and the customer sites. This embodiment includes: an indoor unit
comprising a first modem configured to modulate/demodulate data
transmitted between the base stations and the customer sites, said
indoor unit further comprising a programmable memory adapted to
transmit a control message at a predetermined time with respect to
said preset downlink time segments; an outdoor unit comprising a
micro controller and a signal detector, said outdoor unit being
adapted to receive the control message and, in response to
receiving said control message, read said signal detector; and a
broadband cable linking the indoor unit to the outdoor unit.
Yet another embodiment of the invention is a method for measuring
the strength of a signal transmitted from a base station to a
customer site in a wireless communication system, wherein said
wireless communication system has preset downlink time segments for
transmitting data from the base station to the customer site, and
wherein said customer site comprises an indoor unit and an outdoor
unit. This method provides: transmitting a message from said indoor
unit to said outdoor unit, wherein said message is timed to arrive
at said outdoor unit at a predetermined time relative to said
preset downlink time segment; and reading a detector in said
outdoor unit in response to receipt of said message so that said
detector is read during said preset downlink time segment.
Still another embodiment of the invention is a method for tuning a
wireless communication system, wherein said wireless communication
system has preset downlink time segments for transmitting data from
a base station to a customer site, and wherein said customer site
comprises an indoor unit having a processor and an outdoor unit
having tunable attenuators. This method includes: transmitting a
control message from said indoor unit to said outdoor unit, wherein
said message is timed to arrive at said outdoor unit at a
predetermined time relative to said preset downlink time segment;
reading a detector in said outdoor unit in response to receipt of
said message so that said detector will be read during said
predetermined downlink time segment; transmitting a response
message comprising values from said detector to said indoor unit;
determining the appropriate settings said attenuators in said
outdoor unit; transmitting a second control message comprising
updated attenuator settings to said outdoor unit; and tuning said
outdoor unit based on said updated attenuator settings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an exemplary broadband wireless
communication system for use with the present invention.
FIG. 2 is a block diagram of cell site used in the wireless
communication system of FIG. 1.
FIG. 3 is a block diagram of an embodiment of an Indoor Unit module
from the cell site illustrated in FIG. 2.
FIG. 4 is a block diagram of an embodiment of an Outdoor Unit
module from the cell site illustrated in FIG. 2.
FIG. 5 is a block diagram of an embodiment of the micro controller
circuitry within the Outdoor unit.
FIG. 6 is a state diagram of one embodiment of the initialization
process within an Outdoor unit.
FIG. 7 is a flow diagram of one embodiment of a preliminary
checkout process undertaken in the Outdoor unit.
FIG. 8 is a flow diagram of one embodiment of a handshaking process
between the Indoor unit and the Outdoor unit.
FIG. 9 is a flow diagram of one embodiment of a timing measurement
of a detector process undertaken in the Outdoor unit.
FIG. 10 is a flow diagram of one embodiment of a loopback process
undertaken in the Outdoor unit.
FIG. 11 is a block diagram of a commercial customer site that
includes customer premises equipment.
FIG. 12 is a block diagram of a residential customer site that
includes customer premises equipment.
FIG. 13 is a block diagram illustrating one embodiment of
communications between base stations and consumer premises
equipment in wireless systems.
FIG. 14 is a block diagram of a time frame for transmitting
wireless user data between a base station and consumer premises
equipment.
FIG. 15 is a flow diagram illustrating one embodiment of a process
utilized by an indoor unit to transmit a message to an outdoor
unit
FIG. 16 is a flow diagram illustrating one embodiment of a process
utilized by an outdoor unit to take detector readings during a
downlink from a base station.
FIG. 17 is a block diagram of an alternate embodiment time frame
for transmitting wireless user data between a base station and
consumer premises equipment.
Like reference numbers and designations in the various drawings
indicate like elements.
DETAILED DESCRIPTION OF THE INVENTION
Throughout this description, the preferred embodiment and examples
shown should be considered as exemplars, rather than as limitations
on the present invention.
A. Overview of the Wireless Communication System
As described above, embodiments of the present invention relate to
a broadband wireless communication system. The system is
particularly useful for linking a plurality of customers and
businesses together to share data or access the Internet. In
general, the system provides base stations that are centrally
located from a plurality of customer sites. The base stations are
linked to services desired by customers, such as Internet access,
satellite access, telephone access and the like. Within the base
stations are communication devices, such as routers, switches and
systems for communications with the desired services. In addition,
each base station includes one or more antennas for connecting
wirelessly with one or more customer sites.
A customer desiring, for example, access to the Internet will
install a set of Customer Premises Equipment (CPE) that includes an
antenna and other hardware, as described in detail below, for
providing a high speed wireless connection to one or more base
stations. Through the high-speed wireless connection, the customer
is provided with access to the Internet or to other desired
services. As discussed below, the data transmitted wirelessly
between a base station and a customer site is termed herein "user
data". Of course, at each customer site, a plurality of
simultaneous computers can be provided with wireless access to the
base station through the use of hubs, bridges and routers.
In one embodiment, the base station comprises a plurality of indoor
units that provide an interface between the routers, switches and
other base station equipment and a plurality of outdoor units (ODU)
that transmit/receive data to/from the customer sites. Each indoor
unit typically includes, or communicates with, a modem for
modulating/demodulating user data going to/from the outdoor
unit.
In one embodiment, each of the indoor units is connected to only
one outdoor unit and each IDU/ODU pair transmits and receives user
data with a unique frequency. This format provides a base station
with, for example, 10, 20, 30 or more IDU/ODU pairs that each
communicate with customer sites using unique frequencies. This
provides the base station with a means for communicating with many
customer sites, yet dividing the bandwidth load between several
frequencies. Of course, a base station that serves a small
community of customer sites might only have a single IDU/ODU
pair.
Each ODU at the base station is normally located outside of the
physical building and includes an integrated broadband antenna for
transmitting/receiving wireless user data packets to/from the
customer sites. Of course, the antenna does not need to be
integrated with the ODU, and in one embodiment is located external
to the ODU.
The ODU and the IDU communicate with one another through a
broadband cable connection, such as provided by an RG-6 cable. In
one embodiment the ODU and IDU communicate across about 10 to 100
feet of cable. In another embodiment, the ODU and IDU communicate
across about 100 to 500 feet of cable. In yet another embodiment,
the ODU and the IDU communicate across about 500 to 1000 feet of
cable.
In one embodiment, the IDU controls functions within the ODU by
sending control messages in addition to the user data stream. The
IDU passes messages to the ODU in order for the IDU to control
certain aspects of the ODU's performance. For example, the IDU may
determine that the system needs to be tuned in order to maximize
the signal strength of the user data being received. The IDU will
send a control message in the form of a frequency shift key (FSK)
modulated signal, as described below, to the ODU along the
broadband cable. The control message preferably includes the
identity of a variable voltage attenuator (VVA) or other type of
attenuator in the ODU and a new setting for the designated VVA. An
onboard micro controller in the ODU reads and interprets the
control message coming from the IDU and sends the proper signals to
the designated VVA.
Once the ODU has adjusted the designated VVA, the micro controller
in the ODU sends a response in the form of a response message back
along the broadband cable to the IDU. The response message
preferably includes a confirmation of the new VVA setting, or other
data to confirm that the requested control message has been
fulfilled. The following discussion provides a detailed listing and
the structure of exemplary control messages and response messages
that can be transmitted between the IDU and the ODU.
The ODU in a CPE preferably samples its transmit detectors only
during a transmission to the base station i.e. during an uplink.
Fortunately, the ODU knows when it is transmitting user data, so it
can accurately sample transmit detectors during an ODU
transmission.
In addition to sampling its transmit detectors, the ODU needs to
sample its receive detectors to tune the ODU to optimally receive
the signal from the base station.
Of course, the ODU should only sample the receive detectors during
a transmission from the base station i.e. during a downlink.
Unfortunately, in a TDD system there are transmissions at the same
frequency from other customer premises ODUs directed to the base
station. Because both the uplink transmissions and the downlink
transmissions are on the same frequency in a TDD system, the
customer premises ODU cannot continuously monitor downlink signals
because the ODU might receive a transmission from a nearby CPE that
is at a higher signal strength than the ODU receives from the base
station. If this happened, the ODU might improperly intercept the
transmission from a nearby CPE and proceed to sample its receive
detectors at a time other than during transmission from the base
station.
As described in detail below, embodiments of the invention include
communication systems that only sample receive detectors in the ODU
during times that are known to be during a downlink from the base
station to the CPE. These embodiments send regular control messages
from the IDU to the ODU that request detector values that are
measured at a guaranteed downlink transmission time within the TDD
frame. By only sampling the receive detectors during this
guaranteed downlink transmission time, the ODU in the customer
premises equipment is ensured of reading the base station
transmission and not a transmission from a nearby CPE outdoor unit.
It should be realized that the base stations and the customer sites
each have indoor units and outdoor units that function similarly to
provide a communication link between the external antenna and the
electronic systems in the interior of the buildings. Of course, in
one embodiment within the customer sites, the indoor units are
connected through routers, bridges, Asynchronous Transfer Mode
(ATM) switches and the like to the customer's computer systems,
which can also include telecommunication systems. In contrast,
within the base stations the indoor units are connected to the
routers, switches and systems that provide access to the services
desired by the customers.
Referring now to FIG. 1, a wireless communication system 100
comprises a plurality of cells 102. Each cell 102 contains an
associated cell site 104 which primarily includes a base station
106 having at least one base station indoor unit (not shown). The
base station receives and transmits wireless user data through a
set of base station outdoor units 107. A communication link
transfers control signals and user data between the base station
indoor unit (IDU) and the base station outdoor unit (ODU). The
communication protocols between the base station IDU and base
station ODU will be discussed more thoroughly in the following
sections.
Each cell 102 within the wireless communication system 100 provides
wireless connectivity between the cell's base station 106 and a
plurality of customer premises equipment (CPE) located at fixed
customer sites 112 throughout the coverage area of the cell 102.
The customer premises equipment normally includes at least one
indoor unit (not shown) and one customer ODU 110. Users of the
system 100 can be both residential and business customers. Each
cell can service approximately 1,000 residential subscribers and
approximately 300 business subscribers. As will be discussed below,
each customer ODU 110 is positioned to receive and transmit user
data from and to one of the base station ODUs 107. As discussed
above, the customer IDU (not shown) is located within the site 112
and provides a link between the customer's computer systems to the
ODU.
As shown in FIG. 1, the cell sites 104 communicate with a
communications hub 114 using a communication link or "back haul"
116. The back haul 116 preferably comprises either a fiber-optic
cable, a microwave link or other dedicated high throughput
connection. In one embodiment the communications hub 114 provides a
data router 118 to interface the wireless communications network
with the Internet. In addition, a telephone company switch 120
preferably connects with the communications hub 114 to provide
access to the public telephone network. This provides wireless
telephone access to the public telephone network by the customers.
Also, the communications hub 114 preferably provides network
management systems 121 and software that control, monitor and
manage the communication system 100.
The wireless communication of user data between the base station
ODUs 107 and customer ODU 110 within a cell 102 is advantageously
bidirectional in nature. Information flows in both directions
between the base station ODUs 107 and the plurality of Customer ODU
110. Each of the base station ODUs 107 preferably broadcast single
simultaneous high bit-rate channels. Each channel comprises
different multiplexed information streams. The information in a
stream includes address information which enables a selected
Customer ODU 110 to distinguish and extract the information
intended for it.
.[.The wireless communication system 100 of FIG. 1 also provides
true "bandwidth-on-demand" to the plurality of Customer ODU 110.
Thus, the quality of the services available to customers using the
system 100 is variable and selectable. The amount of bandwidth
dedicated for a given service is determined by the information rate
required by that service. For example, a video conferencing service
requires a great deal of bandwidth with a well controlled delivery
latency. In contrast, certain types of data services are often idle
(which then require zero bandwidth) and are relatively insensitive
to delay variations when active. One mechanism for providing an
adaptive bandwidth in a wireless communication system is described
in U.S. Pat. No. 6,016,211 issued on Jan. 18, 2000, the disclosure
of which is hereby incorporated by reference in its
entirety..].
.Iadd.The wireless communication system 100 of FIG. 1 also provides
true "bandwidth-on-demand" to the plurality of Customer ODU 110.
Thus, the quality of the services available to customers using the
system 100 is variable and selectable. The amount of bandwidth
dedicated for a given service is determined by the information rate
required by that service. For example, a video conferencing service
requires a great deal of bandwidth with a well controlled delivery
latency. In contrast, certain types of data services are often idle
(which then require zero bandwidth) and are relatively insensitive
to delay variations when active. One mechanism for providing an
adaptive bandwidth in a wireless communication system is described
in U.S. Pat. No. 6,016,311 issued on Jan. 18, 2000, the disclosure
of which is hereby incorporated by reference in its
entirety..Iaddend.
1. Cell Site
FIG. 2 illustrates a block diagram of the cell site 104 of FIG. 1
used in the wireless communication system 100. As described above,
the cell site 104 comprises the base station 106 linked to a
plurality of base station ODUs 107. As shown in FIG. 2, the base
station also includes a series of base station indoor units 123,
made up of individual base station indoor units such as indoor unit
122. Each of the indoor units 123 is linked through a broadband
cable to an individual ODU. For example, the indoor unit 122 is
linked through a broadband cable 129 to an ODU 108. The indoor unit
122 sends control messages and user data to the ODU 108 through the
cable 129. The indoor unit 122 also receives response messages and
user data from the base station outdoor unit 108. The indoor units
123 are provided with an interface to a back-haul, for example the
back-haul interface equipment 124.
The base station can also alternatively include a video server 128
and direct broadcast satellite (DBS) receiver equipment 130. The
back-haul interface equipment 124 allows the base station to
bi-directionally communicate with the hub 114 (FIG. 1).
The base station 106 is preferably modular in design. The modular
design of the base station 106 allows the installation of lower
capacity systems that can be upgraded in the field as capacity
needs dictate. The IDU 122 in conjunction with the ODU 108 performs
both the media access protocol layer and the
modulation/de-modulation functions that facilitate high-speed
communication over the wireless link. The IDU 122 preferably is
connected via the broadband cable 129 to the base station outdoor
unit 108 which is preferably mounted on a tower or a pole proximate
the base station 106. The base station outdoor unit 108 contains
high-frequency radio electronics (not shown) and antenna elements
for transmitting user data to the customer sites.
2. Indoor Unit
Referring to FIG. 3, a more detailed block diagram of the indoor
unit 122 is provided. As illustrated, the indoor unit 122 links the
base station equipment 124, 126, 128, and 130 to the base station
outdoor unit 108. The IDU 122 is preferably under the control of a
communications processor 132. One processor is the Motorola MPC8260
Power-QUICC II (PQII). As illustrated, the communications processor
132 connects through a PowerPC bus 134 to a modem 135.
The modem 135 includes a Field Programmable Gate Array (FPGA) 136
that stores instructions for controlling other subcomponents of the
IDU 122. For example, the FPGA 136 communicates with a Frequency
Shift Key (FSK) modem 138 in order to send FSK modulated control
messages from the EDU through the broadband cable 129, to the
outdoor unit 108. A low band pass filter 139 is provided between
the cable 129 and the FSK modem 138. In an alternate embodiment, an
Application Specific Integrated Circuit (ASIC) replaces the FPGA in
order to provide similar functions.
As is discussed in detail below, the IDU and ODU communicate with
one another using messages. The IDU sends control messages to the
ODU, and the ODU responds with response messages. This
communication allows the IDU to request data from ODU detectors,
and then send commands instructing the ODU to reset subcomponents
in order to be more efficient.
Thus, control messages are FSK modulated and sent from the IDU to
the ODU. Similarly, response messages from the ODU to the IDU are
demodulated by the FSK modem 138 and then interpreted by
instructions with the FPGA 136. These control messages and response
messages, and their data structure and format, are discussed in
detail below. In one embodiment, the transmission baud rate of the
FSK modem 138 is 115 kbps with one start bit, one stop bit and one
parity bit. Of course, other data transfer speeds and formats are
contemplated to be within the scope of the invention. Moreover, the
FSK modem 138 preferably transmits and receives in frequencies
between 6-8 MHz.
Messages between the IDU and ODU are preferably transmitted
independently of the other signals being passed along the cable
129. In one embodiment, the ODU acts like a slave in that it does
not originate messages, but only responds to control messages it
receives from the IDU.
As illustrated, power is provided to the ODU through a DC power
supply 140 that provides, in one embodiment, 48V DC to the ODU. A
20 MHz reference signal 142 is also transmitted across the cable
129 in order to keep components in the IDU and ODU synchronized
with one another.
The communications processor 132 is also linked to an Input/Output
port 150 that attaches to the routers, switches and systems within
the base station. The communications processor 132 receives packet
data from the Input/Output port 150 and transmits it to a modem 153
for modulation demodulation. The modulated data signal is then
placed on a 140 MHz main signal 154 for high throughput
transmission to the ODU 108. It should be realized that the data
transmission along the 140 MHz main signal can occur simultaneously
with the control message and response message data that is
Frequency Shift Key modulated across the cable 129.
In order for the IDU and ODU to effectively and rapidly switch
between receiving and transmitting data modes, a 40 MHz switching
signal 158 is also linked to the communications processor 132 and
carried on the cable 129. The 40 MHz switching signal 158 is used
within the system to switch the ODU and IDU from transmit to
receive mode, as will be discussed below with reference to FIG.
4.
In one embodiment, if the 40 MHz signal is present, the ODU and IDU
enter transmit mode to send user data from the base station ODU to
customer ODUs. However, if the 40 MHz signal is not present, the
ODU and IDU enter receive mode wherein user data being transmitted
from other ODU's is received by the base station ODU. The timing of
the switching signal is controlled by instructions residing in the
FPGA 136. For example, in a half-duplex Time Division Duplex
architecture, the switching signal 158 is preferably set to switch
between receive and transmit modes. However, in a full duplex
architecture where user data is constantly being received, the
switching signal 158 can be programmed to switch between a transmit
mode and a null mode.
3. Outdoor Unit
Still referring to FIG. 3, a more detailed block diagram of the
outdoor unit 122 is provided. As illustrated, the outdoor unit 122
receives control messages and user data from the IDU across the
cable 129. Depending on the state of the 40 MHz switching signal
142, a set of switches 160a, b in the ODU are either in transmit or
receive mode. In transmit mode, user data and control messages are
sent from the IDU to the ODU. In receive mode, user data and
response messages are sent from the ODU to the IDU. As illustrated,
and discussed with reference to FIG. 5, a microcontroller 400 is
linked to the components within the ODU in order to manage data
flow.
The microcontroller 400 communicates with a multiplexer 170 that
separates the signals carried on the cable 129. Within the
microcontroller 400 is a programmable memory 161 that stores
instructions for gathering the response data and forming response
messages for transmission to the IDU. In addition, the instructions
within the memory 161 read incoming control messages from the IDU
and send control signals to sub-components of the ODU. A FSK modem
165 is connected to the multiplexer 170 and microcontroller 400 for
modulating/demodulating messages to/from the IDU. As shown a
Universal Asynchronous Receiver/Transmitter (UART) 166 is connected
to the modem 165 and receives modulated serial data from the
multiplexer 170.
a. Transmit Mode
If the ODU is in transmit mode, the modulated user data being sent
from the IDU along the 140 MHz main signal is first routed through
the multiplexer 170 to the switch 160a. If the switch is set to
transmit mode, the main signal is sent to an IF UP CONVERSION block
200 that converts the 140 MHz signal to an approximately 2.56 GHz
(S band) signal. As illustrated, the IF UP CONVERSION block 200
first provides a variable voltage attenuator (VVA) 210 that is used
to compensate for frequency fluctuations from transmission along
the cable 129. The signal then passes to a detector 212 that
measures power levels after compensation at the cable input.
Although the following discussion relates to a system that
transmits user data within the millimeter band at frequencies of
approximately 28 GHz, the system is not so limited. Embodiments of
the system are designed to transmit user data at frequencies, for
example, of 10 GHz to 66 GHz.
The user data signal is then up-converted to an S band signal at an
IF UP CONVERSION block 216 through an associated local oscillator
block 219. The local oscillator block 219 preferably includes an S
band frequency generator 220. In one embodiment, the frequency
generator 220 includes a National Semiconductor LMX 2301 or Analog
Devices ADF41117. The signal is then sent through a second VVA 234
that is used for power adjustment at the S band frequency.
Once the signal has-been up-converted to the S band frequency, it
is sent to an RF UP CONVERSION block 250. The RF UP CONVERSION
block 250 links to a millimeter wave band frequency generator 255
within the local oscillator block 219 for up-converting the 2.56
GHz signal to an approximately 28 GHz signal. The up-converted
signal is then passed through a VVA 264 to provide for millimeter
wave band power adjustment. Once the signal has been adjusted by
the VVA 264 it is sent to a Power Amplifier 268 and then to an
output power detector 269. The signal is then finally passed
through the switch 160b and out an antenna 270.
b. Receive Mode
If the ODU is in receive mode, user data is received along a 28 GHz
signal (LMDS band) and passed through the antenna 270 and into an
RF DOWN CONVERSION BLOCK 272. Within the RF DOWN CONVERSION BLOCK
272 is a Low Noise Amplifier (LNA) 275 which boosts the received 28
GHz signal. The signal is then sent to a VVA 280 for power
adjustment at the millimeter wave band after the LNA 275. The
received 28 GHz signal is then sent to a RF down converter 285 for
down conversion to a 2.56 GHz (S band) signal. The RF down
converter 285 communicates with the Local Oscillator block 219 to
reduce the incoming signal to the S band range.
After the received signal has been down converted to 2.56 GHz, it
is transmitted to an IF DOWN CONVERSION block 290. Within the IF
DOWN CONVERSION BLOCK 290 is a VVA 292 for adjusting the power at
the S band prior to down conversion. Following adjustment by the
VVA 292, the received signal is passed to a detector 294 for
measuring power leakage from the transmission path during signal
transmission. The signal is then passed to an IF down converter 298
which uses the local oscillator block 219 to down convert the S
band signal to a 140 MHz signal for transmission across the cable
129.
After being converted to a 140 MHz signal, the received user data
is passed through another VVA 300 for power adjustment at the low
frequency band and then a detector 304 to measuring power levels
before transmission across the cable 129 (4 dBm at the cable
output).
c. Message Traffic Between the ODU and IDU
It should be realized that the control messages sent by the IDU to
the ODU can control components of the ODU. For example, in one
embodiment, the controlled components in the ODU are the VVAs and
frequency synthesizers. Response messages from the ODU to the IDU
are also generated to include data from the detectors, temperature
sensor and other components described above. As can be imagined,
control messages are sent by the IDU and then interpreted by the
microcontroller in the ODU. After interpreting the message, the
microcontroller sends the appropriate adjustment signals to
components of the ODU.
Referring to FIG. 5, a hardware schematic of circuitry within the
ODU is illustrated. As shown, the ODU is controlled by the micro
controller 400 that manages data flow within the ODU. In one
embodiment, the micro controller is a Motorola MC68HC908GP20
high-performance 8-bit micro controller. Control messages from the
IDU are sent across the cable 129 to the micro controller 400 in
the ODU and then forwarded to the appropriate ODU component. In
addition data signals generated by the ODU components, such as
detectors, are sent from the component to the micro controller 400.
The micro controller 400 builds a response message that is then
transmitted via FSK modulation to the IDU.
As shown in FIG. 5, messages are sent from the IDU along the cable
129 through a 12 Mhz low pass filter 404 to a FSK receiver 408 in
the ODU. In one embodiment, the FSK receiver is a Motorola MC13055
FSK receiver. The receiver 408 accepts the FSK modulated data from
the IDU and inputs it into the micro controller 400. As also
indicated, the micro controller 400 outputs response messages to
the IDU through a voltage controller oscillator 410.
The micro controller 400 is also in communication with the local
oscillator block 219. In addition a digital to analog (D/A)
converter 415 communicates with the micro controller 400 in order
to control the VVAs within the ODU. In one embodiment, the D/A
converter is an Analog Devices model AD8803 D/A converter.
The micro controller 400 also provides an input from a temperature
sensor in order to provide for temperature compensation of the ODU
measurements. In one embodiment, the temperature sensor is a
National Semiconductor LM50 temperature sensor.
As discussed previously, the IDU transmits FSK modulated control
messages to the ODU to control particular components. The structure
and format of the control messages sent by the IDU and the response
messages returned by the ODU are discussed in detail below.
B. Message Format
In one embodiment, the maximum data rate of FSK modulated messages
that can be handled by the Micro Controller is 125 Kbps. However,
in another embodiment, and for compatibility with a conventional
personal computer, FSK data is transmitted at a 115.2 kbps data
rate. Accordingly, the protocol between the Micro Controller 400
and communications processor 124 can be kept as simple as possible
and at the same time flexible for future changes. The message
structure presented in the following section takes into account
this flexible simplicity. In general, the messages passed between
the ODU and the IDU are delivered byte after byte with no delay. In
one embodiment, in the ODU, a time gap of more then 0.5 msec
between bytes will cause the ODU to re-synchronize on the next
preamble.
1. Message Structure
In one data format, each message, starts with a fixed preamble that
is used to identify the beginning of a message. Following the
preamble an identifier is sent. The identifier is unique per
message, i.e., a specific identifier defines completely the
structure of the following message information fields.
The variable information within each message is preferably sent
after the identifier. In addition, a CRC is added at the end of
each message as an integrity check of the message. The Micro
Controller 400 in the ODU receives a control message from the IDU,
controls the required components in the ODU and prepares a response
message. As soon as the IDU finishes sending the control message to
the ODU, it switches from transmit mode to receive mode. The ODU
then begins to transmit FSK modulated response messages to the
IDU.
One embodiment of a data structure of the messages is as
follows:
TABLE-US-00001 Preamble Identifier Information CRC-8
Preamble--the preamble is 1 Byte field and it is always 00.
Identifier--the identifier is 1 Byte field and unique for each
message. Information--the information filed is variable length
according to the message data being sent. The information field is
always padded to be an integer number of bytes. CRC-8--added for
each message for error control. In the IDU, the CRC-8 is
implemented inside the FPGA 130 (FIG. 3). The CRC-8 is implemented
in software in the ODU Micro Controller 400.
In general, the messages are delivered byte after byte with no
delay. When the ODU detects an error, it waits until the next
preamble. No response messages are sent back from the ODU to the
IDU.
2. Message Traffic
In order to keep the protocol simple, only one control message and
one response message are preferably used during normal operation
mode. This "MEGA" control message/response message includes all the
possible basic control/response messages. Additional control
messages are needed for such functions such as software updates and
technical information such as IDU, ODU serial numbers and software
versions. If new control or response messages are needed in the
future, they can be easily implemented by following the data
structure represented above. Table 1 lists preferable
control/response messages and their unique identifiers.
TABLE-US-00002 TABLE 1 Control and Response Messages Message
Direction Identifier Master IDU <=> ODU 0x11 Identify IDU
=> ODU 0x12 Identify IDU <= ODU 0x21 Unexpected Message IDU
<= ODU 0x22 Set Mode IDU <=> ODU 0x33 Test Control IDU
=> ODU 0x34 Download Control IDU => ODU 0x35 Download_Ack
Control IDU <= ODU 0x53 Tune Control IDU <=> ODU 0x66 Mega
Control IDU => ODU 0x96 Mega Response IDU <= ODU 0x69 Mega
VVA IDU => ODU 0x97 Mega Det IDU <= ODU 0x79 Cal Table
Segment IDU => ODU 0x44 Code Segment IDU => ODU 0x55 Segment
Received IDU <= ODU 0x45
In the following tables that describe message data fields, it is
assumed that the messages start with a preamble and identifier, and
end with an 8 bit CRC that is aligned to be in it's own byte.
a. Master Control Message
The Master control message is used in the initialization state for
an IDU to identify itself as a Master IDU. During a master IDU
configuration, the CPE preferably monitors the IDU/ODU link for a
few milliseconds to determine if there is already a master present.
The ODU then responds with the same message.
TABLE-US-00003 TABLE 2 Master Control Message Field Bits
Description IDU Identifier 32 32 bit identifier of the IDU. Used to
distinguish between multiple CPEs in an MDU.
b. Identify Control Message
The Identify control messages has no fields, but is simply the
preamble, identifier (0.times.12), and CRC sent from the IDU to the
ODU.
c. Identity ResDonse Message
The Identity response message is the ODU's response to the Identify
control message from the IDU.
TABLE-US-00004 TABLE 3 Identity Response Message Field Bits
Description ODU.sub.-- 8 0x00 => ODU has not been calibrated
Calibrated 0x01 => ODU has been calibrated MaxTxPow 8
Transmission Power level desired minus 45. Accordingly, values from
0 to 255 represent desired values from 45 to 300. MinRxPow 8
Minimum Receive Power FrequencyBand 8 ODU Frequency Band in GHz 24
=> ODU uses 24 GHz Band 25 => ODU uses 25 GHz Band 28 =>
ODU uses 28 GHz Band 31 => ODU uses 31 GHz Band SW Version 32
ASCII Software version number. Example: SW version 135 `0`, `1`,
`3`, `5` Flags 8 ODU Flags bit 0 (MSB) Reserved bit 1 Reserved bit
2 Reserved bit 3 Reserved bit 4 Reserved bit 5 Reserved bit 6 Tx
MMW detector output is valid 0 No MMW detector 1 MMW detector valid
bit 7 (LSB) AFC Polarity 0 AFC Normal 1 AFC polarity inverted
d. Unexpected Response Message
The Unexpected Response Message is the response to a valid control
message which is not expected in the current mode. For example,
receipt by the ODU of a Mega Control message during initialization,
as could happen after a spontaneous reset of the ODU.
TABLE-US-00005 TABLE 4 Unexpected Response Message Field Bits
Description Current Mode 8 0x00 = Initialization State 0x01 =
Normal Mode 0x02 = Loopback Mode (obsolete) 0x03 = Code Download
Mode (obsolete) 0x04 = Cal Table Download (obsolete) 0x05 = Normal
24 GHz (obsolete) 0x06 = ODU Bootstrap Mode 0x07 = ODU available
for normal operation
e. Set Mode Control Message
The Set Mode control message is used by the IDU to change the state
of the ODU. The ODU responds by repeating the Set Mode message to
the IDU as a response message.
TABLE-US-00006 TABLE 5 Set Mode Control Message Field Bits
Description New Mode 8 0x00 = Initialization State 0x01 = Normal
Mode 0x02 = Loopback Mode 0x05 = Normal 24 GHz (obsolete) 0x06 =
ODU Bootstrap Mode 0x07 = ODU available for normal operation
f. Test Control Message
The Test Control Message is used by the IDU to instruct the ODU to
perform some kind of test operation as described below. The general
form of the message is shown in the table below:
TABLE-US-00007 TABLE 6 Test Control Message Field Bits Description
Operation 8 The particular test being commanded Data Byte 1 8 Data
pertinent to that command if necessary Data Byte 2
i. Test Control Message--FSK Tone Generation
To conduct testing of the ODU it is useful to have the ODU generate
either of the continuous tones corresponding to a 0 or a 1. The
format is shown in the table below:
TABLE-US-00008 TABLE 7 Test Control Message - FSK tone generation
Field Bits Description Operation 8 0x1 => Transmit FSK Tone
FSK_Tone 8 0x0 => transmit the `0` tone 0x1 => transmit the
`1` tone Transmit Time 8 Number of seconds to generate the tone (0
. . . 255)
The FSK tone generation operation causes the ODU to generate either
a continuous `0` tone, or `1` tone for the specified number of
seconds.
While the tone is being generated the ODU will not respond to
control messages since the link is half duplex. When the specified
time has elapsed the ODU will resume listening for control messages
from the IDU.
ii. Test Control Message--Request Break Status (FSK Cut-off
Frequency)
This command determines from the ODU if a "break" character has
been detected on the ODU/IDU message interface. The table below
shows the format of this message.
TABLE-US-00009 TABLE 8 Test Control Message - Request Break Status
Field Bits Description Operation 8 0x2 => Request Break Status
Reserved 8 Reserved 8
In virtually all cases, the ODU responds with a
Test_Command:Break_Status_Report, indicating if it has detected a
"break" character since the last request or not. The message is
used to test the ODU FSK receive modem function. A "break"
character being detected is the result of the ODU detecting a
continuous series of zeros. This can only happen by an external
source injecting a pure low tone into the ODU.
The cut-off frequency of ODU receive circuitry can be determined on
a test stand by injecting different frequency tones onto the
response data interface and repeatedly requesting the ODU detected
a "break" character. Eventually a frequency will be reached where
the ODU does not detect a break--hence the cut-off can be
determined.
iii. Test Control Message--Break Status Report
This message is the response to the Request Break Status and is
shown in the table below:
TABLE-US-00010 TABLE 9 Test Control Message - Break Status Report
Field Bits Description Operation 8 0x3 => Break Status Report
Break_Status 8 0x0 => No break detected since previous request
0x1 => Break detected since previous request Reserved 8
iv. Test Control Message--Tune test
This message contains the response to the Test Control--Tune Test.
It's layout is show below:
TABLE-US-00011 TABLE 10 Test Control Message - Tune test Field Bits
Description Operation 8 Base Frequency in GHz (10-60) 27 =>
works for 28 GHz ODUs Data Byte 16 Frequency offset from base in
100 kHz increments i.e. 1 => <Base Frequency> .0001 GHz
1000 => <Base Frequency> .1000 GHz 10000 => <Base
Frequency+1> .0000 GHz
The Tune test message attempts to tune the ODU to the specified
frequency without regard to the valid frequency range for the ODU,
therefore tuning outside of the normal range is permitted. The step
resolution of the command is 100 kHz. No range checking is
performed so specifying values too far beyond the valid range may
have unpredictable results. The ODU may not be able to tune to the
precise frequency specified, when this occurs it tunes to the
nearest frequency it can.
g. Tune Control Message
The Tune Control instructs the ODU to tune to a given frequency
specified in units of 100 kHz. The ODU responds after performing
the tuning operation by echoing the same Tune Control message back
to the IDU and reporting the frequency to which the ODU is now
tuned. If the specified frequency is outside the valid frequency
range for the ODU, the ODU does not retune. Therefore specifying a
frequency of 0 is a mechanism for querying the ODU as to the
frequency to which it is tuned without changing the frequency.
The frequencies of 1 and 4294967295 (or FFFFFFFF hex) are reserved
as special query-mode frequencies. If the ODU is told to tune to
0.0001 GHz, the ODU will not retune but will respond with the
minimum available frequency. For instance, a 28 GHz ODU would
return the number 272000. If the ODU is told to tune to 429496.7295
GHz, it will not retune but will respond with the maximum available
frequency, or 286500 for a 28 GHz ODU.
TABLE-US-00012 TABLE 11 Tune Control Message Field Bits Description
Frequency 32 The frequency in units of 100 kHz Eg. 28 GHz =>
280,000 28.001 GHz => 280,001
The ODU may not be able to tune to the precise in-band frequency
specified, when this occurs it truncates the value to the nearest
possible frequency and tunes to that frequency instead. 24 GHz ODUs
can be commanded to tune from 24.0000 GHz to 25.5000 GHz. 25 GHz
ODUs can be commanded to tune from 25.0000 GHz to 25.5000 GHz. 28
GHz ODUs can be commanded to tune from 27.2000 GHz to 28.6500 GHz.
31 GHz ODUs can be commanded to tune from 29.8000 GHz to 31.5000
GHz.
h. Mega Control Message
The Mega Control is used by the IDU to instruct the ODU to change
the values of Attenuators or the Frequency.
TABLE-US-00013 TABLE 12 Mega Control Field Bits Description Change
Flags 5 1 bit per field that may change b10000 => Enable/Disable
PA changed b01000 => Rx Power Level changed b00100 => Tx IF1
VVA changed b00010 => Tx Power Level changed OR values to get
combinations of fields changed For Example, b01010 => Rx Power
Level and Tx Power Level both changed. Enable/ 1 1 = use 40 MHz
switching signal Disable PA 0 = disable PA Rx Power Level 10 Per RX
VVA Table in section 1.2 of [1] Tx IF1 VVA 8 0 to -30.5 dB in 0.2
dB steps Tx Power Level 9 0 to -60 dB in 0.2 dB steps LinkAcquired
1 1 => Link is acquired. The ODU reports the value of the RxIF1
the detector 10 used immediately following the start of the frame
(corresponding to the arrival of the second byte of the Mega
Control). The RSL output behaves normally, but with a minimum level
of 0.5 volts 0 => Link is not acquired. The ODU reports the
value of the RxIF1 detector from the time period between any
previous command and the current Mega Control. The RSL output is
always 0 volts. Padding 14 For byte alignment of CRC
i. Mega Response Message
The Mega Response message is the response to the Mega Control
message.
TABLE-US-00014 TABLE 13 Mega Response Message Field Bits
Description Rx IF1 Detector 8 Temperature compensated and converted
to the range -11 to 12 dBm, expressed in 0.2 dBm steps. Rx IF2
Detector or 8 Temperature compensated and converted to Output Power
the range 5 dBm to 22 dBm, expressed in 0.2 Detector dBm steps. Tx
IF1 Detector 8 Temperature compensated and converted to the range
-26 to -4 dBm, expressed in 0.2 dBm steps. Tx IF2 Detector 8
Temperature compensated and converted to the range -5 to -39 dBm,
expressed in 0.2 dBm steps. Temperature 8 -35 to 85.degree. C. Pad
5 For byte alignment of CRC. Can add additional alarms here in the
future. Ref PLL Lock 1 Alarm: 1 = fail Syn Lock 1 Alarm: 1 = fail
2.7 GHz Detect 1 Alarm: 1 = fail
j. Mega VVA Control Message
The Mega VVA Control is used by the IDU to instruct the ODU to
change the values of Attenuators and the Frequency. Unlike the Mega
Control message, it contains the explicit VVA settings.
TABLE-US-00015 TABLE 14 Mega VVA Control Message Field Bits
Description Rx IF1 VVA 8 Explicit value to set Rx IF1 VVA Rx IF2
VVA 8 Explicit value to set Rx IF2 VVA Rx MM VVA 8 Explicit value
to set Rx MM VVA Tx IF1 VVA 8 Explicit value to set Tx IF1 VVA Tx
IF2 VVA 8 Explicit value to set Tx IF2 VVA Tx MM VVA 8 Explicit
value to set Tx MM VVA Padding 10 Change Flags 6 1 bit per field
that may change b100000 => Rx IF1 VVA changed b010000 => Rx
IF2 VVA changed b001000 => Rx MM VVA changed b000100 => Tx
IF1 VVA changed b000010 => Tx IF2 VVA changed b000001 => Tx
MM VVA changed OR values to get combinations of fields changed For
example, b010100 => Rx IF2 VVA and Tx IF1 VVA values have both
changed
k. Mega Det Message
The Mega Det message is the response to the Mega VVA control.
TABLE-US-00016 TABLE 15 Mega Det Message Field Bits Description Rx
IF1 Detector 8 Actual detector value. Rx IF2 Detector 8 Actual
detector value. Tx IF1 Detector 8 Actual detector value. Tx IF2
Detector 8 Actual detector value. Temperature 8 Actual detector
value. Pad 5 For byte alignment of CRC. Ref PLL Lock 1 Alarm: 1 =
fail Syn Lock 1 Alarm: 1 = fail 2.7 GHz Detect 1 Alarm: 1 =
fail
l. Download Control Message
The Download Control message is used by the IDU to instruct the ODU
to perform some kind of test operation. The general form of the
message is shown in the table below:
TABLE-US-00017 TABLE 16 Download Control Message Field Bits
Description Operation 8 The particular test being commanded Data
Bytes 88 Data pertinent to that operation if necessary
i. Download Control Message--Update Block
The ODU maintains a buffer in its internal RAM for accumulating
data to be written to flash memory. This is called the ROW buffer,
and is preferably 64 bytes in size. It is sub-divided into 8
blocks, each of which is 8 bytes. A block is updated using this
Update Block operation. The format of the operation is defined in
the table below:
TABLE-US-00018 TABLE 17 Download Control Message - Update Block
Field Bits Description Operation 8 2 => Update Block
<reserved> 8 0 Offset 8 Offset from the start of the ROW
buffer where the bytes being sent are to be placed, usually: 0, 8,
16, 24, 32, 40, 48, 56 N_Bytes 8 Number of bytes to be copied to
the ROW buffer (0 . . . 8) Data_Bytes 64 Up to 8 bytes of data to
be written sequentially to the ROW buffer
ii. Download Control Message--Write Row
This message initiates an attempt to write the current content of
the ROW buffer in the ODU to flash memory. The format of the
operation is defined in the table below:
TABLE-US-00019 TABLE 18 Download Control Message - Write Row Field
Bits Description Operation 8 3 => Write_Row Flash_Address 16
Address in flash memory where the ROW buffer should be written.
Must be a multiple of 64, and not be within the area reserved for
the Boot_Module. <reserved> 72
iii. Download Control Message--Peek Memory
This message reads up to 4 bytes from the specified address in
memory. The format of the operation is defined in the table
below:
TABLE-US-00020 TABLE 19 Download Control Message - Peek Memory
Field Bits Description Operation 8 4 => Peek Memory Address 16
Address in memory from which the bytes are to be retrieved. N_Bytes
8 Number of bytes (up to 4 to be retrieved). <reserved>
64
iv. Download Control Message--Software Reset
This message instructs the ODU software to reset. Control is
immediately passed through to the address specified in the reset
vector. This mimics behavior at power up. There can be a response
to this message. If successful, the ODU will behave as is it has
just powered on, if not, it will still be in the same state it was
before the reset command had been issued. The format of
Software.sub.13 Reset is defined in the table below:
TABLE-US-00021 TABLE 20 Download Control Message -
Get_Partition_Info Field Bits Description Operation 8 8 =>
Software Reset <reserved> 88
v. Download Control Message--Get Partition Info
This message requests partition information on the specified
partition number. The ODU responds with a download.sub.13
ack:partition_info_report message containing the partition
information requested. The format of get.sub.13 partition_info is
defined in the table below:
TABLE-US-00022 TABLE 21 Download Control Message -
Get_Partition_Info Field Bits Description Operation 8 9 =>
Get_Partition_Info Partition_number 8 The partition number being
requested 0 . . . 255 <reserved> 80
vi. Download Control Message--Request CRC
This message requests the ODU to calculate a 16 bit CRC be
calculated over the specified range. The IDU uses the request to
verify a partition after it has been downloaded. The ODU responds
with a download.sub.13 ack:CRC.sub.13 Report message containing the
calculated CRC. The format of packet is defined in the table
below:
TABLE-US-00023 TABLE 22 Download Control Message - Request_CRC
Field Bits Description Operation 8 12 => Request_CRC Start
Address 16 The address to start the 16-bit CRC calculation Length
16 The number of bytes to run the check <reserved> 56
vii. Download Control Message--Get Row Buffer Address
This message requests the address of the ODU ROW buffer. It is used
by external software manipulating configuration and hardware
parameters to retrieve the values of individual parameters from the
ROW buffer using the Download:Peek.sub.13 Memory command as its
most primitive operation. The ODU responds with a Download_Ack:
Row_Buffer Address packet. The format of Get_Row_Buffer_Address is
defined in the table below:
TABLE-US-00024 TABLE 23 Download Control Message -
Get_Row_Buffer_Address Field Bits Description Operation 8 21 =>
Get_Row_Buffer_Address <reserved> 88
m. Download Ack Control Message
This message contains the response from the ODU to download
commands that generate a response.
i. Download Ack Control Message--Memory Report
This message is the response to a download:peek_memory command. It
returns up to 4 bytes from the specified address in memory. The
format of the operation is defined in the table below:
TABLE-US-00025 TABLE 24 Download_Ack Control Message -
Memory_Report Field Bits Description Operation 8 5 => Memory
Report Address 16 Address in memory where these bytes originate
N_Bytes 8 Number of bytes present Data bytes 32 <reserved>
16
ii. Download Ack Control Message--Partition Info Report
This message is the response to a download_get_partition.sub.13
info command. It returns partition information for the partition
number requested. The format of partition.sub.13 info.sub.13 report
is defined in the table below:
TABLE-US-00026 TABLE 25 Download_Ack Control Message -
Partition_Info_Report Field Bits Description Operation 8 10 =>
Partition_Info_Report Partition_number 8 The partition number being
described 0 . . . 255 Base_Address 16 The starting address of the
partition 0 - 0xffff Type 8 `O` => Operational Software `C`
=> Calibration tables `H` => Hardware parameters `B` =>
Bootstrap module Is_Valid 8 0 => the partition is invalid 16 1
=> the partition is valid Write_Count 16 Number of times this
partition has been written Version_Number 8 A version number
indicating the revision of the partition content 0 . . . 255
iii. Download Ack Control Message--Row Written
This message describes the ODU result of a Download: Write.sub.13
Row processed by the ODU. Normally a write will succeed and the
status below will return 0. If one or more blocks were not updated,
or the ODU was unable to write all the blocks to flash memory
correctly, it will respond with a status of 1, and the "Bit.sub.13
Vector" field will indicate which blocks the ODU has. A `1` in a
bit position indicates the block is present, a `0` indicates its
absence. The remedy to this condition is to resend the missing
blocks, and the attempt the write again. The format is shown
below:
TABLE-US-00027 TABLE 26 Download_Ack Control Message - Row_Written
Field Bits Description Operation 8 11 => Row_Written
Flash_Address 16 the address in flash memory where the write was
attempted. Status 8 0 = row was written successfully to flash
memory 1 = some blocks in the ROW have not been updated,
"Bit_Vector" indicates which blocks are missing 2 = the write to
flash was not successful, the Bit_Vector field indicates which
blocks were not written. This can happen as the write count of the
ODU flash memory approaches its 100 cycle limit. In an operational
system this is indicates that ODU behavior may become erratic. 3 =
=> the flash address is not a legitimate address for the ODU 4 =
flash contents at "flash_address" already contained the ROW buffer
content, no write was performed Bit_Vector 8 If status = 1 or 4,
bit vector contains a 0 in each bit position where a block is
missing. Block offset 0 is the LSB, block offset 56 is the MSB
<reserved> 16
iv. Download Ack Control Message--CRC Report
This message reports a 16 bit CRC calculated by the ODU in response
to a previous Download:Request.sub.13 CRC command. The format of
packet is defined in the table below. The ODU includes the starting
address and the length to identify the CRC being reported.
TABLE-US-00028 TABLE 27 Download_Ack Control Message - CRC_Report
Field Bits Description Operation 8 13 => CRC_Report
Start_Address 16 The address to start the 16-bit CRC calculation
Length 16 The number of bytes to run the check Reported_Value 16
The calculated CRC value <reserved> 16
v. Download Ack Control Message--Block Updated
This message is in response to a previous Download:Update.sub.13
Block. The format of the packet is defined in the table below.
There are no conditions when an update should not be successful.
The only possibility for not receiving a Download.sub.13
Ack:Block_Updated message is that the ODU did not receive the
Download:Update_Block request. The remedy is to re-send the
packet.
TABLE-US-00029 TABLE 28 Download_Ack Control Message -
Block_Updated Field Bits Description Operation 8 14 =>
Block_Updated <reserved> 8 0 Block_Offset 8 Offset from the
start of the ROW buffer where the bytes being sent are to be
placed, may be one of: 0, 8, 16, 24, 32, 40, 48, 56 N_Bytes 8
Number of bytes to be copied to the ROW buffer (0 . . . 7) Status 8
0 = Successfully copied, non-zero an error occurred
<reserved> 32
vi. Download Ack Control Message--Row Buffer Address
This message is the response to the Download:Get_Row_Buffer_Address
command. It provides the absolute address of the Row buffer, which
is where Calibration and Hardware parameters are maintained at
runtime. This enables suitable external software to make temporary
changes to the operating values of these parameters and observer
their effect on the system, without writing them to flash memory
(an operation most often performed when an ODU is being
calibrated). The format of the packet is defined in the table
below:
TABLE-US-00030 TABLE 29 Download_Ack Control Message -
Row_Buffer_Address Field Bits Description Operation 8 22 =>
Row_Buffer_Address Address 16 The Address of the Row buffer
<reserved> 72
3. Error Detection
When the ODU detects an error in the control message, it normally
discards the message. Since all control messages that are sent by
the IDU are responded to by the ODU, the IDU detects the failure to
receive a response message via a timeout.
The IDU, when acting as initiator, sends control messages and then
waits for message responses. If the IDU doesn't receive any
response messages after, for example, two (2) milliseconds, it
resends the control message again. If it doesn't receive any
response messages after sending several control messages in a row,
the IDU takes appropriate corrective action.
4. Control of ODU Components
Table 30 summarizes the components that may be controlled in the
ODU by the IDU, their characteristics and the number of bits
required to set/read their values.
TABLE-US-00031 TABLE 30 ODU Elements Controllable from IDU
Component Description Dynamic Range/Bits VVA for 140 MHz VVA used
to 0 to -30.5 dB. Controlled via Cable Comp compensate for cable
loss 8 bit word. VVA is controlled (210) from the IDU. in 0.5 dB
steps achievable through most of the range of the VVA. Tx IF2 VVA
S-band VVA used to adjust 0 to -30 dB. Controlled via (234)
transmit power of the S 7 bit word in 0.5 dB steps. band frequency.
Used in conjunction with Tx RF VVA (264). Tx RF VVA MM wave band
VVA used 0 to -30 dB. Controlled via (264) to adjust transmit
power. 8 bit word in 0.5 dB steps achievable. Used in conjunc- tion
with Tx IF2 VVA (234). Rx IF1 VVA 140 MHz VVA used to 0 to -32 dB.
Controlled via (300) adjust receive attenuation 8 bit word. Used in
con- prior to transmission along junction with Rx IF2 VVA the
cable. Used for (292) and Rx RF VVA per Automatic Gain Control
(280). (AGC). Rx IF2 VVA S-band VVA used to adjust -1 to -27 dB.
Controlled via (292) receive attenuation. Used 8 bit word. Used in
conjunc- for such purposes as AGC. tion with Rx IF1 VVA (300) and
Rx RF VVA (280). Rx RF VVA MM wave band VVA used 0 to -24 dB.
Controlled via 8 (280) to adjust receive attenua- bit word. Used in
conjunction tion, for such purposes as with Rx IF1 VVA (300) and
AGC. Rx IF2 VVA (292). Syn Freq Synthesizer frequency to be 34
possibilities space 25 MHz (220) used. apart. Syn Ref Starting
point for frequency 0 to 23.75 MHz in 1.25 MHz (308) mapping. This
parameter is steps. dependant upon the Syn Ref Parameter. Enable/
Enables or disables the Enabled means use 40 MHz Disable PA Power
Amplifier, allowing switching signal. Disable (268) transmission to
the ODU means no transmission regard- with out transmission over
less of state of 40 MHz the air. (Disable causes the switching
signal. 40 MHz switching signal to be ignored.) Typically used only
in test modes. May be necessary during cable loss compensation.
Table 31 summarizes the response messages that can be sent from the
ODU to the IDU. The bits used to control/read items are not
necessarily what will appear in the user data making up the
protocol.
TABLE-US-00032 TABLE 31 Response Messages Response Dynamic Data
Description Range/Bits Rx IF1 140 MHz detector located at the
output of Approximately Detector ODU to cable. This detector can be
used -11 to 12 dB. (304) to bring this to 4 dBm. Expressed as 8 bit
word. Rx IF2 S band detector. Can be used to measure Detector Tx
power on the Rx path during trans- (294) or Out- mission. Can also
be used to determine put Power transmitter saturation points.
Optionally Detector (not the absolute output power at the PA in
shown) dBm. Tx IF1 140 MHz detector at cable input to the
Approximately Detector ODU. Used for cable compensation. -4 to -26
dB. (212) Expressed as 8 Tx IF2 S band detector. Can be used to
determine bit word. Detector transmitter saturation points. (230)
Temperature Temperature detector. -35 to 85.degree. C. Ref PLL Lock
detect signal from the 100 MHz High = fail. Lock reference clock.
the synthesizer lock time is 200 msec. Syn Lock Lock detect signal
from the channel High = fail. selection synthesizer. The
synthesizer lock time is 1.5 msec. 2.7 GHz Detects failure of the
2.7 GHz local High = fail. Detect multiplier.
C. Initialization of the System
1. Overview
Referring now to FIG. 6, a software state diagram 500 showing the
possible modes in which the ODU may operate is illustrated. The
initialization process 500 of the Micro Controller in the ODU
includes: Initialization of all I/Os (clock generator, SCI, SPI,
A/D etc.) Reset the local oscillator to inhibit any transmission
before being tuned Determine if the memory partitions for
operational software, calibration tables and configuration
parameters are valid Determine if memory partitions contents are
mutually compatible Establish communications with a master IDU.
On a power-on, or when a watchdog timer expires, the ODU resets and
enters a preliminary checkout phase. This phase is explained more
completely with reference to FIG. 7. Briefly, all peripherals are
reset to a benign state and the ODU places itself in Mode 6 (504).
The ODU then automatically attempts to transition itself to Mode 7
(506). This transition entails performing a CRC test on all memory
partitions in the ODU to verify that the flash memory is correct
and consistent. If it is correct, the initialization procedure in
each partition is invoked. This verifies that the content of the
memory partition is compatible with the content of any other memory
partitions on which it depends. If all memory partitions report
compatibility the boot code transition is successful and the system
moves to Mode 7, otherwise it remains in Mode 6.
If the process 501 moves to Mode 7, a set.sub.13 mode command is
given by the micro controller and the system initiates normal
operation by transitioning the ODU to Mode 0 (512). From
Initialization Mode 6, the only valid transition to Mode 0 is
through Mode 7, which requires all the previous system tests be
successful.
Note that in the State Diagram in FIG. 6, download commands are
valid in both Mode 6 and Mode 7 so on power-up, new software can
always be downloaded to the ODU even if all memory partitions are
invalid.
While in Mode 0, the process 501 can also transition to a loopback
Mode 2 (516) and to a normal operational Mode 1 (520). These other
Modes are discussed more completely in reference to FIGS. 9 and 10
below.
2. Preliminary Checkout (Mode 6)
FIG. 7 illustrates the flow of the first interactions between the
IDU 122 and ODU 108. A preliminary checkout process 600 begins with
the ODU 108 resetting its peripherals, checking its flash memory,
and checking its memory partition compatibility at a state 602.
Once this is complete, the IDU 122 sends a SET.sub.13 MODE (7)
control message that attempts to transition the ODU from the
checkout mode 6 into Mode 7. The ODU responds with a response
message indicating its current mode. A determination of the ODU's
current mode is then made by the IDU 122 at a decision state 610.
If a determination is made that the ODU is still in Mode 6, and did
not transition to Mode 7, the checkout process 600 moves to a state
614 to begin downloading new software to the ODU in an attempt to
help the ODU transition to Mode 7.
However, if a determination was made at the decision state 610 that
the ODU was not still in Mode 6, the IDU then issues a SET.sub.13
MODE (0) control message to move the ODU into its operational mode
(0). The checkout process 600 then terminates at an end state
616.
When the IDU issues the SET.sub.13 MODE (0) command, it learns
several pieces of information from the response message. If there's
no response it indicates thateither the connection to the ODU is
faulty or that the ODU is broken in some way. If there is a
response, then the state returned in the response message indicates
which of the three possible states the ODU is now in. From the
response message the IDU can determine if it must perform some
remedial action on the ODU (see the download procedure described
later), or if it can begin operation.
3. Handshaking Process
After the initialization processes of FIGS. 7 are completed
(identical for Base Station and CPE), a handshake process 800
begins, as shown in FIG. 8. In the handshake process 800, the Micro
Controller in the ODU waits for the first message from the IDU.
Because of the complexity of the software in the IDU (whether CPE
or base station), the ODU normally finishes initialization before
the IDU.
The IDU then issues a SET.sub.13 MODE (1) control message to
transition the ODU into Normal Operational Mode 1. This transition
results in the ODU performing the following functions: Control the
following components: 1. Set Receive (Rx) VVAs attenuation to
minimum. 2. Set Transmit (Tx) VVAs attenuation to maximum. 3. Set
reference frequency (LMX2301) to 100 MHz. 4. Disable the Power
Amplifier
Measure test points.
Once complete, the process 800 then loops continuously, receiving
response messages from the ODU and performing the actions dictated
by the control messages from the IDU. The most typical action in
this process in the ODU is: The ODU receives a MEGA command from
the IDU with instructions to alter the values of the VVAs or
Frequencies in the Frequency synthesizers and: 1. Reads the
temperature (State 804). 2. Adjusts the settings received in the
MEGA control message for temperature, if necessary and applies the
new values (State 808). 3. Calculates and applies the RSL voltage
setting (State 810). 4. Reads detector values and adjusts values
for temperature via the calibration tables (State 812). 5. Reads
the 3 lock/detect indicators. 6. Builds and transmits a mega
response message. 4. Reading Detector Values
As shown in FIG. 9, a process 900 of reading ODU detector values is
illustrated. The process 900 begins when the ODU measures the
output from the RxIF1 detector 304 (FIG. 4) at a precise instant
(state 904) in order to send this value in the Mega Response
Message. Every time the ODU receives the byte immediately following
the preamble byte, it reads the detector 304 at the state 904 and
saves the result. Then it holds the detector in reset for a 10
microseconds at a state 908. The process 900 then de-asserts the
reset signal at a state 914 and waits 10 more microseconds at a
state 920. The process 900 then samples the RxIF1 detector 304
again at a state 926 and saves the result. The VVAs and Power
Amplifier are then set at a state 930 as commanded by the MEGA
control message.
A determination is then made at a decision state 934 whether or not
the LinkAcquired bit was set in the Mega Control message. If the
LinkAcquired bit was set, the ODU reports the measurement taken
immediately after the detector reset at a state 938. However, if
the LinkAcquired bit was zero, the ODU reports the measurement
taken immediately before the detector reset at a state 940.
The process 900 then waits two milliseconds at a state 942 and
proceeds to sample any remaining detectors in the ODU at a state
944. The Mega response message is then sent from the ODU to the
IDU.
5. Loopback Mode
In the loopback mode process 1000 illustrated in FIG. 10, the ODU
108 simply repeats back to the IDU 122 whatever message it has
received. It leaves the loopback mode when it receives the set mode
control message to transition to a different mode. No other work is
performed during loopback mode--no reading of control messages or
setting of control values. The control messages sent to the ODU by
the IDU during loopback mode preferably have a preamble, a CRC, and
at most 14 additional bytes. Other than "set.sub.13 mode" message
data which must follow the format described above, the messages
sent during loopback mode may be composed of any byte pattern.
6. Customer Premises Equipment
Although the previous discussion has focused on IDUs and ODUs that
are installed as part of a base station, these devices are
similarly installed within each customer site for receiving and
transmitting wireless data. As illustrated FIGS. 11 and 12 are
block diagrams of the customer premises equipment (CPE) 110 shown
in FIG. 1. As described above, the subscribers of the wireless
communication system contemplated for use with the present
invention may be either residential or business customers. FIG. 12
is a block diagram of a residential CPE 110. FIG. 11 is a block
diagram of a business CPE 110.
As shown in FIG. 12, the residential CPE 110 preferably includes an
ODU 1140, IDU 1141 and a residential wireless gateway apparatus
1142. The residential gateway 1142 is preferably installed on a
side of the residence 1144. The residential gateway 1142 preferably
includes a network interface unit (NIU) 1146 and a service gateway
unit 1148. The NIU 1146 performs the functions necessary to allow
the residential user to communicate with the wireless communication
system, such as performing low frequency RF communication, modem
and ATM functions.
The NIU 1146 performs the necessary communication interface
functions including airlink and protocol interface functions to
allow the residential user access to the network. The service
gateway unit 1148 allows the residential user to gain access to the
services provided over the communications system.
For example, as shown in FIG. 12, the service gateway unit 1148
preferably includes an MPEG decoder, NTSC video interface,
telephone interface and 10-baseT data interface. The residential
gateway 1142 interfaces to the various service access points within
the residence 1144. The residential gateway 1142 contains the
necessary hardware and software for interfacing to the radio
communications airlink and for driving various services into the
residence 1144. In addition, by interfacing with the telephone
wiring 1147 within the residence 1144, the residential gateway 1142
is capable of providing a variety of telephone services to the
residence 1144.
Similarly, by interfacing with copper or co-axial wiring 1149
within the residence 1144, the residential gateway 1142 is capable
of providing 10-baseT and other data services to equipment 1150
(such as a personal computer depicted in FIG. 12) within the
residence 1144. Finally, the residential gateway 1142 can also
provide broadcast video and data-centric television services to a
plurality of television systems 1152 by interfacing with standard
cable television co-axial cabling 1154 in the residence 1144. The
residential gateway 1142 is designed in a modular fashion to
service multiple data, telephone, and video lines. Thus, a single
residential gateway 1142 is sufficiently flexible to accommodate
the communication needs of any residential customer.
FIG. 11 is a block diagram of the business CPE 110' of FIG. 1. The
business CPE 110' is designed to provision and provide services to
a small business customer site 1112. As shown in FIG. 11, the
business CPE 110' includes an ODU 108' and IDU 122'. The CPE 110'
also includes a business wireless gateway apparatus 142'. The ODU
108' is affixed to a business site building 144' while the business
gateway 142' is installed in a wiring closet within the business
site building 144'.
The communication interfaces of the business gateway 142' are
similar to those of the residential gateway 1142 (FIG. 12).
However, the service interfaces of the business gateway 142' differ
from those of the residential gateway 1142. The business gateway
142' includes interfaces capable of driving voice and data services
typically used by small business customers. These include
integrated services digital network (ISDN), local area network
(LAN), PBX switching and other standard voice and data
services.
As shown in FIG. 11, a "two-box" solution is presently contemplated
for implementing the business gateway 142'. An "off-the-shelf"
multi-service concentrator 1156 can be used to provide the business
user services and to convert the outgoing data into a single
transport stream. The business gateway 142' also includes a
wireless gateway apparatus 1158 which contains the necessary
hardware and software for interfacing to the IDU and for driving
various services into the business site building 144'.
Alternatively, the wireless functionality provided by the business
gateway 142' can be integrated into the multi-service concentrator
1156 in order to reduce costs and provide a more integrated
business gateway solution. Different types of multi-service
concentrators 1156 can be used depending upon the size and needs of
the business customer. Thus, a network provider can deploy a cost
effective solution with sufficient capabilities to meet the
business customer's needs.
Various types of services can be provided to the business customer
using the CPE 110' of FIG. 11. For example, by providing standard
telephone company interfaces to the business customer, the business
CPE 110' gives the customer access to telephone services yet only
consumes airlink resources when the telephone services are active.
Network providers therefore achieve significant improvements in
airlink usage efficiency yet are not required to modify or overhaul
conventional interfaces with the business customer's equipment
(e.g., no changes need to be made to PBX equipment). In addition,
the business gateway 142' can support HSSI router and 10-BaseT data
interfaces to a corporate LAN thereby providing convenient Internet
and wide area network (VVAN) connectivity for the business
customer. The business gateway 142' will also enable a network
provider to provision "frame-relay" data services at the customer's
site. The business gateway 142' can support symmetrical interface
speeds of 10 Mbps and higher.
Finally, the CPE 110' facilitates the transmission of various types
of video services to the business user. The video services
primarily includes distance learning and video conferencing.
However, in addition, the business CPE 110' can include ISDN BRI
interfaces capable of supporting conventional video conferencing
equipment. Using these interfaces, the business users will have the
option of either viewing or hosting distance learning sessions at
the business site building 144'.
D. Measuring Detectors in the ODU
FIG. 13 illustrates a base station 1410 transmitting user data 1440
to an outdoor unit 1422 of customer premises equipment 1420. As
shown, the ODU 1422 is linked to an IDU 1424. The ODU 1422 might
also receive transmissions 1450 from a nearby ODU 1432 of CPE 1430.
As can be imagined, the transmissions 1450 directed towards the
base station 1410 would interfere with power measurements taken by
the CPE 1420 in a TDD system. This is due to the fact that in TDD
systems the CPEs and base stations transmit using the same
frequency.
Due to the proximity of the CPE 1432 to the CPE 1420, the ODU 1422
might receive transmissions from the ODU 1432. This would
especially be possible if the signal strength of the transmission
1450 from ODU 1432 is stronger than the signal strength of the
transmission 1440 from the base station 1410. For this reason, it
is advantageous for the CPE 1420 to only measure power detectors in
the receive pathway during a time when only the base station 1410
is transmitting user data.
The communication system uses the known reception time of the Mega
Control message to address this problem. Each Mega Control message
is timed so that the first byte of the message is received by the
ODU at a time that is set aside in each TDD frame for base station
downlink transmissions. Thus, when the ODU receives the first byte
of the Mega Control message, it can measure the receive path power
detectors and be assured that the only transmissions at that time
are from a base station.
The system is designed such that under normal operation, a Mega
Control Message (see Table 12) is sent along a broadband
transmission cable (not shown) from the IDU 1424 to the ODU 1422
via FSK modulated signals. The Mega Control Message, as described
above, is used by the IDU to control sub-components, such as VVA's,
in the ODU. For this reason, the Mega Control Message is sent
repeatedly, very frequently, and for the duration of the normal
operation. The ODU responds to the Mega Control Message with the
Mega Response Message (see Table 13) that includes settings of the
detectors in the ODU.
FIG. 14 illustrates the timing used by the IDU to send Mega Control
Messages to the ODU. As shown, a TDD time frame 1500 is divided
into a downlink time 1502 and an uplink time 1504. The downlink
time and uplink time include a plurality of time slots for
transmitting or receiving user data from the CPE to the base
station. It should be realized that an adaptive time division
duplex system dynamically adjusts the number of time slots
allocated to uplink and downlink times to provide the most
efficient transfer of user data from the CPEs to the base station.
Accordingly, when the base station has a tremendous amount of user
data to transmit, the number of time slots in the frame 1500
dedicated to downlinking data from the base station to the CPEs
will increase.
As shown in the FIG. 14, at the end of the uplink time 1504 in the
frame 1500 is a transition gap of 6.25 microseconds that provides a
means for the system to change from an uplink mode to a dedicated
downlink time mode. Of course, embodiments of the invention are not
limited to systems that provide such a gap. For example, similar
systems having no transition gap, or transition gaps of varying
times are well within the scope of the invention.
At the front of each frame, and following the previous frame's
transition gap, is a dedicated downlink time. In this embodiment,
the minimum downlink time lasts 16.25 microseconds. Of course, the
invention is not limited to any particular minimum downlink time.
The minimum downlink time is used by the system to allow the base
station to transmits internal command data to each of the CPEs.
This command data, for example, can include the uplink/dowlink
times for the next time frame. As discussed herein, the downlink
time is only required to be long enough for the detectors to make a
measurement from the detectors. Downlink times that are greater or
lesser in duration are thus within the scope of the invention.
Thus, during this time only the base station is communicating with
each CPE. The CPEs do not transmit during the minimum downlink time
since they are receiving their instructions for the next frame.
Because each time frame is of a fixed duration in the TDD system,
and the minimum downlink time occurs at a fixed place (e.g.: at the
end) of the frame in this embodiment, the IDU 1424 in the CPE 1420
knows that power measurements taken by the receive detectors during
the minimum downlink time are guaranteed to only measure
transmissions from the base station 1410.
In one embodiment of the system the micro controller 400 (FIG. 4)
continuously polls the Universal Asynchronous Receiver/Transmitter
(UART) 166 associated with the FSK modem 165 to determine when a
complete byte of data has been received by the ODU. As discussed
previously, under normal operating conditions the only control
message being sent from the IDU to the ODU is the Mega Control
Message. Accordingly, the ODU can be set to begin taking receive
power measurements after the first byte of the message is received
in the UART 166 from the IDU. By knowing the amount of time it
takes the ODU to receive one byte of a message from the IDU, the
IDU can be programmed to always begin transmitting the Mega Control
Message so that the ODU will receive the first byte of the message
at the beginning of each 16.25 microsecond downlink time within
every TDD frame.
In one embodiment, the FSK modem in the IDU transmits data to the
ODU at 115.2 kbps. With this link speed it takes 8.68 microseconds
to transmit a single bit of data from the IDU to the ODU. Assuming
eight data bits, one start bit and one stop bit, one byte of data
can be transmitted from the IDU to the ODU in 86.8 microseconds. If
a parity bit is included, the byte of data is transmitted in
8.68.times.11=95.48 microseconds.
For this reason, if the IDU is programmed to begin sending the Mega
Control Message 86.8 microseconds before the beginning of the 16.25
microsecond downlink time, the first complete byte of the message
will be received at the start of the downlink lime. If the micro
controller 400 in the ODU is polling a UART or other buffer in the
ODU to determine when the first byte of the message has been
received from the IDU, it will be determine that the first byte has
been received in the UART 166 at the start of the minimum downlink
time.
As FIG. 14 illustrates, once the first byte has been received, the
ODU resets the receive detectors. There is then a minimum time
provided to allow the detectors to take a proper reading. In one
embodiment, the minimum time is approximately 10 microseconds,
however other detetctors with other minimum read times are within
the scope of the invention, Note that this entire time is within
the minimum downlink time, and thus is guaranteed to be measuring
transmissions from the base station. Because it only takes 10
microseconds to read the power detectors, there is ample time to
reset and read the detector within the 16.25 microsecond downlink
time shown in this embodiment. After the detectors are read, the
data from them is transmitted to the IDU in a Mega Response
message.
FIG. 15 illustrates one embodiment of a process 1600 for sending
the Mega Control message from the IDU to the ODU to initiate the
process of reading receive detectors in a wireless communication
system. In one embodiment, this process is stored in a memory, such
as the FPGA 136 (FIG. 3). The process 1600 begins at start state
1602 and then moves to a state 1608 wherein the proper start time
for sending a Mega Control message from the IDU to the ODU is
determined. This determination is made to calculate the amount of
time it takes to send one byte of data from the IDU to the ODU.
Once this figure has been determined, the IDU will send the mega
control message so that the last bit of the first byte arrives at
the ODU at the start of the minimum downlink command time. Examples
of these calculations are described above.
Once a determination is made of the proper time to begin sending a
Mega control message, the process 1600 moves to a state 1610
wherein software instructions within the IDU begin to build a Mega
Control message. Once the mega control message has been built, it
is handed to the FPGA 136. The FPGA 136 is aware of the frame
timing and is programmed with an offset time, relative to the start
of the frame, at which time the control message should be sent. The
process 1600 then moves to a decision state 1612 to determine
whether it is the proper time to begin sending the message. If a
determination is made that it is the proper time to begin
transmitting bits of the message from the IDU to the ODU, the
process 1600 moves to a state 1616 wherein the bits comprising the
message are handed to the hardware of the IDU in order to be
transmitted to the ODU.
Once the IDU begins streaming bits from the mega control message to
the ODU, the process 1600 moves to a state 1620 wherein a mega
response message is received from the ODU. As can be appreciated,
the mega response message includes the values that are read from
the detectors in the ODU. After the mega response message has been
received, the process 1600 moves to a state 1622 wherein the
detector measurements stored within the mega response message are
read by instructions stored within the IDU. As can be appreciated,
these detector measurements are then used to determine whether
adjustments need to be made to subcomponents of the ODU in order to
more specifically receive, or transmit, user data with the highest
efficiency. The process 1600 then terminates at an end state
1624.
If a determination had been made at the decision state 1612 that it
was not the proper time to send a mega control message from the IDU
to the ODU, the process 1600 moves to a wait state 1628 before
returning to the decision state 1612. Thus, this loop continues
until the IDU determines it is the proper time to begin
transmitting bits to the ODU.
Referring now to FIG. 16, a process 1700 running within the FLASH
memory 161 of the ODU is exemplified. The process 1700 begins at a
start state 1702 and then moves to a state 1704 wherein the
transmitted bits corresponding to the mega control message start to
be received from the IDU. A determination is then made at a
decision state 1708 whether an entire byte of data has been
received by the ODU. This determination is preferably made by
instructing the microcontroller 400 to continually pole the UART
166 that is buffering the streaming bits from the IDU. Once the
microcontroller poles the buffer and determines that an entire byte
has been received, the microcontroller moves to a state 1710
wherein the received detectors are reset. The process 1700 then
waits 10 microseconds at a state 1714 before taking a reading of
the receive detectors in the ODU at a state 1717.
Once the detector readings have been taken at the state 1717, the
process 1700 moves to a state 1720 wherein the mega response
message is built by instructions within the FLASH memory of ODU.
These instructions then transmit the mega response message to the
IDU at a state 1724. The process 1700 then terminates at an end
state 1730.
Of course it should be realized that embodiments of the invention
are not limited to any particular TDD frame timing or number of
time slots within each frame. For example, while each TDD time
frame might be 1 millisecond in duration, the TDD time frame might
alternatively be 0.5, 2, 5, 7, 10, 12, 15 or more milliseconds of
duration. Moreover, each frame might be divided into any number of
time slots. For example, each frame might be divided into 500 to
10000 time slots.
Moreover, the location and duration of the minimum downlink time is
not limited to the embodiment described in FIG. 14. For example,
the downlink time does not need to be located at the beginning of
each frame. In one alternate embodiment, the minimum downlink time
is located at the end or middle of each frame. The only requirement
being that the minimum downlink time be fixed in relation to each
frame so that the mega control message can be timed so that the
first byte of the message is received by the ODU at the beginning
of the minimum downlink time slot.
E. Other Embodiments
FIG. 17 illustrates an alternate embodiment of a TDD time frame
used to transmit user data and to send Mega Control Messages to the
ODU. As shown, a TDD transmission frame 1800 includes several
uplink time slots Ta, Ta', Ta'' and Ta''' for transmitting user
data from the CPE to the base station. In addition, the
transmission frame 1800 includes several dowlink time slots Tb, Tb'
and Tb'' for transmitting user data from the base station to a
plurality of CPEs. Accordingly, the invention is not limited to TDD
time frames wherein a first set of time slots in the frame are
dedicated to downlinking and a second set of time slots are
dedicated to uplinking user data. Other embodiments of mechanisms
for transmitting user data in a TDD manner, as illustrated in FIG.
17 are also contemplated.
Accordingly, it is to be understood that the invention is not to be
limited by the specific illustrated embodiment, but only by the
scope of the appended claims.
* * * * *