WO2002065715A1 - Communication interface between an indoor unit and an outdoor unit in a wireless communication system - Google Patents

Abstract

A system that provides a wireless broadband connection between base stations and customer sites is described. The system includes indoor units (122) within the base stations (106) and customer sites (112) and communicate across cables to outdoor units (108). The indoor units link to routers, switches and other devices and services. The outdoor units (108) transmit and receive wireless data and sent it to the indoor units (122). The indoor units (122) control the functioning of the outdoor units (108) by transmitting digital messages along the interface cables. The outdoor units (108) report various detector values to the indoor units (122). This allows the indoor units (122) to tune and adjust several functions within the outdoor units (108).

Description

COMMUNICATION INTERFACE BETWEEN AN INDOOR UNIT AND AN OUTDOOR UNIT IN A WIRELESS

COMMUNICATION SYSTEM

BACKGROUND OF THE INVENTION 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. 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 wifeless 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. For example, prior art wireless communication systems have typically used a Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA) or Frequency Division Multiple Access (FDMA) type system to facilitate the exchange of information between two users. These access schemes are well known in the art. As can be imagined, in any of these type of wireless communication systems there are many components that need to be adjusted and tuned so that the system can compensate for frequency shifts and atmospheric disturbances. For example, high or low humidity and temperature, or rain, snow and wind can affect wireless communication systems. Thus, what is needed in the art is a convenient system that detects temperature and/or power levels in the wireless communication transmission and automatically adjusts components within the system to provide for maximum data transmission efficiency.

SUMMARY OF THE INVENTION One embodiment of the invention is a wireless communication system having a plurality of base stations and customer sites. The communication system includes: an indoor unit having a modem for modulating/demodulating data transmitted between the base stations and the customer sites, wherein the indoor unit further includes a frequency shift key modem for transmitting digital control messages; an outdoor unit having tunable sub-components and a transmit path for wirelessly transmitting the data, the outdoor unit being adapted to receive the digital control messages and tune the sub- components based on data in the control messages; and a broadband cable disposed between the indoor unit and the outdoor unit.

Another embodiment of the invention is an outdoor unit for a wireless communication system, wherein the wireless communication system includes a plurality of base stations and customer sites, the outdoor unit providing: a transmit circuit having a first attenuator and a first detector; a receive circuit having a second attenuator and a second detector; a modem for receiving control messages from an indoor unit, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field; and a processor for reading the control messages and tuning sub-components in the outdoor unit in response to the control messages.

Yet another embodiment of the invention is a wireless communication system for transmitting user data from a base station to a customer site. This embodiment provides: an indoor unit having a modem for modulating/demodulating the user data, first instructions for generating control messages; a circuit for generating a switching signal for controlling switching of the wireless communication between transmit mode and receive mode; a power source. This embodiment also includes an outdoor unit having: a transmit circuit having tunable sub-components; second instructions for receiving control messages from the indoor unit, wherein the control messages comprise data for tuning the sub-components of the outdoor unit; and a broadband cable disposed between the indoor unit and the outdoor unit, wherein the cable carries the control messages, the switching signal and power from the power source from the indoor unit to the outdoor unit.

Still another embodiment of the invention is an outdoor unit for a wireless communication system, wherein the communication system has a plurality of base stations and customer sites. This embodiment includes: a modem for receiving control messages from an indoor unit, wherein the control messages comprise a first preamble byte field, a first message identifier byte field, and a first multi-byte message information field; and a processor configured to transmit a response message having a second preamble byte field, a second message identifier byte field, and a second multi-byte message information field to the indoor unit.

One other embodiment of the invention is a method for controlling sub-components of a wireless communication system. This method includes: providing an indoor unit having a modem for modulating/demodulating data transmitted between a base station and a customer site, transmitting a first control message from the indoor unit to an outdoor unit having attenuators and detectors, wherein the detectors are read in response to receipt of the first control message; sending a first response message from the outdoor unit to the indoor unit, wherein the response messages comprises data from the detectors; determining updated settings for the attenuators in the outdoor unit; and transmitting a second control message from the indoor unit to the outdoor unit, wherein the second control message comprises updated values for the attenuators. Still a further embodiment of the invention is a method in an outdoor unit of a wireless communication system for tuning sub-components, wherein the communication system includes a plurality of base stations and customer sites. This method provides: receiving control messages from an indoor unit, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field; reading the digital control messages; and tuning sub-components in the outdoor unit in response to values stored in the control messages. 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 Figure 2.

FIG. 4 is a block diagram of an embodiment of an Outdoor Unit module from the cell site illustrated in Figure 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.

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 preferred 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 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.

Preferably, each of the indoor units is connected to only one outdoor unit and each IDU/DDU pair transmits and receives user data with a unique frequency. This format provides a base station with, for example, 10, 20, 30 or more 1DU/0DU 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.

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 base station outdoor units 108. 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 will preferably 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 the base station ODU 108. 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 ODU 108 and customer ODU 110 within a cell 102 is advantageously bi-directional in nature. Information flows in both directions between the base station ODU 106 and the plurality of Customer ODU 110. The base station ODU 106 preferably broadcasts single simultaneous high bit-rate channels. Each channel preferably 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 preferably 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. Patent 6,016,211 issued on January 18, 2000, the disclosure of which is hereby incorporated by reference in its entirety.

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 preferably comprises the base station 106 and at least one base station ODU 108. As shown in FIG. 2, the base station also preferably includes at least one base station indoor unit 122, back-haul interface equipment 124, an Asynchronous Transfer Mode (ATM) switch 126, a video server control computer 128 and direct broadcast satellite (DBS) receiver equipment 130. The base station can also alternatively include a video server (not shown in FIG. 2). The indoor unit 122 sends control messages and user data to the ODU. The indoor unit 122 also receives response messages and user data from the base station outdoor unit 108. The back-haul interface equipment 124 allows the base station to bi-directionally communicate with the hub 114

(Figure 1). The ATM switch 126 functions at the core of the base station 106 to interconnect the various services and systems at appropriate service and bandwidth levels. 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 a 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 preferably contains high-frequency radio electronics (not shown) and antenna elements for transmitting user data to the customer sites. 2. Indoor Unit

Referring to Figure 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 preferred processor is the Motorola MPC8260

PowerQUICC 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 IDU 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 6-8MHz.

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 20MHz 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 140MHz main signal 154 for high throughput transmission to the ODU 108. It should be realized that the data transmission along the 140MHz 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 40MHz switching signal 158 is also linked to the communications processor 132 and carried on the cable 129. The 40MHz switching signal 158 is used within the system to switch the ODU and IDU between transmit and receive modes, as will be discussed below with reference to Figure 4.

In one embodiment, if the 40MHz 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 40MHz signal is not present, the ODU and IDU enter receive mode wherein user data being transmitted from other ODUs 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

Now referring to Figure 4, 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 40MHz switching signal 142 (shown in Fig. 3), 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 Figure 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. a. Transmit Mode

If the ODU is in transmit mode, the modulated user data being sent from the IDU along the 140MHz 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 140MHz 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 wave 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 28GHz 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 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 28GHz 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 28GHz signal. The signal is then sent to a VVA 280 for power adjustment at the millimeter wave band after the LNA 275. The received 28GHz 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 2.56GHz, 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 140MHz signal for transmission across the cable 129.

After being converted to a 140MHz 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 a preferred 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 Figure 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 Figure 5, messages are sent from the IDU along the cable 129 through a 12Mhz low pass filter 404 to a FSK receiver 408 in the ODU. In one embodiment, the FSK receiver is a Motorola MC 13055 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 a more preferred 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 the preferred 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 (see Figs. 4 and 5) 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.

The preferred data structure of the messages are as follows:

• 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 (Figs. 4 and 5).

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 1: Control and Response Messages

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. 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 2: Master Control Message

b. Identify Control Message

The Identify control messages has no fields, but is simply the preamble, identifier (0x12), and CRC sent from the IDU to the ODU. c. Identity Response Message

The Identity response message is the ODU's response to the Identify control message from the IDU.

Table 3: Identity Response Message

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 4: Unexpected Response Message

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 5: Set Mode Control Message

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 6: Test Control Message

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 7: Test Control Message - FSK tone generation

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 - Reguest Break Status (FSK cutoff 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 8: Test Control Message - Request Break Status

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 9: Test Control Message - Break Status Report

IV. Test Control Message - Tune test

This message contains the response to the Test Control - Tune Test. It's layout is show below:

Table 10: Test Control Message - Tune test

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 100kHz. 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 100kHz. 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 11: Tune Control Message

Field Bits Description

Frequency 32 The frequency in units of 100kHz Eg. 28GHz - > 280,000 28.0001GHz = > 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 12: Mega Control

i. Mega Response Message

The Mega Response message is the response to the Mega Control message.

Table 13: Mega Response Message

I- 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 14: Mega VVA Control Message

. Mega Pet Message

The Mega Det message is the response to the Mega VVA control.

Table 15: Mega Det Message

I. 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 16: Download Control Message

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 17: Download Control Message - Update Block

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 18: Download Control Message - Write Row

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 19: Download Control Message - Peek Memory

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_Reset is defined in the table below:

Table 20: Download Control Message - Get_Partition Info

v. Download Control Message - Get Partition Info

This message requests partition information on the specified partition number. The ODU responds with a download_ack:partition_info_report message containing the partition information requested. The format of get_partitionJnfo is defined in the table below:

Table 21: Download Control Message - Get Partition Info

Field Bits Description

Operation Get Partition Info

Partition number 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_ack:CRC_Report message containing the calculated CRC. The format of packet is defined in the table below:

Table 22: Download Control Message - Request_CRC

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_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 23: Download Control Message - Get_Row Buffer_Address

111. 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 24: Download_Ack Control Message - Memory_Report

ϋ. Download Ack Control Message - Partition Info Report

This message is the response to a download_get_partition_info command. It returns partition information for the partition number requested. The format of partition_info_report is defined in the table below: Table 25: Download Ack Control Message - Partition_lnfo_Report

III. Download Ack Control Message - Row Written

This message describes the ODU result of a Download:Write_ 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_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 26: Download Ack Control Message - Row Written

iv. Dowπload Ack Control Message - CRC Report

This message reports a 16 bit CRC calculated by the ODU in response to a previous Download:Request_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 27: Download_Ack Control Message - CRC_Report

Download Ack Control Message - Block Updated

This message is in response to a previous Download:Update_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_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 28: Download Ack Control Message - Block_Updated

VI. Download Ack Control Message - Ro 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 29: Download_Ack Control Message - Row Buffer Address

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 30: ODU Elements Controllable from IDU

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 31: Response Messages

c. Initialization of the System

1. Overview

Referring now to Figure 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 l/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 Figure 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 setjrade 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 Figure 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 Figure 10 below.

2. Preliminary Checkout (Mode 6)

Figure 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_MODE (7) command 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_M0DE (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_M0DE (0) command, it learns several pieces of information from the response message. If there's no response it indicates that either 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 Figures 7 are completed (identical for Base Station and CPE), a handshake process 800 begins, as shown in Figure 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 SETJvlODE (1) command 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 100MHz.

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 Figure 9, a process 900 of reading ODU detector values is illustrated. The process 900 begins when the ODU measures the output from the RxlFI 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 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 RxlFI 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 Figure 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_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 preferred residential CPE 110. FIG. 11 is a block diagram of a preferred 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 preferred business CPE 110' of FIG. 1. The preferred 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' preferably includes an ODU 108' and IDU 122'. The CPE 110' also includes a business wireless gateway apparatus 142'. The ODU 108' is preferably affixed to a business site building 144' while the business gateway 142' is preferably 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' preferably 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 multiservice 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 (WAN) 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 preferably primarily include 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. Other Embodiments

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.

Claims

WHAT IS CLAIMED IS:

1. A wireless communication system comprising a plurality of base stations and customer sites, comprising: an indoor unit comprising a modem for modulating/demodulating data transmitted between the base stations and the customer sites, wherein the indoor unit further comprises a frequency shift key modem for transmitting digital control messages; an outdoor unit comprising tunable sub-components and a transmit path for wirelessly transmitting said data, said outdoor unit being adapted to receive the digital control messages and tune said sub-components based on data in the control messages; and a broadband cable disposed between the indoor unit and the outdoor unit.

2. The system of Claim 1, wherein the outdoor unit comprises software instructions for receiving the digital control messages and tuning said sub-components of the outdoor unit.

3. The system of Claim 2, wherein the instructions are stored in a memory.

4. The system of Claim 3, wherein the memory is part of a micro controller.

5. The system of Claim 1, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field.

6. The system of Claim 5, wherein the control messages comprise an error checksum byte.

7. The system of Claim 1, wherein the outdoor unit is adapted to transmit a response message to the indoor unit in response to receiving the control message.

8. The system of Claim 7, wherein the digital response message comprises data values from detectors in the outdoor unit.

9. The system of Claim 1, wherein the sub-components comprise variable voltage attenuators or power amplifiers.

10. An outdoor unit for a wireless communication system, wherein the wireless communication system comprises a plurality of base stations and customer sites, the outdoor unit comprising: a transmit circuit comprising a first attenuator and a first detector; a receive circuit comprising a second attenuator and a second detector; a modem for receiving control messages from an indoor unit, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field; and a processor for reading the control messages and tuning sub-components in the outdoor unit in response to the control messages.

11. The system of Claim 10, wherein the instructions are stored in a memory.

12. The system of Claim 11, wherein the memory is part of a micro controller.

13. The system of Claim 10, wherein the control messages comprise an error checksum byte.

14. The system of Claim 10, wherein the outdoor unit is adapted to transmit response message to the indoor unit in response to receiving the control message.

15. The system of Claim 14, wherein the digital response message comprises data values from the first detector or the second detector in the outdoor unit.

16. The system of Claim 10, wherein the sub-components comprise variable voltage attenuators.

17. A wireless communication system for transmitting user data from a base station to a customer site, comprising: an indoor unit comprising: a modem for modulating/demodulating the user data, first instructions for generating control messages; a circuit for generating a switching signal for controlling switching of the wireless communication between transmit mode and receive mode; a power source; an outdoor unit comprising, a transmit circuit comprising tunable sub-components; second instructions for receiving control messages from the indoor unit, wherein the control messages comprise data for tuning said sub-components of the outdoor unit; and a broadband cable disposed between the indoor unit and the outdoor unit, wherein the cable carries the control messages, the switching signal and power from the power source from the indoor unit to the outdoor unit.

18. The system of Claim 17, wherein the second instructions are stored in a memory.

19. The system of Claim 18, wherein the memory is part of a micro controller.

20. The system of Claim 17, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field.

21. The system of Claim 20, wherein the control messages comprise an error checksum byte.

22. The system of Claim 17, wherein the outdoor unit is adapted to transmit a digital response message to the indoor unit in response to receiving the control message.

23. The system of Claim 22, wherein the digital response message comprises data values from detectors in the outdoor unit.

24. The system of Claim 17, wherein the sub-components comprise variable voltage attenuators.

25. An outdoor unit for a wireless communication system, wherein the communication system comprises a plurality of base stations and customer sites, the outdoor unit comprising: a modem for receiving control messages from an indoor unit, wherein the control messages comprise a first preamble byte field, a first message identifier byte field, and a first multi-byte message information field; and a processor configured to transmit a response message comprising a second preamble byte field, a second message identifier byte field, and a second multi-byte message information field to the indoor unit.

26. The system of Claim 25, wherein the instructions are stored in a memory.

27. The system of Claim 26, wherein the memory is part of a micro controller.

28. The system of Claim 25, wherein the modem is a frequency shift key (FSK) modem.

29. The system of Claim 25, wherein the control message is a mega control message comprising values corresponding to settings for a power amplifier or a variable voltage attenuator in the outdoor unit.

30. The system of Claim 25, wherein the response message comprises values corresponding to detector measurements taken from the outdoor unit.

31. A method for controlling subcomponents of a wireless communication system comprising: providing an indoor unit comprising a modem for modulating/demodulating data transmitted between a base station and a customer site, transmitting a first control message from the indoor unit to an outdoor unit comprising attenuators and detectors, wherein the detectors are read in response to receipt of the first control message; sending a first response message from the outdoor unit to the indoor unit, wherein the response messages comprises data from the detectors; determining updated settings for the attenuators in the outdoor unit; and transmitting a second control message from the indoor unit to the outdoor unit, wherein the second control message comprises updated values for the attenuators.

32. The method of Claim 31, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field.

33. The method of Claim 32, wherein the control messages comprise an error checksum byte.

34. The method of Claim 31, wherein the response messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field.

35. The method of Claim 35, wherein the response messages comprise an error checksum byte.

36. The method of Claim 31, wherein the attenuators are variable voltage attenuators.

37. A method in an outdoor unit of a wireless communication system for tuning sub-components, wherein the communication system comprises a plurality of base stations and customer sites, comprising: receiving control messages from an indoor unit, wherein the control messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field; reading the digital control messages; and tuning sub-components in the outdoor unit in response to values stored in the control messages.

38. The method of Claim 37, comprising transmitting response messages to the indoor unit in response to receipt of control messages.

39. The method of Claim 38, wherein the response messages comprise a preamble byte field, a message identifier byte field, and a multi-byte message information field.

40. The method of Claim 38, wherein the response message comprises data values from detectors in the outdoor unit.

41. The method of Claim 39, wherein the response messages comprise an error checksum byte.

42. The method of Claim 37, wherein the control messages comprise an error checksum byte.

43. The method of Claim 37, wherein the sub-components comprise variable voltage attenuators.