System and method for generating signal waveforms in a CDMA cellular telephone system

Description: TECHNICAL FIELD [Detailed description of the invention]

I. Technical field of invention The present invention relates to breakthrough and improved systems and methods for information communication in cellular telephone systems, particularly mobile cellular telephone systems or satellite mobile telephone systems using spread spectrum communication signals. II. Explanation of related technologies The use of code division multiple access (CDMA) modulation technology is one of a variety of technologies that facilitate communications with a large number of system users. Other multi-connection communication system technologies such as time-division multiple access (TDMA), frequency-division multiple access (FDMA), and AM modulation schemes such as amplitude expansion single sideband (ACSSB) are known in the technology. .. However, CDMA spectral spread modulation techniques have significant advantages over these modulation techniques for multiple access communication systems. The use of CDMA technology in multiple access communication systems is described in US Pat. No. 4,901,307, entitled "SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS" filed February 13, 1990. This aforementioned patent, which describes multiple access techniques, allows users of multiple mobile telephone systems, each with a transceiver, to use code-division multiple access (CDMA) spread spectrum communication signals to satellite repeaters or base stations on Earth. Communicate through (cell site station, cell site or cell for short). The frequency spectrum can be reused many times using CDMA communication, thus increasing the capacity of the system user. With CDMA, spectral efficiency is significantly higher than the results obtained using other multiple access technologies. Satellite channels experience fading, which is typically characterized as lysian. Therefore, the received signal consists of a direct component combined with a multiple reflection component having Rayleigh fading statistics. The power ratio between the direct component and the reflected component is determined by the characteristics of the antenna of the mobile unit and the environment of the mobile unit, and is typically about 6 to 10 dB. In contrast to satellite channels, Earth channels experience signal fading, which typically consists of Rayleigh-faded components without direct components. Therefore, the Earth channel exhibits a more severe fading situation than the satellite channel, where rician fading is the main fading characteristic. The Rayleigh fading characteristics of Earth channel signals are caused by signals reflected from many different features of the physical environment. As a result, the signal arrives at the mobile unit receiver from many directions with different transmission delays. Typically, UHF frequency bands that use mobile radio communications, including cellular mobile telephone systems, result in significant phase differences in signals propagating different paths. The possibility of destructive addition of signals arises as a result of deep fades. Earth channel fading is a very strong function of the physical position of a mobile unit. A small change in the position of the mobile unit changes the physical delay of all signal propagation paths, which in turn makes each path out of phase. Therefore, the movement of the mobile unit through the environment results in a fairly rapid fading process. For example, in the cellular radio frequency band of 850 MHz, this fading is typically the same as the mobile speed of one fade per second, mile, and hour. This severe fading is very destructive to the signals of the Earth channel, resulting in poor communication quality. Additional transmit power can be used to overcome fading problems. However, such power effectively increases excessive power consumption by both the user and the system due to increased interference. The CDMA modulation technology described in US Pat. No. 4,901,307 offers many advantages over the narrowband modulation technology used in communication systems using satellite or terrestrial repeaters. Earth channels pose special problems for communication systems, especially with regard to multipath signals. The use of CDMA technology allows the special problems of the Earth channel to be overcome by mitigating the adverse effects of multipathing, for example, fading, while taking advantage of it. In a CDMA cellular telephone system, the same frequency band can be used for communication of all cells. CDMA waveform characteristics that provide processing gain are also used to discriminate signals that occupy the same frequency band. In addition, fast pseudo-noise (PN) modulation allows many different propagation paths to be separated if the path delay difference exceeds the PN chip duration or 1 / bandwidth. When a PN chip speed of about 1 MHz is used in a CDMA system, the full spread spectrum processing gain equal to the ratio of system data speed to spread bandwidth is applied to paths that differ by more than 1 microsecond with path delay from the desired path. Can be used. A path delay difference of 1 microsecond corresponds to a path distance difference of about 1,000 feet. It has been reported that urban situations typically give path delay differences in excess of 1 microsecond, reaching 10 to 20 microseconds in some areas. In narrowband modulation systems such as analog FM modulation used by ordinary telephone systems, the presence of multipath causes significant multipath fading. However, in wideband CDMA modulation, different paths are discriminated by demodulation processing. This discrimination reduces the importance of multipath fading. Multipath fading is not completely eliminated in the use of CDMA discrimination technology, as there are sometimes paths with a delay difference less than the duration of the PN chip for a particular system. Signals with this degree of path delay are not discriminated by the demodulator and cause some fading. Therefore, it is desired to provide some form of diversity that allows the system to reduce fading. Diversity is one way to mitigate the harmful effects of fading. There are three main types of diversity. That is, time diversity, frequency diversity, and spatial diversity. Time diversity can be best obtained by using iteration, time interleaving, error detection, and iteration forms of encoding. The present invention uses each of the three techniques as a form of time diversity. Due to the essential nature of wideband signals, CDMA provides a form of frequency diversity by spreading the signal energy over a wide bandwidth. Therefore frequency-selective fading affects only a small portion of the CDMA signal bandwidth. Spatial or path diversity is obtained by providing multiple signal paths through simultaneous links from mobile users passing through two or more cell sites. In addition, path diversity is obtained by leveraging a multipath environment through spectral diffusion processing by allowing signals arriving with different propagation delays to be received and processed separately. An example of paradiversity is US Patent Application No. 07 / 433,030 filed on November 7, 1989, entitled "SOFT HANDOFF IN A CDMA CELLUAR TELEPHONE SYSTEM" (US Patent No. 5,101,501 issued on March 31, 1992). ), And also DIVERSITY RECEIVER IN A CDMA CELLULAR TELEPHONE It is described in US Patent Application No. 07 / 432,522 (US Pat. No. 5,109,390 issued April 28, 1992), filed November 7, 1989, entitled "SYSTEM". Harmful fading effects can also be controlled to some extent in the CDMA system by controlling the transmitter power. The system for cell site and mobile unit power control is US Patent Application No. 07 / 433,031 (1991), filed November 7, 1989, entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM". It is described in US Pat. No. 5,056,109) issued on October 8). CDMA technologies, such as those described in US Pat. No. 4,901,307, consider the use of coherent modulation and demodulation of bidirectional links in mobile and satellite communications. Therefore, what is described here is to use the pilot carrier signal as a coherent phase reference for the satellite-to-mobile link and the cell-to-mobile link (hereinafter referred to as the "cell-mobile link"). Is. However, in the Earth cell situation, the severity of multipath fading with the resulting phase collapse of the channel uses coherent demodulation technology for mobile-to-cell links (hereinafter referred to as "mobile-cell links"). Prevents you from doing. The present invention provides a means of overcoming the adverse effects of mobile-cell link multipath by using non-coherent modulation and demodulation techniques. The CDMA technology described in US Pat. No. 4,901,307 attempts to use relatively long PN sequences, with different PN sequences assigned to each user's channel. The cross-correlation between different PN sequences and the autocorrelation of PN sequences for any non-zero time shift both have a zero mean value, which allows different user signals to be discriminated in reception. However, such PN signals are not orthogonal. At short time intervals such as information bit time, the cross-correlation has an average of zero, but the cross-correlation has a binomial distribution. In this way, the signals interfere with each other exactly as if they were Gaussian noise with a wide band width at the same power spectral density. Therefore, other user signals or mutual interference noises ultimately limit the achievable capacitance. Wide band PN in the presence of multipath It can provide path diversity for CDMA systems. If two or more paths are available with a value greater than the one microsecond path delay difference, then two or more PN receivers can be used to receive these signals separately. The outputs of the two receivers can be diversity coupled because these signals typically exhibit independence in multipath fading, i.e. they usually do not fade together. Therefore the loss of performance only occurs when both receivers fade at the same time. One aspect of the present invention is to provide two or more PN receivers in combination with a diversity coupler. In order to take advantage of the presence of multipath signals to overcome fading, it is necessary to use waveforms that allow path diversity coupling operations to take place. Therefore, an object of the present invention is to generate orthogonal PN sequences to allow more user capacity by reducing mutual interference and to overcome fading by supporting path diversity. is there. Outline of the invention The realization of spread spectrum communication technology, especially CDMA technology, in the mobile cellular telephone environment provides features that greatly enhance the reliability and capacity of the system over other communication system technologies. The aforementioned CDMA technology makes it possible to easily overcome problems such as fading and interference. Therefore, CDMA technology promotes more frequency reuse and allows for a substantial increase in the number of system users. The present invention presents with new and improved methods and systems for constructing PN sequences that provide orthogonality between users to reduce mutual interference and allow for higher capacitance and better link performance. is there. As long as the code time frames are time aligned with each other, the orthogonal PN code causes the cross-correlation to be zero for a predetermined time interval, resulting in no interference between the orthogonal codes. In an embodiment, the signal is communicated directly between the cell site and the mobile unit using a sequence spectrum spread communication signal. Cell-mobile links define pilot, synchronization, paging, and voice channels. Information communicated on a cell-moving link channel is typically encoded, interleaved, and covered with a quadrature phase shift key (QPSK) spread and a two phase shift key (QPSK) with orthogonal covering of each BPSK symbol. It is modulated by BPSK). Mobile-Cell links define access and voice channels. The information communicated on the mobile-cell link channel is usually an quadrature signal that is encoded, interleaved, and with QPSK spread. The features, objects, and advantages of the present invention are apparent from the detailed description below with reference to the drawings, and the reference numbers in the drawings are shown for the same. A brief description of the drawing FIG. 1 is a schematic diagram of an embodiment of a CDMA cellular telephone system. FIG. 2 is a block diagram of a cell site device provided in a CDMA cellular telephone system. FIG. 3 is a block diagram of the cell site receiver. FIG. 4 is a block diagram of the cell site transmission modulator. FIG. 5 is a timing diagram of an example of synchronization channel symbol synchronization. FIG. 6 is a timing diagram of an embodiment of synchronous channel timing having orthogonal covering. Figure 7 is an example of a comprehensive cell-mobile link timing timing diagram. FIG. 8 is a block diagram of a mobile telephone switching station device. FIG. 9 is a block diagram of a mobile unit telephone device arranged for CDMA communication of a CDMA cellular telephone system. FIG. 10 is a block diagram of the mobile unit receiver. FIG. 11 is a block diagram of the mobile unit transmission modulator. Figure 12 is an example of a mobile-cell link timing diagram with variable data rates for burst transmission. FIG. 13 is an example of a timing diagram of a comprehensive mobile-cell link timing. Description of preferred examples In a CDMA cellular telephone system, each cell site has a plurality of modulator demodulator units or spectral diffusion demodulators. Each modulation / demodulator comprises a digital spread spectrum transmit modulator and at least one digital spread spectrum data receiver and a search receiver. Each cell site modulator / demodulator is assigned to a mobile unit as needed to facilitate communication with the assigned mobile unit. Flexible handoff schemes are used for CDMA cellular telephone systems where old cell site modulators and demodulators continue to service calls, while new cell site modulators and demodulators are assigned to mobile units. When the mobile unit is located in the transition area between the two cell sites, the call can be switched between the cell sites as directed by the signal strength. Since the mobile unit is always communicated through at least one cell site modulator / demodulator, the effect of interruptions on the mobile unit in service is small. The mobile unit therefore uses multiple receivers to facilitate handoff processing, in addition to diversity features that mitigate the effects of fading. In a CDMA cellular telephone system, each cell site carries a "pilot carrier" signal. When a cell is divided into sectors, each sector has a different associated pilot signal within the cell. This pilot signal is used by the mobile unit to obtain initial system synchronization and to track the coarse time, frequency, and phase of the cell site transmit signal. Each cell site also transmits spectral diffusion modulation information such as cell site identification, system timing, mobile paging information, and various other control signals. The pilot signals transmitted by each sector of each cell have the same spread code but different code phase offsets. The phase offset allows the pilot signals to be distinguished from each other and thus the outgoing cell site or sector. By using the same pilot signal code, the mobile unit can find the system timing synchronization with a single search through all pilot signal code phases. The strongest pilot signal, as determined by correlation processing for each code phase, is easily identifiable. The strongest identified pilot signal usually matches the pilot signal transmitted by the nearest cell site. However, the strongest pilot signal is used regardless of whether it was transmitted by the nearest cell site. In supplementing the strongest pilot signal, i.e., in the initial synchronization of the mobile with the strongest pilot signal, the mobile unit searches for another carrier that will be received by all system users in the cell. This carrier, called the sync channel, carries broadcast messages containing system information used by mobiles in the system. The system information is intended to convey information that can be used by the mobile unit to synchronize long PN codes, interleaver frames, vocoders, and other system timing information without additional search. In addition, identify the cell site and system. Another channel, called a paging channel, is also provided to send a message to the mobile indicating that a call to the mobile has arrived and to respond to the channel assignment when the mobile initiates the call. The mobile unit continues to operate the receive pilot carrier signal code of the code offset corresponding to the cell site adjacent sector, i.e. the adjacent transmit pilot signal. This scan is performed to determine if the pilot signal emanating from the adjacent sector or cell is stronger than the pilot signal initially determined to be the strongest. On the other hand, in the inactive mode of this call, when the pilot signal of the adjacent sector or the adjacent cell site becomes stronger than the pilot signal of the first cell site sector, that is, the transmission pilot signal of the cell site, the mobile unit becomes stronger. Captures strong pilot signals and the corresponding synchronization and paging channels of new sectors or cell sites. When a call is initiated, a pseudo-noise (PN) code address is determined for use during the duration of the call. The code address is assigned by the cell site or determined by pre-adjustment based on the mobile unit identifier. After the start of the call, the mobile unit continues to scan the pilot signal of the adjacent sector or cell in addition to the pilot signal transmitted by the cell site and used to establish the communication. Scanning of the pilot signal is continued to determine if one of the adjacent sectors or cell transmission pilot signals is stronger than the pilot signal transmitted by the cell site with which the mobile unit is communicating. When the pilot signal associated with an adjacent cell or cell sector becomes stronger than the pilot signal of the current cell or cell sector, this tells the mobile unit that it must enter a new cell or cell sector and a handoff must be initiated. It shows. The telephone system of the embodiment of the present invention is shown in FIG. The system shown in FIG. 1 uses spectral diffusion modulation technology for communication between the system mobile unit or mobile phone and cell sites. The metropolis cellular system has hundreds of cell site stations that handle hundreds of thousands of mobile phones. The use of spectral diffusion technology, especially CDMA, easily facilitates an increase in user capacity for systems of this size compared to conventional FM modulated cellular systems. In Figure 1, the system controller and switch 10 are also called mobile telephone switching stations (MTSOs) and typically include interfaces and processing circuits that control the system over cell sites. The controller 10 also controls the routing of telephone calls from the public switched telephone network (PSTN) to the appropriate cell site for transmission to the appropriate mobile unit. The controller 10 also controls the routing of calls from the mobile unit to the PSTN via at least one cell site. The control device 10 connects calls between mobile users via appropriate cell sites, as mobile units typically do not communicate directly with each other. The control device 10 is coupled to the cell site by various means such as a dedicated telephone line, an optical fiber link or a microwave communication link. In FIG. 1, two such cell sites 12, 14 are illustrated, respectively, together with mobile units 16, 18 including a cellular telephone device, respectively. It is believed that cell sites 12, 14 as described and illustrated here serve the entire cell. However, it should be understood that cells are geographically divided into sectors, each of which is treated as a different coverage. Thus, while handoffs are made between sectors of the same cell for multiple cells as described herein, diversity is also done between sectors as for cells. In FIG. 1, the lines 20a-20b and 22a-22b of the arrows define possible communication links between the cell site 12 and the mobile units 16 and 18, respectively. Similarly, the lines 24a-24b and 26a-26b of the arrows define possible communication links between the cell site 14 and the mobile units 16 and 18, respectively. Cell sites 12 and 14 transmit using substantially the same power. The cell site service area or cell is geographically designed so that the mobile unit is usually closest to one cell site and the cell is divided into multiple sectors within one cell sector. When the mobile unit is idle, i.e. no call is taking place, the mobile unit sends a pilot signal from each nearby cell site, if applicable, the cell is split into multiple sectors. Always monitor pilot signal transmissions from a single cell site. As shown in FIG. 1, the pilot signal goes out, that is, is transmitted to the mobile unit 16 by the cell sites 12 and 14 at the forward communication links 20a and 26a, respectively. The mobile unit 16 can determine which cell it is in by comparing the signal intensities of the pilot signals transmitted from the cell sites 12 and 14. In the example shown in FIG. 1, the mobile unit 16 is considered to be closest to the cell site 12. When the mobile unit 16 initiates a call, a control message is sent to the nearest cell site, cell site 12. When the cell site 12 receives the call request message, it sends the call number to the system controller 10. System controller 10 connects the call to the designated recipient through the PSTN. When the call is initiated within the PSTN, controller 10 sends the call information to all cell sites in the area. The cell site sends a paging message directed to the called receive mobile user within its coverage. When the specified receive mobile unit hears the page message, it responds with a control message sent to the nearest cell site. This control message signals the system controller that this particular cell site is communicating with the mobile unit. The controller 10 routes the call to the mobile unit through this cell site. When the mobile unit 16 moves out of the coverage of the first cell site, cell site 12, an attempt is made to continue the call by routing the call through another cell site. For cellular telephone systems, the Federal Communications Agency (FCC) has collectively assigned 25MHz for mobile-cell links and 25MHz for cell-mobile links. The FCC is equally assigned between the two service providers, one is the wire line telephone company in the service area and the other is selected by lottery. Due to the order of allocation, the 12.5MHz allocated to each carrier in each direction of the link is further divided into two subbands. For wire carrier waves, the subbands are 10MHz and 2.5MHz wide, respectively. For carrier waves without wires, the subbands are 11MHz and 1.5MHz wide, respectively. Therefore, signal bandwidths smaller than 1.5 MHz can be adapted to any subband, and bandwidths smaller than 2.5 MHz can be adapted to all but one band. To maintain maximum flexibility in assigning CDMA technology to the available cellular frequency spectrum, the waveform used in the cellular telephone system must be less than 1.5 MHz in bandwidth. A suitable second choice is about 2.5 MHz bandwidth, which allows sufficient flexibility for wire-wired cellular carriers and nearly sufficient flexibility for wire-free cellular carriers. Using wider bandwidth has the advantage of providing increased multipath discrimination, but there are also disadvantages in the form of expensive equipment costs and less flexibility in frequency allocation within the allocated bandwidth. To do. In a spectral diffusion cellular telephone system as shown in FIG. 1, the preferred waveform design realized involves a direct sequence pseudo-noise spectral diffusion carrier. The chip speed of the PN sequence is selected to 1.2288 MHz in the preferred embodiment. This particular chip speed is chosen so that the resulting bandwidth of about 1.25 MHz after filtering is about one-tenth of the total bandwidth allocated to a single cellular service carrier. Another consideration for choosing the correct chip speed is that it is preferable that the chip speed be accurately divided by the baseband data rate used in the system. It is also desirable that the divisor is a power of 2. In a preferred embodiment, the baseband data rate is 9600 bits per second, which is a choice of 1.2288 MHz, which is 128 times the PN chip speed of 9600. In cell-mobile links, binary sequences for spectral diffusion are assembled from two different types of sequences, each with different properties that provide different functions. There is an external code shared by all signals in the cell or sector used to discriminate multipath signals. External codes are also used to discriminate signals transmitted to the mobile unit by different cells or sectors. There are also internal codes used to discriminate user signals transmitted by a single sector or cell. The carrier waveform design in the preferred embodiment of the signal transmitted by the cell site uses a sinusoidal carrier that is quadrature (4 phases) modulated by a pair of binary PN sequences, which the binary PN sequence pair is a single sector or Submit the external code sent by the cell. The sequence is generated by two different PN generators of the same sequence length. Two phases in one sequence modulate the in-phase channel (1 channel) of the carrier, and two phases in the other sequence modulate the quadrature phase (Q channel) of the carrier. The resulting signals are summed to form a composite four-phase carrier. The values of logic "zero" and logic "1" are usually used to indicate a binary sequence, but the signal voltage used for modulation is + V volt for logic "1" and -V volt for logic "zero". is there. In order for the two phases to modulate the sinusoidal signal, the sine of the zero volt mean is multiplied by the + V or -V voltage level as controlled by the binary sequence using a multiplication circuit. The resulting signal may be band limited by passing through a band pass filter. It is technically known to pass a binary sequence stream through a lowpass filter before being multiplied by a sinusoidal signal to swap the order of operation. The quadrature phase modulator consists of two two-phase modulators, each driven by a different sequence, and the sine signal used in the two-phase modulator has a phase shift of 90 °. In a preferred embodiment, the sequence length of the transmitted signal carrier is selected for 32768 chips. This length sequence can be generated by adding zero bits to the length 32767 chip sequence with a modified maximum length linear sequence generator. The resulting sequence has good cross-correlation and autocorrelation characteristics. Good cross-correlation and autocorrelation characteristics are needed to prevent cross-correlation between pilot carriers transmitted by different cells. This short sequence is desirable to minimize the capture time of the mobile unit when it first enters the system without knowledge of system timing. Since the timing is unknown, it is necessary to search the entire sequence length to determine the exact timing. The longer the sequence, the longer the time required for the capture search. Although sequences shorter than 32768 can be used, it must be understood that the code processing gain decreases as the sequence length decreases. As the processing gain decreases, the elimination of multipath interference as well as interference from adjacent cells and other sources is reduced to unacceptable levels. Therefore, it is desirable to use the longest sequence captured in a reasonable amount of time. Also, the same in all cells so that when the synchronization is first captured, the mobile unit, which does not know which cell it is in, can get enough synchronization by searching for a single code polynomial. It is also preferable to use a polynomial of code. All cells in the system are synchronized with each other to simplify the synchronization process. In an embodiment, cell synchronization is achieved by synchronizing all cells to a common time standard, the satellite navigation system of the Nabsta Global Positioning System, which is synchronized to Universal Coordinated Time (UTC). Signals from different cells are differentiated by providing a time offset for the basic sequence. Each cell is assigned a different time offset in a basic sequence that is different from the adjacent cells. In a preferred embodiment, the 32768 iteration period is divided into a set of 512 timing offsets. The 512 offsets are 64 chips apart. Each sector of each cell of the cellular system is also assigned to one with a different offset for use in all transmissions. With 512 or more sectors or cells in the system, the offset can be reused in a manner similar to the frequencies used in current analog FM cellular systems. Other designs use different numbers other than 512. Reasonable management of pilot signal offset allocation eliminates the need for adjacent cells to use offsets at adjacent times. All signals transmitted by a cell or one of the cell's sectors share the same external PN code for the I and Q channels. The signal is also spread with an internal orthogonal code generated by using the Walsh function. The signal addressed to a particular user is multiplied by an external PN sequence by one sequence of the particular Walsh sequence or Walsh sequence assigned by the system controller during the duration of the user's telephone call. The same internal code is fed to both the I and Q channels, resulting in effective two-phase modulation for the internal code. For n to the power of 2, n orthogonal binary sequences of each length n are documented by SW Golom et al. (Digital Communication with Space Applications, It is known in technology that it can be designed with reference to Prentice-Hall, 1964, pp. 45-64. In fact, orthogonal binary sequence sets are known for most lengths that are multiples of 4 and less than 200. One set of such sequences that is easy to generate is called the Walsh function and is also known as the Hadamard matrix. The Walsh function of the n ordinal can be iteratively specified as follows.<img file="JP2958433B2_D0001.tif" /> Here, W'indicates the logical complement of W, and W (1) = | 0 |. Therefore,<img file="JP2958433B2_D0002.tif" /><img file="JP2958433B2_D0003.tif" /> W (8) is as follows.<img file="JP2958433B2_D0004.tif" /> The Walsh sequence is one row of the Walsh function matrix. The Walsh function of ordinal n has n sequences, each of which is n bits in length. If the sequences are time-aligned with each other, the Walsh function of ordinal n (like any other orthogonal function) has the property that the cross-correlation between all the different sequences in the set is zero over the time interval of the n-code symbols. Have. This is evident by noting that at exactly half the bits every sequence differs from all other sequences. It should also be noted that there is always one sequence with all zeros and all other sequences have half ones and half zeros. Adjacent cells and sectors have different external PN codes used for adjacent cells and sectors, so the Walsh sequence can be reused. Due to the particular mobile position and the different propagation times of the signal between two or more different cells, it is not possible to satisfy the time alignment conditions required orthogonally to the Walsh function of both cells at once. Therefore, trust must be placed in the external PN code to discriminate between signals arriving at the mobile unit from different cells. However, all signals transmitted by the cell are orthogonal to each other and therefore do not participate in each other's interference. This eliminates most of the interference at most locations and allows higher capacitance to be obtained. The system also assumes an acoustic channel, which is a variable speed channel, and the data speed of this variable speed channel is changed from data block to data block with the minimum overhead required to control the data speed in use. The use of variable data rates reduces mutual interference by eliminating unnecessary transmissions when non-beneficial conversations are transmitted. An algorithm is used within the vocoder to generate a changing number of bits in each vocoder block as the conversational activity changes. During conversational activity, the vocoder produces 20 milliseconds of data blocks containing 20,40,80,160 bits depending on the speaker's language activity. It is desirable to transmit a data block in a certain amount of time due to a change in transmission speed. Furthermore, it is desirable that no signal bits are needed to inform the receiver how many bits are transmitted. The block is further encoded by using an attached periodic redundancy check code (CRCC) to block the applicable parity bit, which determines whether the block of data has been correctly decoded. Can be used for The CRCC check code is generated by dividing a data block with a predetermined binary polynomial. The CRCC has all or part of the remaining bits of the division process. The CRCC is checked at the receiver by regenerating the same residual bit and checking if the received residual bit is similar to the regenerated check bit. In this disclosed invention, the receiving decoder decodes a block as if it contained 160 bits, 80 bits, etc., until all possible block lengths were tested. The CRCC is calculated for each experimental decoding. When one of the test decoding results in an accurate CRCC, the data block is received and transmitted to the vocoder for further processing. If the experimental decoding does not generate a valid CRCC, the received symbol is transmitted to the system's signal processor, where other processing operations are selectively performed. In the cell transmitter, the power of the transmission waveform changes as the data rate of the block changes. The highest data rate uses the highest carrier power. If the data rate is below the maximum, in addition to lowering the power, the modulator repeats the encoding of each data symbol as many times as necessary to achieve the desired transmission rate. For example, at the lowest transmission rate, each encoded symbol is repeated four times. In mobile transmitters, the peak power remains constant, but the transmitter is gated at 1/2, 1/4, or 1/8 of the time, depending on the number of bits transmitted in the data block. The on-time position of the transmitter changes pseudo-randomly according to the user code addressed by the mobile user. Cellul mobile link In a preferred embodiment, the Walsh function size n is set equal to 64 (n = 64) in the cell-mobile link. In addition, up to 64 different signals transmitted are each assigned a specific orthogonal sequence. The forward error correction (FEC) encoded symbol stream for each voice conversation is multiplied by the assigned Walsh sequence. The Walsh-encoded / FEC-encoded symbol stream for each audio channel is multiplied by an external PN code waveform. The resulting diffuse symbol streams are summed together to form a composite waveform. The resulting composite waveform is modulated into a sinusoidal carrier, passed through a passband filter, converted to the desired operating frequency, amplified and radiated by the antenna system. Another embodiment of the present invention exchanges some sequence of cell site transmission signal forming operations just described herein. For example, it is preferable to multiply each audio channel by an external PN code waveform and perform a filter operation prior to adding up all the channel signals radiated by the antenna. It is also known in the art that the sequence of waveform movements can be interchanged to obtain the benefits of different configurations and different designs. The waveform design of the preferred embodiment for cellular services uses the cell-mobile link pilot carrier method as described in US Pat. No. 4,901,307. All cells transmit pilot carriers using the same 32768 length sequence but are offset at different times to prevent mutual interference. The pilot waveform uses the Walsh sequence of all zeros, that is, the Walsh sequence of all zeros found in all Walsh functions. Using an all-zero Walsh sequence for the pilot carrier of all cells allows an initial search for the pilot waveform to disable the Walsh function until after PN synchronization of the external code is obtained. The Walsh frame is fixed to the PN code cycle by the length of Walsh Fleming, which is a factor of the PN sequence length. Therefore, if the cell addressing offset of the PN code is a multiple of 64 chips (or Walsh frame length), Walsh Fleming is absolutely known from the external PN code timing cycle. Accurate synchronization is provided to all cells in the service area. In a preferred embodiment, the GPS receiver in each cell synchronizes the local waveform timing to Universal Coordinated Time (UTC). The GPS system allows for better time synchronization than 1 microsecond accuracy. Accurate cell synchronization is desired because it allows for easy handoff of simple calls between cells as the mover moves from one cell to another while the call is in progress. When adjacent cells are synchronized, the mobile unit does not have difficulty synchronizing to a new cell, thus facilitating a smooth handoff. The pilot carrier is transmitted at a higher power level than a typical voice carrier to provide a higher signal-to-noise ratio and an interference margin for this signal. The high power level pilot carrier allows for very accurate tracking in the carrier phase of the pilot carrier due to the high speed initial capture search and the relatively wide bandwidth phase tracking circuit. The carrier phase obtained from the tracking of the pilot carrier is used as a carrier phase reference for demodulation of the carrier modulated by the user's information signal. This technique allows multiple user carriers to share a common pilot signal with respect to the carrier phase reference. For example, in a system that fuses and transmits 15 simultaneous acoustic carriers, the pilot carrier is assigned transmission power equal to 4 acoustic carriers. In addition to the pilot carrier, another carrier that will be received by all system users is transmitted by the cell site. This carrier, called the synchronous channel, also uses the same 32768 length PN sequence in spectral diffusion but has a different pre-allocated Walsh sequence. Synchronous channels transmit broadcast messages containing system information for use by mobiles in the system. System information discriminates between cell sites and systems and conveys information that allows the long PN code used for mobile information signals to be synchronized without additional search. Another channel, called a paging channel, is provided to send a message to the mobile that the call has reached the mobile and to respond to the channel assignment when the mobile initiates a call. Each voice carrier carries a digital display of the telephone call conversation. Analog conversation waveforms are digitized using standard digital telephone technology and compressed to a data rate of approximately 9600 bits per second using bocode processing. This data signal has a speed r = 1/2, binding length K = 9, is iterative, convolution-encoded, and provides error detection and correction capabilities that enable the system to operate with very low signal-to-noise ratios and interference ratios. It is interleaved to do. Convolution encoding, iteration, and interleaving techniques are well known techniques. The resulting encoded symbol is multiplied by the assigned Walsh sequence and multiplied by the external PN code. This process results in a 1.2288MHz PN sequence, or 128 times the 9600pbs data rate. The resulting signal modulates the RF carrier and is summed with the pilot and setup carriers along with the other voice carriers. Addition is achieved at some difference in processing such as IF frequency or baseband frequency either before or after multiplication by the PN sequence. Each acoustic carrier is also multiplied by a value that sets the transmit power associated with the power of the other acoustic carrier. This power control characteristic allows the recipient to be assigned power to a link that requires higher power by being in a relatively unfavorable position. The moving body is provided with means for reporting the received signal-to-noise ratio, which allows the power to be leveled to perform proper operation without waste. The orthogonality of the Walsh function is not disturbed by using different power levels of different acoustic carriers if time alignment is maintained. FIG. 2 shows a block diagram of an embodiment of the cell site device. At cell sites, the two receiving systems are used, each with a separate antenna and an analog receiver for spatial diversity reception. In each receiver system, the signal is processed the same until the signal finishes the diversity coupling process. The elements within the dashed line correspond to the communication and corresponding elements between the cell site and one mobile unit. It is also provided for the output of the analog receiver or other elements used to communicate with other mobile units. In FIG. 2, the first receiver system has an antenna 30, an analog receiver 32, a search receiver 34, and a digital data receiver 36. The first receiver system also has an optional digital data receiver 38. The second receiver system has an antenna 40, an analog receiver 42, a search receiver 44, and a digital data receiver 46. It has a cell site or a cell site control processor 48. The control processor 48 is coupled to the data receivers 36,38,46 along with the search receivers 34,44. The control processor 48 provides functions such as signal processing, timing signal generation, power control, handoff, diversity, diversity coupling and system control processing interface with MTSO (Fig. 8) among other functions. Walsh sequence assignments are also provided by the control processor 48 along with transmitter and receiver assignments. Both receiver systems are coupled to the diversity coupler and decoder circuit 50 by data receivers 36,38,46. The digital link 52 is coupled to receive the output of the diversity coupler and the decoder circuit 50. The digital link 52 is also coupled to the control processor 48, the cell site transmit modulator 54, and the MTSO digital switch. The digital link 52 is used under the control of the control processor 48 to communicate the signal to or from MTSO with the cell site transmit modulator 54 and circuit 50. The transmitted signal of the mobile unit is a diffuse signal of a direct sequence modulated by a PN sequence clocked at a predetermined speed, the predetermined speed being 1.2288 MHz in a preferred embodiment. This clock speed is chosen to be an integral multiple of the 9.6Kbps baseband data speed. The signal received by the antenna 30 is supplied to the analog receiver 32. Details of receiver 32 are further shown in FIG. The signal received by the antenna 30 is supplied to the frequency down converter 100, which includes the RF amplifier 102 and the mixer 104. The received signals are supplied as inputs to the RF amplifier, where they are amplified and output to the input of the mixer 104. The mixer 104 is fed another input, which is the output from the frequency synthesizer 106. The amplified RF signal is converted to the 1F frequency by mixing with the frequency synchronization output signal by the mixer 104. The IF signal is output from the mixer 104 to a bandpass filter (BPF) 108, typically a surface elastic wave (SAW) filter with a passband of 1.25 MHz, where they are bandpass filtered. The filtered signal is output to the IF amplifier 110 where the signal from the BPF 108 is amplified. The amplified IF signals are output from the IF amplifier 110 to the analog-to-digital A / D converter 112, where they are digitized at a clock speed of 9.8304 MHz, which is exactly eight times the PN chip speed. The analog-to-digital converter 112 is shown as part of the receiver 32, but may instead be part of the data and search receiver. The digitized IF signal is output from the A / D converter 112 to the data receiver 36, any data receiver 38, and the search receiver 34. The signal output from the receiver 32 is the I and Q channel signals described later. Although the A / D converter 112 in Figure 3 is shown as a single device, in the I and Q channel signal separation described below, channel separation is provided for the digitization of the I and Q channels. It is presumed to be executed prior to digitization by the D converter. Devices for RF-IF-baseband frequency downconverters and analog-to-digital conversion of I and Q channels are well known in technology. The search receiver 34 receives a signal at the cell site to ensure that the associated digital data receiver 36 and, when used, the data receiver 38 track and process the strongest valid time domain signal. Used to scan the time domain for. The search receiver 64 supplies the signal to the cell site control processor 48, which feeds the control signals to the digital data receivers 36, 38 to select the appropriate received signal for processing. The signal processing of cell site data receivers and search receivers differs in several respects compared to signal processing by similar elements in the mobile unit. On the incoming side or reverse link or mobile-cell link, the mobile unit does not transmit a pilot signal that can be used for coherent reference purposes in cell site signal processing. Mobile-cell links feature non-coherent modulation and demodulation schemes that use 64-ary orthogonal signals. In 64-ary orthogonal signal processing, the number of symbols transmitted by the mobile unit is 2.⁶That is, it is encoded in one of 64 different binary sequences. The set of selected sequences is known as the Walsh function. The optimal receive function for the Walsh function m-ary signal encoding is the fast Hadamard transform (FHT). Referring again to FIG. 2, the search receiver 34 and the digital data receivers 36, 38 receive the signal output from the analog receiver 32. Appropriate PN sequences must be generated to decode the spectral spread signal transmitted by the mobile unit to the particular cell site receiver with which it communicates. Details regarding the generation of the mobile unit signal will be described later. As shown in FIG. 3, receiver 36 includes two PN generators, ie, PN generators 120,122, which generate two different short code PN sequences of the same length. These two PN sequences are common to all cell site receiver and mobile unit PN sequences with respect to the external code of the modulation scheme described below. The PN generators 120 and 122 are therefore output sequence PN, respectively._I, PN_QI will provide a. PN_I, PN_QThe sequences are called in-phase (I) and quadrature (Q) channel PN sequences, respectively. Two PN sequences PN_I, PN_QIs generated by different polynomials of 15 degrees and is incremented to produce a sequence of length 32768 instead of the normally generated 32767. For example, the increase occurs in the form of adding a single zero to 14 0 runs in a row that appears at one time in any maximum linear sequence of 15 degrees. In other words, one state of the PN generator is repeated in the generation of the sequence. Therefore, the transformed sequence contains 15 1s in one run and 15 zeros in one run. In an exemplary embodiment, receiver 36 corresponds to a PN sequence generated by a mobile unit in a mobile-cell link._UAlso includes a long code PN generator 124 to generate. The PN generator 124 is the largest linear sequence generator that generates a very long user PN code, for example around 42, and is timed by additional factors such as mobile unit address and user ID that give identification between users. Be shifted. The signal received at such a cell site is a long code PN_USequence and short code PN_IAnd PN_QModulated by both sequences. In another embodiment, a non-linear cryptographic generator, such as a cryptographic standard (DES) that encodes a universal 64 symbol display that uses a user's specific key, replaces the PN generator 124. Can be used for. PN from PN generator 124_USequence output is sequence PN_I'And PN_Q'PN at exclusive or gates 126 and 128 to supply_IAnd PN_QEach is exclusively or processed by the sequence. Sequence PN_I'And PN_Q'Is supplied to the PN QPSK correlator 130 in addition to the I and Q channel signal outputs from receiver 32. Correlator 130 is a PN_I'And PN_Q'It is used to correlate I and Q channel data with sequences. The correlated I and Q channel outputs of the correlator 130 are fed to accumulator 132, where symbol data is accumulated by a 4-chip period, respectively. The outputs of accumulators 132 and 134 are provided as inputs to the fast Hadamard transform (FHT) processor 136. The FHT processor 148 produces a set of 64 coefficients for every 6 symbols. The coefficients of 64 are multiplexed by the weighting function generated in control processor 48. The weighting function is related to the strength of the demodulated signal. The weighted data output from the FHT136 is fed to the diversity coupler and decoder circuit 50 (see Figure 2) for further processing. The second receiver system processes the signal received in a manner similar to that discussed with respect to the first receiver system of FIGS. 2 and 3. The weighted 64 symbol outputs from receivers 36 and 46 are supplied to the diversity coupler and decoder circuit 40. Circuit 50 includes an adder that adds the weighted 64 coefficients from receiver 36 to the weighted 64 coefficients from receiver 46. The resulting 64 coefficients are compared to each other to determine the maximum coefficient. The magnitude of the comparison result, along with the discriminant value or the maximum 64 coefficients, is used to determine a set of decoder weights and symbols for use in the Viterbi algorithm decoder performed in circuit 50. The Viterbi decoder included in the circuit configuration 50 is a type capable of decoding data encoded by a mobile unit having a forced length of K = 9, and has a code speed of r = 1/3. The bidavi decoder is used to determine the most appropriate information bit sequence. Periodically, a signal quality assessment is usually obtained in 1.25 ms and sent to the mobile unit along with the data as a mobile unit power adjustment command. Further information on the occurrence of this quality assessment is discussed in more detail in the separate application described above. This quality assessment is the average signal-to-noise ratio over a period of 1.25 ms. Each data receiver tracks the timing of the received signal it is receiving. This is achieved by known techniques that correlate signals received with a slightly faster local reference PN and correlate signals received with a slightly slower local reference PN. The difference between these two correlations averages 0 in the absence of timing errors. Conversely, if there is a timing error, this difference indicates the magnitude and symbol of the error and the receiver timing is gradually adjusted. The cell site further includes an antenna 62 coupled to the GPS receiver 64. The GPS receiver processes the signal received from the satellite to the antenna 62 in the NshRNA Global Positioning System satellite navigation system, which provides Uniersal Coordinated Time (UTC). The GPS receiver 64 supplies these timing signals that control the processor 48 to synchronize the timing at the cell site as described above. The optional digital data receiver 38 in FIG. 2 is included due to the improved characteristics of the system. The structure and operation of this receiver is similar to that described for data receivers 36 and 46. The receiver 38 is utilized at the cell site to obtain an additional diversity mode. This additional data receiver alone or in combination with the additional receiver can track and receive another possible delay path of the transmitted signal of the mobile unit. Selective additional digital data receivers such as receiver 38 are highly effective additional diversity in these cell sites located in dense urban areas where the potential for multipath signal generation is high. Supply mode. The signal from the MTSO is coupled to a suitable transmit modulator via the digital link 52 under the control of the control processor 48. The transmission modulator 54 under the control of the control processor 48 spectrally expands and modulates the data for transmission to the desired receive mobile unit. Further details regarding the structure and operation of the transmit modulator 54 are discussed below with reference to FIG. The output of the transmission modulator 54 is supplied to the transmission power control circuit 56 whose transmission power is controlled under the control of the control processor 48. The output of circuit 56 is fed to totalizer 57, which is summed with the output of the transmit modulator / transmit power control circuit, which is directed to another mobile at the cell site. The output of the totalizer 57 is supplied for transmission to the power amplifier circuit 58 which outputs to the antenna 60 for radiating to the mobile unit in the cell site service area. FIG. 2 further shows the pilot / control channel generator and transmit power control circuit 66. Under the control of the control processor, circuit 66 generates a pilot signal, a sync channel, and a paging channel for coupling to the output to circuit 58 and antenna 60 to control power. A block diagram of an exemplary embodiment of a cell site transmitter is shown in FIG. The transmitter contains a pair of PN sequence generators used in the generation of external code. These PN generators have two different PN sequences, i.e. PN as described with respect to FIG._IAnd PN_QGenerate a sequence. However, these PNs_IAnd PN_QThe sequence is delayed in time depending on the sector and cell site addresses. In FIG. 4, the transmitter circuit of FIG. 3 is shown in more detail with respect to pilot, synchronization, paging and voice channel signals. Transmitter circuit is PN_IAnd PN_QIncludes two PN generators, 196 and 198, which generate the sequence. The PN generators 196 and 198 respond to an input signal corresponding to a sector or cell site address signal from the control processor to provide a predetermined time delay for the PN sequence. These time-delayed PNs_IAnd PN_QSequences are associated with in-phase (I) and quadrature (Q) channels, respectively. Only two PN generators PN for the corresponding channel of cell site or sector_IAnd PN_QAlthough shown for each occurrence of the sequence, it should be understood that many different PN generator plans are being implemented. For example, a pair of PN generators at a cell site that is not divided into sectors is a PN that is used synchronously for external code._IAnd PN_QSupplied to each pilot, sync, paging and voice channel that produces the sequence. In such a case, PN through many circuits_IAnd PN_QConveniently avoid distributing sequences. In a preferred embodiment, a Walsh function that encodes the channel signal is utilized as the internal code. In the exemplary numbers as disclosed herein, the sum of 64 different Walsh sequences is valid by three of these sequences supplied to the pilot, synchronization and paging channel functions. In synchronization, paging and voice channels, the input data is convolutionally encoded and interleaved as in known techniques. In addition, the convolved and encoded data is given iteratively before interleaving, as in known techniques. The pilot channel does not include data modulation and is characterized as an unmodulated spectral diffusion signal used by all users of a particular cell site or sector for capture or tracking purposes. Each cell site, or each sector when divided into sectors, has a unique pilot signal. However, it is understood that a more effective way to generate different pilot signals is to use shifts in the same basic sequence, rather than using different PN generators for the pilot signals. Utilizing this technique, the mobile unit continuously searches the entire sequence and adjusts to the offset or shift that produces the strongest correlation. In the use of shifts and basic sequences, shifts must be ensured that pilots at adjacent cell sites or sectors must not interfere or eliminate. The pilot sequence must be long enough for many different sequences to be generated by shifts in the basic sequence to support many pilot signals in the system. In addition, the separation or shift must be good enough to ensure that it is not interfered with in the pilot signal. Therefore, the pilot sequence length in the exemplary embodiment of the present invention is 2¹⁵Is selected. The sequence is an extra 0 added to the sequence when a particular state is detected Sequence 2¹⁵-1 starts the outbreak. In an exemplary embodiment, 512 different pilot signals with offsets in the basic sequence of 64 chips are selected. However, the offset is an integral multiple of the 64-chip offset due to the corresponding reduction in the number of different pilot signals. Walsh 0 (W) consisting of all 0s in the generation of the pilot signal₀) Sequences are used so as not to modulate the pilot signal, PN in essence_IAnd PN_QIt is a sequence. Therefore, Walsh "0" (₀) Sequence is PN in exclusive or gate_IAnd PN_QMultiplexed by sequence. The resulting pilot signal is PN_IAnd PN_QIncludes only sequences. For all cell sites or sectors that have the same PN sequence as the pilot signal, the distinguishing characteristic between the cell sites or sectors of transmission origin is the phase of the sequence. Walsh generator (W) for parts of the pilot channel transmit modulator and power control circuit 66₀) 200 produces a signal corresponding to a function of all zeros, as just discussed. The timing of Walsh function generation is provided by the control processor as in the case of all Walsh function generators in cell sites and mobile units. The output of generator 200 is provided as an input to both exclusive or gates 202 and 204. The other input of the exclusive orgate 202 is PN_IReceives a signal and the other input of the exclusive orgate 204 is a PN_QReceive a signal. PN_IAnd PN_QThe signals are exclusively or exclusively by the output of the generator 200 and are supplied as inputs to the finite pulse response (FIR) filters 206 and 208, respectively. The filtered signal is output from FIR filters 206 and 208 for supply to a transmit power control circuit consisting of gain control elements 210 and 212. The signals supplied to the gain control elements 210 and 212 are gain controlled according to an input signal (not shown) from the control processor. The signal output from the gain control element is supplied to the transmit power amplifier circuit 58, the detailed structure and function of which will be described later. The synchronization channel information is encoded and multiplexed in an exclusive orgate by a pre-allocated Walsh sequence. In an exemplary embodiment, the selected Walsh function consists of 32 "1" s, followed by 32 "0" s (W).₃₂). The resulting sequence is the PN in the exclusive orgate_IAnd PN_QMultiplexed by sequence. In an exemplary embodiment, synchronous channel data information is typically fed to the transmit modulator at a rate of 1200 bps. In an exemplary embodiment, the synchronous channel data is preferably convolved and encoded at a velocity r = 1/2 with a forced length K = 9, and each code symbol is repeated twice. This encoding speed and forced length are common to all encoded forward link channels: synchronous, paging and audio channels. In an exemplary embodiment, the shift register structure is code G.₁= 753 (octal) and G₂Used for = 561 (octal) generator. The symbol speed for a synchronous channel is 4800sps in an exemplary embodiment, i.e. one symbol is a 208μsec or 256PN chip. The code symbol is interleaved by the spread of the convolutional interleaver at 40 ms in the exemplary embodiment. The experimental parameters of the interleaver are I = 16 and J = 48. For more information on interleaving, see Data Communication, Networks and Co., by Howard W. Sams &amp; Co., 1987. Approved in Systems 343-352. The effect of convolutional interleaving is to disperse unreliable channel symbols, so any two symbols in adjacent sequences of I-1 or a few symbols are separated by at least J + 1 symbols in the deinterleaver output. Will be done. Similarly, any two symbols in a contiguous sequence of J-1 symbols are separated by at least the I + 1 symbol at the deinterleaver output. In other words, when I = 16 and J = 48, in a series of 15 symbols, the symbols are transmitted separated by 885 μsecs, resulting in time diversity. The synchronization channel symbol of a particular cell site or sector is coupled to the pilot signal corresponding to the cell site or sector. Figure 5 shows the timing of two different pilot channels (N) and (N + 1) separated by a shift of 64 chips. FIG. 5 shows the timing diagram of an exemplary pilot channel and synchronous channel as an example, and does not show the actual state of the pilot signal chip and the synchronous channel symbol. Each sync channel has a pair of code symbols (C) due to two code iterations that are shifted in absolute time by an amount equal to the corresponding pilot._x, C'_x) First code symbol (C)_X) Starts a new interleaver cycle. As shown in Figure 5, the Nth pilot channel is at time t_xStart a new interleaver cycle or pilot synchronization with. Similarly, the N + 1th pilot channel is time t_yStart a new interleaver cycle or pilot synchronization at time t_xProduces 64 chips in a slower time. The pilot period in the exemplary embodiment is 26.67 ms long and corresponds to 128 synchronization channel code symbols or 32 synchronization channel information bits. Synchronous channel symbols are interleaved by a convolutional interleaver that extends 26.67 ms. Thus, when a mobile unit obtains a pilot signal, it has immediate synchronization channel interleaver synchronization. Synchronous channel symbols are covered by a pre-assigned Walsh sequence that gives orthogonality in the signal. In a synchronous channel, one code symbol spans four cover sequences. That is, one code symbol for four iterations of the "32 1"-"32 0" sequence, as shown in Figure 6. As shown in Figure 6, a single logical 1 represents the occurrence of 32 1 Walsh chips, and a single logical 0 represents the occurrence of 32 0 Walsh chips. Represent. The sync channel symbol is distorted by the absolute time that depends on the associated pilot channel because the sync channel shift is an integral multiple of the Walsh frame, but the orthogonality in the sync channel is still preserved. The sync channel message in the exemplary embodiment is varied in length. The message length is an integral multiple of 80 milliseconds corresponding to the three pilot cycles. The Cyclic Redundancy (CRC) bit for error detection is included in the synchronization channel information bit. FIG. 7 shows a timing diagram of a comprehensive exemplary system timing. There are 75 pilot cycles in a 2-second cycle. In Figure 7, the N-pilot and synchronization channels correspond to sectors or cell sites that use unshifted pilots, so the pilot and synchronization signals are precisely aligned in UTC time. Such pilot synchronization, that is, the signal of 1 pulse (pps) per second, which is common as the initial state, aligns accurately. In all cases where a shifted pilot is used, a PN phase offset corresponding to the pilot shift is introduced. In other words, pilot synchronization (initial state) and synchronization channel messages are distorted with respect to the 1pps signal. The synchronous message carries this phase offset information because the mobile unit can gradually adjust the timing. Sync Channel As soon as the message is received correctly, the mobile unit has the ability to instantly sync to either the paging channel or the voice channel. Pilot synchronization begins a new 40ms interleaver cycle that corresponds to the end of each synchronization message. At the same time, the mobile unit repeats the code or (c_x, c_{x + 1}) Deinterleave of the first code symbol of the pair is started and decoder synchronization is achieved. The deinterleaver write address is initialized to 0, the read address is initialized to J, and memory deinterleaver synchronization is achieved. Synchronous channel messages carry information about the state of the 42-bit long PN generator that corresponds to the voice channel assigned to communicate with the mobile unit. This information is used in the mobile unit digital data receiver that synchronizes the corresponding PN generator. For example, the sync channel message N + 1 in Figure 7 contains a 42-bit field that displays the state, and state X is pre-populated with the sector or cell site voice channel corresponding to the long code PN generator, such as 160 ms. Have a fixed time. After successfully decoding the sync channel message, the mobile unit loads state X into the long-coded PN generator in the correct time. Therefore, the long code PN generator of the mobile unit is synchronized to allow descramble of the user's message. With respect to the transmit modulator for the synchronous channel and the portion of the power control circuit 66, the synchronous channel information is input from the control processor to the encoder 214. As described above, the synchronization channel data in the exemplary embodiment is convolved and encoded by the decoder 214. The encoder 214 further repeats the encoded symbol, repeating the encoded symbol in the case of a synchronous channel. The symbol output from the encoder 214 is supplied to the interleaver 215, and the symbol is convolved and interleaved. The interleaved symbol output from the interleaver 215 is supplied as an input to the exclusive orgate 216. Walsh generator 218 is supplied as another input to the exclusive orgate 216 Walsh (W)₃₂) Is generated. Synchronous channel symbol stream and Walsh (W)₃₂The sequence is exclusively orered by an exclusive orgate 216 whose output is supplied as input to both the exclusive orgate 220 and 222. Another input for exclusive orgate 220 is PN_IReceives a signal and another input of exclusive orgate 222 is PN_QReceive a signal. PN_IAnd PN_QThe signal is exclusively or exclusively by the output of the exclusive orgate 218 and is supplied as an input to the finite pulse response (FIR) filters 224 and 226, respectively. The filtered signal output from the FIR filters 224 and 226 is supplied to a transmission power control circuit composed of digital variable gain control elements 228 and 230. The signals supplied to the gain control elements 228 and 230 are digitally gain controlled according to an input digital signal (not shown) from the control processor. The signals output from the gain control elements 228 and 230 are supplied to the transmission power amplifier circuit 58. The paging channel information is iteratively encoded, interleaved and multiplexed by a pre-allocated Walsh sequence. The resulting sequence is PN_IAnd PN_QMultiplexed by sequence. The data rate of the page channel for a particular sector or cell site is indicated by the assigned field in the sync channel message. The paging channel data rate is variable, but fixed for each system at one of the following exemplary data rates: 9.6, 4.8, 2.4 and 1.2 kbps. With respect to the transmission modulator and the paging channel power control circuit, the paging channel information is input from the control processor to the encoder 232. Encoder 232 is a convolution encoder in an exemplary embodiment that supplies symbol iterations at the assigned data rate of the channel. The output of the encoder 232 is supplied to the interleaver 233 where the symbols are convolved and interleaved. The output from the intake device 232 is supplied as an input to the exclusive orgate 234. The paging channel data changes, but the code symbol speed remains constant at 19.2 ksps with code iterations. The Walsh generator 236 generates a signal, which corresponds to a pre-allocated Walsh sequence supplied as a separate input to the exclusive orgate 234. The symbol data and the Walsh sequence are exclusively orered by the exclusive ore gate 234 and are supplied as inputs to both the exclusive ore gates 238 and 240. Another input for exclusive orgate 238 is PN_IReceive the signal and another input of the exclusive orgate 240 is the PN_QReceive a signal. PN_IAnd PN_QThe signal is exclusively orored by the output of the exclusive orgate 234, respectively, and is supplied as an input to the finite pulse response (FIR) filters 242 and 244, respectively. The filtered signal from FIR filters 242 and 244 is supplied to a transmit power control circuit composed of gain control elements 246 and 248. The signals supplied to the gain control elements 246 and 248 are gain controlled according to an input signal (not shown) from the control processor. The signal output from the gain control element is supplied to the transmission power amplifier circuit 58. The data in each audio channel is iteratively encoded, interleaved, scrambled, and assigned Walsh sequences (W)._i-W_j) Multiplexed by PN_IAnd PN_QMultiplexed by sequence. The Walsh sequence used by a particular channel is assigned by the system controller at a set time in the same way that the channel is assigned to a call in an analog FM cell site system. In the exemplary embodiments shown here, up to 61 different Walsh sequences are effectively used by the audio channel. In an exemplary embodiment of the invention, the voice channel utilizes variable data rates. The purpose of utilizing variable data rates is to reduce the data rate when reducing the interference caused by a particular voice channel to another user due to lack of voice activity. Vocoders that supply variable speed data generate data at four different data rates based on 20ms frame-based voice activity. Exemplary data rates are 9.6kbps, 4.8kbps, 2.4kbps and 1.2kbps. The data rate varies on a 20ms basis, but the code symbol rate is 19.2ksps, which is kept constant by code iterations. Therefore, the code symbol is repeated 2, 4 and 8 times for each data rate of 4.8kbps, 2.4kbps and 1.2kbps. Low speed code symbols have low energy because variable speed schemes are devised to reduce interference. For example, code symbol energy (E) for exemplary data rates of 9.6kbps, 4.8kbps, 2.4kbps and 1.2kbps._s) Are E respectively_{b b}/ 2,E_{b b}/ 4, E_{b b}/ 8 and E_{b b}/ 16 and E_{b b}Is the information bit energy for a transmission speed of 9.6 kbps. Since the code symbols are interleaved by the convolution interleaver, the code symbols with different energy levels are scrambled by the operation of the interleaver. To keep track of energy levels, code symbols have a label attached to each symbol that specifies the data velocity for scaling purposes. After the quadrature Walsh cover and NP spread, the quadrature phase channels are digitally filtered by a finite pulse response (FIR) filter. The FIR filter receives a signal corresponding to the symbolic energy level to achieve energy scaling according to the data rate. I and Q channels<img file="JP2958433B2_D0005.tif" />Scaled by the factor of. In one embodiment, the vocoder supplies the FIR filter with a data velocity label in the form of a 2-bit number to control the filter scaling factor. In FIG. 4, two exemplary audio channel circuits, audio channels (i) and (j), are shown. The audio channel (i) data is input from the associated vocoder (not shown) to the transmit modulator 54 (see Figure 3). Transmission modulator 54 is encoder 250_i, Interleaver 251_i, Exclusive Orgate 252_i,255_i,256_iAnd 258_i, PN generator 253_iAnd Walsh Generator (W_i)254_iConsists of. Audio channel (i) data is convolved and encoded by code symbol iterations according to the input data rate in an exemplary embodiment._iIs entered in. Encoded data is interleaver 251_iIt is convoluted and interleaved in an exemplary embodiment. Interleaver 251_iReceives a 2-bit data velocity label interleaved by the symbolic data identified by the data velocity for the FIR filter from the vocoder associated with the voice channel (i). No data velocity label has been sent. The mobile unit decoder checks all executable code. Interleaved symbol data is exclusive or gate 252_iInterleaver 251 at an exemplary speed of 19.2ksps for the input of_iIs output from. In an exemplary embodiment, each voice channel signal is scrambled to provide tightness in transmission from the cell site to the mobile. Such scrambling is not required, but it increases the tightness of the communication. For example, scrambling of a voice channel signal is achieved by a PN encoding a voice channel signal having a PN code determined by the mobile unit address of the user ID. Such scrambling is a PN as discussed with reference to Figure 3 regarding the specific receiver of mobile-to-cell site communication._UUse sequences or cryptographic mechanisms. Therefore, the separated PN generator is configured for the function shown in FIG. Scramble is discussed with respect to PN sequencing, but scrambling is achieved by another technique that includes these known techniques. Seeing FIG. 4 again, the scramble of the voice channel (i) signal receives the mobile unit address assigned by the control processor PN generator 253._iIs achieved by supplying. PN generator 253_iIs an exclusive orgate 252_iGenerates a unique PN code that is supplied as a separate input to. Exclusive Orgate 252_iOutput is exclusive orgate 255_iIs supplied instead of one input. Walsh Generator (W_i)254_iGenerates a signal corresponding to a pre-allocated Walsh sequence according to a function selection signal and a timing signal from the control processor. The value of the function selection signal is determined by the address of the mobile unit. The Walsh sequence signal is an exclusive orgate 255_iIs supplied as a separate input to. Scrambled symbol data and Walsh sequences are exclusive orgate 256_iAnd 258_iExclusive or gate 255 with output supplied as input to both_iExclusively or by. PN generator 253 in addition to all other PN generators and Walsh generators at cell sites_iProvides output at 1.2288MHz. PN generator 253 is an exclusive orgate 255_iIt should be noted that it includes a decimeter that supplies output at a speed of 19.2 kHz. Exclusive Orgate 256_iAnother input is PN_IReceives a signal, while exclusive orgate 258_iAnother input is PN_QReceive a signal. PN_IAnd PN_QThe signal is an exclusive orgate 252_iFinite pulse response (FIR) filter 260_iAnd 262_iIt is supplied as input to each. The input symbol is the convolution interleaver 251_iInput data from is filtered according to velocity label (not shown). FIR filter 260_iAnd 262_iThe filtered signal output from the gain control element 264_iAnd 266_iIt is supplied to a part of the transmission power control circuit 56 composed of. Gain control element 264_iAnd 266_iThe signal supplied to the control processor is controlled according to an input signal (not shown) from the control processor. The signal output from the gain control element is supplied to the transmission power amplifier circuit 58. In addition to the voice bits, the forward link voice channel carries power control information. The power control bit rate is 800 bps in the exemplary embodiment. A cell site receiver demodulating a mobile-cell signal from a given mobile generates power control information that is inserted into a cell-mobile voice channel addressed to a particular mobile. Further details of the power control characteristics are disclosed in the separate US patent specification described above. The power control bits are inserted at the output of the convolution interleaver by a technique called code symbol puncture. In other words, if the power control bits need to be transmitted, the two code symbols are replaced by two equal code symbols with the polarity given by the power control information. In addition, the power control bits are transmitted at an energy level that corresponds to a 9600 bps bit rate. The additional coercion given to the power control information stream must be that the bit positions are randomized between the mobile-cell channel. The total energy power control bits, on the other hand, generate interference spikes at regular intervals, reducing the detection power of such bits. Figure 4 further shows the audio channel (j), which is equivalent to the audio channel (i) in function and structure. It is noted that there are more voice channels (not shown) with a total of up to 61 voice channels in the examples shown. For the Walsh generator in Figure 4, the Walsh function is a set of orthogonal binary sequences that are easily generated by known methods. A relevant property of the Walsh function is that each of the 64 sequences is completely orthogonal to all the other sequences. Thus, any pair of sequences differ at the bit positions where they match, that is, exactly as many bit positions as 32 with respect to the spacing of 64 symbols. When the information is thus encoded for transmission by the Walsh sequence, the receiver can select any one of the Walsh sequences as the desired "carry" signal. Any signal energy encoded in another Walsh sequence is eliminated and no mutual interference occurs with one desired Walsh sequence. In an exemplary embodiment of a cell-mobile link, the synchronization, paging and voice channels as described above use a forced length K = 9 and code speed r = 1/2 convolution encoding. That is, the encoded symbol is generated and transmitted for each information bit transmitted. In addition to convolution encoding, it is further utilized from the convolution interleave of symbol data. Imagine that iterations are used with convolution encoding. The optimal decoder for this type of encoding in a mobile unit is a flexible Viterbi algorithm decoder. The standard design is used for decoding purposes. The resulting decoded information bits are passed through the mobile unit digital baseband equipment. Seeing Figure 4 again, circuit 58 is a PN for pilot, synchronization, paging and voice channels._IAnd PN_QIncludes a digital-to-analog (D / A) converter for converting digital information from diffuse data to analog form. In particular, pilot channel PN_IThe diffusion data is output from the gain control element 210 to the D / A converter 268. The digitized data is output from the D / A converter 268 to the totalizer 284. Similarly, synchronization, paging and voice channel PN_ICorresponding gain control elements for diffuse data, ie gain control elements 228,246 and 264_i-264_jThe output of the D / A converters 272,276 and 280, where the signal is digitized and fed to the totalizer 284._i-280_jWill be supplied to each. PN for pilot, sync, paging and voice channels_QDiffusion data is gain control elements 221,230,248 and 266_i-266_jD / A converters 270,274,278 and 282 that are output from and the signal is digitized and fed to the totalizer 286._i-282_jWill be supplied to each. Summoner 284 is a PN for pilot, sync, paging and voice channels_ISumming the spread data, the summer 286 is the PN of the same channel_QSum the spread data. The summed I and Q channel data is input to the mixers 288 and 290 along with the sine (2πft) and cosine (2πft) of the local oscillator (LO) frequency signal, where they are mixed and fed to the summer 292. The sine (2πft) and cosine (2πft) of the LO frequency signal are sourced from a suitable frequency source (not shown). These mixed IF signals are summed in the summer 292 and supplied to the mixer 294. Mixer 294 mixes the FR frequency signal supplied by the frequency synthesizer 296 with the summed signal to convert the frequency upwards into the RF frequency band. The RF signal output from the mixer 294 is output to the RF amplifier 299 via the bandpass filter 298. The amplifier 299 amplifies the band-limited signal according to the input gain control signal from the transmission power control circuit 56 (see FIG. 3). It should be understood that the examples shown with respect to the transmit power amplifier circuit 58 are merely illustrations of many changes in signal summing, mixing, filtering and amplification as possible with known techniques. The cell site control processor 48 (see Figure 3) has a response to the digital data receiver and the assignment of the transmit modulator to a particular cell site. The control processor 48 monitors the progress of the call, the quality of the signal, and the start of decomposition of the signal loss. Cell sites communicate with MTSO over a link 52 coupled by a standard telephone line, fiber optic or microwave link. FIG. 8 shows a block diagram of the equipment used in MTSO. The MTSO typically includes a system controller or control processor 300, a digital switch 302, a diversity coupler 304, a digital vocoder 306 and a digital switch 308. Although not shown, additional diversity couplers and digital vocoders are coupled between digital switches 302 and 308. When cell site diversity mode is active, the call is processed by two cell sites. Therefore, the signal arrives at MTSO from one or more cell sites with the same information. However, due to the fading and interference of arrivals or reverse links from the mobile unit to the cell site, the signal from one cell site is of better quality than the signal from another cell site. The digital switch 302 corresponds to the information stream corresponding to the given mobile unit from one or more cell sites to the diversity coupler 304, or as determined by a signal from the system control processor 300. Used to define the path of the information stream to the diversity combiner. When the system is not in cell site diversity mode, the diversity coupler 304 bypasses or supplies the same information for each input port. Multiple series-coupled diversity couplers and vocoders are provided in parallel, one for each call processed. The diversity coupler 304 compares signal quality indicators associated with information bits from two or more cell site signals. The diversity coupler 304 selects the bit corresponding to the highest quality cell site that sends information about the output to the vocoder 306 frame by frame. The vocoder 306 converts the format of a digitized audio signal into a standard 64Kbps PCM telephone format, analog, or any other standard format. The resulting signal is transmitted from the vocoder 306 to the digital switch 308. Under the control of the system control processor 300, the call is routed to the PSTN. The audio signal output from the PSTN directed to the mobile unit is supplied to the digital switch 308 for coupling to a suitable digital vocoder such as the vocoder 306 under the control of the system control processor 300. The vocoder 306 encodes the digitized input audio signal and supplies the resulting bit stream of information directly to the digital switch 302. The digital switch 302, which is based on the system control processor, directly controls the data encoded in the cell site in which the mobile unit is talking. Although previously discussed regarding the information transmitted to MTSO analog voice, it is further envisioned that digital information will be communicated in the system. Care must be taken in the proper frame structure of the data to ensure system suitability. When the mobile unit is in handoff mode or cell site diversity mode transmitting to multiple cell sites, the digital switch 302 makes a call to the appropriate cell site for transmission to the receiving mobile unit by the appropriate cell site transmitter. Route. However, if the mobile unit communicates with only a single cell site or is not in cell site diversity mode, the signal is directed only to a single cell site. The system control processor 300 is controlled by digital switches 302 and 306 to route data to and from MTSO. The system control processor 300 also determines the allocation of calls to cell sites and MTSO vocoders. In addition, the system control processor 300 communicates with each cell site control processor for specific call assignments between MTSO and cell sites and PN code assignments for calls. Although the digital switches 302 and 306 are shown as two separate switches, as shown in FIG. 8, it should be understood that this function can be performed by a single physical switching device. When cell site diversity mode is used, the mobile unit uses a search receiver that identifies and captures the strongest multipath signals from each of the two cell sites. The digital data receiver is controlled by the search receiver and control processor to modulate the strongest signal. Switching diversity capabilities are possible when the number of receivers is less than the number of cell sites transmitting information in parallel. For example, for a single data receiver only and two cell site signals, the search device monitors pilots from both cell sites and selects the strongest signal for the receiver to demodulate. In this embodiment, the selection is made at the same frequency for each vocoder frame or every 20 milliseconds. The system control processor is responsive to cell site digital data receiver and modulator allocations to handle a particular call. Thus, in a cell-mobile link, the system control processor handles the allocation of Walsh sequences used at the cell site in sending a particular call to the mobile unit. In addition, the system control processor controls the receiver Walsh sequence and PN code. In the mobile-cell link, the system control processor also controls the PN code of the mobile unit user for the call. Therefore, allocation information is transmitted from MTSO to the cell site and from there to the mobile-cell. The system control processor also monitors the start of analysis of call progress, signal quality and signal loss. Mobile-Cell Link In mobile-cell links, channel characteristics name modulation techniques to change. The pilot carrier must be stronger than the voice carrier to provide a good phase reference for data modulation. For cell sites that transmit many voice carriers at the same time, a single pilot signal is shared by all voice carriers. Therefore, the pilot signal power per voice carrier is very small. However, in a mobile-cell link, there is usually one voice carrier per mobile. When pilots are used, they require significantly more power than voice carriers. This situation is clearly undesirable as the total system capacitance is greatly reduced due to the interference caused by the presence of very high power pilot signals. Therefore, modulation must be used that allows effective demodulation without a pilot signal. For mobile-cell channels interrupted by Rayleigh fading, coherent demodulator techniques such as the Costas loop, which produces a rapidly changing channel phase and obtains the phase from the received signal, are inadequate. Other techniques such as differential coherent PSK are used, but cannot provide the desired level of signal-to-noise ratio characteristics. Thus, forms of orthogonal signal communication such as 2, 4 or m signal communication should be used. In an exemplary embodiment, 64 orthogonal signal communication techniques are utilized using Walsh functions. Demodulators for m quadrature signal communication require channel coherence over the duration of transmission of the m symbol. In an exemplary embodiment, this is only 2 bits of time. Message encoding and modulation processing is initiated by a convolution encoder with forced length K = 9 and code speed r = 1/3. At a normal data rate of 9600 bits per second, the encoder produces 28800 binary symbols per second. These are classified into 64 possible characters, each containing 6 symbols at a rate of 4800 characters per second. Each character is encoded into a 64 length Walsh sequence containing 64 binary bits or "chips". The Walsh chip speed of 64 is 307,200 chips per second in an exemplary embodiment. The Walsh chip is "covered" or multiplexed by a PN sequence operating at a speed of 1.2288 MHz. Each mobile unit is assigned a unique PN sequence for this purpose. This PN sequence is assigned only during the duration of the call or permanently to the mobile unit. The assigned PN sequence is called the user PN sequence. The user PN sequence generator operates at a clock speed of 1.2288 MHz to generate four PN chips for each Walsh chip. Eventually, a pair of short 32768 PN sequences is generated. In an exemplary embodiment, the same sequence is used for cell-mobile links. The user PN sequence covered by the Walsh chip sequence is covered or multiplexed by two short PN sequences each. The two resulting sequences two-phase-modulate a pair of right-angled sine waves and sum them into a single signal. The resulting signal is bandpass filtered, converted to the final RF frequency, amplified, filtered and radiated by the mobile unit's antenna. As described for cell-mobile signals, the order of filter, amplification and modulation operations can be interchanged. In another embodiment, two different phases of the user PN code are generated and used to modulate the two carrier phases of a quadrature phase waveform, eliminating the need to use a sequence of length 32768. In another embodiment, the mobile-cell link utilizes only double phase modulation, eliminating the need for short sequences. The cell site receiver for each signal produces a short PN sequence in which each active mobile signal is received and a user's PN sequence. The receiver correlates the received signal energy with each encoded waveform in a separate correlator. The output of each correlator is processed separately to demodulate 64 codes, and the convolutional encoding uses a fast Hadamard transform processor and a Viterbi algorithm decoder. In another modulation scheme for mobile-cell links, the same modulation scheme is used as the cell-mobile link. Each mobile uses a pair of 32768 long sector codes as the external code. The internal code utilizes a Walsh sequence of length 64, which is assigned to the mobile for use and resides within a sector. Normally, the same Walsh sequence is assigned to mobile-cell link mobiles, such as those used for cell-mobile links. The orthogonal PN encoding scheme limits 19200 Hz to the effective bandwidth spread used by the modulation system for the maximum velocity of the chip velocity divided by 64 and the number used in the exemplary embodiments. This preliminarily includes the use of m encoded by a magnitude m as described in the exemplary embodiment. However, another, such as velocity r = 1/2, a forced length K = 9 convolution code is used by the differential binary phase shift key modulation of the encoded binary symbol. The demodulators at the cell site are described in the paper "Nonlinear Spectrum of PSK-Modulated Carrer" by Andrew J. Viterbi and Andrew M. Viterbi of IEEE Transactions On Information Theory, July 1983, Vol. 29, No. 4. with Application to Burst Digital The phase reference is enhanced over short intervals using the techniques described in "Transmission". For example, the phase reference is averaged by only four symbols that do not require channel uniformity, as in the 64 schemes above. However, the properties of the other scheme just described are inferior to the preferred embodiments in the presence of strict Rayleigh fading and multipath situations. However, in environments where, for example, satellite-mobile and ground station-mobile channels fading and multipathing are not severe, the characteristics of this other system are better than in preferred embodiments. This occurs because the gain from the formation of mobile signals that are orthogonal to each other outweighs the loss in the efficiency of DPSK detection. To meet the time alignment requirements of another mobile-cell link orthogonal Walsh function, each cell site receiver determines a time error from the nominal time of each received signal. If the time of a given received signal is delayed, the cell site modulator and transmitter involved will send instructions to this mobile in small increments to advance the time of transmission. Conversely, if the time of the received signal of the mobile is advanced by a small amount of time, a delay instruction with a small increment is transmitted to the mobile. Time adjustment increments are made on approximately 1/8 PN chips or 101.7 nanoseconds. Instructions are transmitted at a relatively low speed of about 10 to 50 Hz and consist of a single bit inserted into a digital audio data stream. During flexible handoff operation, the mobile unit receives signals from two or more cell sites. Since the mobile unit can align the time according to one of the cell site time adjustment instructions, the mobile unit normalizes the time according to the instruction received from the strongest cell site received. The signaled mobile unit is aligned by the cell site with the best path. Otherwise, mutual interference with another user will occur. When each cell site receiver receiving the mobile signal performs the above time error measurement and correction transmission operation, the received signals of all the mobiles are usually received at about the same time, and the interference is reduced. .. FIG. 9 shows an exemplary block diagram of a mobile unit CDMA telephone device. The mobile unit CDMA telephone unit includes an antenna 430 coupled to an analog receiver 344 and a transmit power amplifier 436 through a diplexer 432. Antenna 430 and Diplexer 432 are standard designs and allow simultaneous transmission and reception through a single antenna. Antenna 430 collects the transmitted signal and feeds it through the diplexer 432 to the analog receiver 434. The receiver 434 receives the RF frequency signal from the diplexer 432, which is typically in the frequency band of 850 MHz, amplifies and decrements the frequency, and converts it to the IF frequency. This conversion process is performed using a standard-designed frequency synthesizer that allows the receiver to tune to any frequency within the reception frequency band of all cell site telephone frequency bands. The signal is filtered and digitized to feed the digital data receivers 540 and 542 in addition to the search receiver 544. Details of receiver 434 are further shown in FIG. The received signal from the antenna 430 is supplied to the down converter 500 composed of the RF amplifier 520 and the mixer 504. The received signals are supplied as inputs to the RF amplifier 502, which they are amplified and output as inputs to the mixer 504. The mixer 504 is supplied with another input, which is the signal output from the frequency synthesizer 506. The amplified RF signal is mixed with the frequency synthesizer output signal and converted in the IF frequency hemixer 504. The IF signal is output from the mixer 504 to a bandpass filter (BPF) 508, which is typically a surface acoustic (SAW) filter with a passband of approximately 1.25 MHz. The characteristics of the SAW filter are selected to match the waveform of the signal transmitted by the cell site. The cell site transmit signal is a direct sequence spectral spread signal modulated by a PN sequence clocked at a predetermined rate of 1.2288 MHz in an exemplary embodiment. This clock speed is chosen to be an integral multiple of the baseband data speed of 9.6 kbps. The filtered signal is output from the BPF 508 as an input to the variable gain IF amplifier 510 where the signal is amplified again. The amplified IF signal is output from the IF amplifier to the analog-to-digital (A / D) converter 512 where the signal is digitized. The conversion of the IF signal to a digital signal occurs at a clock speed of 9.8304 MHz, which is exactly eight times the PN chip speed in the exemplary embodiment. The (A / D) converter 512 is shown as part of receiver 534, but may instead be part of a data and search receiver. The digitized IF signal is the search receiver 444, which is output from the (A / D) converter 512 to the data receiver 440. The receiver 434 executes a power control function that adjusts the transmission power of the mobile unit. The automatic gain control (AGC) circuit 514 is coupled to the output of the IF amplifier 510. Depending on the level of the amplified IF signal, the AGC circuit 514 provides a feedback signal to the gain control input of the IF amplifier 510. The receiver 434 uses the AGC circuit 514 to generate the analog power control signal supplied to the transmit power control circuit 438. In FIG. 9, the digitized signal output from receiver 434 is fed to digital data receivers 440 and 442 and search receiver 444. It should be understood that low-cost, low-performance mobile units have only one data receiver, and high-performance mobile units have two or more data receivers that allow diversity reception. Is. The digitized IF signal includes many ongoing in-call signals along with pilot carriers transmitted by the current cell site and all neighboring cell sites. The function of receivers 440 and 442 is to correlate IF samples by the appropriate PN sequence. This correlation processing provides a property known as a "processing gain" technique that increases the signal-to-interference ratio of the signal matching the appropriate PN sequence and not another signal. Correlated outputs are simultaneously detected using the pilot carrier from the closest cell site as the carrier phase reference. The result of this detection process is a sequence of encoded data symbols. A characteristic of the PN sequence used in the present invention is that identification is performed on a multipath signal. When the signal arrives at the mobile receiver after passing one or more paths, there is a difference in signal reception time. This difference in reception time corresponds to the difference in distance divided by the propagation speed. If this time difference exceeds 1 microsecond, the correlation process identifies between paths. The receiver can choose to track and receive fast or slow paths. If two receivers, such as receivers 440 and 442, are provided, the two independent paths are tracked and processed in parallel. The search receiver 444, which is under the control of control processor 446, has another multipath pilot signal from the same cell site and the nominal time of the received pilot signal at the cell site to another cell site where the pilot signal is transmitted. Continuously scan the time domain around. The receiver 444 measures any reception intensity of the desired waveform from the nominal time. The receiver 444 compares the signal strengths in the received signals and supplies the signal strength signal to the control processor 446 which indicates the strongest signal. Processor 446 supplies control signals to the data receivers 440 and 442 to process the different strongest signals, respectively. Occasionally, another cell site to which the pilot signal is transmitted will be stronger than the current cell site signal. The control processor 446 generates a control message for transmission to the system controller over the current cell site requesting transfer to the cell site corresponding to the strongest pilot signal. Receivers 440 and 442 process the call through two different cell sites. During the flexible handoff operation, the mobile unit is receiving signals from two or more cell sites. Since the mobile unit aligns the time according to the instruction for adjusting the timing of the cell site, the mobile unit normally moves the time according to the instruction received from the strongest cell site received. The signal transmitted by the mobile unit is temporally aligned with the cell site with the best path. Otherwise, there will be significant mutual interference with other users. Further details of an exemplary receiver, such as the data receiver 440, are shown in more detail in FIG. Data receiver 440 is a PN_IAnd PN_QIncludes PN generators 516 and 518 that generate sequences and correspond to those generated by cell sites. Time and sequence control signals are supplied by control processor 446 to PN generators 516 and 518. The data receiver 440 includes a Walsh generator 520 that supplies the appropriate Walsh function for communication between the cell site and the mobile unit. The Walsh generator 520 generates a time signal (not shown) and a signal corresponding to the Walsh sequence assigned according to the ability to select a signal from the control processor. A function selection signal is sent by the cell site to the mobile unit as part of the call setup message. PN output from PN generators 516 and 518_IAnd PN_QThe sequence is entered in the exclusive or-gates 522 and 524, respectively. The Walsh generator 520 has an exclusive signal or sequence PN_Q'Gives output to both exclusive orgates 522 and 524. Sequence PN_I'And PN_Q'Are fed to receiver 440 where they are input to PN QPSK correlator 526. The PN correlator 526 is configured in a manner similar to the PN correlator of a cell site digital receiver. PN correlator 526 is a PN_I'And PN_I'And PN_Q'It correlates received I and Q channel data with a sequence and supplies the correlated I and Q channel data to the corresponding accumulators 528 and 530. The accumulators 528 and 530 accumulate input information over one symbol period or 64 chips. The accumulator output is supplied to the phase rotating device 532 which receives the pilot phase signal from the control processor 446. The phase of the received symbol data is rotated according to the phase of the pilot signal determined by the search receiver and the control processor. The output from the phase rotating device 532 is the I-channel data supplied to the deinterleaver and decoder circuits. The control processor 446 includes a PN generator 534 that generates a user PN sequence according to the address or user ID of the input mobile unit. The PN sequence output from the PN generator 534 is supplied to the diversity coupler and decoder circuits. Since the cell-mobile signal is scrambled with the mobile user address PN sequence, the output from the PN generator 534 is in the cell site descramble where the signal directed to the mobile user is transmitted, such as in a cell site receiver. used. The PN generator 534 specifically supplies the output PN sequence to the deinterleaver and decoder circuits used to descramble the scrambled user data. Although scrambling is discussed for PN sequencing, other scrambling techniques that include known techniques may be utilized. The output of receivers 440 and 442 is supplied to the diversity coupler and decoder circuit 448. The diversity coupler circuit contained within circuit 448 simply adjusts the time of the two flows of the received symbols to align and sums them. This addition process is performed by multiplying the two streams by a number that corresponds to the relative signal strength of the two streams. This behavior is considered the maximum speed diversity coupler. The resulting combined signal stream is decoded using a forward error detector (FEC) decoder contained within circuit 448. A typical digital baseband device is a digital vocoder system. CDMA systems are designed to accommodate a variety of different vocoder designs. The baseband circuit 450 typically includes a digital vocoder (not shown) of the variable speed type as disclosed in the separately filed US patent specification described above. The base bud circuit 450 is supplied as a handset or a connector in another type of peripheral device. The baseband circuit 450 adapts to a variety of different vocoder designs. The baseband circuit 450 supplies an output information signal to the user according to the information supplied from the circuit 448. In a mobile-cell link, a user analog audio signal is typically supplied through the handset as an input to baseband circuit 560. The baseband circuit 450 includes an analog-to-digital (A / D) converter (not shown) that converts an analog signal into a digital signal. The digital signal is supplied to the digital vocoder to encode. The vocoder output is fed to a forward error correction (FEC) encoding circuit for error correction. The execution of the error correction encoding in the exemplary embodiment is performed by the convolution encoding method. The digitized encoded signal is output from the baseband circuit 450 to the transmission modulator 452. The first Walsh of the transmit modulator 452 encodes the transmit data and the PN sequence modulates the PN carrier signal selected according to the assigned address function for the call with the encoded signal. The PN sequence is determined by the control processor 446 from the call configuration information transmitted by the cell site and decoded by the receivers 440 and 442 and the control processor 446. In another embodiment, control processor 446 determines the PN sequence by cell site scheduling. The control processor 446 supplies PN sequence information to the transmit modulator 452 and the receivers 440 and 442 for decoding the call. The output of the transmission modulator 452 is supplied to the transmission power control circuit 438. The signal transmission power is controlled by an analog power control signal supplied from the receiver 434. The control bits transmitted by the cell site in the formal power adjustment instruction are processed by the data receivers 440 and 442. The power adjustment instruction is used by the control processor 446 in setting the power level of the mobile unit transmission. In response to this instruction, the control processor 446 generates a digital power control signal supplied to circuit 438. Additional information regarding the relationship between receivers 440 and 442, control processor 446 and transmit power control circuit 438 with respect to power control is further described in the US patent specification of the separate application above. The transmit power control circuit 438 outputs a power-controlled modulated signal to the transmit power amplifier circuit 436. Circuit 436 amplifies the IF signal and converts it to an RF frequency by mixing it with a frequency synthesizer output signal that tunes the signal to an appropriate output frequency. Circuit 436 includes an amplifier that amplifies power to the final output level. The transmission signal to the receiver is output from circuit 436 to diplexer 432. The diplexer 432 couples the signal to the antenna 340 for transmission to the cell site. Control processor 446 can also generate control messages such as cell site diversity mode requests and cell site communication termination instructions. These instructions are supplied to the transmit modulator 452 for transmission. The control processor 446 responds to the data received from the data receivers 440 and 442, and the search receiver 444 makes handoff and diversity coupling decisions. For transmission by the mobile unit, the mobile user's analog audio signal first passes through the digital vocoder. The vocoder output is a sequence of 64 orthogonal sequences that are sequentially convolved forward error correction (FEC) encoded, encoded with a PN carrier signal, and modulated. The 64 orthogonal sequences are generated by the Walsh function encoder. The encoder is controlled by six consecutive binary symbol outputs from the convolution FEC encoder. Collectively determine what the six binary transmissions are from the 64 Walsh sequences. Walsh sequences are 64-bit long. Therefore, the Walsh "chip" speed must be 9600 * 3 * (1/6) 64 = 307 200Hz with respect to the 9600bps data transmission speed. In mobile-cell links, the general short PN sequence is used for the entire voice carrier in the system, and the encoding of the user's address is done using the user's PN sequence generator. The user PN sequence is uniquely assigned to at least the mobile during the call. The user PN sequence is exclusively or over by a common PN sequence, which is the maximum length linear shift register sequence whose length has been increased to 32768. The resulting binary signal is double phase modulated on each quadrature carrier, summed to form a composite signal, bandpass filtered and converted to an IF frequency output. In an exemplary embodiment, part of the filtering is actually performed by a finite impulse response (FIR) digital filter operating on a binary sequence output. The modulator output is power controlled by signals from a digital control processor and analog receiver, converted to the operating RF frequency by mixing with a frequency synthesizer that tunes the signal to the appropriate output frequency, and amplified to the final output level. Will be done. The transmitted signal is sent to the diplexer and antenna. FIG. 11 shows a preferred exemplary embodiment of the mobile unit transmit modulator 452. The data is digitally fed from the user's digital baseband circuit to the convolutionally encoded encoder 600 in the exemplary embodiment. The output of the encoder 600 is supplied to the interleaver 602, which is a block interleaver in an exemplary embodiment. The interleaved symbol is output from the block interleaver 602 to the transmission modulator 452 to the Walsh encoder 604. The Walsh encoder 604 utilizes input symbols to generate code sequence outputs. The Walsh sequence is fed to one input of the exclusive orgate 606. Transmission modulator 452 further includes a PN generator 608 that receives the address of the mobile unit as an input in determining the output PN sequence. The PN generator 608 generates a user-specific 42-bit sequence as described with reference to FIGS. 3 and 4. A further characteristic of the PN generator 608, which is common to all user PN generators and is not clearly explained, is the use of masking techniques in the generation of output user PN sequences. For example, a 42-bit mask is provided for its user with each bit of a 42-bit mask that is exclusively or exclusive with the bit output from each register in the sequence of shift registers forming the PN generator. The result of the exclusive or operation of the mask and shift register bits is both exclusively or operated to form the PN generator output used as the user's PN sequence. Output PN sequence of PN generator 608 and sequence PN_UIs input to the exclusive or gate 606. Walsh symbol data and PN_UThe sequence is exclusively orered at exclusive orgate 606 and is supplied as input to both exclusive orer gates 610 and 612. Transmission modulator 452 is a PN_IAnd PN_QIt further includes PN generators 614 and 616 that generate the sequence, respectively. All mobile units have the same PN_IAnd PN_QUse a sequence. These PN sequences are zero shifts used in cell-mobile communications in the exemplary embodiments. Another input for exclusive orgates 610 and 612 is the PN from PN generators 614 and 616._IAnd PN_QEach sequence is provided. Sequence PN_IAnd PN_QIs exclusively or at each exclusive or gate that has an output supplied to the transmit power control circuit 438 (see FIG. 9). In an exemplary embodiment, the mobile-cell link uses a convolution cord with a forced length K = 9 and a velocity r = 1/3. The code generator is G₁= 557 (octal), G₂= 663 (octal) and G₃= 711 (octal). Similar to cell-mobile links, code iterations are used by vocoders to adapt four different data velocities that occur on a 20ms frame basis. Unlike cell-mobile links, repeated code symbols are not transmitted in the air at low energy levels, only one code symbol in the repeating group is transmitted at the nominal power level. In conclusion, the code iterations in the exemplary examples are simply used as a means of adapting variable data velocity schemes in interleaving and modulation structures as shown below. Exactly one vocoder frame, a block interleaver spanning 20 ms, is used in mobile-cell links. Assuming a data rate of 9600 bps and a code rate of r = 1/3, the number of 20 ms code symbols is 576. The N and B parameters, where N is equal to the number of rows in the interleaver array and B is equal to the number of columns in the interleaver array, are 32 and 18, respectively. Code symbols are written by rows into the interleaver memory array and read by columns. The modulation format is 64 orthogonal signals. In other words, the interleaved code symbols are grouped into 6 groups to choose one from 64 orthogonal waveforms. The 64 time orthogonal waveforms are the same Walsh function used as the cover sequence in the cell-mobile link. The data modulation time interval is equal to 208.33 μs and is called the Walsh symbol interval. 208.33 μs at 9600 bps corresponds to 2 information bits, and the code symbol speed equal to 6 code symbols is 28800 sps. The Walsh symbol intervals are invariably further divided into 64 equal time intervals of 208.33 / 64 = 3.25 μsec, called Walsh chips. The Walsh chip speed is 1 / 3.25 μsec = 307.2 kHz. Since the PN diffusion rate, 1.2288MHz, is symmetrical to the two links, there are four PN chips per Walsh chip. A sum of three PN generators, a user-specific 42-bit PN generator and a pair of 15-bit I and Q channel PN generators, is used in the mobile-cell link path. According to the user's specific spreading behavior, the signal is QPSK spreading as is done in the cell-mobile link. Each sector or cell site has a unique length 2¹⁵Unlike cell-mobile links identified by the sequence of, all mobile units use the same I and Q PN sequences. These PN sequences are zero-shift sequences used in cell-mobile links and are called pilot sequences. Code iteration and energy scaling are used in cell-mobile links to adapt the variable velocities produced by the vocoder. Mobile-cell links use a different method based on burst transmission. The vocoder produces four different data rates of 9600, 4800, 2400 and 1200 bps based on 20 ms frames, such as in cell-mobile links. The information bits are encoded by a convolution encoder with a velocity r = 1/3, and the code symbols are repeated 2, 4 and 8 times at three low data velocities. Therefore, the code symbol speed is kept constant at 28800sps. According to the encoder, the code symbols are interleaved by a single vocoder frame or a 20ms block interleaver. The sum of the 576 code symbols is generated by the convolution encoder every 20 milliseconds, some of which are repeating symbols. The code symbol sequence transmitted is shown in FIG. Notice that the 20ms vocoder frame is further subdivided into 16 slots of 1.25ms each. The mobile-cell link number sequence is that there are 36 code symbols at 28800sps velocities or 6 equivalent Walsh symbols at 4800sps velocities in each slot. At 1/2 speed, or 4800 bps, the slots are divided into 8 groups, each containing 2 slots. At 1/4 speed, or 2400 bps, the slots are grouped into 4 groups, each containing 4 slots, and finally at 1/8 speed, or 1200 bps, the slots are grouped into 2 groups, each containing 8 slots. An exemplary symbol burst transmission pattern is further shown in FIG. For example, at 1/4 speed, or 2400 bps, during the 4th slot period of the 1st group, the 4th and 8th rows of the interleaver memory array are read in columns and transmitted continuously. The slot positions of the transmitted data must be randomized to reduce interference. The timing of the mobile-cell link is shown in FIG. FIG. 13 is spread over a mobile-cell channel, the timing diagram of FIG. 7, which includes voice and access. Mobile-cell link synchronization comprises the following steps: 1. Successfully decrypt, or CRC check, the sync message. 2. Load a long PN shift register 1 star with the state received in the synchronization message. 3. Compensate for the pilot code phase offset when receiving from a sector that uses a shifted pilot. At this point, the mobile completes synchronization, i.e. PN synchronization and real-time synchronization, and begins transmitting to either the access channel or the voice channel. The mobile unit for making a call must be provided with signal characteristics to complete the call to another system user via the cell site. The envisioned access technology for mobile-cell links is slotted ALOHA. An exemplary transmit bit rate for an inverting channel is 4800 bps. Access channel packets consist of information-guided preambles. The length of the preamble is an integral multiple of the 20ms frame in the exemplary embodiment and is a sector / cell site parameter that the mobile receives in one of the messages on the paging channel. Since the cell site receiver uses the preamble to resolve the propagation delay, this method can vary the length of the preamble based on the cell site radius. The access channel user PN code is scheduled or sent to the paging channel mobile unit. The modulation is fixed and constant during the preamble period. The orthogonal waveform used in the preamble is W₀That is, it is a Walsh function of all zeros. All zero patterns at the input of the convolution encoder are the desired waveform W₀Note that it occurs. An access channel data packet consists of one or at most two 20 ms frames. Access channel encoding, interleaving and modulation are exactly the same as audio channels at 9600bps speeds. In an exemplary embodiment, the sector / cell site requires a mobile unit that sends a 40 ms preamble, and the access channel message type requires one data frame. N is the number of preamble frames where k is the number of 20 milliseconds that elapses from the origin of a predetermined time._pAnd. The moving body is the formula: (k, N_p+2) Start transmission of access channel only when = 0 is satisfied. For different communication applications, it is desirable to rearrange various devices with error correction encoding, orthogonal sequence encoding and PN encoding that are more compatible with the application. For example, in satellite mobile communications where the signal is relayed between a large Hub Earth station and a mobile terminal by one or more Earth orbit satellites, the channel is even more phase coherent than the Earth's mobile channel. It is desirable to use coherent modulation and demodulation techniques in both directions of the link. In such applications, the mobile modulator does not utilize the m encoding as described above. Instead, two-phase or four-phase modulation of the forward error correction symbol uses normal coherent demodulation with a carrier phase extracted from the received signal using Costas loop technology. In addition, the channels of the orthogonal Walsh function as described here for cell-mobile links are used. As long as the channel phase remains reasonably coherent, this modulation and demodulation system provides operation with lower Eb / No than the m orthogonal signal that produces high system capacitance. In another embodiment, it is preferred to encode the speech waveform directly into the RF waveform instead of utilizing vocoder and FEC techniques. The use of vocoder and FEC technology results in very high link characteristics, but is very complex to implement, resulting in additional cost and high power consumption. These drawbacks are particularly undesirable in pocket mobile phones, where battery consumption and cost are important. In the execution of a normal digital telephone transmission, the speech waveform is represented in digital format as an 8-bit speech sample at a sample speed of 8 kHz. CDMA systems encode 8-bit samples directly into the carrier phase angle. This eliminates the need for a vocoder or FEC encoder / decoder. This requires a well-characterized signal-to-noise ratio that produces low capacitance. In another embodiment, the 8-bit speech sample is directly encoded into the carrier amplitude. In another embodiment the speech waveform sample is encoded in carrier phase and amplitude. The above description of preferred embodiments is provided to allow one of ordinary skill in the art to form and use the present invention. Various modifications of these embodiments will be readily apparent to those of skill in the art, and the comprehensive principles limited herein apply to other embodiments that do not utilize the features of the present invention. As such, the invention is not limited to the examples presented herein, but allows a wide range of technical scope adapted to the principles and new features disclosed herein.