FR2763195A1 - METHOD AND DEVICE FOR PERFORMING A COMMUNICATION PASS BETWEEN COMMUNICATION SYSTEMS HAVING DIFFERENT SCHEMES WITH MULTIPLE ACCESS - Google Patents

Abstract

Method in a cellular telecommunication system for effecting a communication pass from a subscriber (28) from a first multiple access system to a second multiple access system, wherein a subscriber unit measures a signal characteristic d a signal from the second multi-port system to produce a signal characteristic value. A subscriber communication pass is made from the first multiple access system to the second multiple access system.

Description

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  METHOD AND DEVICE FOR PERFORMING A CROSSING

  COMMUNICATION BETWEEN COMMUNICATION SYSTEMS

  HAVING DIFFERENT DIAGRAMS HAS SEVERAL ACCESSES

  The present invention relates, in general, to wireless communication systems and more particularly, to an improved method and system for

  perform a communication pass between cellular communication systems having different patterns with multiple accesses.

  In order to maximize the use and reuse of the radio frequency spectrum, wireless communication systems use various schemes to allow multiple users to access communication resources at the same or almost the same time. For example, in cell phone systems, many cellular subscribers can

  access wired communication resources (i.e. the public switched telephone network (PSTN)) via various aerial interfaces allowing multiple subscriber accesses.

  A multiple access scheme can be defined as a set of rules for sharing a communication resource, such as the radio frequency spectrum, by allocating combinations of transmission or reception times, channel frequency, channel bandwidth, channel codes, transmit or receive positions, or the like. Examples of well known multiple access schemes include: AMPS (Advanced Mobile Telephony System), GSM (Satellite System30 for Mobile Communications), TDMA (Time Division Multiple Access), and CDMA (Multiple Access to Division by Code). Most of these multi-access schemes are well documented in industry standards

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  promulgated by the Association of Industries of

  Cellular Telecommunications (CTIA), the Association of Telecommunications Industries (TIA) and other standardization organizations. An example is standard5 IS-95 for cellular communication systems with multiple accesses divided by code.

  While multiple new access schemes are being developed, the coverage area of the new multi-access system is not usually as extensive10 as previous, more established communication systems using a different multiple access scheme. Therefore, in order to provide subscribers using the new multiple access scheme with a larger communication service area, dual mode subscriber units have been developed so that subscribers can use the system & more

  more recent access and when they move outside the system coverage & several more recent accesses, the subscriber unit can communicate with an older or optional multiple access system20.

  Referring now to Figure 1, a usual relationship is illustrated between the coverage of a communication system having a first multi-access scheme and the coverage of a communication system having a second multi-access scheme. More specifically, the cell coverage area 20 of Figure 1 illustrates a cellular system using a CDMA scheme, illustrated by hexagonal cells 22, and, for clarity of illustration, an optional multiple access scheme ( MA), illustrated by circular cells 24. The boundary between the area covered by the

  CDMA cells 22 and an area covered by an optional MA diagram using optional MA cells 24 is illustrated by the border 26 itself illustrated by a bold line.

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  While the subscriber 28 travels between CDMA cells 22, a CDMA base station control unit 30 supervises or manages the communication passages between the CDMA cells 22. Likewise, while the subscriber 28 travels between MA cells option 24, an optional MA base station control unit 32 supervises or manages the communication passages between optional MA cells 24. A communication passage is a process in a cellular communication system 10 according to which a traffic channel is switched from a communication with a cell to a communication with

another cell.

  The problem solved by the present invention arises when the communication system using a first MA scheme desires to pass the communication of a subscriber into a communication system using a

  second MA diagram. This problem occurs in Figure 1 when the subscriber 28 moves from the CDMA cell 22, cutting the border 26 to an optional MA cell 24.

  The problem can be raised, likewise, without a subscriber 28 cutting the border 26 when, for example, the first communication system MA wishes to pass the

  communication of the subscriber 28 on an optional MA cell 24 having coverage in the area covered by the first MA communication system.

  In the prior art, when for example the first diagram MA is a CDMA, a control beacon 34 is used to warn the CDMA base station control unit 30 that the subscriber 28 is approaching the edge of the CDMA cover ( that is to say the border 26). As used in this case, a control beacon 34 is a transmission signal which is defined or received, in the usual way, by a component in the first diagram MA, the diagram MA which is the source of the communication passage. For example, 35 when the CDMA is the source MA diagram, the control tag 34 is a control channel tag that makes optional MA cells 24 that are outside and adjacent to the border 26 look like another CDMA cell 22 This means that the subscriber 285 reports the presence and the intensity of the piloting beacon 34 to the base station control unit CDMA 30

  according to the rules of CDMA IS-95 in such a way that it can carry out a communication pass with the optional base station control unit MA 32 via a communication link between base station control units MA 36. For a more detailed description, we will do

  reference to U.S. Patent No. 5,594,718 to Weaver Jr. and Ass. issued January 14, 1997.

  The placement of pilot beacons 34 in cells adjacent and outside the border 26 presents many problems. First of all, it is expensive. Each

  control beacon 34 requires a transmitter coupled to an antenna mounted on a suitable structure.

  Second, it increases the complexity of the communication system. CDMA pilot beacons must be synchronized with the rest of the system and identified with

  using only one time lag. Power levels must be set correctly.

  Next, additional antenna sites must be rented or purchased. Some of these site approvals may require negotiation with competitors of

  cellular system for space on a competitor's tower.

  Then, the piloting beacons can be added to the

  noise level of a system used, in the same radio frequency band, by another licensee.

  Finally, the piloting beacon measured by the first system or MA communication source system may not

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  not be a good indicator of the communication quality of a radio frequency link using the second MA communication system. Thus, the quality of the signal from a CDMA control beacon emitted from an AMPS cell in co-occurrence and measured at a subscriber position may not correspond, in a precise manner, to an AMPS signal quality at the same position of subscriber; the AMPS signal can be attenuated while the CDMA pilot beacon is not subjected to it. This can be caused10 by propagation differences between the CDMA control signal at one frequency and the AMPS signal on one

other frequency.

  An alternative to using piloting beacons for communication passages between different MA systems is a blind communication passage beacon without any prior knowledge of

  traffic channel conditions in the second MA communication system. This option can easily cause loss of call. And when the second MA communication system can handle more than one cell.

  For the reasons set out above, an improved method and device are sought for performing a

  communication passage between communication systems having different schemes with more than one access.

  The features of the invention are set out in the appended claims. However, the invention

  itself as well as its preferred mode of use, additional objects and advantages, will be better understood with reference to the following detailed description of an implementation mode, by way of illustration, taken in conjunction

  with the accompanying drawings in which:

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  FIG. 1 illustrates a sample coverage area provided by two communication systems using two different diagrams with several accesses in which the communication passage between the two systems uses piloting beacons according to the prior art; Figure 2 is a high level diagram of a device for effecting communication passage between different multi-access communication systems 10 according to the method and system of the present invention; Figure 3 illustrates an optional mode of implementation of a device for effecting a communication passage between different communication systems with multiple accesses according to the method and the system of the present invention; Figure 4 illustrates a high level diagram of a system with multiple code division accesses for effecting a communication pass with an optional MA communication system according to the method and system of the present invention; Figure 5 is a more detailed block diagram of a first embodiment of a signal characteristic measurement circuit that can be used for the implementation of the method and system of the present invention; Figure 6 illustrates a second embodiment of a signal characteristic measurement circuit that can be used for the implementation of the method and system of the present invention; Figure 7 is a high level logic flow diagram illustrating the method for performing a pass from

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  communication with an optional MA communication system according to the present invention; Figure 8 is a more detailed flow diagram illustrating the subscriber unit initiation method according to the present invention; Figure 9 is a more detailed flow diagram illustrating the method of measuring a signal characteristic in an optional MA communication system according to the present invention; and Figure 10 is a more detailed flow diagram illustrating the method of configuring a receiver for

  measuring a signal characteristic in an MA communication system according to the present invention.

  Referring now to the Figures and in particular to Figure 2, there is illustrated a high level diagram of a device for effecting a communication passage between different communication systems with multiple accesses according to the method and the system of the present invention. As illustrated, a subscriber unit 50 generally includes a first multi-port transmitter / receiver 52 and a second multi-port transmitter / receiver 54 which are both coupled to an antenna 56. The first MA transmitter / receiver 52 is provided for communicating with cells in a first communication system using a first multiple access scheme. Likewise, the second MA transceiver 54 is provided for communicating with cells in a second communication system using a second multi-access scheme. Suitable duplexers (not shown) can be used30 to separate the transmit signals from the receive signals. The frequency of the first MA transmitter / receiver 52 is controlled by a local oscillator 58 and the frequency of the second MA transmitter / receiver 54 is controlled by a

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  local oscillator 60. Each of the local oscillators 58 and can be adjusted to a selected frequency using a command or a signal supplied by a

command 62.

  A second measurement circuit MA 64 is illustrated, likewise, in the embodiment of Figure 2, having an input coupled to an antenna 56 and a measurement output coupled to the control circuit 62. The second measurement circuit MA 64 likewise receives control signals via a command line from control circuit 62. With reference again to the first MA transceiver 52, the downlink traffic 66 is generated from the first MA transceiver 52 and can be coupled to the control circuit 62 and to the clock 68. The downlink traffic 66 may contain a

  control information, clock or synchronization information and voice or other data for processing circuits in the subscriber unit which are not illustrated.

  Uplink traffic 70 is an input signal for the first MA 52 transceiver.

  uplink traffic 70 may contain voice or other subscriber data and control circuit control information 62.

  The second MA transceiver 54 may include an output for downlink traffic 72 and an input for uplink traffic 74 in a similar fashion. Both the downlink traffic 6630 and the downlink traffic 72 as well as the uplink traffic 70 and the uplink traffic 74 are processed in parts of a subscriber unit 50 which are not illustrated, in a way known in the

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  field of art of cellular subscriber units,

  to provide either voice or computer data communication services.

  In operation, the subscriber unit 50 communicates with a cell in a first multi-access communication system via the first MA transceiver 52. The subscriber unit 50 is provided for tuning to the first MA transceiver 52 at a particular frequency which is established or inferred from the local oscillator 58. Periodically, the control circuit 62 can receive an instruction which starts the process of switching or passing communication over a traffic channel in the second system of communication with several accesses. After receiving such an instruction, the control circuit 62 causes the second measurement circuit MA 64 to measure a signal characteristic of a signal from the second communication system MA. Such a signal characteristic is usually the signal strength. The second MA signal characteristic is measured to determine whether or not a successful communication pass can take place between the first MA communication system and the second MA communication system. The measurement of the second signal MA is carried out, in the usual way, at a predetermined instant according to the clock circuit 68, preferably at an instant avoiding an interruption of the downlink traffic 66 or the uplink traffic 70. The second circuit MA measurement signal returns the characteristic measurement signal to the control circuit 62. The control circuit 62 then determines if and how to return the second MA signal characteristic measurement to the first base station control unit MA via the traffic of uplink 70 and the first

MA 52 transmitter / receiver.

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  The measurement frequency of the second MA measurement circuit

  64 is controlled by the frequency of the local oscillator 60 which can be adjusted by the control circuit 62.

  Once the second MA signal measurement referrals are received by the base station control unit in the first MA communication system, the base station control unit can determine that a communication pass in the second system MA communication is adapted and will be successful. Optionally, this communication passage determination10 can be made by the subscriber unit; in this case, the subscriber requests the

  first base station control unit MA to plan the communication pass.

  The subscriber communication passage in the second MA communication system is initiated by a command received via the antenna 56 and the first MA transmitter / receiver 52. At the instant granted, the control circuit 62 switches the downlink traffic and uplink traffic in the subscriber unit 50 from the first MA transceiver 52 to the second MA transceiver 54, thereby completing a communication pass from the first MA communication system to

  the second MA communication system.

  Referring now to Figure 3, there is illustrated an optional embodiment of a device for effecting a communication passage between different communication systems with multiple accesses according to the method and the system of the present invention. In this embodiment, the measurement of the signal from the second multi-access communication system is carried out by the second MA 80 transmitter / receiver. Such a measurement can be implemented using an RSSI ( Reception Signal Amplitude Indicator) like those included in many AMPS transceivers. For 11h 2763195 to carry out, correctly, the characteristic measurement of the second signal MA, the control circuit 62 can pass control information into the second transmitter / receiver MA 80. Such control information can include gain settings , frequencies, frequency ranges, signal type & several accesses to

  measure, a time interval information and the timing of the measurement of the second signal MA.

  The embodiment of FIG. 3 likewise comprises a single local oscillator 82. Then, each of the transceivers 52 and 80 for the first and second MA communication systems shares the same local oscillator 82 which is under the control of the control circuit 62. The local oscillator 82 must be able to switch quickly between two frequencies and stabilize in a short time so that a characteristic of the second signal MA

  can be measured without unduly interrupting downlink traffic 66 or uplink traffic 70.

  Referring now to Figure 4, there is illustrated a high level diagram of a CDMA system for effecting a communication pass with an optional communication system according to the method and system of the present invention. As illustrated, a subscriber unit 9025 includes an antenna 56 for receiving and transmitting signals from cells in both an optional CDMA communication system and an MA communication system. In this example, an optional MA communication system is a communication system using a scheme30 with several different accesses from the CDMA. The CDMA receiver 92 comprises a CDMA downlink traffic circuit comprising a down converter 94, a gain control unit 96, a filter 98, an analog / digital (A / D) converter 100, a grouping means 10235 and a CDMA 104 demodulator. Link traffic

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  CDMA downlink 106 is generated by the CDMA demodulator 104. The down converter 94 performs a frequency shift from the radio frequency signals on the antenna 56 to a lower intermediate frequency passing through the gain control unit 96 .

  Local oscillator 108 provides an input reference frequency for the down converter 44.

  The gain control unit 96 can be implemented using a variable gain amplifier operating under the control of signals from the

command 110.

  The analog / digital converter (A / D) 100 converts the analog signals into a digital word which has

  was sampled at discrete times.

  Such a digital word is provided by grouping means 102 in which, during a CDMA operation

  normal, the numeric word is multiplied by a grouping code from a grouping code source20 112.

  According to an important aspect of the present invention, the grouping signal 114 is selected by a 116 under the control of the control circuit 110. When the grouping code source 112 is selected to supply the grouping signal 114, the output of the means pool 102 is directed to the CDMA demodulator 104 which provides CDMA downlink traffic 106 for operation in a normal CDMA demodulation mode. In a measurement mode, the group signal selector 116 selects the group signal 114 from an optional signal source 118. Then, when the signal from the optional signal source 118 is supplied to the group means 102, the way out of

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  pool 102 is directed to a signal characteristic measurement circuit 120. A signal characteristic value 122 produced by the signal characteristic measurement circuit 120 is then supplied to the control circuit 110. Two modes of implementation of the circuit signal characteristic measurement 120 will

  described below with reference to Figures 5 and 6.

  Reference levels 124, control signals 126, clock 128 and optionally a measurement signal 130 from the optional MA transceiver 132 also constitute inputs for the

command 110.

  The CDMA 134 transmitter is coupled to the antenna 56 for transmitting the CDMA uplink traffic 136.

  The CDMA 134 transmitter likewise operates under the control of signals from the control circuit 110.

  The optional MA transceiver 132 is coupled to an antenna 56 for receiving downlink traffic 138 and uplink traffic 140 according to the rules of the optional MA scheme. The optional MA transceiver 132 operates under the control signals of the control circuit 110. Such control signals can control the frequency of the optional MA transceiver 132, the type of MA used by the transmitter / optional MA receiver 132, precise timing for switching to link traffic

  downlink 138 and uplink traffic 140 which are to be received and transmitted via the optional MA transceiver 132, as well as other similar commands.

  In operation, the control circuit 110 receives a command, via the CDMA downlink traffic 106, to initiate a communication transfer procedure in an optional communication system MA. Before

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  communication passage itself, however, a measurement of a signal is carried out from the communication system MA and this measurement is sent to the base station control unit CDMA. In the mode of implementation illustrated5 in FIG. 4, the CDMA receiver 92 operates in two modes: a normal CDMA demodulation mode and a mode in

MA signal measurement option.

  In the normal CDMA demodulation mode, the grouping signal selector 116 selects a signal from the grouping code source 112 as 114 supplied by grouping 102. In this mode, regular CDMA 106 downlink traffic is generated by the CDMA demodulator 104. Such CDMA downlink traffic 106 may include control signals and timing signals or queues which are respectively supplied to the control circuit 110

and clock 128.

  In the optional MA signal measurement mode, the grouping signal selector 116 selects a signal from an optional signal source 118 as the grouping signal 114 which is supplied to the grouping means 102. The output of the means Aggregation 102 is then used by the signal characteristic measurement circuit 120 to measure a signal characteristic of a signal from an optional MA system. A signal characteristic value 122, the result of the measurement, is supplied to the control circuit 110 and can be compared with a reference level recalled or calculated from the reference levels 124. According to an approval criterion during the report , the control circuit 110 returns such a comparison to the base station control unit CDMA 30 (see FIG. 1) via the transmitter CDMA 134. When the data relevant for a communication transfer decision35 have been gathered, the communication transfer decision

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  is taken either by the subscriber unit, by the

  base station control, either elsewhere; the specific location or functional unit making the decision concerns the system designer.

  When communicating between communication systems, the unit

  Subscriber 90 will transition from using CDMA 106 downlink traffic and CDMA 136 uplink traffic to using optional 138 MA downlink traffic and optional 140 MA uplink traffic.

  Referring now to Figure 5, there is illustrated a more detailed block diagram of a first mode of implementation of a signal characteristic measurement circuit 15 which can be used for implementing the method and system of the present invention. As illustrated, the signal characteristic measurement circuit 120 includes a narrow band filter 150, a power measurement function 152 and an integrator 154. Then, the output of the signal characteristic measurement circuit 120 may be a level of estimated power integrated over a period of time. Such a power level value can be compared to a reference level in the control circuit 110. If the signal characteristic measurement circuit 120 measures a signal from a single channel of the AMPS communication system, the filter narrow band

  can be tuned to the bandwidth of an AMPS channel which is 30 kHz.

  Referring now to Figure 6, a second embodiment of a signal characteristic measuring circuit can be used which can be used for implementing the method and system of the present invention. As illustrated, this second embodiment of the signal characteristic measurement circuit 120 16 t / Jr

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  includes a wideband filter 156 and a circuit

  frequency analysis 158. In operation, the broadband filter 156 may, for example, be adjusted to receive a range of frequencies spanning multiple AMPS channels. The frequency analysis circuit 158 can be used to perform a Fourier transform on the filtered signal.

  Such a Fourier transform can reveal multiple AMPS frequencies from multiple AMPS base stations, any of which can be selected as the base station for a communication pass from a CDMA system to an AMPS system.

  Before the measurements made by the signal characteristic measuring circuit 120 illustrated either in FIG. 5 or in FIG. 6, it may be necessary to adjust an adapted gain on the gain control unit 96 (see FIG. 4) . Depending on the measurement circuit used and which

  Multi-access system must be measured, the control circuit 110 can adjust the gain control unit 96 in such a way that a valid measurement can be made.

  Referring now to Figure 7, a high level logic flow diagram is illustrated illustrating the method for effecting a communication pass with an optional communication system according to the present invention. As illustrated, the method begins at block 200 and then proceeds in block 202 o the method initializes the subscriber unit. This initiation process involves the transfer of parameters and negotiation of protocols between the base station control unit and the subscriber unit. Such an initiation process is described in more detail below with reference to Figure 8. Next, the subscriber unit measures a signal characteristic of a signal from the system

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  optional multi-port communication, as shown in block 204. Such a measurement can be performed using an optional MA transceiver in the subscriber unit, as shown in Figure 3, or Using an optional MA measurement circuit in the subscriber unit, as shown in the example in Figure 2.

  Yet another way to measure the optional MA signal is to use the current MA receiver, as shown in Figure 4, where a CDMA receiver can be reconfigured10 to measure a signal in an optional MA system, such as AMPS.

  After the optional MA signal measurement, the subscriber unit optionally measures a signal characteristic of a signal from the current MA communication system, as shown in block 206. In some communication systems, this step can be optional because the signal characteristic of a signal from the current MA system may be unrelated to the decision to switch communication. However, some systems can be designed to compare the signal characteristic of the signal.

  from the optional MA system with the signal characteristic of the signal from the current MA system.

  After taking the appropriate signal measurements, the subscriber unit returns these signal characteristic measurements to the base station control unit, as shown in block 208. The criteria for returning the signal characteristic measurements can be negotiated during the initiation procedure for block 202. Certain measurements can only be reported if they exceed a certain threshold value, the absence of a signal characteristic report then being

  interpreted as the measurement of a value lower than the threshold value.

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  Note that the step in block 208 may not be required if the system is designed to leave the

  subscriber to decide when and where to communicate; in this case, the subscriber may request a communication pass rather than a report of signal measurement values.

  After the return of all signal characteristic measurements to the current control unit of the MA base station, the method determines whether or not a communication pass should be attempted to the optional MA communication system, as shown in the block. 210. If, for any reason, a communication pass attempt is not to be made, the process returns iteratively to block 204 to update the signal measurements. If the system determines that a communication pass should be made from the

  MA communication in progress in the optional MA communication system, the method then determines whether the optional MA system can accept subscriber traffic or not, as illustrated in block 212.

  If the optional system cannot accept subscriber traffic, the process returns by iterations to block 204 where the measurements are updated. If the optional MA communication system can accept subscriber traffic, the method coordinates a communication pass with the optional MA communication system, as illustrated in block 214. This step can be implemented using communication between the current base station control unit MA and the optional base station control unit MA via a communication link between base station control units MA 36 (see Figure 1). Communication passage coordination may include parameters such as a destination frequency of a channel in the communication system.

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  MA communication optional and a specific time for

  make the communication passage.

  After coordinating the communication pass, the method performs a subscriber communication pass from the current MA communication system to the optional MA communication system, as illustrated in block 216. As for communication passages between the cells any cellular communication system, the communication transition between communication systems with different MAs must take place quickly so that the traffic channel of

  subscriber is not unduly interrupted.

  The method for effecting a communication pass from a communication system with a first MA in a

  communication system with a second MA is then terminated in block 218.

  Referring now to Figure 8, there is illustrated a more detailed flowchart showing the method of initiating a subscriber unit according to the present invention. As illustrated, the initiation procedure begins at block 300 then proceeds to block 302 where the method sends the type of the optional communication system MA to the subscriber. This step may be implicit if the subscriber unit is only designed for a communication passage in another type of optional communication system. The type of system

  optional communication can specify for example an AMPS system, a TDMA system, a GSM system or any other standardized system with several accesses.

  After receiving the type of the optional MA communication system, the process sends a list or

  frequency range to be used by the optional MA communication system, as shown in block 304.

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  The frequency list may include a frequency list of control channels used on various base stations, for example in an AMPS system. Optionally, a frequency range can be specified in which the signal amplitude or other signal characteristic of several frequencies in the range can be

  returned to the base station control unit.

  Then, the subscriber unit receives the reporting criteria for returning the signal measurements from the optional MA communication system, as illustrated in block 306. Such reporting criteria may include instructions for not reporting the characteristics. signal from the optional MA system passing below a threshold value. Then, the absence of a response to a report request can be interpreted by the base station control unit as a measure of a value.

  passing below the accepted threshold. The reason for such reporting criteria may be to reduce the reporting traffic between the subscriber unit and the base station control unit.

  Then, the process negotiates the timing over time of the optional MA signal measurements with the

  MA communication in progress, as shown in block 308. Such negotiation can provide actions taken at predetermined time intervals or actions taken only on demand.

  The initiation process is then complete, as shown in block 310.

  Referring now to Figure 9, a more detailed flow diagram is illustrated showing the method of measuring a signal characteristic or a signal in an optional MA communication system according to the method of the present invention. As illustrated, the process

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  begins at block 400 then proceeds to block 402 o the process determines whether or not it is time to measure a signal characteristic of a signal from an optional MA communication system. If it is not the time to take a measurement, the process makes an iterative loop until the instant of the measurement. The measurement time can be set at predetermined intervals or only upon request from a base station control unit in the current MA communication system. 10 The time taken for optional MA communication system measurements can be negotiated during the procedure

  of initiation, as described with reference to Figure 8.

  If it is time to perform a signal characteristic measurement of a signal from an optional communication system, the method configures the subscriber unit for optional MA signal measurement, as illustrated in block 404. In certain preferred embodiments of the present invention, this configuration method prepares a measurement circuit of signal characteristic 120 to carry out the measurement and can similarly adjust various filters and gains of such

  so that the measurement circuit can provide a valid measurement. This subscriber configuration method is described in more detail below with reference to Figure 10.

  Then, the method measures the signal characteristic of the signal from the optional MA communication system, as illustrated in block 406. In a preferred embodiment, this signal characteristic is the signal amplitude. Depending on the architecture of the subscriber unit, the signal measurement can be carried out using a special configuration of the current MA demodulator or using a dedicated receiver receiving optional MA signals or using the receiver part of the optional MA transceiver. These various 22 lav

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  subscriber architectures are described with reference

in Figures 2 to 4.

  After the signal characteristic measurement, the method reconfigures the subscriber unit for normal operation in the current MA communication system, as illustrated in block 408. If the circuit used

  to measure the signal characteristic is not completely independent of the current MA transceiver, the time period between blocks 404 and 408 must be minimized so as not to unduly interrupt the subscriber traffic .

  After reconfiguring the subscriber unit for normal demodulation in the current MA communication system, the method determines whether the measurement of the optional MA15 signal has been valid or not, as illustrated in block 410. If the measurement is valid, the process ends, as illustrated in the "return" block 412. Optionally, if the measurement is not good, the process adjusts the measurement configuration parameters, such as filter and gain settings, as illustrated in the block 414. Then, the process returns by iterations to block 402 to wait for another

  instant of measurement. For obvious reasons, the underwriter unit will likely return to normal operations while waiting for the next opportunity25 to make a measurement.

  Referring now to Figure 10, there is illustrated a more detailed flowchart showing the method of configuring a receiver for measuring a signal characteristic in an optional MA communication system according to the method of the invention. As illustrated, the method begins at block 500 then passes to block 502 o the method suspends the conversation and listening to several accesses to division by code or modulation and demodulation. Note that the process described in

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  reference to Figure 10 relates specifically to a

  CDMA receiver which is used to perform signal characteristic measurements of a signal from an optional MA communication system, such as the CDMA receiver5 shown in Figure 4.

  Next, the method establishes the frequency of the local oscillator to receive an optional MA communication system frequency, as illustrated in block 504. This step can be used to adjust the local oscillator 108 using a signal. for controlling the control circuit 110 in the subscriber unit 90 illustrated in

Figure 4.

  After setting the local oscillator 108, the method establishes the signal gain and filters for receiving the signal from the optional MA communication system, as shown in block 506. Likewise, the circuit

  Control 110 can send signals to the gain control unit 96 and to the filter 98 for preparing the measurement of a signal from an optional MA communication system.

  Note that steps 504 and 506 can be referenced as configuring a channel selector for receiving a signal from an optional MA system. Such a channel selector is illustrated by the reference numeral 142 in Figure 4. Next, the method selects an optional grouping signal for use in the CDMA grouping means, as illustrated in block 508. With reference to Figure 4 , this step can be accomplished by switching the grouping signal selector 11630 to the optional signal source position so that the grouping signal 114 is from the optional signal source 118. The optional signal source 118 can be a series of zeros or ones producing a constant value signal suspending

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  the grouping operation in the grouping means 102. After selecting the optional grouping signal, the method validates the optional signal characteristic measurement circuit MA, as illustrated in block 510. This step can be carried out by erasing

  registers or in other cases, by resetting the signal characteristic measurement circuit 120. Then, the configuration process ends, as illustrated in block 512.

  In order to configure a subscriber unit having an architecture as illustrated in FIG. 3, the configuration method can execute blocks 502, 504, 506 then jump to block 510 to validate the measurement circuit in the second transmitter / receiver MA 80. In a subscriber unit with an illustrated architecture

  in Figure 2, the measurement configuration method can execute step 506 and then jump to step 510 to perform the measurement in the second measurement circuit MA 64.20 An adjustment of a local oscillator is not necessary because the measurement circuit uses a local oscillator 60.

  In summary, the invention described above allows a communication pass from a first multi-access communication system to a second multi-access communication system, a dual mode subscriber unit assisting the communication passage by measuring signals from the second multi-port communication system in the subscriber unit. A plurality of control beacons emitting signals in the MA30 diagram of the first multi-access communication system are not required, thereby reducing the cost of

  the infrastructure required to allow the passage of communication between systems.

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  While some of the specific examples described above relate to a communication pass from a subscriber unit from a CDMA system to an AMPS system, the basic principles and architectures of the present invention can be used to effect a pass from communication of any system

  multi-port communication in any other multi-port communication system.

  Various means for measuring the optional MA signal characteristics have been described, including a subscriber system using an independent measurement circuit, a subscriber unit sharing a local oscillator circuit between transmitters / receivers for the different communication systems to multiple ports, and a subscriber unit using a reconfigured CDMA receiver to measure a signal characteristic of a signal from an optional multi-port communication system. Such a CDMA receiver can be adjusted in such a way that the grouping operation is suspended20 and that the optional signal passing through the grouping means can be analyzed by integration of

  power over a narrow band or by analysis of a broadband frequency spectrum.

  In certain preferred embodiments of the present invention, the optional signal source 118 may be a dedicated signal improving the measurement of one or more optional MA signals having characteristics

  known. For example, such a signal may contain several discrete frequencies which can be used to detect the power of several optional MA signals.

  The foregoing description of a preferred embodiment of the present invention has been presented for purposes

  of illustration and description. It is not intended to be exhaustive or to limit the invention to the

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  precise shape described. Modifications or variations are possible in light of the above teachings. The mode of implementation has been chosen and described to provide the best illustration of the principles of the invention and5 of its practical application and to allow those skilled in the art to use the invention in various modes of implementation.

  work and according to various modifications such as those adapted to the particular use envisaged. Such modifications and variations are within the scope of the invention as determined by the appended claims interpreted according to the scope of protection

  conferred in a fair, lawful and equal manner.

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Claims (16)

  1. A method in a cellular telecommunication system for effecting a subscriber communication pass from a first multi-access communication system5 in a second multi-access communication system, characterized in that it comprises the following steps: - from a subscriber unit in communication with said first multi-access communication system, measuring a signal characteristic of a signal from said second multi-access communication system to produce a characteristic value of signal; - in response to said signal characteristic value, configuring said subscriber unit to communicate with said second multi-port communication system; and - the realization of a subscriber communication passage from said first system of   multi-port communication in said second multi-port communication system.   2. Method for carrying out a subscriber communication pass according to claim 1,   characterized in that said signal characteristic is the amplitude of the signal.   3. A method for effecting a subscriber communication pass according to claim 1, characterized in that said first multi-access communication system is a multi-access system divided by code and said subscriber unit comprises grouping means using a signal from 28 2763195   grouping and in that the step of measuring a signal characteristic further comprises: - selecting an optional grouping signal for use in said grouping means; the passage of said signal from said second communication system to several accesses in said grouping means; and - measuring a signal characteristic of a signal from said second communication system to   multiple accesses to produce a signal characteristic value.   4. Method for carrying out a subscriber communication pass according to claim 3,   characterized in that said optional grouping signal comprises a grouping signal of constant value.   5. Method for carrying out a subscriber communication pass according to claim 3, characterized in that said optional grouping signal comprises a signal having several preselected discrete frequencies for power measurement   in several signals of said second multi-port communication system having different frequencies.   6. Method for carrying out a subscriber communication pass according to claim 3, characterized in that said step of measuring a signal characteristic of a signal from said second multi-access communication system for the production of a signal characteristic value further comprises frequency analysis of a signal from said second communication system & several 29 2763195   access to produce signal strength values on a range of frequencies.   The method for effecting a subscriber communication pass according to claim 1, characterized in that said step of configuring said subscriber unit to communicate with said second multi-port communication system in response to said signal characteristic value comprises , further, configuring said subscriber unit to communicate with said second multi-port communication system in response to said value   signal characteristic exceeding a predetermined threshold.   8. Method for carrying out a subscriber communication passage according to claim 1, characterized in that it further comprises the following steps: - from said subscriber unit, the measurement of a signal characteristic of a signal from said first multi-port communication system to produce a signal characteristic value of the first system; - comparing said signal characteristic value with said signal characteristic value of the first system; and - configuring said subscriber unit to communicate with said second multi-port communication system in response to said signal characteristic value exceeding said value of   signal characteristic of the first system.   9. Method for carrying out a subscriber communication pass according to claim 1, 2763195   characterized in that said step of configuring said subscriber unit to communicate with said second multi-port communication system in response to said signal characteristic value5 further comprises switching the uplink and downlink traffic from subscriber to from a first multiple access transceiver on a second multiple access transceiver to communicate with said second multiple access communication system   response to said signal characteristic value.   10. Method in a code division multiple access subscriber unit for measuring a signal characteristic of a signal from an optional multiple access communication system, characterized in that it comprises the following steps: - configuring a channel selector to receive said signal from said optional multiple access communication system; - the selection of an optional grouping signal for use in a grouping means in said subscriber unit with several accesses divided by code; - the passage of said signal from said communication system to several optional accesses by said grouping means; and - measuring said signal characteristic of said signal from said multiple communication system optional access.   11. Method in a code division multiple access subscriber unit according to claim, characterized in that said step of configuring a channel selector for the reception of said signal to 31 2763195   from said optional multiple access communication system further includes adjusting a frequency, adjusting a gain and adjusting a filter, each of which is adjusted to receive said signal from said system optional multiple access communication. 12. Method in a code division multiple access subscriber unit according to claim   , characterized in that said optional grouping signal is a constant value signal.   13. Method in a code division multiple access subscriber unit according to claim, characterized in that said step of measuring said signal characteristic of said signal from said optional multiple access communication system15 further comprises, frequency analysis of said signal from said optional multi-port communication system. 14. Device for receiving a signal with several accesses divided by code and for measuring a signal characteristic of a signal from an optional communication system with multiple accesses, characterized in that it comprises: a grouping means having a signal input, a grouping input and a grouping means output; - a grouping code signal source; - an optional grouping signal source; a grouping means signal selector having inputs coupled to said grouping code signal source and to said group signal source 32 2763195   optional grouping, and an output coupled to said grouping input; - a channel selector having an output coupled to said signal input; - a signal characteristic measurement circuit coupled to said grouping means output; and a control circuit coupled to said channel selector and to said grouping means signal selector for configuring said device for receiving said signal with multiple accesses division by code or for measuring a signal characteristic of a   signal from an optional multi-port communication system.   15. Device according to claim 14,   characterized in that said optional grouping signal source is a constant value signal source.   16. Device according to claim 14, characterized in that said grouping signal source   optionally produces a signal with several discrete preselected frequencies20.