MXPA96005914A - Radio subscriber unit that has an apparatus in diversity of switched antenna and method for opera - Google Patents

Abstract

A radio subscriber unit (102) comprises a controller (108) and a switched antenna diversity apparatus (106) that includes a first antenna (114) and a second antenna (116). The first antenna (114) is adapted to receive a first representation (158) of a radiofrequency signal (156). The second antenna (116) is adapted to receive a second representation (160) of a composite radiofrequency signal (156). The receiver (126), selectively coupled to the first antenna (114) and the second antenna (116), generates a received signal (153) in response to the reception of at least one of the first representation (158) of the signal composite radiofrequency (156) from the first antenna (114) and the second representation (160) of the radiofrequency signal (156) from the second antenna (116). The controller (108), coupled to the receiver (126), selectively couples the receiver (126), in response to the received signal (153), one of: only the first antenna (114), only the second antenna (116) and both the first antenna (114) and the second antenna (11)

Description

UNIT OF RADIO-PAIRING THAT HAS AN APPARATUS IN DIVERSITY OF SWITCHED ANTENNA AND METHOD TO OPERATE IT Field of the Invention This invention relates generally to radio subscriber units and, more particularly, to a radio station unit having an antenna diversity apparatus and a method for operating it.

Background of the Invention Radio systems offer wireless communications to users of radio subscriber units. A particular type of radio system is a cellular radiotelephone system. A particular type of radio subscriber unit is a cellular radiotelephone subscriber unit, sometimes referred to as a mobile station. Cellular radiotelephone systems generally include a switch controller connected to a public switched telephone network (PSTN) and a number of base stations. Each of the number of base stations generally defines a geographic region close to the base station to produce coverage areas. One or more mobile stations communicate with a base station that facilitates a call between the base station and the public switched telephone network. In the book "Mobile Cellular Communications Systems" by Dr. William C.Y.Lee, 1989, a cellular radiotelephone system is described.

Some mobile stations have diversity to improve the reception of communication signals sent from the base station. Diversity employs redundancy or duplication of equipment to achieve improved receiver performance under multipath fading conditions. Spatial diversity, in particular, employs two or more antennas that are physically spaced at a distance in relation to the wavelength. In a spatial diversity system, a transmitted signal travels slightly different paths from the transmitter to the two receiver antennas. In addition, there may be reflected paths, where the transmitted signal received by each antenna has also traveled through different paths from the transmitter. Experience has shown that when the reflected trajectory causes fading by interference with the transmitted signal, the two received signals may not be affected simultaneously to the same extent by the presence of the multipath fading, due to the different trajectories. Although the path from the transmitter to one of the antennas can cause phase cancellation of the transmitted waves and reflected path, it is less likely that multiple paths to the other antenna will cause phase cancellation at the same time. The probability that the two antennas are receiving exactly the same signal is called the correlation factor.

Known spatial diversity systems include switched antenna diversity (S-AD), selection diversity (SD), and maximum ratio combining diversity (MRCD). Each diversity system includes a controller that has an algorithm programmed to control the diversity system. In "On Optimizing Receivers in Simple Switched Diversity" by Zdunek et al., Canadian Conference on Communications and Energy of the IEEE of 1978, Montreal, Canada and in "Operation and Optimization of Receivers in Switched Diversity" by Zdunek et al., Communications Conversations of the IEEE, Dec. 1979, a detailed comparison of these three diversity systems is offered.

Following is a brief description of these three diversity systems.

The SAD uses two antennas connected to a single receiver through a two-way, single-pole radiofrequency switch. A controller samples the signal received from each antenna to connect only one of the two antennas to the receiver at a time.

The SD uses two antennas and two receivers, where each antenna is connected to its own receiver. The receiver with the highest ratio of the baseband signal to the noise (SNR) is selected to be the demodulated signal. The SD provides improved performance over the SAD because the signals produced by the receivers can be monitored more frequently than with the SAD and suffer less transient switching effects. However, a defect of both the SAD and the SD is that only one antenna is used at any instant in time, while the other is left out.

The MRCD also employs two antennas and two receivers, where each antenna is connected to its own receiver. The MRCD attempts to exploit the signals from each antenna by switching each signal in proportion to its SNR and then adding them. Consequently, the individual signals in each diversity branch are phased and combined, exploiting all signals, even those with poor SNRs. However, the disadvantage of MRCD is that it is more difficult and complicated to implement than SAD or SD.

A particular type of cellular radiotelephone system employs extended spectrum signaling. The extended spectrum can be defined in general as a mechanism whereby the bandwidth occupied by a transmitted signal is much greater than the bandwidth required by a baseband information signal. Two categories of extended spectrum communications are the extended direct sequence spectrum (DSSS) and the extended frequency hopping spectrum (FHSS). The essence of the two techniques is to extend the energy transmitted from each user by such a bandwidth (1-50 Mhz) that the energy per unit bandwidth, in watts per hertz, is very low.

The frequency jump systems achieve their processing gain avoiding interference, while the direct sequence systems use an interference attenuation technique. For DSSS, the objective of the receiver is to choose the signal transmitted from a wide received bandwidth in which the signal is below the noise level. The receiver must know the carrier frequency signal, the modulation type, the pseudorandom noise code rate and the code phase to do this, since the signal to noise ratios are generally less than 15 to 30 dB. The most difficult is the determination of the code phase. The receiver uses a process known as synchronization to determine the starting point of the code from the received signal to de-spread the required signal while extending all the unwanted signals.

The DSSS technique acquires superior noise performance, compared to the frequency jump, at the expense of increasing the complexity of the system. The spectrum of the signal can be more easily extended by multiplying it with a signal generated by pseudorandom code of bandwidth. It is essential that the extension signal be known precisely so that the receiver can demodulate (ie de-spread) the signal. Moreover, it must automatically follow the correct phase of the received signal within a short time (ie a sub-or partial bit period). At the receiving end, a series search circuit is used. There are two feedback loops, one to automatically follow the correct code phase and the other to track the carrier. For the tracking of the code phase, the code clock and the carrier frequency generator in the receiver are adjusted in such a way that the locally generated code moves back and forth in time in relation to the incoming received code. At the point at which a maximum occurs at the output of the correlator, the two signals are synchronized, which means that the correct code phase has been acquired. The second loop (carrier tracking loop) then tracks the carrier's phase and frequency to ensure that phase tracking is maintained.

A cellular radiotelephone system using DSSS is commonly known as a Direct Sequence Code Division (SD-CDMA) Multiple Access System. Individual users of the system use the same radio frequency but are separated by the use of individual extension codes.

In a DS-CDMA system a forward channel is defined as a communication path from the base station to the mobile station, and a back channel is defined as a communication path from the mobile station to the base station. The operation of the outgoing channel of the DS-CDMA can be greatly improved by adding tilt indicators to the receiver of the mobile station. The performance improvement provided by these additional tilt indicators can approach the operation of MRCD by optimally exploiting the solvable delay extension and soft control transmission. Unfortunately, the field tests have measured only a small percentage of time during which there is a significant solvable delay extension and both the theory and the simulations have shown that the soft control transmission extension is in a very limited range of amplitude of the signal. As a consequence, the outbound channel suffers degradation of operation with respect to the return channel that has antenna diversity and fully exploits all its indicators.

Not only is there a reduced range in the outbound channel but the channel quality is poorer due to the frame error ratio (FER) frequencies being correlated. While channel errors are much more random over time which produces higher quality voice sound. The reason for the correlation is the nature of the fading channel and the slowness of the energy control loop of the forward channel.

The combination of coherent antennas could solve the issue of range imbalance and go a long way in eliminating FER correlation problems. But the combination of coherent antennas is usually avoided in mobile stations due to the cost of duplicating the receiver and especially in DS-CDMA mobile stations due to the high complexity of the receiver.

The SAD can be a solution. SAD is necessary in Pacifica Digital Cellular (PDC) mobile stations. But its multiple time division access (TDMA) method allows you to make an antenna decision immediately before the arrival of a time segment. Switching within the time segment is not allowed. The Ardis ™ Portable Data Terminal uses switched diversity that operates within the message; but it is ineffective at speeds above 10 MPH. This is because the traditional switch algorithm can not be maintained with fast fades.

Accordingly, a radio subscriber unit having a switched antenna diversity apparatus and a method for operating it that overcomes the disadvantages of the prior art and works well in DSSS systems is needed.

Brief Description of the Figures Fig. 1 shows a block diagram of a radio system including the first embodiment of a radio subscriber unit. Fig.2 shows a flow chart describing the operation of the radio subscriber unit of Fig.l. Fig.3 shows a flowchart that describes more a portion of the flowchart of Fig.2. Fig. 4 shows a flow chart that describes more a portion of the flow chart of Fig. 3. Fig.5 shows graphs of probability distribution functions at various levels of chip integration that support the description of the flow diagram in Fig.4. Fig.6 shows a flow chart that describes more of another portion of the flow chart in Fig.2. Fig.7 shows a block diagram of a radio system including a second embodiment of a subscriber unit as an alternative embodiment of the first embodiment of the subscriber unit of Fig.l. Fig.8 shows a block diagram of a radio system including a third embodiment of a radio subscriber unit. Fig.9 shows a block diagram of a radio system including a fourth embodiment of a radio subscriber unit as an alternative embodiment for the third embodiment of the radio subscriber unit of Fig.8. Fig.10 shows a block diagram of a radio system including a fifth embodiment of a radio subscriber unit as an alternate embodiment for the third and fourth embodiments of the radio subscriber unit of Figs.8 and 9. FIG. 11 shows a block diagram of a radio system including a radio subscriber unit incorporating the first embodiment of the radio subscriber unit of FIG. 1 and the third embodiment of the radio subscriber unit of FIG. Fig.8 Detailed Description of the Preferred Embodiment The three general embodiments described below are briefly summarized first for reasons of organization and understanding. The three embodiments can be implemented independently or combined in any way to achieve a desired result. Therefore, there are several possible combinations of the three general embodiments. Many more specific combinations are possible if the particular characteristics of each of the three general embodiments described below are considered.

A first general embodiment, described with reference to Figs. 1-6, describes a radio subscriber unit that includes a diversity antenna receiving apparatus and a method for controlling it. The radio subscriber unit includes a controller and the switched antenna diversity receiving apparatus having a first antenna, a second antenna and a receiver. The controller selectively connects one of only the first antenna to the receiver, only the second antenna to the receiver and both the first and second antenna to the receiver in response to a received signal generated by the receiver.

A second general embodiment, described with reference to Figs. 1-7, describes a method for controlling a diversity receiving apparatus in a radio subscriber unit. The radio subscriber unit includes a controller and the diversity receiving apparatus having a first antenna and a second antenna. The controller controls a selected state of the first antenna and the second antenna in response to at least one of: a ratio (Ec / Io) of the coded pilot signal (Ec) to the received signal strength of all received signals ( lo) and an integration of the received signal intensity indication (IFRS) of the received signal.

A third general embodiment, described with reference to Figs.8-11, describes another method for controlling a diversity receiver in a radio subscriber unit. The diversity receiver receives a first radiofrequency signal modulated by a digital modulation method or a second radio frequency signal modulated by an analog modulation method. In one embodiment the controller controls the diversity receiver in response to a first diversity algorithm when the diversity receiver receives the first radio frequency signal modulated by the digital modulation method and in response to a second diversity algorithm when the diversity receiver receives the second radiofrequency signal modulated by the analog modulation method. In another embodiment, the controller controls the receiver in diversity in response to a first set of information received when the diversity receiver receives the first radio frequency signal modulated by the digital modulation method and in response to a second set of information received when the Diversity receiver receives the second radiofrequency signal modulated by the analog modulation method.

Starting now with the figures, Fig. 1 shows a block diagram of a radio system 100. The radio system generally includes a radio subscriber unit 102 and a base station transceiver 104. The radio subscriber unit 102 generally includes a switched antenna diversity receiver apparatus 106, a controller 108, a user interface unit 110 and a transmitter 112. The switched antenna diversity receiver apparatus 106 generally includes a first antenna 114, a second antenna 116, a first switch 118, a second switch 120, a third switch 122, a load 124 and a receiver 126, a first bandpass filter 133, a first preamplifier 135, a second bandpass filter 137 and a second preamp 139. receiver 126 generally includes a demodulator 128, an intermediate frequency processor 141 that includes a received signal strength determiner (RSSI) 129, an integrator 130, a frequency converter the decentral 155, a first analog-to-digital converter (ADC) 157 and a second analog-to-digital converter (ADC) 170. The block diagram of the radio subscriber unit 102 is amplified to facilitate the understanding of this invention. Practically, the radio subscriber unit 102 also includes many other blocks and connections, as is well known to those skilled in the art.

In the radio subscriber unit 102, the first antenna 114 is connected to the first bandpass filter 133. The first bandpass filter 133 is connected to the first preamplifier 118. The second antenna 116 is connected to the second bandpass filter 137. The second band pass filter 137 is connected to the second pre-amplifier 139. The second pre-amplifier 139 is connected to the second switch 120. The load 124 is connected to the third switch 122. The first switch 118, the second switch 120 and the third switch 122 are each connected at a single point to the line 145 at an input of the receiver 126. The first switch 118 receives a first control signal on the line 146. The second switch 120 receives a second control signal on line 148. Third switch 122 receives a third control signal on line 150.

Receiver 126 receives a radio frequency signal on line 145. The radio frequency signal received on line 145 is connected to an input of descending frequency converter 155 to produce a received signal (Rx) on line 153. The signal received in line 153 is connected to intermediate frequency processor 141. Intermediate frequency processor 141 produces an intermediate frequency signal on line 143 and an RSSI on line 132. The intermediate frequency signal on line 143 is converted to signal analog to digital signal on line 159 by the A / D converter (ADC) 157. The demodulator 128 receives the digital signal on line 159 and produces a demodulated signal (Dx) on line 140. The demodulator 128 also produces a ration (Ec / Io) on line 142 that indicates the ratio of pilot energy (Ec) to all the received signal energy (lo). The second A / D converter (ADC) 170 converts the signal received in line 153 from analog signal to digital signal in line 138. Integrator 130 receives digital RSSI in line 138 and produces an integrated RSSI (JRSSI) in the line 144. The RSSI on line 138, the demodulated signal (Dx) on line 140, the IFRS on line 144, and the relation (Ec / Io) on line 142 are provided to controller 108.

The controller 108 is connected to receive the RSSI on the line 138, the demodulated signal (Dx) on the line 140, the JRSSI on the line 144 and the Ec / Io relation on the line 142. The controller 108 generates the first signal of control on line 146, the second control signal on line 148 and the third control signal on line 150. Controller 108 generates information for transmission on line 152. Controller 108 transmits user interface information to the user interface unit 110 on line 154 and also receive user interface information from user interface unit 110 on line 154.

The user interface unit 110 generally includes, for example, a screen, a keyboard, a headset, a microphone, which are known in the art.

The transmitter 112 is coupled to receive the information on the line 152 and produces information transmitted on the line 154 for transmission by the second antenna 116.

When in operation, the radio system 100 generally operates in the following manner. The base station transceiver 104 communicates with the radio subscriber unit 102 through radio frequency channels. It is generally known that the radio subscriber unit 102 needs to be within the coverage area provided by the base station transceiver 104 to provide effective communication between them. The base station transceiver 104 transmits a radiofrequency signal 156. The radio subscriber unit 102 receives a first representation of the radio frequency signal 156 and a second representation 160 of the radio frequency signal 156. The radio subscriber unit 102 it also generates a transmission signal 162 to be received by the base station transceiver 154.

The radio system 100 generally describes any communication system that operates by radio frequency channels. Radio systems that are intended to be included within the scope of this invention include, for example, cellular radiotelephone communication systems, two-way radio communication systems and personal communication systems (PCS).

In the preferred embodiment, the radio system 100 is a cellular radiotelephone communication system. The types of cellular radiotelephone communication systems that are intended to be included within the scope of this invention include, for example, Direct Sequence Code Division Multiple Access (DS-CDMA) cellular radiotelephone systems, cellular radiotelephone systems of Global System for Mobile Communications (GSM), North American Digital Cellular Cellular Radio (NADC) systems, Time Division Multiple Access (TDMA) systems and TDMA-Extended cellular radiotelephone systems (E-TDMA). GSM systems have been adopted in Europe and in many countries of the Pacific coast. The GSM uses 200 kHz channels with 8 users per channel that use TDMA and has a voice coder speed of 13 kbit / s. NADC systems use 30 kHz channels, with three users per channel and have a speech encoder speed of 8 kbit / s. The E-TDMA uses 30 kHz channels, but has 6 users per channel with a voice coder speed of 4 kbit / s.

In the preferred embodiment, the cellular radiotelephone communication system is a DS-CDMA cellular radiotelephone communication system. The model for this system is described in the Compatibility Model for Wideband Broadband Spectrum Cellular System Double Modality, TIA / ElA, IS-95, published in July 1993 (hereinafter referred to as "Model IS-95"), incorporated herein by reference.

In the IS-95 Model, a nomenclature is given to name the data elements within the subscriber unit (i.e., the mobile station receiver). Table 1 below illustrates the time relationships between various elements in a CDMA radio subscriber unit 102. In the preferred embodiment, the RSSI output of the A / D converter 170 (see Fig. 1) is sampled at the speed of chip while the IFRSSI and Ec / Io ratio entries are sampled in a symbol period.

Table The DS-CDMA is a technique for extended spectrum multiple access digital communications that creates channels through the use of unique code sequences. DS-CDMA signals can be and are received in the presence of high levels of interference. The practical limit of the reception of signals depends on the conditions of the channel, but the reception of DS-CDMA described in the IS-95 Model mentioned above can take place in the interference persistence that is 18 dB greater than the signal for a static channel. Generally, the system operates with a lower level of interference and in dynamic channel conditions.

The DS-CDMA cellular radiotelephone communication system can be divided into sectors or coverage areas as is well known in the art. In a DS-CDMA system the frequencies for communication are reused in all sectors of all cells and most of the interference at a given frequency as seen by the radio subscriber unit 102 is from cells outside the cell. where the radio subscriber unit 102 resides. The residual interference at a given frequency seen by the radio subscriber unit 102 is from the user traffic from within the same cell on the same frequency from (reflected) beams delayed in time where each beam is a composite signal 156 from the base station transceiver 104 that reaches the antennas 114 and 116 in multiple paths each with approximately the same delay.

A DS-CDMA base station transceiver communicates with the radio subscriber unit 102 with a signal having a basic data rate of 9600 bits / s. The signal is then extended at a transmitted bit rate, or chip rate, of 1.2288 Mhz. The extension consists of applying digital codes to the data bits that increase the data rate while adding redundancy to the DS-CDMA system. The chips of all users in that cell are added to form a composite digital signal. The composite digital signal is then transmitted using a form of quadrature phase shift manipulation (QPSK) that has been filtered to limit the bandwidth of the signal.

When a transmitted signal is received by the radio subscriber unit 102, the encoding of the desired signal is removed, returning it to the data rate of 9600 bit / s. When coding is applied to other user codes, there is no de-extention; the received signal maintains the bandwidth of 1.2288 Mhz. The ratio of bits or chips transmitted to data bits is the coding gain. The coding gain for a DS-CDMA system according to the IS-95 Model is 128, or 21 dB. Due to this 21 dB coding gain, interference up to 18 dB above the signal level) 3 dB below the signal strength after the coding gain) can be tolerated for a static channel.

The radio subscriber unit 102 is adapted to be compatible with the radio system type 100. Accordingly, in accordance with the preferred embodiment, the radio subscriber unit 102 is a cellular radio subscriber unit. The radio subscriber unit 102 can have many shapes that are known in the art, for example, a vehicle mounted unit, a portable unit, or a transportable unit. According to the preferred embodiment, the radio subscriber unit 102 is a DS-CDMA radio unit designed to be compatible with the DS-CDMA cellular radiotelephone system as described in the aforementioned IS-95 Model.

The operation of the first general embodiment of the radio subscriber unit 102 is now described in general. In general, the radio subscriber unit 102 includes the first antenna 114, second antenna 116, the receiver 126 and the controller 108. The first antenna is adapted to receive the second representation 160 of the radiofrequency signal 156. The receiver 126, selectively connected to the first antenna 114 and the second antenna 116, generates the received signal (Rx) on the line 153 in response to the reception of at least one of the first representation 158 of the radiofrequency signal 156 from the first antenna 114 and the second representation 160 of the radiofrequency signal 156 from the second antenna 116. The controller 108, connected to the receiver 126, selectively connects to the receiver 126, in response to the signal received on the line 153, one of: only the first antenna 114, only the second antenna 116 and both the first antenna 114 and the second antenna 116.

In the preferred embodiment, the diversity antenna receiving apparatus 106 in the radio subscriber unit 102 has two antennas 114 and 116. However, more than two antennas can be incorporated in a diversity receiving apparatus in the subscriber unit of radio 102 as experts in the art know well. The first antenna 114 and the second antenna 116 generally include any antenna that can receive and / or transmit radio frequency signals. In the preferred embodiment, the first antenna 114 and the second antenna 116 are dipole antennas having a wavelength of half lambda. The location, spacing, orientation, etc. of the first antenna 114 and the second antenna 116, within the radio subscriber unit 102 is well known to one of ordinary skill in the art. The first antenna 114 can be located in a flange element of a portable telephone as a person with ordinary art knowledge knows.

In the preferred embodiment, the second antenna 116 is considered the main antenna because it is connected to both the receiver diversity diversity of the switched antenna 106 and the transmitter 112. The first antenna 114 is considered auxiliary (or alternative) antenna that allows the function in diversity of the receiver. The transmitter 112 is not connected to the first antenna 114.

The first display 158 of the radiofrequency signal 156 and the second display 160 of the radio frequency signal 156 provide information identical to the radio subscriber unit 102. However, due to the spatial relationship of the first antenna 114 and the second antenna 116, the radiofrequency signal received in an antenna may be delayed and attenuated with respect to the radio frequency signal received in the other antenna. The processes of the switched antenna diversity receiver apparatus 106 take advantage of these difficulties to improve the reception of the radio subscriber unit 102.

The receiver 126 is generally of the type designed to process radio frequency signals. An example of the receiver 126 is generally described in the book "Digital Communications" by John Proakis, McGraw-Hill, 1989, or in "Theory of Extended Spectrum Communications-Instructions" by Raymond L. Pickhotz et al., Communications Conversations of the IEEE, vol.com-30, pp. 855-884, 1992. Many functions of the receiver 126 may be implemented in separate parts or as an integrated circuit (IC) as is known in the art.

The analog to digital (A / D) converter 157 samples the intermediate frequency signal on line 143 in a multiple (8X) chip rate. In the preferred embodiment, the energy of the signal received on line 153 has been divided into phase (I) and quadrature phase (Q) components that are normally sampled with an A / D converter pair. An example of an A / D converter suitable for use in the preferred embodiment is a CDX1172 manufactured by Sony Corp.

The demodulator 144 is generally known to those skilled in the art. In the preferred embodiment, the demodulator 144 includes a de-expansion operation, I-Q demodulation, synchronization, tilt indicators, de-interleaving, convolutional decoding of the data determination and the Ec / Io ratio. In the preferred embodiment, the demodulator 144 is a DS-CDMA digital demodulator incorporated within an application-specific integrated circuit (ASIC) described in "CDMA Mobile Station Modem ASIC", Proceedings, Conference on Special Integrated Circuits 1992 of the IEEE, section 10.2, pages.1-5; and "The CDMA Digital Cellular System, a Review of the ASIC", Proceedings of the 1992 Conference on Special Integrated Circuits of the IEEE, section 10.1, pp.1-7.

The second A / D converter. 170 produces samples of a chip speed. An example of the second A / D converter 170 suitable for use in the preferred embodiment is a CDX1175 manufactured by Sony Corp. The RSSI data on line 138 can be determined using only one or both I-Q components of the received radio frequency signal 145.

The integrator 130 provides multi-sample matching of the RSSI data on the line 138. This can be done with dedicated hardware, as shown, or with a software algorithm on the controller 108.

The controller 108 is generally a microcomputer, for example a microprocessor or a digital signal processor (DSP). The controller 108 may be, for example, an MC68332 microcontroller or an MC56156 DSP manufactured and available from Motorola Inc. The controller 108 is generally separated from the receiver 126. However, the controller 108 and the receiver 126 may be combined to form an integral unit , for example an IC.

The radio subscriber unit 102 also includes the first switch 118 and the second switch 120. The first switch 118, connected to the first antenna 114, the receiver 126 and the controller 108, selectively connects the first antenna 114 to the receiver 126 in response to the first control signal on line 146. The second switch, connected to the second antenna 116, the receiver 126 and the controller 108, selectively connect the second antenna 116 to the receiver 126 in response to the second control signal in line 148. Controller 108 is connected to first switch 118 and second switch 120 and generates the first control signal on line 146 and the second control signal on line 148 in response to the signal received on line 153. The controller 108 controls the first switch 118 through the first control signal in the line 146 and the second switch 120 through the second control signal in the line 148 for selectively connect with the receiver 126 one of: only the first antenna 114, only the second antenna 116 and both the first antenna 114 and the second antenna 116.

In the preferred embodiment, the first switch 118, the second switch 120 and the third switch 122 are generally field effect transistors (FETs) formed in an integrated circuit (IC). The switching of the FETs is done by controlling the FETs as is well known in the art. As is characteristic of the diversity antenna dispositions of the switched antenna, the FETs in the reception path produce some loss of receiving sensitivity due to their insertion loss. But the transmission path (Tx) is not affected because there are no switches in the transmission path.

In the preferred embodiment, the deviation of the first preamplifier 135 and the deviation of the second preamplifier 139 are also controlled by the controller 108 (control lines not shown) at the same time as the first switch 118 and the second switch 120, respectively. The pre-amplifiers are deflected when the corresponding switch is opened, connected in series with the pre-amplifier. This helps to reduce the current loss and to improve the insulation when the corresponding antenna is not selected.

Although the first switch 118, the second switch 120 and the third switch 122 are represented as switches of a pole direction, hard switching is not necessary to operate the switch antenna diversity receiver apparatus 106. The first switch 118, the second switch 120 and third switch 122 may alternatively be attenuators controlled by the first control signal on line 147, the second control signal on line 149 and the third control signal on line 151. A typical attenuation value that can be used for attenuation is 20 dB. Therefore, the selected state of the first antenna 114, the second antenna 116 and the load 124 can be achieved by varying the degree of attenuation in the lines 132, line 134 and line 136, respectively.

The selective coupling of the first antenna 114 and the second antenna 116 with the receiver are defined as selected states. In the preferred embodiment, there are three selected states. In the preferred embodiment, the first selected state is produced when only the first antenna 114 is coupled to the receiver 126. In the preferred embodiment, the second state occurs when only the second antenna 116 is coupled to the receiver 126. In the embodiment Preferred, the third selected state occurs when both the first antenna 114 and the second antenna 116 are coupled to the receiver 126. Of course, the description of the selected states is arbitrary and is not limited to the antenna configurations that have just been define.

An advantageous feature provided by a radio subscriber unit 102 are the three selected states of the first antenna 114 and the second antenna 116. In the prior art, only two selected states are possible. In the prior art the two selected states are usually implemented using a two-way one-pole switch controlled by the controller. In the prior art, a selected state is defined as that which occurs when only a first antenna is coupled to a receiver and another selected state occurs when only a second antenna is coupled to the receiver. The prior art does not disclose a third selected state that occurs when both the first and the second antenna are coupled to the receiver, as if disclosed in this application.

Furthermore, in the preferred embodiment, the controller 108 uses a complex set of decisions, indicated here with reference to Figs.2-6, to control the selected states of the first antenna 114 and the second antenna 116. Prior art traditionally uses a simple level of comparison of signals received between the first antenna 114 and the second antenna 116 (with perhaps some added hysteresis).

Moreover, in the preferred embodiment the controller 108 controls the selected states of the first antenna 114 and the second antenna 116 in response to the IFRSSI on line 144 and / or the Ec / Io relation on the line 142. The controller 108 uses these three parameters to optimize alternating antenna sampling as well as when to choose an alternate antenna configuration as server antenna configuration. The prior art does not disclose control of the selected states of the first antenna 114 and the second antenna 116 in response to the IFRSSI on line 144 and / or the Ec / Io relation on the line 142. The advantages of controlling the selected states of the first antenna 114 and the second antenna 116 in response to the IFRSSI on line 144 and / or the Ec / Io relation on the line 142 are described with reference to Figs.2-6 below.

The operation of the diversity antenna receiving apparatus 106 with the first antenna 114 and the second antenna 116 is particularly advantageous when an extended spectrum signal is received, e.g. the DS-CD signal] A. In a DS-CDMA signal the same information, intended for the radio subscriber unit 102, is present in both the first antenna 114 and the second antenna 116. Due to this characteristic of the DS-CDMA signal, the signal ratio The noise of the received signal (Rx) on line 153 will probably improve when the antennas are connected simultaneously. The conditions in which the improvement occurs include signal levels within 10 dB of one another and not in phase opposition.

The third selected state of the first antenna 114 and the second antenna 116 offers an advantage not obtained in the prior art. Previous art also did not use the equivalent of the Ec / Io relation. The appropriate Ec / Io during the third selected state indicates that the antennas can remain both connected even though they may not be in the optimal state. This is discussed in more detail with reference to Figs.2-6.

The radio subscriber unit 102 also includes the load 124 and the third switch 122. The load 124 is coupled to the signal ground potential on the line 164. The third switch, coupled to the load 124, the receiver 126 and the controller 108, selectively couples the load 124 to the receiver 126 in response to the third control signal 150. The controller 108 selectively couples to the receiver 126, in response to the received signal (Rx) ) on line 153, one of: only the first antenna 114 and the load 124, only the second antenna 116 and the load 124 and both the first antenna 114 and the second antenna 116.

In the preferred embodiment, the first selected state is produced when only the first antenna 114 and the load 124 are coupled to the receiver 126. In the preferred embodiment, the second selected state is produced when only the second antenna 116 and the load 124 are coupled to the receiver 126. In the preferred embodiment, the third selected state is produced when both the first antenna 114 and the second antenna 116 are coupled to the receiver 126. The load 124 is not coupled to the receiver 126 in the third selected state.

The load 124 has a predetermined impedance. In the preferred embodiment the charge forms a predetermined loss termination. An example of load 124 is a resistor. In the preferred embodiment, the load has an impedance of 100 ohms.

It is desired to design the receiver 126 with a predetermined input impedance that suits a predetermined output impedance on the line 145. Accordingly, it is desired that, the predetermined output impedance on the line 145 be substantially constant without taking into account the selection among the three selected states of the first antenna 114 and the second antenna 116. This is achieved first by designing the receiver 126 with a predetermined input impedance adapted to the predetermined output impedance on the line 145 when the first switch 118 and the second switch 120 are both coupled to the receiver 126 in the third selected state. In the preferred embodiment, the predetermined input impedance of the receiver 126 is 50 ohms. In the preferred embodiment, the predetermined output impedance on line 145 when the first switch 118 and the second switch 120 are both coupled to the receiver 126 in the third selected state is 50 ohms.

By ignoring the load 124 for the moment, the output impedance on the line 145 when the first antenna 114 and the second antenna 116 are in the first selected state or in the second selected state (ie, when only one antenna is coupled to the receiver 126), is not equal to the output impedance on the line 145 when the first antenna 114 and the second antenna 116 are in the third selected state (ie, when both the first antenna 114, and the second antenna 116 are coupled to the receiver 126). In the preferred embodiment, the predetermined output impedance on line 145 is 100 ohms when only the first switch 118 and the second switch 120, without the load 124, are coupled to the receiver 126 in the first and second selected states, respectively.

The load 124 is then added to be in parallel with the first antenna 114 or the second antenna 116 when only one antenna is coupled to the receiver 126. The impedance of the load 124 is chosen such that the impedance of the load 124 that is in parallel with the output impedance on line 145 of first switch 118 or second switch 120 is substantially equal to the output impedance on line 145 of first switch 118 or second switch 120 in parallel. In the preferred embodiment, the output impedance on the line 145 when only one of the first switch 118 and the second switch 120, with the load 124, is coupled to the receiver 126 in the first and second selected states, respectively, is 50 ohms .

The selective coupling of the load 124 to the receiver 126 when the first antenna 114 is selected or when the second antenna 116 and the nonselective coupling of the load 124 are selected to the receiver 126 when both the first antenna 114 and the second antenna 116 are selected , maintains a predetermined predetermined output impedance on line 145. Therefore, the predetermined input impedance of receiver 125 is adapted to the predetermined output impedance on line 145.

The prior art does not reveal switching on a load when only one antenna is selected. The prior art does not reveal the third selected state (ie, when both the first and the second antenna are selected at the same time). Since the predetermined output impedance in the prior art is already the same when only one antenna or only the other antenna is selected, the prior art has not faced the problem of maintaining a constant predetermined output impedance towards the receiver.

In the preferred embodiment, the controller 108 couples both the first antenna 114 and the second antenna 116 to the receiver 126 for a period of time before selectively coupling only the first antenna 114 or only the second ar. 116 to the receiver 126. This activity performed by the controller 108 can be summarized with the phrase "do before interrupting the switch". The purpose of this type of switching is to reduce the effects of the switching antennas and to allow time to evaluate the possible benefit of using both antennas in parallel. • In the preferred embodiment, the typical "make time" is a period of symbols. '' In the preferred embodiment / the radiofrequency signals 158 and 160 are composite radiofrequency signals that include a desired radio frequency signal 156 and interference signals represented by the signal 166. In the preferred embodiment, the desired signal is an extended spectrum signal. In particular, the spectrum signal ^ "Tendi or is a direct sequence extended spectrum (DSSS) signal adapted for a CDMA communication system. A general description of the desired radiofrequency signal 156 is shown in the IS-95 Model mentioned above.

The desired radiofrequency signal 156 includes a data signal and at least one coded pilot signal. The data signal contains the information intended for the radio subscriber unit 102. The data signal corresponds to the demodulated signal (Dx) on the line 140. The coded pilot signal is used to synchronize the receiver 126. The coded pilot signal (Ec) is a part of the Ec / Io relation determined on line 142.

Interference signals 166 may come from a variety of sources such as, for example, delayed rays of the radio frequency signal 156, transmissions from other DS-CDMA base stations and spurious energy from other radio transmissions.

A summary of the preferred operation of the second general embodiment of the radio subscriber unit 102 is given below. The first antenna 114 receives the first display 158 of the spread spectrum radio signal 156. The second antenna 116 receives the second display 160 of the spread spectrum radio signal 156. The receiver, selectively coupled to the first antenna 114 and the second antenna 116, generates a second received signal 153, including at least one Ec / Io relation on the line 142, in response to receiving at least one of the first display 158 of the spread spectrum radio signal 156 from the first antenna 114 and the second display 160 of the spread spectrum radio signal 156 from the second antenna 116. first switch 118, coupled to the first antenna 114, the receiver 126 and the controller 108, selectively couples the first antenna 114 to the receiver 126 in response to the first control signal on line 146. Second switch 120, coupled to second antenna 116, receiver 126 and controller 108, selectively couples second antenna 116 to receiver 126 in response to the second signal control on line 148. Load 124 has a predetermined impedance. The third switch 122, coupled to the load 124, the receiver 126 and the controller 108, selectively couples the load 124 to the receiver 126 in response to the third control signal 150. The controller 108, coupled to the first switch 118, the second switch 120 and the third switch 122, generates the first control signal on line 146, the second control signal on line 148 and the third control signal on line 150 in response to the Ec / Io relationship on line 142.

The controller 108 controls the first switch 118 in response to the first control signal on line 146, the second switch 120 in response to the second control signal on line 148 and the third switch 122 in response to the third control signal in line 150 for selectively coupling receiver 126, one of: only the first antenna 114 and the load 124, only the second antenna 116 and the load 124 or both the first antenna 114 and the second antenna.116.

The controller 108 controls the first switch 118, the second switch 120 and the third switch 122 to selectively couple both the first antenna 114 and the second antenna 116 to the receiver 126. For a period of time before the selective coupling of the first antenna 114 and the load 124 or the second antenna 116 and the load 124 to the receiver 126, the controller 108 couples both the first antenna 114 and the second antenna 116 to the receiver 126.

The three selected states of the first antenna 114 and the second antenna 116 are controlled by the controller 108 in response to the IFRS on line 144 and / or the Ec / Io relation on the line 142. Details of the operation of the controller 108 in response to their input signals are now described with reference to Figs.2-6.

The flowcharts illustrated in Figs.2,3,4,6 are incorporated into the read-only memory (ROM) (not shown) associated with the controller 108. Fig.2 illustrates decisions made by the controller 108 which generally consider a level of the IFRSI with respect to a predetermined threshold, the level of the desired radio frequency signal in relation to the composite radiofrequency signal, the number of selected antenna states and the level of relationship (Ec / Io) and / or the level of the JRSSI. Fig.3 illustrates decisions made by the controller 108 that generally consider when to change the selected states of the antennas based on the JRSSI level at various time points. Fig.4 illustrates decisions made by the controller 108 that generally consider how to measure the JRSSI level. Fig.5 provides support to determine how the JRSSI level is measured. Fig.6 illustrates decisions made by the controller 108 that generally consider when to change the selected states of the antennas based on the level of the relationship (Ec / Io) in relation to a predetermined threshold.

Fig.2 illustrates a flow diagram 200 describing the operation of the radio subscriber unit 200 of Fig.l. The flow chart 200 comprises a set of steps 202,204,205,206,208,210,212 which define a predetermined set of operating conditions for the controller 108.

In step 202 it is determined whether an IFRS is greater than a predetermined threshold. In the preferred embodiment, the predetermined threshold is 6 dB. The predetermined threshold is adjusted empirically to represent a level above the sensitivity of the receiver 126.

In step 202, when it is determined that the IFRS is greater than the sensitivity of the receiver, for example, greater than 6 dB, the first antenna 114 and the second antenna 116 may be left in parallel most of the time. In the preferred embodiment, the third selected state is produced when both the first antenna 114 and the second antenna 116 are connected in parallel with the receiver 126. The change from an antenna state in parallel to a single antenna switch is performed when there is a fall in the IFRS that would indicate that the thermal threshold has been reached due to a peak fading in both the first antenna 114 and the second antenna 116, or a signal cancellation between the first antenna 114 and the second antenna 116.

If the determination of step 202 is positive, then, in step 204, it is determined whether the desired radio frequency signal 156 dominates the composite radiofrequency signal 158 or 160. In the preferred embodiment, the desired radiofrequency signal 156 dominates the signal from composite radiofrequency 158 or 160 when the demodulator 128 detects the desired radiofrequency signal 156 at levels 10 dB higher than other detected signals. The purpose of the determination of step 204 is to provide an indication of the radio subscriber unit 102 is a multipath fading condition or soft control transmission versus a flat fading condition. The multi-path fade conditions, soft control transmission and plane fading are well understood by those skilled in the art. The multipath fading condition or soft control transmission occurs when the desired radio frequency signal does not dominate the composite radio frequency signal. The flat fading condition occurs when the desired radiofrequency signal 156 does not dominate the composite radio frequency signal 158 or 160.

If the determination of step 204 is negative, then, in step 205, the controller 108 selects the first antenna 114 or the second antenna 116, or both the first antenna 114 and the second antenna 116 in response to a ratio of Ec / Io . The reason why only one ratio of Ec / Io and not JRSSI is used is the IFRSI does not represent the magnitude of the desired radiofrequency signal 156. Further details of step 205 are discussed with reference to Fig.6.

If the determination in step 204 is positive, then, in step 206, the controller 108 selects the first antenna 114, the second antenna 116 or both the first antenna 114 and the second antenna 116 in response to the IFRS or the ratio of Ec / Io. The reason why the JRSSI OR the Ec / Io relation can be used is that the RSSI now represents substantially the magnitude of the desired radiofrequency signal 156 and Ec / Io is always representative of the magnitude of the desired radio frequency signal 156 The details of step 206 with respect to the selected state of antennas 114 and 116 in response to JRSSI are described in detail with reference to Figs.3-5. The details of step 206 with respect to the selected state of the antennas in response to the Ec / Io relation are described in detail with reference to Fig.6.

Turning now to step 202, if the determination in step 202 is negative, then, in step 208, it is determined whether the desired radio frequency signal 156 dominates the composite radiofrequency signal 158 or 160. This step is essentially the same as that described. in step 204.

In step 202, when it is determined that the IFRS is close to the thermal noise (No), for example, less than 6 dB, only one antenna should be connected at a time to the receiver 126. In the preferred embodiment, a first selected state connects only the first antenna 114 to the receiver 126 and a second selected state connects only the second antenna 116 to the receiver 126. This ensures that the added thermal noise (No) of the two antennas in parallel does not degrade the reception. In this case, the antenna switching is synchronized with the edges of symbols and there is no practical reason to perform a "do before interruption". However, there should not be a significant period during which any antenna is connected. Otherwise, valuable information could be lost. Accordingly, there should be close simultaneous switching between a first and second selected antenna states.

If the determination in step 208 is negative, then, the controller selects the first antenna 114 or the second antenna 116 in response to the Ec / Io ratio. step 210 is equal to step 205, with the exception that step 210 does not have a third antenna status selected (ie antennas in parallel). The details of step 210 with respect to the selected states of the antennas in response to the Ec / Io relationship are described in detail with reference to Fig.6.

If in step 208, the determination is positive, then, in step 212, the controller 108 selects the first antenna 114 or the second antenna 116 in response to the IFRSSI or the Ec / Io ratio. Step 212 is the same as step 206, except that step 210 does not have a third antenna status selected (ie antennas in parallel). The details of step 212 with respect to the antenna status selected in response to the IFRS are described in detail with reference to Figs. 3-5. The details of step 212 with respect to the selected states of the antennas in response to the Ec / Io relation are described in detail with reference to Fig.6.

After completing steps 205,206,210,212, the flow chart returns to step 202 where it is again determined whether the IFRS is greater than the predetermined threshold.

Fig. 3 illustrates a flow chart 300 describing a portion of the flow diagram 200 of Fig. 2. In particular, the flow chart of Fig. 3 expands each of the steps 206 and 212 of Fig. 2 to describe how the controller 108 selects the status of the antennas in response to the JRSSI. The general goal of the flow chart of Fig.3 is to have the controller 108 select the state of the antennas that produces the measured JRSSI value.

Fig.3 illustrates that the three antenna states selected in steps 304,310,320 can be selected with controller 108. If controller 108 only needs to select between two selected antenna states, in steps 304 and 310, for example, the current takes the path indicated by dotted line 319 between steps 318 and 302. A brief reference to Fig. 2 shows that only two selected antenna states are used in steps 210 and 212. If controller 108 needs to select between three states of selected antenna, in steps 304,310,312, for example, the current takes the path indicated by line 321 between steps 318 and 320. A brief reference to Fig. 2 shows that three antenna states selected in steps 205 and 3 are used. 206 The flowchart is started in step 302. In step 302 it is determined whether a predetermined period of time has elapsed. The purpose of the predetermined time period is to have the domain verification of the desired radio frequency signal 156 evaluated on a periodic basis. In the preferred embodiment, the predetermined time period has a duration of one second.

If the determination in step 302 is positive, the predetermined time period of one second has elapsed and the flow chart returns to step 202 of Fig.2.

If the determination of step 302 is negative, then, in step 304, the controller places the first antenna 114 and the second antenna 116 in the first selected state by configuring the first switch 118, the second switch 120 and the third switch 122. In In a preferred embodiment, the switches are configured on an edge of a chip that corresponds to an edge of a symbol. In step 206 the first selected state can be any of the three possible antenna combinations. Also, when step 212 is performed, the first selected state excludes placing antenna 114 and antenna 116 in parallel.

In step 306, the controller 108 measures and stores in the memory register one (not shown) the JRSSI. The memory may be, for example, free access memory (RAM) associated with the controller 108.

In step 308, it is determined whether the multiple symbol times have elapsed. The purpose of monitoring symbol times is to provide a delay between successive JRSSI measurements when the selected antenna status changes. If there is no delay, the successive measurements of the ISRSSI could be so similar that there would be no benefit from taking a second measurement. However, if the delay were too long, the first measurement could become too old in time to be of practical use to improve reception.

In general, the sampling of an alternative antenna status is a function of the JRSSI. When the JRSSI is sufficiently high, it is not necessary to sample the alternative antenna. When the IFRS falls, the alternative antenna should be sampled incrementally until it reaches a maximum speed, for example 1020 samples / sec.

The alternative antenna should be sampled often enough to explain Rayleigh's fades. This means that frequent sampling of a slowly varying channel is not necessary and that the average of more samples can be taken to determine a composite sample. In this way, the duration of the sample is less likely to affect reception.

If the determination in step 308 is negative, then the current returns to step 308 until the multiple symbol times have elapsed. If the determination in step 308 is positive, the current goes to step 310.

In step 310 the controller 108 changes the first antenna 114 and the second antenna 116 to a second selected state by configuring the first switch 118, the second switch 120 and the third switch 122. In the preferred embodiment, the switches are configured on one edge of a chip corresponding to an edge of a symbol. In step 206, the second selected state can be any of the three possible antenna combinations. Further, when step 121 is performed, the second selected state excludes placing antenna 114 and antenna 116 in parallel.

In step 312 the controller measures and stores in memory in register two (not shown), the / RSSI. The memory may be, for example, free access memory (RAM) associated with the controller 108. The controller 108 now has a second measurement of the JRSSI to make a comparison with the first measurement of the JRSSI.

In step 314 the controller compares the JRSSI in register two with the JRSSI in register one and stores the result in memory (not shown). The result of the comparison provides an indication as to which selected antenna status would give a better reception.

In step 316, it is determined whether the IFRS measured in register two was raised above or at the same level as the measure in register one. If the determination in step 316 is positive, in step 318 the controller replaces the IFRS measured in register one with the JRSSI measured at time T2. The purpose of the replacement is to load the most recent measurement of the JRSSI into a known memory location for later comparison by a new measurement of the JRSSI. Then the stream returns to step 308 where it is determined whether multiple symbol times have elapsed. Then if the measured JRSSI did not decrease, the antenna configuration remains in the second selected state as long as the IFRSI does not decrease with each measurement.

If, in step 316, the determination is negative, the current passes to step 320 when three selected antenna states are desired and, alternatively, to step 302 when only two selected antenna states are desired.

The dashed line 319 indicates the alternative path of the current between step 318 and step 302. Line 321 indicates the path of current between step 318 and step 320.

If a third selected antenna state is desired, the current passes from step 318 to step 320 where the controller 108 changes the first antenna 114 and the second antenna 116 to the third selected state. The third selected state can be any of the three possible antenna configurations. In step 320, the change to the third selected antenna state occurs at a chip edge corresponding to a symbol border. This portion of step 320 is the same as the portion of the description for the preceding steps 304 and 310.

In step 322 the controller 108 measures and stores in memory (not shown) the IFRS in register two. The controller 108 now has a new measurement of the IFRS to make a comparison with the previous measurement.

In step 324 the controller compares and stores in memory (not shown) the IFRS measure in record two with the JRSSI measured in record one. The result of the comparison provides an indication as to which selected antenna status would give a better reception.

In step 326, the controller 108 determines whether the IFRS measured in register two was raised above or at the same level as the JRSSI measured in register one. If the determination in step 326 is positive, then in step 328, the controller 108 replaces the JRSSI measured in register one with the JRSSI measured in register two. The purpose of the replacement is to load the highest JRSSI measurement into a known memory location for later comparison by a new JRSSI measurement. The stream proceeds to step 308 where it is determined whether multiple symbol times have elapsed. If the measured JRSSI increased, the antenna configuration again performs a measurement of the JRSSI in the second selected state.

If in step 326 the determination is negative, then the current goes to step 302 where it is determined whether the predetermined time period has elapsed.

In steps 304,310,320 the change to the selected state of the antennas occurs at a chip edge corresponding to a symbol edge. The controller coordinates the switching instant with a chip transition of the strongest tilt indicator (not shown in the demodulator 128). This minimizes the effects of oscillation in an intermediate frequency filter of the receiver 126. U.S. Patent No. 4,584,713 shows the bit / switch coordination and recognizes that the transient oscillation is a function of the bandwidth of the intermediate frequency filter and the delay from the number of poles of the intermediate frequency filter. The symbol edge and chip edge detection circuits (not shown in the receiver 126 and the controller 108) involve the synchronization of the antenna switching time with a time advance of a chip clock found in the demodulator 128. degree of advancement is a function of the time delay between the antenna terminals and the demodulator 128 (i.e., chip period module).

Fig. 4 shows a flow diagram 400 that further describes a portion of the flow chart 300 of Fig. 3. In particular, the flow diagram 400 of Fig. 4 describes how the controller 108 measures and stores the IRSSI in memory in each of steps 306,312,322 of Fig. 3.

The flow chart 400 of Fig. 4 generally includes a group of steps such as step 402 and a group of steps generally designated as step 404. Step 402 includes steps 406,408,410,412,414. Step 402 generally shows a method for measuring and storing the JRSSI in consecutive chips. Step 404 generally includes steps 416,418,420,422. Step 404 generally describes the method for measuring and storing the IFRS in non-consecutive chips. The dotted line 415 designates the current path taken between steps 412 and 408 when measuring consecutive chips. Otherwise, current path 417 is taken between steps 412 and 416 when non-consecutive chips are measured.

Referring now to step 406, the controller 108 readjusts the sampling value and the new value of the IFRSSI. The sampling value is a measure of the number of RSSI samples in the IFRS measurement. In the preferred embodiment, the sampling value is zero and the new value of IFRSSI is zero.

In step 408 the controller measures a sample of RSSI taken during a period of chips and adds it with the new value of IFRS.

In step 410, the controller 108 increases the sampling value. In the preferred embodiment, the sampling value is increased by one. In step 412, it is determined whether the sampling value is greater than or equal to a predetermined threshold. In the preferred embodiment, the predetermined threshold is thirty-two sampling values. If the determination in step 212 is positive, then in step 414, the new value of IFRS is stored in memory (not shown). Therefore, the value of IFRS is determined in steps 408, 440, 412 by adding individual samples of the IFRS in a plurality of samples. From step 414, the current passes to step 310.314, or 324 of Fig.3. If the determination in step 412 is negative, then the current continues on path 415 to step 408 when a measurement of consecutive chips is desired. If a measurement of the IFRS for non-consecutive chips is desired, the current passes to step 416 along the path 417.

In step 416, the controller increases a skip value. A skip value is a measure of the number of chips that have to be skipped. In step 418, it is determined whether the skip value is greater than or equal to a predetermined skip value threshold. In the preferred embodiment, the predetermined skip value threshold is ten. If the determination in step 418 is negative, then in step 420 the controller waits a chip period and returns to step 416 where the controller 108 again increases the skip value. If the determination in step 418 is positive, then in step 422 the controller resets the skip value and the current returns to step 408. In the preferred embodiment, the skip value, when readjusted, is zero. Therefore, steps 416,418,420,422 together offer a chip count loop that determines how many chip periods are skipped between successive RSSI measurements.

Fig.5 shows graphs of probability distribution functions 501,502,503,504,505 at various chip speeds to support the description of flow diagram 400 of Fig.4. Fig.5 shows in general a sampling strategy used in the flow diagram of Fig.4. Graphs 501-505 each represent probability distribution functions of five different sample integrations where the unit of the abscissa line is energy in watts. The graph 501 represents a sample integration of 1 chip. The graph 502 represents a sample integration of 2 chips. The graph 503 represents a sample integration of 4 chips. The graph 504 represents a sample integration of 8 chips. The graph 505 represents a sample integration of 16 chips. The graphing of the chip sample reflects the fact that the example limits the voltage to odd integers.

The following provides a practical discussion of a sampling strategy used by the radio subscriber unit 102. The sample duration versus the number of samples is an intermediate solution that needs to be considered in order to achieve a practical design. In the preferred embodiment, the radiofrequency signal 156 transmitted from the base station transceiver 104 is composed of the sum of independent fixed voltages of different amplitude and polarity plus a DC voltage (ie the pilot) significantly stronger than any another individual tension. The result is a probability-of-probability (PDF) function of Gaussian amplitude deviated by the DC voltage. For example, the deviation of DC voltage appears as a peak of 0.05 to 40 watts in the graph 505. The decrease in the number of chips used in the integration degrades the likelihood that the IFRS has been measured exactly as it was. shows in the graphics 504,503,502,501.

Insofar as the channel has not changed much between the samples, the required integration can be made by combining the average of different samples and increasing the sampling interval. For example, an integration of sixteen separate chips is equivalent to an integration of sixteen consecutive chips. Also, an integration of sixty-four chips would derive from sixty-four chip samples in consecutive or alternating symbol boundaries.

Sometimes the signal from the alternative antenna is much louder and an extended sampling interval causes a degradation in the frame error ratio. This problem can be avoided essentially by decreasing the sampling interval. In general, the alternative antenna can be sampled for extremely short time intervals (in the order of a chip sample). For example, consider the digitized sampling power at the output of the falling frequency converter 155 of FIG. The descending frequency converter 155 is adapted to a chip of 0.81 μs of the radio frequency signal 156. Now, considering that, in the worst case, Eb / No of 7 dB is needed, processing gain of 21 dB and Tx energy of 1 W traffic channel over a total of 25 W, the average sample S / N is 7-21 + 25: 1 = 0 dB. Consequently, the average chip sample is almost always a positive S / N. However, the instantaneous chip sample energy is a variable and shows very low chip-to-chip correlation. Then, a sample of a single chip can be too noisy just like the subsequent integration of samples. To overcome this problem, the sampling interval can be extended to more symbols. An important technique is to mount on both symbols borders to minimize deterioration per symbol.

If the sampling interval is in the order of a few chips, the entire sampling interval can be eliminated from the symbol demodulator 128 with only a slight degradation in receiver operation. This is especially effective because the total energy contains transient switching effects and the alternative antenna can be quite noisy.

When only one antenna is coupled to the receiver and a measurement of the IFRS is made, a connection to be made before the interruption in the sampling of the alternative antenna is preferred. This can degrade the S / N up to 3 dB but not introduce transient switching effects particularly if the alternative signal is low. However, adding the two signals together could produce a zero in specific phase and amplitude conditions.

When there is a significant degree of delay extension, due to the channel itself, a soft control transmission region or a combination of both, the chip sample or the RSSI calculation may not be a good indicator of signal fading . Here the sample may need to be a symbol in duration and the measured parameter may need to be the Ec / Io relation.

Following is a practical discussion of the sampling rate. An alternative antenna status is periodically sampled. Sampling can be periodically disconnected when the server signal falls below the ISRSSI S / N threshold or Ec / Io ratio. The radio subscriber unit 102 can reach a calculation of its S / N by means of the parameters: Ec / Io, degree of delay extension derived from the activity of the indicators and scan reports and degree of transmission of control (HO ), again derived from the activity of tilt indicators and exploration reports. The calculated S / N should be an indicator as to whether alternate antenna sampling should occur or not. Of course, a simple rule is to take samples at a minimum speed at all times and at a higher speed when the S / N falls below the threshold.

A sampling rule should be that when the serving antenna has S / N < threshold = > Alternative antenna sample every 10th symbol (1920 samples per second). The sampling rate can be as high as a sample / symbol (19200 s / s) or even higher. As mentioned above, the benefit of high sampling rates is that they can be averaged to reduce the pre-sampling veriation.

In any case, if such a high sampling rate is available, the switching diversity should be able to follow the Rayleigh fading (worst case), even at very high speeds. Therefore, an approximation reasonably close to the optimum switched diversity should be achieved. The typical Doppler frequencies of the worst cases should be less than 100 Hz (@ 75 MPH &894 MHz, Doppler is 75x0.894x1.49). At 1920 samples per second, there are 20 samples for each minimum fading period that is enough time to decide to switch to the other antenna.

It is relatively simple to achieve a calculation of the fading speed from the data and to return the sampling rate to a direct function of the fading speed. The sampling rate could vary from 96 to 1920 samples / s according to the fading speed.

Therefore, the ability to track signal peaks at much higher speeds than a non-CDMA radio subscriber unit makes a fundamental difference with respect to traditional dial-up methods.

Fig.6 shows a flow diagram 600 that further describes another portion of the flow chart 200 of Fig.2. In particular, the flow diagram 600 further details the steps 205, 20, 241, 222 of the flow chart 200 of FIG. 2 with respect to the selection by the controller of the selected antenna states in response to the Ec / Io ratio. If the controller 108 only needs to select between two selected antenna states, in steps 602 and 608, for example, the current takes the path indicated by the dotted line 615 between steps 612 and step 202 of Fig.2. A brief reference to Fig. 2 shows that two antenna states selected in steps 210 and 212 are used. If the controller needs to select between three selected antenna states, in steps 602, 608, 622, for example, the current takes the indicated path by line 623 between steps 622 and step 602 of Fig.2. A brief reference to Fig. 2 shows that three antenna states selected in steps 205 and 206 are used.

In step 602, the controller places the first antenna 114 and the second antenna 116 in the first selected state by configuring the first switch 118, the second switch 120 and the third switch 122. When it represents the steps 205 or 206, the first selected state it can be any of the three possible antenna combinations. Further, when using steps 210 or 212, the first selected state precludes placing the antennas 114 and 116 in parallel. In the preferred embodiment, the changes are made to the chip edge corresponding to the symbol edge. The change of the selected state of the antennas in a chip edge was discussed above with reference to Fig.3.

In step 604, the demodulator determines the Ec / Io ratio from its tilt indicators. Referring briefly to Fig. 1, Ec / Io is provided on line 142 for each of the tilt indicators.

In step 606 it is determined if any of the Ec / Io ratios is above a predetermined threshold that is adjusted to maintain a desired maximum frame error ratio (FER). In the preferred embodiment, the maximum FER is 1% and the predetermined threshold is -14 dB. The new Ec / Io information is available after each symbol period.

If the determination in step 606 is positive, then, in step 607, the controller 108 maintains the first antenna 114 and the second antenna 116 in the first selected state. From step 607, the current returns to step 604 where the Ec / Io ratio is determined again from the tilt indicators of the demodulator 128. Therefore, the selected state of the antennas will be maintained in the first selected state until all Ec / Io ratios fall below the predetermined threshold.

If the determination in step 606 is negative, then in step 608, the controller changes the first antenna 114 and the second antenna 116 to the second selected state by configuring the first switch 118, the second switch 120 and the third switch 122. When it represents in steps 205 or 206, the second selected state can be any of three possible antenna combinations and when steps 210 or 212 are used, the second selected state excludes placing antenna 114 and antenna 116 in parallel. In the preferred embodiment, the changes are made to a chip edge corresponding to a symbol edge. The change of the selected state of the antennas in a chip edge was discussed above with reference to Fig.3.

In step 610, the controller again determines the Ec / Io ratios from the tilt indicators of the receiver 126 as in step 604. In step 612, it is determined whether at least one Ec / Io ratio is above the default threshold. Step 612 fulfills a function similar to step 604 where, for exe, the predetermined threshold is -14dB. If the determination in step 612 is positive, then in step 614. the controller 108 maintains the first antenna 114 and the second antenna 116 in the second selected state. The current from step 614 then returns to step 610 where the controller again determines the Ec / Io ratio from the tilt indicators of the demodulator 128. Then, the selected state of the antennas will be maintained in the second selected state until all the Ec / Io ratios fall below the predetermined threshold.

If the determination in step 612 is negative, then the current returns to step 202 of Fig.2 through path 615 when only two selected states are desired. The controller 108 selects between only two states selected in flow chart 200 of Fig.2 in steps 210 and 212. If the determination in step 612 is negative, then the current goes to step 616 when the controller 108 selects between three selected states of the first antenna 114 and the second antenna 116. In the flow chart 200 of Fig. 2, the controller 108 selects between three selected states of the antennas 114 and 116 in steps 205 and 206.

In step 616 the controller 108 changes the first antenna 114 and the second antenna 116 to a third selected state by configuring the first switch 118, the second switch 120 and the third switch 122. When it represents the steps 205 or 206, the third selected state it can be any of the three possible antenna combinations. In the preferred embodiment, the change to the third selected state is performed at the chip edge corresponding to the symbol edge. The change of the selected state of the antennas in a chip edge was discussed above with reference to Fig.3.

In step 618 the controller again determines the Ec / Io ratio from the tilt indicators of the demodulator 128 as in steps 604 and 610.

In step 620 it is determined whether the Ec / Io ratio is above the predetermined threshold. The determination in step 620 is similar to the determination already made in steps 606 and 612.

If the determination in step 620 is positive then, in step 621, the controller 108 maintains the first antenna 114 and the second antenna 116 in the third selected state. The current then returns from step 621 to step 616 where the controller again determines the Ec / Io ratio from the inclination indicators of the demodulator 128.

If the determination in step 620 is negative, then in step 622 the controller changes the first antenna 114 and the second antenna 116 to the first selected state. In the preferred embodiment, the change occurs at the chip edge corresponding to the symbol edge. The change in the selected state of the antennas at the chip edge was discussed above with reference to Fig.3. The current then passes from step 622 to step 202 of Fig.2.

The second general embodiment, described with reference to Figs. 1-6 and the following Fig. 7, describes a method for controlling a diversity receiving apparatus in a radio subscriber unit. The radio subscriber unit includes a controller and a diversity receiving apparatus having a first antenna and a second antenna. The controller controls a selected state of the first antenna and the second antenna in response to at least one of: an Ec / Io ratio of a coded pilot signal Ec to a calculation of a received signal strength indication RSSI of the signal of composite radiofrequency, and / or an integration of the RSSI (ÍRSSI) of the received signal.

Fig.7 shows a block diagram of a radio system 700 including a second embodiment of a radio subscriber unit 702. In general, the radio subscriber unit 702 of Fig.7 is equal to the unit of radio subscriber 102 of Fig.l except that the diversity receiving apparatus of the radio subscriber unit 702 is a receiver diversity selection device 704, while the diversity receiver apparatus of the radio subscriber unit 102 is a plurality of switched antenna diversity receiving apparatus 106. Therefore, all the common elements between Fig. and Fig. 7 are indicated with the same reference number and no new description of said reference numbers will be made. Fig.7 is presented to show that the same principles illustrated in the switched antenna diversity receiver apparatus 106 of Fig. 1, supported by Figs. 2-6, also apply to the receiver apparatus in diversity selection of the Fig.7 The selection diversity receiver apparatus 704 generally includes the first antenna 114, the second antenna 116 and the first receiver 126 (each shown in FIG. 1) as well as a second receiver 706 and a switch 708. The second receiver 706 in general it includes the same elements as the receiver 126 shown in Fig.l. The second receiver 706 produces a demodulated signal on line 714, and an RSSI on line 716, an IFRS on line 718 and an Ec / Io relation on line 720. The operation of second receiver 706 is equal to the operation of first receiver 126, as described in Fig.l. Consequently, no additional explanations are given here.

In addition, of the signals received from the receiver 126, the controller 108 receives the RSSI on line 716, the IFRS on line 718 and the Ec / Io relation on line 720. The switch receives the demodulated signal on a first terminal ( Dx) on line 140 from first receiver 126 and on a second input terminal the demodulated signal (Dx) on line 714 from second receiver 706. Switch 708 also receives a control signal on line 722 from the controller 108. The control signal 722 controls whether the demodulated signal of line 140 from the first receiver 126 or the demodulated signal on line 714 from the second receiver 706 is routed to the controller on line 724. Accordingly, when in operation , the controller 108 controls the receiver apparatus in selection diversity 704 in response to the ratio of Ec / Io, IFRSSI or both the ratio of Ec / Io as the IFRSI.

The operation of the radio subscriber unit 702 in response to the Ec / Io ratio is described below. The first receiver 126 generates a first signal received on the line 153 (see Fig. 1) including at least one Ec / Io relation on the line 142 in response to reception of the first representation 158 of the composite radio signal 156 from the first antenna 114. The second receiver 706 generates a second received signal (not shown) that includes at least one Ec / Io relation on the line 720 in response to receiving the second representation 160 of the composite radio signal 156 from the second antenna 116. The controller 108 then selects the first demodulated signal on line 140 or the second demodulated signal on line 714 in response to at least one of the first Ec / Io ratio and the second Ec / Io ratio. Therefore, the radio subscriber unit 702 can operate to control the receiver apparatus in selection diversity in response to the Ec / Io ratio.

The operation of the radio subscriber unit 702 in response to the IFRS is described below. The controller measures a first RSSI on the line 138 of the composite radio signal 156 in response to the reception of the first display 158 of the composite radiofrequency signal 156. The controller also measures a second RSSI on the line 716 of the radio signal. composite radiofrequency 156 in response to receipt of the second representation 160 of the composite radio frequency signal 156. The integrator 130 of the first receiver 126 integrates the first RSSI of the composite radiofrequency signal 156 into a plurality of chips to produce a first IFRSI of the composite radio frequency signal 156. The integrator 712 of the second receiver 706 integrates the second RSSI of the composite radiofrequency signal 156 into a plurality of the chips to produce a second IFRSI on the line 718 of the composite radiofrequency signal 156. The controller 108 selects the first demodulated signal on line 140 or the second demodulated signal a on line 714 in response to at least the first IFRSI on line 144 of the composite radiofrequency signal 156 and the second IFRSI on line 718 of the composite radiofrequency signal 156.

The third general embodiment, now described with reference to Figs.8-11, describes another method for controlling a diversity receiving apparatus in a radio subscriber unit. The diversity receiver receives a first modulated radio frequency signal with a digital modulation method or a second radiofrequency signal modulated with an analog modulation method. In one embodiment, the controller controls the receiver in diversity in response to a first diversity algorithm when the diversity receiver receives the first radio-frequency signal modulated with the digital modulation method and in response to a second diversity algorithm when the receiver in diversity receives the second radiofrequency signal modulated with the analog modulation method. In another embodiment, the controller controls the receiver in diversity in response to a first set of information received when the diversity receiver receives the first radio-frequency signal modulated by the digital modulation method and in response to a second set of information received when the Diversity receiver receives the second radiofrequency signal modulated with the analog modulation method.

FIGS. 8, 9, 10 show each a block diagram of a radio system 800 that includes an embodiment of a radio subscriber unit. Figs. 8,9,10 are generally described with reference to Table 2, which is shown below.

U. of Radio Information Sets Received Algorithms Art prior 1 1 Fig.8 1 2 Fig.9 2 1 Fig.10 2 2 Table 2 The radio subscriber unit of the prior art, as shown in Table 1, uses only one diversity algorithm in response to only one set of received information. In general, the only one received information set is calculation of the received signal strength indication (RSSI). In general, only one diversity algorithm is used to control a diversity receiver apparatus within a radio subscriber unit adapted to receive a modulated radio frequency signal with an analog modulation method.

The radio subscriber unit of Fig. 8, as shown in Table 1, uses two or more diversity algorithms in response to only one set of received information. The radio subscriber unit of Fig. 9, as shown in Table 1, uses only one diversity algorithm in response to two or more received information sets. The radio subscriber unit of Fig. 10, as shown in Table 1, uses two or more diversity algorithms in response to two or more received information sets respectively.

Fig.8 illustrates a block diagram of a radio system 800 that includes a third embodiment of a radio subscriber unit 802. The radio system 800 generally includes the radio subscriber unit 802, a first unit transceiver of base 804 and a second base unit transceiver 806.

The first base station transceiver 804 transmits and receives radiofrequency signals 808 using a first modulation method 805. The second base station transceiver 806 transmits and receives radiofrequency signals 810 using a second modulation method 807.

The radio subscriber unit 802 generally includes a diversity receiver apparatus 812, a controller 814, a user interface unit 816 and a transmitter unit 818. The diversity receiver apparatus 812 generally includes a first antenna 820, a second antenna 822. Controller 814 generally includes a first diversity algorithm 834 and a second diversity algorithm 836.

The operation of the radio subscriber unit 802 is described below. The diversity receiving apparatus 812 receives one of the first composite radiofrequency signal 866 and the second composite radiofrequency signal 868. The first composite radio frequency signal 866 includes a desired radio frequency signal 808 modulated with a first modulation method 805 and radio signals. interference 864. The second composite radiofrequency signal 868 includes a desired radio frequency signal 810 modulated with the second modulation method 806 and interference signals 864. The controller 814 controls the diversity receiver apparatus 812 in response to a first diversity algorithm 834. when the diversity receiving apparatus 812 receives the first radiofrequency signal 808 modulated with the first modulation method 805 and a second diversity algorithm 836 when the diversity receiving apparatus 812 receives the second radio frequency signal 810 modulated with the second modulation method 807. The controller 814 control to the diversity receiving apparatus 812 by one or more control signal lines 842.

In the preferred embodiment, the diversity receiving apparatus 812 produces a first received information set 835 in response to receiving the first radiofrequency signal 808 modulated with the first modulation method 805 and a second received information set 837, different from the first received information set 835, in response to the reception of the second radio frequency signal 810 modulated with the second modulation method 807. The first diversity algorithm 834 operates in response to the first received information set 835 and the second diversity algorithm it operates in response to the second set of information received 837.

In the preferred embodiment, the first received information set 835 is exclusive of the second received information set. For example, the first received information set 835 includes IFRS and the Ec / Io relation and the second received information set 837 includes an RSSI. Alternatively, the second received information set 837 may be a subset of the first received information set 835.

Alternatively, the diversity receiving apparatus 812 produces a received information set 835 in response to the reception of one of the first radio frequency signal 808 modulated with the first modulation method 805 and the second radio frequency signal 810 modulated with the second radio frequency method. Modulation 807. Both the first diversity algorithm 834 and the second diversity algorithm 836 operate in response to the received information set 835 through the line 838. Under these conditions the second received information set 837 is not used. For example, the first diversity algorithm 834 and the second diversity algorithm 836 can operate in response to an RSSI. The example can be implemented in a dual-mode radio subscriber unit capable of operating both in an AMPS radio system and in a GSM radio system. In consecunecia the algorithm of diversity changes in response to the type of radio system while the RSSI is used to optimize the control of the receiver in diversity in different radio systems.

The controller 814 determines whether the radio subscriber unit 802 is configured to receive the first radiofrequency signal 808 modulated with the first modulation method 805, the second radio frequency signal 810 modulated with the second modulation method 807 based on an algorithm of predetermined system selection or responding to an entry from the user of the radio subscriber unit 802.

In the preferred embodiment, the diversity receiving apparatus 812 is a switched antenna diversity receiving apparatus 106 as shown in full lines. A modulated antenna receiver apparatus 106 is generally described in the background of the invention herein and is shown in Fig. 1, for example.

Alternatively, the diversity receiver apparatus 812 may be a selection diversity receiver apparatus 704. A selection diversity receiver apparatus 704 is generally described in the background of the invention herein and is shown in Fig.7, by example. In addition, the diversity receiver apparatus 812 may also be a combiner diversity receiver apparatus of maximum ratio 844. A combiner diversity receiver apparatus of maximum ratio 844 is generally described in the background of the invention herein and is well known for the experts in art.

The first modulation method 805 and the second modulation method 807 can each be a digital modulation method or an analog modulation method. Also, the first modulation method 805 and the second modulation method 807 may each be different digital modulation methods or different analog modulation methods. Then, for example, the radio subscriber unit 802 can adapt the diversity receiver apparatus 812 in response to the different modulation methods.

For example, the first modulation method 805 may be a digital modulation method or it may be an analog modulation method. Again, for example, the first modulation method 805 may be a first digital modulation method and the second modulation method 807 may be a second digital modulation method, different from the first digital modulation method. Again, for example, the first modulation method 805 can be a first analog modulation method and the second modulation method 807 can be a second analog modulation method, different from the first analog modulation method.

Digital modulation methods may include, for example, Code Division Multiple Access (CDMA) modulation methods, Time Division Multiple Access (TDMA) modulation methods, Time Division Multiple Access modulation methods - Extended (E-TDMA), modulation methods of Global System for Mobile Communications (GSM). The analog modulation method may include, for example modulation methods of Advanced Mobile Telephone System (AMPS), modulation methods of Advanced Narrow-Band Mobile Phone System (NAMPS), modulation methods of Total Access Communications System (TACS). and modulation methods of Total-Extended Access Communications System (E-TACS).

In the preferred embodiment, the first modulation method 805 is a digital modulation method and in particular a modulation method of CDMA. In the preferred embodiment, the second modulation method 807 is an analog modulation method and in particular an AMPS modulation method.

A radio subscriber unit 802 that can communicate signals using a first modulation method or a second modulation method is known in the art as a dual-mode radio subscriber unit. This means, for example, that the same radio subscriber unit 802 can operate with different radio systems, each radio system modulating its radio frequency signal transmitted using a different modulation method. In the preferred embodiment, one radio system is a digital system and another system is an analog system.

The prior art does not adapt the diversity receiving apparatus of a radio subscriber unit according to the radio system in which the radio subscriber unit is operating. Accordingly, the radio subscriber unit 802 advantageously optimizes the operation of the diversity receiver apparatus 812 according to the radio system in which the radio subscriber unit 802 is operating. Without this advantage, a receiver apparatus in diversity of the art The prior art in a radio subscriber unit can be optimized using only a diversity algorithm when the radio frequency signal is modulated with the first modulation method in a first radio system. When the second radio frequency signal is modulated with the second radiofrequency signal, the same diversity algorithm may have only a minimal improvement in the reception of the second radio frequency signal or may even potentially damage the reception of the second radio frequency signal. In these circumstances, the same diversity algorithm may simply not be compatible between the modulation methods. Alternatively, a radio subscriber unit of the prior art can compromise the operation of a diversity algorithm when one of the first and second radio frequency signals is received to work properly with the first and second modulation methods, respectively. This invention does not damage the received radio frequency signal and does not need to take these compromises.

The first diversity algorithm 834 and the second diversity algorithm 836 can each be known in the art. In the preferred embodiment, the first diversity algorithm 834 is a unique CDMA diversity algorithm and is described in this application with reference to Figs. 1-7. Figsl-7 describe a diversity algorithm for controlling a diversity receiving apparatus that receives a modulated radio frequency signal with a modulation method of CDMA. In the preferred embodiment, the second diversity algorithm 836 is a diversity algorithm used for an AMPS modulation method.

In summary with respect to the preferred embodiment shown in Fig.8, the radio subscriber unit 802 is a radiotelephone subscriber unit. The radiotelephone subscriber unit comprises the plurality of switched antenna diversity receiving apparatus 106 and the controller 814. The switched antenna diversity receiving apparatus 106 receives the first radiofrequency signal 808 modulated with the digital modulation method 805, or the second signal radio frequency 810 modulated with an analog modulation method 807. The controller 814 controls the diversity antenna receiving apparatus 106 in response to the first diversity algorithm 834 when the diversity antenna receiving apparatus 106 receives the first radio frequency signal 808 modulated with the digital modulation method 805 and the second diversity algorithm 836 when the modulated antenna diversity receiver apparatus 106 receives the second radiofrequency signal 810 modulated with the analog modulation method 807.

Therefore, the radio subscriber unit 802 not only adapts its operation to the dual-mode characteristics of the radio system 800, but also adapts its operation to control the receiver apparatus in diversity 812 according to the mode selected in the radio system 800. Accordingly, the diversity receiver apparatus 812 also has dual-mode capability to offer improved receiver operation in dual radio systems.

Fig.9 shows a block diagram of a radio system including a fourth embodiment of a radio subscriber unit 902 as an alternative embodiment to the third embodiment of the radio subscriber unit 802 of Fig.8. All the elements common to Fig.8 and Fig.9 are indicated with the same reference number and no new descriptions are given for these reference numbers.

The diversity receiver apparatus 812 produces a first received information set 835 in response to reception of the first radiofrequency signal 808 modulated with the first modulation method 805 and the second received information set 837, different from the first set of information received 835, in response to the reception of the second radiofrequency signal 810 modulated with the second modulation method 807. The controller 814 controls the diversity receiving apparatus 812 in response to one of the first received information set 835 and the second set of information received 837.

In the preferred embodiment, the controller 814 controls the diversity receiving apparatus 812 in response to the first diversity algorithm 834 operating in response to the first received information set 835 and the second diversity algorithm 836, shown in dotted lines, which operates in response to the second received information set 837. In this case, the second diversity algorithm 836 operates in response to the second received information set 837 by the dotted line 904. The first diversity algorithm 834 does not operate in response to the second set of received information 837, but only to the first received information set 835. An example of this case is described with reference to Fig.8.

Alternatively, the controller 814 may control the diversity receiving apparatus 812 in response to the diversity algorithm 834 operating in response to one of the first received information set 835 and the second received information set 837. For example, the first set of information received 835 includes an Ec / Io relation and the second received information set 837 includes RSSI. For example also, the diversity algorithm 834 controls the receiving apparatus in diversity in response to the quality of information of the received information set. For example, the quality of information can be defined as the magnitude of the Ec / Io relationship or the RSSI. In general, a higher magnitude of the ratio of Ec / Io or a higher value of the RSSI indicates better quality.

As in the third embodiment of the radio subscriber unit shown in FIG. 8, the first modulation method 805 and the second modulation method 807 may each be a digital modulation method or an analog modulation method. In addition, the first modulation method 805 and the second modulation method 807 may each be different digital modulation methods or different analog modulation methods.

Also, as with the third embodiment of the radio subscriber unit shown in Fig.8, the diversity receiving apparatus is preferably a diversity antenna receiving apparatus 106. However, the diversity receiving apparatus may also be a receiving device in selection diversity 704 or a receiving device in combining diversity of maximum ratio 844.

In summary with respect to a preferred embodiment of the fourth embodiment of the radio subscriber unit 902 of FIG. 9, the radio subscriber unit 902 is a radiotelephone subscriber unit. The radiotelephone subscriber unit comprises the diversity antenna receiving apparatus 106 and the controller 814. The diversity antenna receiving apparatus 106 produces the first received information set 835 in response to the reception of the first radio frequency signal 808 modulated with the digital modulation method 805 and the second received information set 837, different from the first received information set 835, in response to the second radiofrequency signal 810 modulated with the analog modulation method 807. The controller 814 controls the apparatus diversity receiver of switched antenna 106 in response to one of the first received information set 835 and the second received information set 837.

Fig.10 shows a block diagram of a radio system including an embodiment of a radio subscriber unit 1002 as an alternate embodiment to the third 802 and fourth 902 embodiments of the radio subscriber unit of Figs. and 9. All the elements common to Figs.8,9,10 are indicated with the same reference numbers and no new descriptions of such reference numbers are given.

The radio subscriber unit 1002 comprises a diversity receiving apparatus 812 and a controller 814. The diversity receiving apparatus 812 produces a first received information set 835 in response to the reception of the first radio frequency signal 808 modulated with a first method modulation 805 and a second received information set 837, different from the first received information set 835, in response to the reception of a second radio frequency signal 810 modulated with a second modulation method 807. The controller 814 controls the receiving apparatus in diversity 812 in response to a first diversity algorithm 834 operating in response to the first received information set 835 and a second diversity algorithm 836 operating in response to the second received information set. 837 As with the third embodiment of the radio subscriber unit 802, shown in Fig.8 and the fourth embodiment of the radio subscriber unit 902 shown in Fig.91, the first method of modulation 805 and the second method of Modulation 807 can each be a digital modulation method or an analog modulation method. In addition, the first modulation method 805 and the second modulation method 807 may each be different digital modulation methods or different analog modulation methods.

Also, as with the third embodiment of the radio subscriber unit 802 shown in Fig.8 and the fourth embodiment of the radio subscriber unit 902 shown in Fig.9, the diversity receiving apparatus 812 is preferably an apparatus diversity receiver of switched antenna 106. However, the diversity receiver apparatus 812 can also be a selection diversity receiver 704 or a combiner diversity receiver apparatus of maximum ratio 844.

In summary with respect to a preferred embodiment of the fifth embodiment of the radio subscriber unit 1002 of FIG. 10, the radio subscriber unit 1002 is a radiotelephone subscriber unit. The radiotelephone subscriber unit 1002 comprises the switched antenna diversity receiving apparatus 106 and the controller 814. The switched antenna diversity receiving apparatus 106 produces the first received information set 835 in response to the reception of the first radio frequency signal 808 modulated with the digital modulation method 805 and the second received information set 837, different from the first received information set 835, in response to the reception of the second radiofrequency signal 810 modulated with the analog modulation method 807. The controller 814 controls the diversity antenna receiving apparatus 106 in response to the first diversity algorithm 834 operating in response to the first received information set 835 and the second diversity algorithm 836 operating in response to the second received information set 837.

Fig.11 shows a block diagram of a radio system 1100 including a sixth embodiment of a radio subscriber unit 1102 incorporating the first embodiment of the radio subscriber unit 102 of Fig. 1 and the third embodiment of the radio subscriber unit 802 of Fig.8. All the elements common to Figs. 1, 8, 11 are indicated with the same reference numbers and no new descriptions of said reference numbers are given.

In the sixth embodiment, the radio subscriber unit 1102 is a cellular radiotelephone subscriber unit of double modality. The dual-mode cellular radiotelephone subscriber unit 1102 receives one of the first composite radiofrequency signal 866 and a second composite radiofrequency signal 868. The first composite radiofrequency signal 866 includes a desired radio frequency signal 808 and interference signals 864. The desired radiofrequency signal 808 is a direct sequence spread spectrum (DSSS) signal. The DSSS signal includes at least one coded pilot signal (Ec). The second composite radiofrequency signal 868 includes a desired radiofrequency signal 810 and interference signals 864.

The dual mode cellular radiotelephone subscriber unit 1102 comprises a diversity antenna receiving apparatus 106 and a controller 108. The receiver diversity diversity apparatus 106 produces a first set of received information (IFRSSI 144 and Ec / Io 142) in response to receiving the signal from desired radiofrequency 808 modulated with a code division multiple access modulation (CDMA) method 805. The first received information set (IFRSSI 144 and Ec / Io 142) comprises a relation (Ec / Io) of the at least one coded pilot signal (Ec) to the first composite radiofrequency signal (lo) and an integration of a calculation of a signal intensity indication received from the first composite radio frequency signal (IFRS). The diversity antenna receiving apparatus 106 also produces a second set of received information (RSSI 138), different from the first received information set (IFRSSI 144 and Ec / Io 142), in response to the reception of the second radio frequency signal 868 including the desired radiofrequency signal 810 modulated with an analog modulation method 807. The second received information set (RSSI 138) comprises a calculation of a second signal intensity indication received from the second radio frequency signal (RSSI) 138 The controller 108 controls the diversity antenna receiving apparatus 106 in response to a first diversity algorithm 834 operating in response to the first set of received information (IFRSSI 144 and Ec / Io 142) and a second diversity algorithm 836 which it operates in response to the second set of information received (RSSI 138).

The first diversity algorithm 834 controls the diversity antenna receiving apparatus 106 through the first 146, second 148 and third 150 control line. The second diversity algorithm 834 controls the diversity antenna receiving apparatus 106 through the first 146 and second 148 control lines.

Claims (11)

REGVINDICATIONS

1. A method (200,300,400,600) for operating a radio subscriber unit (102) adapted to receive a composite radiofrequency signal (156) including a desired radio frequency signal and interference signals, the method (200,300,400,600) characterized in that it comprises the following steps : receiving, by a first antenna (114), a first representation (158) of a composite radiofrequency signal (156); receiving, by a second antenna (116) a second representation (160) of a composite radiofrequency signal (156); 'generating, by a receiver (126), a received signal (153) in response to reception of at least one of the first representation (158) of the composite radiofrequency signal (156) from the first antenna (114) and the second representation (16) of the composite radiofrequency signal ( 156) from the second antenna (116); and selectively coupling the receiver (126), in response to the received signal (153), one of: only the first antenna (114); only the second antenna (116); both the first antenna (114) and the second antenna (116).

2. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1, characterized in that it comprises the following steps: selectively coupling, by a first switch (118), the first antenna (114) to the receiver ( 126) in response to a first control signal (146); and selectively coupling, by a second switch (120), the second antenna (116) to the receiver (126) in response to a second control signal (148); generating the first control signal (146) and the second control signal (148) in response to the received signal (153) to control the first switch (118) and the second switch (120) to selectively couple the receiver (126) one of: only the first antenna (114); only the second antenna (116); both the first antenna (114) and the second antenna (116).

3. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1 characterized in that the radio subscriber unit (102) includes a load having a predetermined impedance, the method (200,300,400,600) characterized in that it also it comprises the following steps: selectively coupling the receiver (126), in response to the received signal (153), one of: only the first antenna (114) and the load (124); only the second antenna (116) and the load (124); both the first antenna (114) and the second antenna (116).

4. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1: sequentially coupling both the first antenna (114) and the second antenna (116) to the receiver (126) for a period of time before of selectively coupling only the first antenna (114) to the receiver (126) or only the second antenna (116) to the receiver (126).

5. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1: characterized in that the desired radio frequency signal is an extended spectrum signal; characterized in that the desired radio frequency signal includes a coded pilot signal (Ec), and characterized in that the step of selectively coupling selectively couples the receiver (126) in response to the at least one coded pilot signal (Ec), one of: the first antenna (114); only the second antenna (116); both the first antenna (114) and the second antenna (116).

6. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1 characterized in that the desired radiofrequency signal includes a coded pilot signal (Ec), the method (200,300,400,600) also comprises the following steps: determining at least one relation (Ec / Io, 142) of the at least one coded pilot signal (Ec) to a calculation of the composite radio signal (lo) in response to the received signal (153); and selectively coupling the receiver (126), in response to the at least one relation (Ec / Io, 142) one of: only the first antenna (114); only the second antenna (116); and both the first antenna (114) and the second antenna (116).

7. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1 characterized in that the desired radiofrequency signal includes at least one data signal (140), characterized in that the at least one signal of data (140) includes a plurality of symbols in sequence (Table 1) that represent data, and characterized in that each of the plurality of symbols in sequence (Table 1) is divided into a plurality of time periods called chips (Table 1), the method (200,300,400,600) characterized in that it also comprises the following steps: measuring an indication of received signal strength (RSSI) of the composite radiofrequency signal (156 ) in response to the received signal (153); integrating the RSSI of the composite radiofrequency signal (156) into a plurality of the chips to produce an integrated RSSI of the composite radiofrequency signal (156); and selectively coupling the receiver (126) in response to the integrated RSSI, one of: only the first antenna (114); only the second antenna (116); and both the first antenna (114) and the second antenna (116).

8. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1 characterized in that the desired radiofrequency signal includes at least one data signal (140), characterized in that the at least one signal of data includes a plurality of symbols in sequence (Table 1) representing data, characterized in that each of the plurality of symbols in sequence (Table 1) is divided into a plurality of time periods called chips (Table 1), the method ( 200,300,400,600) characterized in that it comprises the following step: changing a selectively coupled state of the first antenna (114), the second antenna (116) and the receiver (126) to an edge of a chip.

9. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 8 characterized in that the edge of the chip corresponds to an edge of a symbol.

10. A method (200,300,400,600) for operating a radio subscriber unit (102) according to claim 1 characterized in that the desired radiofrequency signal includes at least one data signal (140) and at least one coded pilot signal (Ec ), characterized in that the at least one data signal includes a plurality of symbols in sequence (Table 1) representing data and characterized in that each of the plurality of symbols (Table 1) is divided into a plurality of time periods called chips (Table 1), the method (200,300,400,600) characterized in that it also comprises the following steps: determining if the desired radio frequency signal substantially dominates the composite radiofrequency signal (156); when it is determined that the desired radio frequency signal does not substantially dominate the composite radiofrequency signal (156) perform the following steps: determine at least one relation (Ec / Io, 142) of the at least one coded pilot signal (Ec ) to a calculation of the composite radiofrequency signal (156) in response to the received signal (153); and selectively coupling the receiver (126) in response to the at least one relation (Ec / Io, 142), one of: only the first antenna (114); only the second antenna (116); and both the first antenna (114) and the second antenna (116); and when it is determined that the desired radiofrequency signal substantially dominates the composite radiofrequency signal (156) perform the following steps: measure an intensity indication (RSSI) (138) of received signal (153) of the composite radio frequency signal (156) in response to the received signal (153); integrating (130) the RSSI (138) of the composite radiofrequency signal (156) into a plurality of the chips (Table 1) to produce an integrated RSSI (144) of the composite radiofrequency signal (156); and selectively coupling the receiver (126), in response to the at least one ratio (Ec / Io, 142) or the integrated RSSI (144) of the composite radiofrequency signal (156), one of: only the first antenna ( 114); only the second antenna (116); and both the first antenna (114) and the second antenna (116).

11. A radio subscriber unit (102) characterized in that it comprises: a first antenna (114) for receiving a first representation (158) of a composite radiofrequency signal (156) including a desired radio frequency signal and interference signals, characterized in that the desired radiofrequency signal includes at least one coded pilot signal (Ec); a second antenna (116) for receiving a second representation (160) of the composite radiofrequency signal (156); a receiver (126), selectively coupled to the first antenna (114) and to the second antenna (116), to generate a received signal (153), which includes at least one coded pilot signal (Ec), in response to reception of at least one of the first representation (158) of the composite radiofrequency signal (156) from the first antenna (114) and the second representation (160) of the composite radiofrequency signal (156) from the second antenna (116). ); a first switch (118), coupled to the first antenna (114), the receiver (126) and a controller (108), for selectively coupling the first antenna (114) to the receiver (126) in response to a first control signal (146); a second switch (120), coupled to the second antenna (116), the receiver (126) and a controller (108), for selectively coupling the second antenna (116) to the receiver (126) in response to a second control signal (148); a load (124) having a predetermined impedance; a third switch (122), coupled to the load (124), the receiver (126) and a controller (108), for selectively coupling the load (124) to the receiver (126) in response to a third control signal (150) ); and characterized in that the controller (108), coupled to the first switch (118), the second switch (120) and the third switch (122), generates the first control signal (146), the second control signal (148) and the third control signal (150) in response to the at least one coded pilot signal (Ec); characterized in that a controller (108) controls the first switch (118) in response to the first control signal (146), the second switch (120) in response to the second control signal (148) and the third switch (122) in response to the third control signal (150) for selectively coupling to the receiver (126) one of: only the first antenna (114); only the second antenna (116); both the first antenna (114) and the second antenna (116).