Transceiver

0001The invention relates to a transmitter and receiver unit (transceiver).

0002The now widespread mobile radio system GSM, Global System for Mobile Communication, is of technological and economic Sake of a mobile radio system of the third generation be replaced. This system is in Europe under the Name UMTS, Universal Mobile Telecommunications System, and internationally as IMT-2000, International Mobile Telecommunication System 2000, known. UMTS or IMT-2000 is a allow much higher data transmission capacity than GSM.

0003to simultaneously send a system which is capable of to receive and is referred to as a full duplex system. It will also be spoken of full-duplex systems, when sending and receiving are not simultaneous, the Switching between the two phases but the participants unnoticed happens. There are two basic methods Duplex: Frequency division duplex (Frequency Division Duplex, FDD), in which transmission and reception in different accordingly separate frequency bands take place, and time division duplex (Time Division Duplex, TDD), in which the two directions in different time slots are separated. A sending a Mobile station to a base station as an uplink, receiving the mobile station as a downlink, respectively.

0004In TDD transmit and receive frequencies are the same. In FDD fixed duplex frequency in UMTS a duplex frequency provided of 190 megahertz. Finally, a UMTS FDD introduced variable duplex frequency which between may be 134.8 and 245.2 megahertz. When duplex frequency is in this case the frequency spacing of transmit and receive frequency designated. TDD in UMTS is in two frequency bands provided, from 1900 to 1920 megahertz and 2010 to 2025 Megahertz. FDD transmission with fixed duplex spacing of 190 Megahertz is in a transmission band 1920 to 1980 megahertz and a reception band 2110 to 2170 megahertz provided.

0005Data transfer with FDD variable frequency is introduced, to the case of asymmetric data transmission more flexibility to have. It can, for example, two downlink channels be combined with an uplink channel. In this way, a Channel in the FDD transmission band free because in FDD is usually each a transmitter with one receiver channel to a channel pair assigned. This liberated channel in the FDD transmission band can now be used for TDD transmission. This combination two downlink to an uplink channel, however, is only possible if FDD with variable duplex frequency available stands.

0006The combination of two downlink channels with an uplink channel is therefore useful and desirable, since the for UMTS provided mobile internet services, the expected amount of data to the mobile station higher than that of mobile station may be fixed station.

0007Object of the present invention is to provide a transmitting and specify receiving unit, which for all three duplex method FDD, TDD and FDD suitable variable frequency spacing is, and which is also highly integrated.

0008According to the invention, the object is a transmitting and receiving unit solved with<ul><li>a crossover, to an intermediate path and a first are connected the receive path,</li><li>a switch which is connected to the intermediate path and with the incremental path between a transmission path and a is second reception path can be switched, </li><li>a first amplifier connected to the first receive path is and</li><li>a second amplifier coupled to the second receive path connected.</li></ul>

0009The assembly includes a crossover, where a transmission and receiving antenna can be connected. The crossover can in frequency duplex operation between sending and Reception band separated. At the crossover is a Between path connected a switch with respect to a Time division duplex operation between transmit and receive time slots can switch. At the crossover is over a first receive path connected a first amplifier, can be designed which regulated. At the switch a second reception path is connected, to which a second Amplifier is connected, which is likewise adjustable can be.

0010The arrangement described enables highly integratable Filter solution for time division duplex mode, frequency duplex operation with fixed duplex spacing as well as for frequency duplex operation suitable variable frequency separation. The described Arrangement has the advantage that the number of required filter and the number of required high-frequency switch is low. The arrangement of switch and crossover has the advantage that harmonic interference, from the Switch, which is not ideal, are introduced, by the crossover will be filtered out.

0011The arrangement of two amplifiers, each receiving amplifier are, and which can be designed adjustable, has the advantage that these little chip area integrated on a need circuit and that they can be easily integrated are. Each amplifier can respect a minimum are noise component adapted as or for TDD FDD frequency bands used are separately amplified. furthermore can each amplifier individually regarding minimal distortion be adjusted, bearing in mind that the linearity requirements in the UMTS standard with respect to TDD and FDD are different.

0012In an advantageous embodiment of the present invention is connected to the diplexer, an antenna. This antenna may be a transmitting and receiving antenna. furthermore can this antenna directly to the crossover be connected, that is to say without an intermediate high-frequency switch.

0013In a further advantageous embodiment of the present Invention is the transmitting and receiving unit is a UMTS transceiver. The demanded by UMTS support time division duplex, Frequency division duplex and frequency division duplex with variable frequency be of the described transmitting and receiving unit supported.

0014In a further advantageous embodiment of the present Invention is in the transmit path, a power amplifier (Power Amplifier) ​​connected. This power amplifier can be an amplifier with adjustable output power. Of the Power amplifier can be carried out so that both Frequenzduplex- as well as for time division duplex operation, only one power amplifier is required.

0015In a further advantageous embodiment of the present Invention, the crossover, a transmission filter and a reception filter, wherein the passband of the transmit filter the bands of the time division duplex operation and the frequency division duplex transmission mode, and the receiving filter the frequency range the FDD reception band as the pass band has. The transmission filter is compared with a conventional duplex filter extended such that its passband next the FDD uplink band also includes the TDD bands.

0016In a further advantageous embodiment of the present Invention, the transmit filter a passage area 1900-2025 megahertz, and the reception filter a Passage area from 2110 to 2170 megahertz. The transmission filter thus comprises the two TDD bands, and the FDD transmission band the UMTS standard, and the reception filter comprises the FDD reception band. As in TDD mode both transmit and receiving is possible, the relevant separation where the crossover downstream switch performed. As crossover, a duplexer filter use Find, whose pass in the transmission filter from 1920 to 1980 megahertz for FDD transmission on 1900 to 2025 megahertz for FDD and TDD transmission is expanded.

0017In a further advantageous embodiment of the present Invention, the first and the second amplifier low noise preamplifiers (Low Noise Amplifier, LNA). Such LNA whose gain can be controlled, additional High-frequency switches in the two receiver branches are unnecessary. This allows chip area savings and integration be simplified in an integrated circuit.

0018Further details of the invention are defined in the subclaims indicated.

0019The invention is described using two embodiments explained in more detail with reference to the drawings. Show it:<dl tsize="8"><dt>figure 1</dt><dd>a first embodiment of the present invention with reference to a block diagram,</dd><dt>figure 2</dt><dd>the transmission characteristics of the crossover,</dd><dt>figure 3</dt><dd>A second embodiment of the present Invention, </dd><dt>4a</dt><dd>the passband of the first bandpass filter of Figure 3, and</dd><dt>4b</dt><dd>the transmission characteristics of the second bandpass filter according to FIG. 3</dd></dl>

0020Figure 1 shows a crossover DUP, which as a duplexer filter is performed, and to which a transmitting and receiving antenna ANT is connected. Further, at the crossover a first receive path Rx and an intermediate path Tx connected. At the intermediate path Tx is a switch SW connected. It switches either a transmission path on the intermediate path Tx, or the intermediate path Tx on a second Receive path through. At the first and the second receive path is respectively a low-noise preamplifier LNA1, LNA2 connected.

0021The crossover DUP separates first the FDD transmission band from FDD reception band. The transmission-side filter of the diplexer but is extended such that the time division duplex method used belts also in the transmission side fall passband of crossover. As in the time division duplex operation sent in corresponding time slots or is received, is the intermediate path Tx switch SW downstream of the TDD receiving a second low-noise Amplifier that is a receiving amplifier, supplies. There If the present embodiment is a UMTS transceiver is, the passband of the transmission filter comprises the duplex filter the frequency range from 1900 to 2025 megahertz. This is illustrated in FIG. 2 The passband the reception filter in the duplex filter comprises the Frequency range 2110 to 2170 megahertz.

0022The circuitry described enables the operation both in the time division duplex mode, and the frequency duplex operation fixed or variable duplex spacing. The two low-noise receive amplifier LNA1, LNA2, the first of which Receiving amplifiers LNA1 for FDD, and the second receiving amplifier LNA2 adapted for TDD operation, can respect Frequency range, noise and distortion to the respective Needs to be adjusted independently. Since in this case separately controlled receiving amplifier LNA1, LNA2 can be used, the receiving amplifier can also alternate between FDD and TDD without the use ensure additional high-frequency switch.

0023Figure 3 shows an extended transmitting and receiving unit according to Figure 1, the basis of which the present UMTS filter concept with additional band-pass filters and their filter characteristics is explained in detail. The block diagram in Figure 1 is extended to in Figure 3 that the two low noise preamplifiers LNA1, LNA2 ever a band downstream. The first bandpass filter BP1 is respect its frequency range to the frequency duplex receive adapted FDDRx. According to the specified in the UMTS standard FDD downlink frequency band, which from 2110 to 2170 megahertz enough, the first bandpass filter BP1 one at this Frequency band adapted to the pass band, while the remaining suppresses frequencies or strongly attenuated will. The second bandpass filter BP2 which the second low noise amplifier LNA2 downstream, located in time division duplex reception branch TDDRx the UMTS transceiver. the Time division duplex method in accordance with UMTS specification two frequency bands assigned a 1900-1920 of which and another from 2010 to 2025 megahertz ranges. The bandpass filter BP2 accordingly has a passband which both TDD bands, and the intervening FDD transmission band includes, as in FDD operation with variable duplex spacing in the FDD transmission band, a reception and transmission in the context of a done TDD operation with asymmetric data transmission can.

0024If the receiving branch runs as superheterodyne Receiver , that is with a non-zero intermediate frequency, is the second bandpass filter BP2 as image frequency filter and to filter unwanted sidebands may result in a superheterodyne transmitter, indispensable. If the receiver is, however, for an intermediate frequency of 0 MHz designed, the second bandpass filter BP2 can be omitted, since in this case no image frequency occurs and TDD send no unwanted sidebands.

0025The passage characteristics of the first bandpass filter BP1 and the second bandpass filter BP2 are in Figure 4a and 4b together with the receive and transmit bands presented in accordance with UMTS specification. The first and second bandpass filter BP1, BP2 can amplifier stages V1, V2 be followed, in the example an intermediate frequency conversion and subsequent feeding of the received signals can be connected to a baseband module. At the switch SW is in accordance with Figure 3, the time division duplex and Frequency duplex operation common transmission path FDDTx, TDDTx connected. Furthermore, a directional filter FI is provided, which is connected to the transmission path. At this directional filter FI in turn is a variable power amplifier PA (Power Amplifier) ​​connected to a third bandpass filter BP3 is connected upstream. The third bandpass filter BP3 has a center frequency of 1950 megahertz. According to UMTS specifications must bandpass filter BP3 and power amplifier PA a Forward or gain region have, which ranges from 1900 to 2025 megahertz. Thus, the two time division duplex frequency bands and the uplink frequency band duplex covered. The third bandpass filter BP3 , a control amplifier AGC (Automatic Gain Control) upstream be. The this variable gain amplifier can be fed signals For example, from an intermediate frequency with a upconverted mixer to the transmission frequency required in each case will.

0026The circuitry of a UMTS transceiver according to Figure 3 supports specified according to UMTS FDD duplexing, TDD and FDD with variable frequency spacing. The number of required Filter is low, as the number of required High-frequency switch. Between crossover or Duplexer DUP and antenna ANT is arranged no switch, so that the harmonic generated by the switch SW filtered distortion with the duplexer from the useful signals can be. The separation of described allows FDD and TDD reception path of the duplexer filter the use of two, each of the requirements matched low noise receiving amplifiers LNA1, LNA2 which in an integrated circuit a small chip area requirement have and can be easily integrated. This can the low noise amplifier LNA1, LNA2 to noise and Linearity requirements or distortion regardless be matched each other. In addition, with the controllable low noise amplifiers LNA1, LNA2 between switching Frequenzduplex- and time division duplex operation be done.

0027allows the circuit described in FIG 3 an asymmetric data transmission, whereby on the one hand increased utilization of mobile radio channels and at the same time a Mobile unit available downlink bandwidth increased respect commonly used frequency pairs can be. The described compact transceiver architecture is suitable for high-density integration, so that the mobile handsets decreased again can be.

0028With minor changes in the architecture or the passage characteristics of duplexer filters and bandpass filters the circuit described can easily other frequency bands for time division duplex and frequency division duplex operation be adapted, if the described for use Arrangement in other countries is necessary.