WO1999008407A2

WO1999008407A2 - Device for transmitting data to mobile radio telephone networks

Info

Publication number: WO1999008407A2
Application number: PCT/DE1998/002090
Authority: WO
Inventors: Stefan Bahrenburg; Christoph Euscher; Tobias Weber; Paul Walter Baier; Jürgen Mayer; Johannes Schlee
Original assignee: Siemens Aktiengesellschaft
Priority date: 1997-08-05
Filing date: 1998-07-24
Publication date: 1999-02-18
Also published as: JP2001512952A; WO1999008407A3; CN1266596A; EP1002434A2; DE19733860A1; AU9430998A; CN1143574C

Abstract

The invention relates to a data transmission device which is used in radio telephone networks for radio transmission in a TDAMA framework and/or a TDD/CDMA transmission procedure. The inventive device comprises control means, an HF part, signal filters, channel estimators, modulators, at least one means of switching controlled by the control means to enable switching between the transmission procedures, data estimators, and channel coders/decoders. According to the invention, at least one signal filter and/or one HF part is jointly used for both transmission procedures.

Description

description

Device for data transmission in mobile radio networks

The invention relates to a device for data transmission in mobile radio networks, in particular base stations and mobile stations in mobile radio networks with TDMA and / or TD / CDMA radio interface.

In mobile radio networks, messages (for example voice, image information or other data) are transmitted with the aid of electromagnetic waves via a radio interface between the transmitting and receiving radio station (base station or mobile station). The electromagnetic waves are emitted at carrier frequencies that lie in the frequency band provided for the respective system. With GSM (Global System for Mobile Communication), the carrier frequencies are in the range of 900, 1800 and 1900 MHz. For future mobile radio networks with TDMA or TD / CDMA transmission methods via the radio interface, for example the UMTS (Universal Mobile Telecommunication System) or other 3rd generation systems, frequencies in the frequency band of approx. 2000 MHz are provided.

The emitted electromagnetic waves are attenuated due to losses due to reflection, diffraction and radiation due to the curvature of the earth and the like. As a result, the reception power that is available at the receiving radio station decreases. This damping is location-dependent and also time-dependent for moving radio stations.

From DE 195 49 158 a radio communication system is known which uses CDMA subscriber separation (CDMA code division multiple access), the radio interface additionally having a time division multiplex subscriber separation (TDMA time division multiple access). It therefore becomes a TD / CDMA transmission method for the radio interface used. On the receiving side, a JD method (JD joint detection) is used in order to perform an improved detection of the transmitted data with knowledge of spreading codes of several participants. It is known that at least two data channels can be assigned to a connection via the radio interface, each data channel being distinguishable by an individual spreading code. The radio communication system shown here is a candidate for a system of the third generation of mobile communications.

P. Vary, "Implementation Aspects of the Pan-European digital mobile radio system", IEEE 1989, pp. 4-17 to 4-22, describes the structure of a GSM radio station with an RF part, filters, channel estimators, modulators / demodulators The GSM standard uses a combination of FDMA (Frequency Division Multiple Access) and TDMA for the radio interface and has found worldwide acceptance. Over 20 million subscribers are served via this standard in Europe alone. Extensive investments in Infrastructure and in mobile stations have been done so far.

The transition from the 2nd generation of mobile communications (GSM) to the 3rd generation of mobile communications will again require considerable investments for network operators if network elements such as mobile switching centers, base station controllers or base stations have to be replaced or additionally installed. Significant development expenditure is also required from the manufacturers of the infrastructure and mobile stations.

The invention is based on the object of specifying a device for data transmission in a mobile radio network which supports TD / CDMA transmission and can be produced economically. This object is achieved by the device with the features of patent claim 1. Advantageous further developments can be found in the subclaims. According to the invention, the device for data transmission in mobile radio networks is used for radio transmission as part of a TDMA and / or as part of a TD / CDMA transmission method. The device contains: control means for controlling the device,

at least one RF part for processing high-frequency transmit and receive signals,

- signal filter for filtering the transmit and receive signals,

at least one channel estimator for evaluating the received signals with regard to their transmission channel,

at least one modulator for modulating the transmission signals,

at least one switching means controlled by the control means for connecting a respective signal filter to a channel estimator or to a modulator, at least one data estimator evaluating received signals for detecting the transmitted data, and

- Channel encoder / decoder for coding or decoding the transmit or receive signals.

According to the invention, at least one signal filter and / or one HF part is used jointly for both transmission methods.

Such a device for data transmission, which provides modulators, channel estimators and data estimators for both transmission methods (TDMA and TD / CDMA), but uses common components - signal filter and / or HF part in common - increases the acceptance of new mobile radio networks and reduces development expenditure , because previously used components can be taken over.

The implementation of CDMA algorithms is simplified and the development effort for these data transmission devices, which also support the evaluation and generation of signals transmitted according to a CDMA transmission method, is considerably reduced. This makes these facilities more economical to manufacture. According to an advantageous embodiment of the invention, the device for data transmission contains a means for power regulation, by means of which the transmission power of the transmission signals is regulated for both transmission methods. Furthermore, it is advantageous to equip the device with at least one block encoder / decoder for additional coding of signaling information. In addition, the control means can be designed in such a way that the received signaling information is evaluated and the signaling information to be sent is processed for both transmission methods.

Signaling algorithms, signaling mechanisms, synchronization and algorithms for power control can be adopted by the GSM mobile network. Adjustments for a TD / CDMA transmission are only necessary in the transmission method for the data via the radio interface.

According to a further advantageous embodiment of the invention, its HF part consists of a receiving part and a transmitting part. It is not necessary to redesign the RF section, just a modification that takes into account the larger bandwidth of the transmit and receive signals.

The higher bandwidth is to be taken into account in the receiving section for signal amplification, filtering and transmission in the baseband and in the transmitting section for signal amplification, filtering and transmission in the high-frequency transmission band. The same applies to the signal filters, which consist of a digital transmission filter and a digital reception filter.

Since at least parts of the functions of the signal filter, the channel estimator, the modulators, the control means, the data estimator, the channel encoder / decoder and block encoder / decoder are advantageously implemented by program components, the implementation of these components is can work together with a digital signal processing device that enables easy updating of the components.

The program components are advantageously structured in such a way that they can be at least partially replaced by new program components transmitted from the mobile radio network or can be switched to the respective other transmission method by new parameters. A software update is thus possible by exchanging or supplementing program components, so that, for example, a mobile station can adapt to the current network environment. For GSM mobile stations, the digital signal processing only needs to be expanded to include the algorithms for joint detection for the transmission layer. Higher layers (layer 2, ..) advantageously remain unaffected.

Exemplary embodiments of the invention are explained in more detail with reference to the accompanying drawings.

Show

1 shows a block diagram of a mobile radio network,

2 to 5 show different combinations of mobile stations and base stations and their ability to support TDMA and TD / CDMA transmission methods,

6 shows a schematic representation of the signaling for exchanging program components,

7 shows a block diagram of the device for data transmission, 8 shows a block diagram of the HF part of the transmitter of the device,

9 shows a block diagram of the HF part of the receiver of the device,

10 shows a detailed block diagram of the transmitter of the device,

11 shows a detailed block diagram of the receiver of the device,

12 shows a block diagram of the signal processing means with program components.

The structure of the radio communication system shown in FIG. 1 corresponds to a known GSM mobile radio network which consists of a multiplicity of mobile switching centers MSC which are networked with one another or which provide access to a fixed network PSTN. Furthermore, these mobile switching centers MSC are each connected to at least one base station controller BSC. Each base station controller BSC in turn enables a connection to at least one base station BTS. Such a base station BTS is a radio station which can establish a radio connection to mobile stations MS via a radio interface. A service control unit SCP in the sense of an intelligent network (IN) implements functions for software updates for the mobile radio network or for parts thereof.

When dividing up the mobile radio network, a distinction can be made between facilities BTS, BSC, the services according to the GSM standard, services according to a 3rd generation standard (UMTS) with TD / CDMA radio interface, or which support both standards. The radio cells of the corresponding base stations BTS (GSM / UMTS), BTS (GSM), BTS (UMTS) can also overlap. According to the invention, the mobility of the mobile stations MS should not be hindered by the different standards available. A mobile station MS that only supports the GSM standard can continue to establish a radio connection to a base station BTS of the GSM standard (FIG. 2). However, the mobile station MS can also be supplied by a base station BTS which supports both standards (UMTS, GSM) (FIG. 5).

A mobile station MS that supports both standards (FIGS. 3 and 4) can communicate with a GSM base station BTS (GSM) as well as with a base station BTS that only allows TD / CDMA transmission or both transmission methods. Such a mobile station MS is a device for data transmission according to the invention. A base station BTS, which supports TD / CDMA or both transmission methods, is also a device according to the invention.

A mobile station MS or a base station BTS, which support TD / CDMA or GSM transmission, do not have to have all the necessary program modules Pl to P9 permanently stored. 6 shows how loading program modules P1 'to P9' replaces or supplements the existing program modules in the sense of a software update or a parameter setting.

An exchange of messages between a mobile station MS and a service control unit SCP, which can also be operated as an operations and maintenance center, begins with information on the network side via an organizational channel. This information signals to the mobile station MS which standards are supported in the corresponding radio cell.

If the subscriber of the mobile station MS specifies a call request (MOC) or a connection to the MobilStation MS (MTC) is requested and the mobile station does not yet have one the necessary program modules Pl 'to P9' for processing the signals in accordance with the available standard, this is reported to the service control unit SCP, which then overwrites the program modules Pl 'to P9' of the mobile station MS or a switchover to the corresponding modules Performs parameter update. A broadcast service or an individual transmission can be selected. The same applies to the base station BTS, which does not have the necessary program modules or parameters P1 'to P9'. The base station BTS can also load the necessary program modules P1 'to P9' from the service control unit SCP.

If both the base station BTS and the mobile station MS have the necessary software, the connection can be established. An alternative way of downloading the software is to store the program modules P1 'to P9' in the base station BTS and from there to make them available to the requesting mobile stations MS.

Furthermore, it is possible to use a dialog between the service control unit SCP and the mobile station MS to select a standard that best (according to performance or cost) corresponds to the service profile desired by the subscriber. During the dialog for the selection of a standard, the service control unit SCP offers the subscriber this in the form of a menu or a table, possibly supplemented by information on costs and the required storage capacity. The subscriber can then make the selection of the standard via the input means of the mobile station MS. The program modules P1 'to P9' (programs, data and / or parameters) belonging to the selected standard are then transmitted from the service control device SCP to the mobile station MS.

The structure of a device for data transmission is shown in Fig. 7, with a division into a digital part, the is realized by digital signal processing means DSP, and an HF part, which consists of a transmitting part HF-S and a receiving part HF-E, is made. The transmitting part HF-S and the receiving part HF-E are connected to a common antenna device A.

The transmission path of the digital signal processing consists of a convolutional encoder FC for channel coding of user data and signaling data which were previously block-coded in a block encoder BC. The data is then scrambled in an interleaver I and, depending on the transmission standard, fed to a modulator GSM-MOD for GSM modulation or a modulator JD-MOD for TD / CDMA modulation. A first switching device UM1, which, like a second switching device UM2 shown later, is controlled by a control device SE, connects the selected modulator GSM-MOD or JD-MOD with a digital transmission filter SF and further with the transmission part HF-S. A means LR for regulating the transmission power controls the transmission power for transmission signals tx in accordance with the specifications of the control means SE.

In the receive path, received signals rx received by the antenna device A are processed in the receiving part HF-E and fed to the digital signal processing. A digital reception filter EF filters the broadband reception signals rx and outputs the signals via the second switching means UM2 to a channel estimator, which is either a channel estimator GSM-KS according to the GSM standard or a channel estimator JD-KS according to the TD / CDMA standard. After the channel estimation, the signals are sent to the respective data estimator

GSM-D or JD-D supplied, which perform the data detection. In a deinterleaver DI, the data from both paths are again descrambled and then fed to a folding decoder FD for channel decoding. Signaling information is fed to a block decoder BD, which decodes this data to the control means SE. The control means SE forwards the signaling data to be transmitted or received into the transmission or reception path and establishes the connection to a human-machine interface MMI (keyboard, screen) at a mobile station MS or to network-side signaling channels at the base station BTS ago.

8 contains a digital / analog converter D / A for real and imaginary parts, first analog transmit filter FS1 for low-pass filtering of the signals in the baseband, a first mixer MSI for converting the transmit signals tx into the transmit frequency band, and one Power amplifier PA for amplifying the transmission signals tx.

9 contains a first analog reception filter EF1, a reception amplifier RPA for measuring and amplifying the reception signals rx, a second mixer MS2 for converting the reception signals rx into the baseband (several mixing stages can also be used), second analog receive filter EF2 and finally an analog / digital converter A / D for real and imaginary parts, which generates digital receive signals rx which can be processed in the digital signal processing means DSP.

The receiving section HF-E and transmitting section HF-S are designed to be broadband, for example for a frequency band of B = 1.6 MHz.

Only the TD / CDMA mode is explained in more detail below.

The transmission path of the device is shown in detail in FIG. 10. It is shown in the usual description form for modeling and simulating a communications system, in which the dependency between different functions and the system structure is shown. In the submodule S2, the input data d ⁽ , k = l..K, which either from the uncoded data d ^, k = l..K, or from the data coded in the submodule S1, d ₂ , k = l..K, The data from a first data source Q1 are transmitted via a user data channel TCH, the data from a second data source Q2 via a signaling channel SACCH or FACCH.

A 4-PSK modulation and a spreading of the data with the

(k) modulated subscriber-specific CDMA codes c, k = l..K takes place in submodule S3. This is followed by the summation of all the spread data sequences in the sub-module S4 and a subsequent integration of the midamble into the burst structure in the sub-module S5. The spectral shaping of the transmission signal s follows in the submodule S6; in the modules S7 to S9 the conversion of the time-discrete 4-times oversampled transmission signal in the baseband s _S6 into the time and value-continuous bandpass range of the transmission frequency band.

11 shows the reception path of the device in detail. In the sub-module E1 according to FIG. 11, the reception signals rx are converted from the transmission frequency band into the low-pass range and the splitting into a real and an imaginary component. Analog sub-pass filtering is carried out in sub-module E2 and, in sub-module E3, a double oversampling of the received signal with 13/3 MHz and a word length of 12 bits is carried out.

In the sub-module E4, digital low-pass filtering is carried out using a filter with a bandwidth of 13/6 MHz with the highest possible slope for channel separation. This is followed by a 2: 1 decimation of the double oversampled signal in sub-module E4.

The received signal e obtained in this way essentially consists of two parts, namely a part em for the channel Estimate and from parts el and e2 for data estimation.

All channel impulse responses are estimated in submodule E5.

(k) words h by means of a known midamble basic code m of all data channels transmitted in the respective time slot.

(k) In sub-module E6, parameters b for adapted filters

(k) determined for each data channel using the CDMA codes c. The sub-module E7 eliminates those of the

(k) Midambles resulting from interference in the reception blocks el / 2 used for data estimation. This is through the

_^ (k) _^ (k) ..,. , _ Knowledge of h and m possible.

In sub-module E8, the calculation of the cross-correlation matrix A A takes place. Since A A has a töplitz structure, only a small part of the matrix has to be calculated here, which can then be used to expand to the full size. In the sub-module E9, Cholesky decomposes A A into H H, where H is an upper triangular matrix. Due to the pottery structure of A A, H also has an approximate pottery structure and does not have to be fully calculated. A vector s represents the reciprocal of the diagonal elements of H, which can be used to advantage in solving equations.

Adapted filtering (matched

(k) filter) of the received symbol sequences el / 2 with b. Sub-module Eil realizes the system solver 1 for H * zl / 2 = el / 2, and

Submodule E12 the system solver 2 for H * dl / 2 = zl / 2. in the

Sub-module E13, the estimated data dl / 2 are demodulated, descrambled and finally fold-decoded using a Viterbi decoder. The decoded data blocks d _E13 are either fed to a first data sink D1 or via the source decoder E14 to a second data sink D2. Source decoding is necessary for data blocks that were transmitted via SACCH or FACCH signaling channels. Fig. 12 shows the device for data transmission, the HF part HF-S and HF-E is pronounced according to Fig. 7 and the digital signal processing means DSP in addition to one or more digital signal processors - not shown - several program modules Pl to stored in a memory P9 contains. These program modules Pl to P9 represent the components of the digital signal filters P8, P9, the channel estimator P6, the modulators P4, the control means Pl, the data estimator P6, the channel encoder / decoder P2, P3 and block encoder / decoder P2, P3. According to a software update, at least parts of the program modules P1 to P9, in particular the program modules P4 and P6 for modulation, channel and data estimation, can be supplemented by program modules P4 'and Pβ', which then also enable transmission with the respective other standard .

The device for data transmission BTS, MS presented in the exemplary embodiments for a mobile radio network with a combination of FDMA, TDMA and CDMA is suitable for requirements on 3rd generation systems. In particular, it is suitable for implementation in existing GSM mobile radio networks, for which only a small amount of change is required. The design of dual-mode mobile stations MS, which function both according to the GSM standard and according to the presented TD / CDMA standard, is facilitated.

Claims

claims

1. Device for data transmission in mobile radio networks, radio transmission being carried out as part of a TDMA and / or as part of a TD / CDMA transmission method,

- with control means (SE) for controlling the facility,

with at least one HF part (HF-E, HF-S) for processing high-frequency transmit and receive signals (tx, rx),

- with signal filters (EF, SF) for filtering the transmit and receive signals (tx, rx),

with at least one channel estimator (JD-KS, GSM-KS) for evaluating the received signals (rx) with regard to their transmission channel,

with at least one modulator (JD-MOD, GSM-MOD) for modulating the transmission signals (tx),

- With at least one switching means (UM1, UM2) controlled by the control means (SE) for connecting a respective signal filter (EF, SF) to one of the channel estimators (JD-KS, GSM-KS) or to one of the modulators (JD-MOD , GSM-MOD), - with at least one data estimator (JD-D, GSM-D) evaluating the received signals (rx) for detecting the transmitted data, and

- With channel coders / decoders (FC, FD) for coding or decoding the transmit or receive signals (tx, rx), at least one signal filter (EF, SF) and / or HF part (HF-E, HF-S ) is used for both transmission methods.

2. Device according to claim 1, with a means (LR) for power control, by which a control of the transmission power of the transmission signals (tx) is carried out for both transmission methods.

3. Device according to one of the preceding claims, with at least one block encoder / decoder (BC, BC) for additional coding of signaling information.

4. Device according to one of the preceding claims, in which the control means (SE) are designed in such a way that the received signaling information is evaluated and the signaling information to be sent is processed.

5. Device according to one of the preceding claims, the HF part of which consists of a receiving part (HF-S) and a transmitting part (HF-S).

6. Device according to claim 5, the receiving part (HF-E) for the high-frequency received signals (rx) performs signal amplification, filtering and transmission in the baseband.

7. Device according to claim 5, the transmitting part (HF-S) for the transmission signals (tx) performs signal amplification, filtering and transmission in the high-frequency transmission band.

8. Device according to one of the preceding claims, the signal filter (EF, SF) has a digital transmission filter (SF) and a digital reception filter (EF).

9. Device according to one of the preceding claims, with a digital signal processing device (DSP), the at least parts of the functions of the signal filter (EF, SF), the channel estimator (JD-KS, GSM-KS), the modulators (JD-MOD, GSM - MOD), the control means (SE), the data estimator (JD-D, GSM-DJ, the channel encoder / decoder and block encoder / decoder (BC, BD) realized by program components (Pl, .., P9).

10. The device according to claim 9, wherein the program components (Pl, .., P9) are structured such that they can be at least partially replaced by new program components or parameters (Pl ', .., P9') transmitted from the mobile radio network.

11. Device according to one of the preceding claims, in which the TDMA transmission method is carried out according to the GSM standard.

12. Device according to one of the preceding claims, which is pronounced as a mobile station (MS).

13. Device according to one of claims 1 to 11, which is pronounced as a base station (BTS).