EP1792418A2

EP1792418A2 - Wireless communication apparatus with multi-antenna and method thereof

Info

Publication number: EP1792418A2
Application number: EP05776345A
Authority: EP
Inventors: Yanzhong Philips Electronics China DAI; Xuecheng Philips Electronics China QIAN
Original assignee: Koninklijke Philips Electronics NV
Current assignee: Koninklijke Philips NV
Priority date: 2004-09-10
Filing date: 2005-09-01
Publication date: 2007-06-06
Also published as: WO2006027728A2; WO2006027728A3; JP2008512921A

Abstract

This invention proposes a wireless communication apparatus and its method. The wireless communication apparatus comprises: multiple antennas, a multiple-antenna signal processing module, a RF signal processing module and a baseband processing module. The multiple-antenna signal processing module is designed to combine multiple RF signals received from the multiple antennas into a single RF signal. The RF signal processing module is designed to convert the combined single RF signal into a single baseband signal. The baseband processing module is designed to perform baseband processing on the single baseband signal. This wireless communication apparatus realizes a multi-antenna system by simply inserting a multiple-antenna signal processing module into a typical singleantenna system. Both the RF signal processing module and baseband processing module of existing single-antenna system remain unchanged. Therefore, the redesign process is greatly simplified, which results in remarkable reduction of design difficulty and implementation cost.

Description

WIRELESS COMMUNICATION APPARATUS WITH MULTI-ANTENNA

AND METHOD THEREOF

FIELD OF THE INVENTION

This invention relates to a wireless communication apparatus and its method, and more particularly to a wireless communication apparatus with multiple antennas and its method.

BACKGROUND FO THE INVENTION

As the number of mobile phone users is on the rise, modern mobile communication system is confronted with the challenge of maintaining high voice quality while increasing traffic carrying capacity. To this concern, multi-antenna technology has become a heated topic among the technologies of the third-generation mobile communication. Multi-antenna technology usually includes spatial diversity and adaptive antenna technique. In the receiving direction, at least two antennas are employed to receive signals. At the same time, processing methods, such as diversity and beamforming, are adopted to combine multiple parallel signals to obtain a better performance over the conventional single antenna technology. Researches indicate that the deployment of multi-antenna technology can effectively enhance the signal noise ratio (SNR) of the signal, thereby remarkably improving the voice quality of the communication. However, most of existing communication systems have employed processing modules aiming at single-antenna systems in their mobile terminals. If the multi-antenna technology is applied to existing mobile terminals, then both the hardware and software sections of the processing modules need to be redesigned. Therefore it will be very expensive. How to improve basing on existing mobile terminals to efficiently utilize the hardware and software resources in the processing modules of single-antenna systems has become a key issue in the application of multi-antenna to mobile terminals. In the following paragraphs, a mobile terminal conforming to TD-SCDMA standard will be taken as an example to illustrate the configuration of single-antenna system in existing mobile terminals and the problems confronted when deploying multi-antenna to this single-antenna system. Fig. 1 is a system structure block diagram of a typical single-antenna mobile phone. This system includes an antenna 100, a radio-frequency (RF) module 200, an analog- digital converter / digital-analog converter (ADC/DAC) module 300, a baseband physical layer processing module 400 and a baseband upper layer processing module 500. Wherein, the baseband physical layer processing module 400 may include Rake Receiver or joint detection (JD), the spreading/despreading module, the modulating/demodulating module and the viterbi/turbo encoding/decoding module. The baseband upper layer processing module 500 may include system controller and source encoder, for example, it can be realized by using digital signal processor or microprocessor. The processing of downlink signals goes as follows. Firstly, the wireless signals received by the antenna 100 will be amplified and down converted into intermediate frequency signals or analog baseband signals in the RF module 200. Then, after being sampled and quantized in the ADC/DAC module 300, the intermediate frequency signal or analog baseband signal will be converted to digital baseband signal and transmitted to the baseband physical layer processing module 400. In the baseband physical layer processing module 400, according to the control signal given by the baseband control module, the digital baseband signal will be processed by the operations, such as Rake Receiver or joint detection (JD), despreading, demodulation, deinterleave, Viterbi/Turbo decoding successively, before entering the baseband upper layer processing module 500. In the baseband upper layer processing module 500, the signals from the baseband physical layer processing module 400 will be further processed in data link layer, network layer or higher layers by operations, such as upper layer signaling process, system control and source encoding/decoding.

So far, the single antenna mobile telephone technology stated above has been quite mature and many manufacturers have developed chipset solutions of considerable maturity.

In these solutions, the function of the baseband physical layer processing module 400 is usually realized by a baseband modem made up of Application Specific Integrated Circuits (ASIC).

However, the introduction of multi-antenna into existing mobile telephone systems will cause a changeover in the setting of most modules of single-antenna system, whose hardware and relevant software, such as the standard design Rake Receiver and despreading function of baseband physical layer processing module, will be hard to utilize in the new systems. On account of this, the applicant of the invention had proposed two solutions respectively in two applications submitted in Dec 27, 2002. One was by the name of "Multiple-antenna Mobile Terminal and Its Method", China Invention Patent Application No. 02160403.7. The other was by the name of "Smart-antenna Mobile Terminal and Its Method", China Invention Patent Application No. 02160402.9. These applications are hereby incorporated by reference in their entirety. With the two solutions stated above, single-antenna systems can be upgraded to multiple-antenna systems without major modification. The software and hardware design of existing standard baseband processing modules can be utilized in the new system, which will result in a remarkable reduction in design cost. However, in regard to utilizing the design of single-antenna mobile terminals, the two solutions only realized the utilization of software and hardware design of the baseband section. The utilization of the RF section is left untouched, that is, multiple parallel paths are needed to process RF signals given by multiple antennas with several operations including amplification, down-conversion and analog-digital conversion, after which the multiple signals are combined and transmitted to the baseband section. Therefore, the single signal processing path in the RF section of existing single-antenna system needs modification and redesign to be deployed in a multiple-antenna system, which to some extent will increase the design difficulty and executive cost.

' In conclusion, how to modify on the existing mobile terminals and more efficiently utilize the hardware and software resources of single-antenna system's processing modules still remains a question to be resolved in the deployment of multi-antenna to mobile terminals.

OBJECT AND SUMMARY OF THE INVENTION One object of the invention is to provide a multiple-antenna wireless communication apparatus and method. The multiple-antenna wireless communication apparatus can utilize the software and hardware design of the RF and baseband signal processing sections of existing standard single-antenna systems without much modification.

To fulfill the above object, the invention provides a wireless communication apparatus comprising multiple antennas, a multiple-antenna signal processing module, a

RF signal processing module and a baseband processing module. The multiple-antenna signal processing module is designed to combine the multiple RF signals received by the multiple antennas into a single RF signal. The RF signal processing module is designed to convert the combined single RF signal into a single baseband signal. The baseband processing module is designed to perform baseband processing on said single baseband signal.

To fulfill the above object, the invention provides a method used in the multiple- antenna wireless communication apparatus, which comprises the step of: receiving a plurality of RF signals and combining them into a single RF signal; converting the single

RF signal into a single baseband signal; and performing baseband processing on the single baseband signal.

Since the multiple-antenna wireless communication apparatus and its method proposed by the invention combine multiple RF signals into a single RF signal before the

RF signal is processed, only one multiple-antenna module is required to be inserted into existing standard single-antenna system for the combination operation, and the design of the existing standard single antenna system can be reused by the followed RF and baseband signal process. Therefore, the design can be simplified to decrease the design difficulty and implementation cost.

Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described by reference to the accompanying drawings wherein:

Fig.1 illustrates a block diagram of a typical single-antenna mobile telephone in a TD-SCDMA system; Fig. 2 illustrates a block diagram of the receiving apparatus of a multiple-antenna mobile terminal with TD-SCDMA system according to an embodiment of this invention.

Fig.3 illustrates an equivalent structure diagram of the MA module of the receiving apparatus in Fig. 2.

Fig.4 illustrates a block diagram of the receiving apparatus of a multiple-antenna mobile terminal with TD-SCDMA system according to another embodiment of this invention.

Fig.5 illustrates an equivalent structure diagram of the MA module of the receiving apparatus in Fig. 4. DETAILED DESCRIPTION OF THE DRAWINGS

The invention is explained in further detail, and by way of example, with reference to the accompanying drawings. Fig. 2 is a block diagram of the receiving device of a multi-antenna mobile terminal in a TD-SCDMA system according to an embodiment of this invention. Compared to the receiving devices of existing single-antenna mobile terminals, the receiving device in Fig.2 has one additional multiple-antenna (MA) module 600. The delay generated by this MA module 600 is so little that it can be neglected. As illustrated by Fig. 2, this receiving device includes two antennas 100 and 101, a

MA module 600, a RF signal processing module including a RF module 200 and a ADC/DAC module 300, and a baseband processing module comprising a baseband physical layer processing module 400 and a baseband upper layer processing module 500. The two antennas 100 and 101 are designed to receive RF signals. The MA module 600 is connected with the two antennas 100 and 101 and is designed to combine the received two

RP signals into a single-channel RF signal. The operations executed by the MA module 600 includes: performing weight calculation on the parameter information contained in the two channels of RF signals received by the two antennas 100 and 101, performing amplitude and phase adjustment on the two channels of RF signals according to the calculation result to combine the two channels of signals into a single-channel signal and transmit the combined signal to the RF module 200. Detailed operations of the MA module 600 will be illustrated later.

The RF module 200 is designed to perform amplification and down-conversion on the signals combined by the MA module 600 to convert them into intermediate frequency signals or analog baseband signals. The ADC/DAC module 300, which is connected to the output end of the RF module 200, is designed to sample and quantize the intermediate frequency signals or analog baseband signals from the RF module 200 to convert them into digital baseband signals, during the course of downlink data processing. The baseband physical layer processing module 400 is designed to perform baseband signal processing operations on digital baseband signals outputted from the ADC/DAC module 300, including: Rake receiving, despreading, demodulation, deinterleave, joint detection (JD), Viterbi/Turbo decoding and so on. The baseband upper layer processing module 500 is designed to perform the processing operation of the data link layer, the network layer or higher layer on the data outputted from the baseband physical layer processing module 400, including: upper layer signaling processing, source encoding/decoding and so on.

The following is a detailed illustration of the structure of the MA module 600 and its signal process in a TD - SCDMA system in conjunction with Fig. 3. As illustrated in Fig. 3, the MA module 600 includes: weight adjusting modules 601 and 602, a combination module 610, two RF modules 621 and 622, two ADC modules 631 and 632, a weight-generating module 640 and two DAC modules 651 and 652.

The weight adjusting modules 601 and 602 are connected to the two antennas 100 and 101 respectively, to adjust the amplitude and phase of RF signals. In this embodiment, the weight adjusting module 601 and 602 can be realized by two multipliers. The combination module 610 is designed to combine the signals after amplitude and phase adjustment in multipliers 601 and 602 and transmit the combined signals to the RF module 200. In this embodiment, the combination module 610 can be realized through an adder. The input of the RF modules 621 and 622 are respectively connected with the two antennas 100 and 101, to amplify and down-convert the received RF signals from side paths and convert them into analog baseband signals. The ADC modules 631 and 632, whose input are connected respectively with the two output of the two RF modules 621 and 622, are designed to sample and quantize the analog baseband signals from the RF modules 621 and 622, to convert them into digital baseband signals. The weight-generating module 640 is designed to process the digital baseband signals outputted from the ADC modules 631 and

632, calculate the corresponding weight coefficient for the weight adjusting modules 601 and 602 to adjust the amplitude and phase of RF signals. The calculation of relevant weight coefficients can be performed with the prior techniques such as the method proposed in the descriptions of patent application No.02160403.7. No more detailed explanation will be given here. The DAC modules 651 and 652 will respectively convert the two sets of weight coefficients generated by the weight-generating module 640 to analog quantity and perform amplitude and phase adjustment respectively on radio frequency signals through the two multipliers 601 and 602 according to the two sets of analog weight coefficients. When mobile terminal is in cell search phase, the signal combination operation executed by the MA module 600 in this embodiment can be carried out with Blind Equal - Ratio - Combining method (BERC). Since existing technologies offer many ways for realizing Blind Equal-Ratio-Combining method, the following is only a simple introduction of its working process.

Firstly, one of the signals from the two antennas 100 and 101 is chosen as reference signal. For example, if the signal from antenna 100 is chosen as reference signal Sr, then the signal from antenna 101 is the. other signal So.

Secondly, the reference signal Sr is multiplied by a constant from the DAC module 652, for example, constant 1, in the multiplier 601.

Thirdly, the weight-generating module 640 will estimate the amplitude difference and phase difference between digital baseband signals corresponding to the reference signal Sr and the other signal So drawn via side path. For example, the corresponding weight coefficients can be obtained by normalizing the multiplication of the reference signal Sr by the conjugate signals of the other signal So.

Then, the amplitude and phase compensation of the other signal So in respect to the reference signal Sr can be realized in multiplier 602 by multiplying the other signal So by the analog value of the weight coefficient converted by the DAC module 651.

Finally, the output signals of the multipliers 601 and 602 are added together in the adder 610, for combining the reference signal Sr and other signal So into a single signal in the RF band. . . .

The method stated above multiplies the reference signal by a constant. Other techniques are also available, for example, multiplying reference signal Sr and other signal

So by their corresponding weight coefficients, respectively. These corresponding weight coefficients can be the respective conjugate values of the reference signal Sr and the other signal So, so that no more detailed explanation will be given here.

, When a mobile terminal is in a state of normal connection, for example this mobile terminal is receiving signals from only one base station which utilizes a normal transmitting antenna rather than an antenna diversity or a smart antenna, the signal combination operation in the MA module 600 can be executed with the techniques of

Maximum-Ratio-Combining method, such as the improved the least meansquare error

(LMS). Since the patent application No.02160403.7 stated above gives three such processing methods, no more detailed explanation will be given here.

The methods of Blind Equal-Ratio-Combining and Maximum-Ratio-Combining can be realized by both computer software and hardware. The above description indicates that the MA module 600 is a separate module in the embodiment. It doesn't need any feedback signals from the baseband signal processing section. It can realize the combination of multiple RF signals by estimating the parameters contained in the received multiple RF signals. This solution simplifies the system design by adding directly additional antennas and an independently designed MA module 600 into a standard single-antenna mobile terminal to upgrade it into a multiple-antenna mobile terminal. However, this solution totally relies on weight coefficients used for adjusting amplitude and phrase by calculating the received multiple RF signals, which will complicate the design of its weight-generating module 640. To simplify the design of amplitude and phase calculation module 640 to further reduce the design cost of the MA module 600, the invention offers another embodiment, as illustrated in Fig. 4 and Fig. 5. Fig. 4 is a block diagram of another embodiment of the receiving means of a multiple-antenna mobile terminal of a TD - SCDMA system. Fig. 5 is the equivalent structure diagram of the MA module 600' of the receiving means in Fig. 4. ^■ This embodiment is distinguished from the formepembodiment in the point that in this embodiment the MA module 600' realizes the combination operation of multiple RF signals according to the MA control information that is transmitted from the baseband processing module through control bus. The MA control information transmitted to MA module 600' through control bus may include, but not limited to, enabling signal, algorithm selection signal, downlink pilot frequency information and training sequence.

The function of an enabling signal is to enable the MA module 600'. The function of algorithm selection signal is to tell MA module 600' which weight algorithm to select. MA control information can be transmitted to the MA module 600' through control bus or other interfaces. The MA module 600' in this embodiment is different from the MA module 600 of the former case in the following points. Firstly, its weight-generating module 640' takes the information such as user-specific training sequence contained in MA control information from the baseband processing module as reference signals, instead of the channel parameters of signals ( Sr, So), and calculates the corresponding weights according to regular weight algorithm designated by MA control information. After the weights are converted through the DAC modules 651 and 652, they are transmitted to the two multipliers 602 and 601 for signal weight adjustment. Since MA control information is provided only once through control bus when the MA module starts working, no dynamic feedback signals from the baseband physical layer processing module 400 are needed.

In comparison with the MA module 600 of the former embodiment which totally depends on weight estimation of the received multiple RF signals, the MA module 600' of this embodiment employs a simpler and quicker approach by utilizing the known information, such as training sequence, to generate weights.

Although both the two embodiments of this invention given above take the dual- antenna receiving apparatus as example, the designing approaches are applicable to receiving apparatus with more than two antennas as well. In addition, although this invention only introduces embodiments of the multiple-antenna receiving apparatus of mobile telephone and its techniques, due to the symmetry between up-link and downlink, similar solutions can be applied to the design of transmitting device and its method. For instance, in a transmitting apparatus with two antennas, the signal processing procedure is reverse to that in a receiving device. AU that needs to be done is to replace the combination module 610 of MA module 600 or 600' with a separation module (such as signal splitter, not shown in the drawing) to separate single RF signals into two RF signals and send them out after weighting them respectively.

According to the multiple-antenna wireless communication apparatus and its methods offered by this invention, the incorporation of multi-antenna into wireless communication apparatus can be realized by simply inserting a MA module into the single- antenna wireless communication devices without much modification to the hardware and software design of existing mobile telephones.

Of course, it is apparent to those skilled in the art that, the multiple-antenna wireless communication apparatus and its method offered by the present invention are not limited to mobile telephone systems. They can also be applied to other wireless communication apparatus such as wireless communication base stations, wireless LAN terminals and so on.

Also, it is apparent to those skilled in the art that, the multiple-antenna wireless communication apparatus and method offered by this invention should not be confined to the TD - SCDMA system, they can also be applied to cellular communication systems such as GSM (Global Mobile System), GPRS (General Packet Radio Service) , EDGE

( Enhanced Data Rate for GSM Evolution ) , WCDMA (Wideband Code Division

Multiple-Access), CDMA IS95, CDMA 2000 Standard and so on.

Those skilled in the art will appreciate that various change and modification can be made on the multiple-antenna wireless communication apparatus and method in light of foregoing description while remaining within the scope of the appended claims.

Claims

CLAIMS:

1. A wireless communication apparatus, comprising: multiple antennas; a multiple-antenna signal processing means for processing a plurality of RF signals received by said multiple antennas, to combine the plurality of RF signals into a single RF signal; a RF signal processing means for converting the single RF signal into a single baseband signal; and a baseband processing means for performing baseband processing on the single baseband signal.

2. The wireless communication apparatus according to claim 1, wherein the baseband processing means provides control information for the multiple-antenna signal processing means to combine the plurality of RF signals, before said multiple-antenna signal processing means is enabled.

3. The wireless communication apparatus according to claim 2, wherein the multiple- antenna signal processing means comprises: a plurality of weight adjusting means for weighting the plurality of RF signals from said multiple antennas; a combination means for combining the weighted plurality of RF signals from each weight adjusting means and transmitting the combined signal to said RF signal processing means; and a weight-generating means for generating weights for adjustment of each RF signal for the plurality of RF signals, according to said control information, and providing the weights to said corresponding weight adjusting means.

4. The wireless communication apparatus according to claim 2 or 3, wherein said control information at least comprise downlink pilot frequency timeslot data and training sequence data.

5. The wireless communication apparatus according to Claim 3, wherein said multiple-antenna signal processing means further comprises: a plurality of RF means for converting the plurality of RF signals received by the multiple antennas into a plurality of baseband signals for the weight-generating means to generate corresponding weights.

6. The wireless communication apparatus according to claim 1, wherein said multiple-antenna signal processing means comprises: a plurality of weight adjusting means for weighting the plurality of RF signals from said multiple antennas according to the weights received respectively; a combination means for combining the weighted the plurality of RF signals outputted from each weight adjusting means and transmitting the combined signal to said RF signal processing means; and a weight-generating means for estimating weights for adjustment of each RF signal, according to channel parameters contained in the plurality of RF signals, and providing the weights to the corresponding weight adjusting means.

7. The wireless communication apparatus according to claim 6, wherein the multiple-antenna signal processing means further comprises: a plurality of RF means for converting the plurality of RF signals received by said multiple antennas to the plurality of baseband signals for the said weight-generating means to generate corresponding weights.

8. A method for a wireless communication apparatus with multiple antennas, the method comprising the steps of:

(a)receiving a plurality of RF signals from said multiple antennas; (b) combining the plurality of RF signals into a single RF signal; (c ) converting said single RF signal into a single baseband signal; and

(d) performing baseband processing on said single baseband signal.

9. The method according to claim 8, before step (b) , further comprising the step of providing control information, wherein step (b) performs the combination operation based on said control information.

10. The method according to stated in claim 9, wherein step (b) further comprises the steps of: calculating weights for adjustment of the plurality of RF signals, according to the control information; weighting the plurality of RF signals in accordance with the calculated weights, and combining the weighted signals.

11. The method according to claim 9 or 10, wherein said control information at least comprises downlink pilot frequency timeslot data and training sequence data.

12. The method according to claim 8, wherein step (b) comprises the step of: calculating weights for adjustment of the plurality of RF signals, according to channel parameters contained in the plurality of RF signals ; weighting the plurality of RF signals respectively, in accordance with the calculated weights; and combining the weighted signals.

13. A wireless communication apparatus comprising: a baseband processing means for outputting a single baseband signal; a RF signal processing means for converting said single baseband signal into a single RF signal; a multiple-antenna processing means for processing said single RF signal, to separate it into a plurality of RF signals; and multiple antennas for transmitting the plurality of RF signals.

14. The wireless communication apparatus according to claim 13, wherein the baseband processing means provides control information for the multiple-antenna signal processing means to separate the single RF signal, before said multiple-antenna signal processing means is enabled.

15. The wireless communication means according to claim 14, wherein said multiple-antenna signal processing means comprises: a separation means for separating said single RF signal into the plurality of RF signals; a weight-generating means for generating weights for the adjustment of said plurality of RF signals, according to the control information; and multiple weight adjusting means for weighting said plurality of RF signals according to the weights generated by said weight-generating means and transmitting the weighted plurality of RF signals to said multiple antennas.

16.A method for a wireless communication apparatus with multiple antennas comprising the steps of: ( a)generating a single baseband signal;

( b)converting said single baseband signal into a single RF signal; ( c)separating said single RF signal into a plurality of RF signals; and

(d) transmitting said plurality of RF signals via the multiple antennas, respectively.

17. The method according to claim 16, before step (c) , further comprising the step of: providing control information, wherein the step( c ) executes the separation operation according to the control information.

18. The method according to claim 17, wherein step (c) further comprises the step of: separating said single RF signal into the plurality of RF signals; generating weights for adjustment of said plurality of RF signals, according to said control information; and weighting said plurality of RF signals respectively according to said generated weights.

19. A processing apparatus of a plurality of RF signals received by multiple antennas comprising: a plurality of weight adjusting means for weighting said plurality of RF signals received by multiple antennas, according to weights they receive respectively; a combination means for combining the weighted plurality of RF signals from each weight adjusting means and transmitting the combined signal to said RF signal processing means; and a weight-generating means for generating weights for adjustment of each RF signal with respect to said plurality of RF signals according to said control information, and providing the weights to the corresponding weight adjusting means.

20. A processing apparatus of a plurality of RF signals received by multiple antennas comprising: a plurality of weight adjusting means for weighting said plurality of RF signals received by the multiple antennas according to weights they receive respectively; a combination means for combining the weighted plurality of RF signals outputted from each weight adjusting means and transmitting the combined signal to said RF signal processing means; and a weight-generating means for estimating weights for the adjustment of each RF signal according to channel parameters contained in said plurality of RF signals, and providing the weights to the corresponding weight adjusting means.