WO2002093861A1 - Procede d'application d'une modulation d'amplitude en quadrature sur un systeme de radiocommunication - Google Patents

Procede d'application d'une modulation d'amplitude en quadrature sur un systeme de radiocommunication Download PDF

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Publication number
WO2002093861A1
WO2002093861A1 PCT/CN2001/000804 CN0100804W WO02093861A1 WO 2002093861 A1 WO2002093861 A1 WO 2002093861A1 CN 0100804 W CN0100804 W CN 0100804W WO 02093861 A1 WO02093861 A1 WO 02093861A1
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Prior art keywords
star
modulation
signal
qam
channel
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PCT/CN2001/000804
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English (en)
Chinese (zh)
Inventor
Yongzhong Zou
Liwen Shi
Daoben Li
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Linkair Communications, Inc.
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Priority to CN01812972.2A priority Critical patent/CN1443416A/zh
Priority to PCT/CN2001/000804 priority patent/WO2002093861A1/fr
Publication of WO2002093861A1 publication Critical patent/WO2002093861A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems

Definitions

  • the present invention relates to wireless mobile communication technologies, and in particular, to a method for digital transmission using a quadrature amplitude modulation (QAM, Quadrature Amplitude Modulation) in a wireless mobile communication system, especially a wireless high-speed mobile communication system.
  • QAM quadrature amplitude modulation
  • Quadrature Amplitude Modulation Quadrature Amplitude Modulation
  • spectrum efficiency refers to the maximum number of users that the system can accommodate in a cell (sector) or sector (sector) when a user's transmission rate and system bandwidth are given.
  • the measurement unit is per cell (or sector) per The total transmission rate supported by the unit bandwidth system. Obviously, the higher the spectral efficiency, the larger the system capacity.
  • Quadrature Amplitude Modulation is a kind of amplitude modulation, which is a mature and efficient narrowband modulation method. With the development of mobile communications, high-speed, high-spectrum-efficiency digital transmission is required. QAM has attracted people's attention because of its characteristics of high spectral efficiency, especially the 16QAM and 64QAM modulation methods.
  • y (t) A m cos ⁇ ⁇ ⁇ + B m sin oj 0 ⁇ t ⁇ T b
  • the modulated signal is formed by superposing two mutually orthogonal carriers, and the two carriers are respectively modulated by two sets of discrete amplitudes ⁇ and ⁇ , ⁇ .
  • Amplitude modulation. Its amplitude 4, and ⁇ can be expressed as:
  • A is a fixed amplitude and is related to the average power of the signal.
  • ( ⁇ , E réelle,) represents the coordinates of the vector endpoints of the QAM modulation signal in the signal space, and is determined by the input information data.
  • the process of determining the vector endpoint coordinates by the input information data is called constellation mapping, and the coordinate map formed by these vector coordinate mappings It can be called a constellation diagram.
  • a typical rectangular QAM modulation constellation is shown in Figure 1.
  • the input information bit stream 0100 is mapped to a vector (3a, a) in the constellation map
  • the input information bit stream 1011 is mapped to a vector (-a,-3a) in the constellation map.
  • a is determined by the average power of the signal.
  • the bandwidth of the QAM modulation signal is equal to the bandwidth of the multi-amplitude modulation, and in the case of occupying the same bandwidth, the QAM modulation has twice as many symbols as the multi-amplitude modulation. Transmission rate. It can be seen that QAM is a narrow-band modulation with high spectral efficiency.
  • Binary bit stream data is input into the modulator, and is divided into two channels through serial-to-parallel conversion, and then converted from two levels to L levels to form ⁇ and ⁇ .
  • ⁇ and ⁇ In order to suppress the out-of-band radiation of the modulated signal, ⁇ and ⁇ must pass through a pre-modulated low-pass filter, and then multiply them with the two carriers to form two ASK signals. Finally, the two signals are added to obtain a modulated QAM output signal.
  • the principle of QAM demodulation is shown in Figure 3.
  • the input signal is divided into two channels, which are multiplied with two orthogonal carriers restored locally, and passed through low-pass filtering, multi-level decision, and L-level to two. Level conversion, and finally, receiving the data by parallel-serial conversion of the two signals.
  • a more general QAM demodulation principle is shown in Fig. 4.
  • an estimate (d, e) of the modulated signal (, B m ) can be obtained, Then, by calculating the distance between (d, e) and all possible signal points (A m ,), the signal point with the smallest distance from (d, e) is the best output signal point obtained after the decision. This decision method is called the minimum Euclidean distance decision.
  • Measuring the performance of a modulation method can be performed by its constellation diagram.
  • the signal is x limestone,, (' ⁇ m), which is a wrong decision.
  • the error performance is related to
  • the upper limit of the error performance is determined by the minimum distance between the endpoints of the signal vector in the constellation. A good signal constellation distribution should ensure a maximum distance between each signal constellation point.
  • wireless mobile communication especially wireless high-speed mobile communication
  • wired communication has stronger random changes than wired communication, so its requirements for anti-fading performance during signal transmission and its adaptability to mobile speed are higher, as follows:
  • the mobile communication channel is a typical random time-varying channel. Random frequency spread by effects, and random time spread by multipath propagation effects. Random frequency diffusion will cause time-selective fading of the received signal, that is, the level of the received signal will have different random fluctuations over time; random time diffusion will cause frequency-selective fading of the received signal, that is, different spectral components of the received signal will There are different random fluctuations. In addition to severely degrading system performance, fading will also significantly reduce system capacity.
  • the signal transmitted in the fading channel is not only affected by noise, but also by multiplicative interference such as flat fading or frequency selective fading, which causes the amplitude of the received signal to be attenuated and the phase to generate an additional phase shift.
  • Frequency selective fading can also cause inter-symbol crosstalk.
  • the Doppler spread due to motion also produces an irreducible BER.
  • BPSK binary phase-shift modulation
  • QPSK / DQPSK differential coding four-phase phase shift keying
  • GMSK Gaussian filtered minimum frequency shift keying
  • the threshold signal-to-noise ratio required by QAM is high (such as John G. Proakis in his Digital Communications P788 to get the threshold signal required by 4QAM under the condition of Rayleigh fading channel with double diversity Noise ratio is 32dB), but due to intersymbol interference existing in existing mobile communication systems (ISI), adjacent cell and adjacent channel interference (ACI), multiple access interference (MAI) in CDMA systems, which makes it difficult for the carrier-to-interference ratio (C / I) to reach the threshold signal-to-interference ratio required for high-dimensional QAM .
  • ISI existing mobile communication systems
  • ACI adjacent cell and adjacent channel interference
  • MAI multiple access interference
  • the wireless mobile communication environment has a wide range of changes. For the same mobile terminal, it may communicate indoors and outdoors while standing still, or it may communicate at a walking speed of several kilometers, or it may be at a speed of tens of kilometers to several kilometers. Communication is performed at a speed of 100 km / h, which requires strong adaptability to the speed of movement.
  • the main object of the present invention is to provide a method for applying quadrature amplitude modulation to a wireless communication system, so that it has better anti-fading performance in mobile communication channels, especially high-speed mobile communication systems. At the same time, it has a good adaptability to the moving speed of the mobile terminal.
  • a method for applying quadrature amplitude modulation to a wireless communication system includes at least the following steps:
  • the sender uses the star QAM constellation selected and optimized in step a to perform QAM modulation on the signal to be transmitted;
  • the receiver uses the star QAM selected and optimized in step a and consistent with the sender. Constellation diagram, QAM demodulation and decision reception of the received signal.
  • the optimization of the constellation diagram is to optimize the scaling coefficient of the amplitude of each signal in the constellation diagram.
  • the requirements of the wireless mobile communication system refer to the capacity and spectrum efficiency requirements of the wireless mobile communication system, or to the requirements of high-speed data transmission services and the fading environment of the system and the Doppler frequency shift range.
  • the anti-fading method is maximum ratio combining, or channel interleaving, or multipath (Rake) receiving anti-fading.
  • the system interference is determined by the size of multiple access interference (MAI), inter-symbol interference (ISI), or adjacent channel and adjacent cell interference (ACI).
  • MAI multiple access interference
  • ISI inter-symbol interference
  • ACI adjacent channel and adjacent cell interference
  • the technology for improving the judgment front-end signal-to-interference ratio is equalization technology, or channel coding technology, or diversity technology, or spread spectrum technology.
  • step c further includes the following steps:
  • Each discrete amplitude value corresponds to log 2 binary bits.
  • step d further includes the following steps:
  • the estimated value of the modulated signal is output after channel compensation and channel estimation remove multiplicative interference from the fading channel;
  • the channel estimation is a decision feedback channel estimation, a linear interpolation channel estimation, a Gaussian interpolation channel estimation, or a continuous pilot channel estimation.
  • the channel compensation is phase compensation, or amplitude compensation, or multipath (Rake) receiving channel compensation.
  • the star QAM modulation constellation diagram is a 16QAM star modulation constellation diagram, a 32QAM star modulation constellation diagram, or a 64QAM star modulation constellation diagram.
  • the 16QAM star modulation is two 8-phase star modulation constellation diagrams, or four 4-phase star modulation constellation diagrams, or other equivalent star QAM modulation constellation diagrams.
  • the 32QAM star modulation is two 16-phase star modulation constellation diagrams, or four 8-phase star modulation constellation diagrams, or eight 4-phase star modulation constellation diagrams, or other equivalent star QAM modulation constellation diagrams.
  • the 64QAM star modulation is two 32-phase star modulation constellation diagrams, or four 16-phase star modulation constellation diagrams, or eight 8-phase star modulation constellation diagrams, or other equivalent star QAM modulation constellation diagrams.
  • FIG. 1 is a schematic diagram of a typical rectangular QAM modulation constellation
  • Figure 2 is a principle block diagram of QAM modulation
  • Figure 3 is a principle block diagram of QAM demodulation
  • FIG. 4 is a block diagram of another QAM demodulation
  • Figure 5 is a block diagram of QAM demodulation transmitted through a fading channel
  • FIG. 6 (a) is a schematic diagram of two 8-phase star 16QAM constellations used in the present invention.
  • FIG. 6 (b) is a schematic diagram of a general rectangular 16QAM constellation
  • Figure 7 is a performance comparison chart of two 8-phase star 16QAM and rectangular 16QAM
  • Figure 8 is a schematic diagram of four 4-phase star 16QAM constellations used in the present invention
  • Figure 10 is a performance comparison of two 8-phase star 16QAM and rectangular 16QAM under AWGN channel;
  • FIG. 11 is a schematic diagram of a homogeneous random time-varying channel model
  • Figure 12 Schematic diagram of three-path uniform delay power spectrum
  • FIG. 13 is a structural frame diagram of a system used in the embodiment.
  • Figure 14 is a schematic diagram of a RAKE receiver
  • Figure 15 is a schematic diagram of the decision domain
  • Figure 16 is a schematic diagram of a universal rectangular 64QAM constellation
  • Figure 17 shows four 16-phase star 64QAM (64qam4al6p) constellation diagrams;
  • Figure 18 shows four 16-phase star 64QAM and rectangular 64QAM performance comparison diagrams at different vehicle speeds;
  • Figure 19 is a combination of four 16-phase star 64QAM and Turbo Coding technology. Schematic diagram of the error performance. Mode of Carrying Out the Invention
  • selecting an optimized signal constellation diagram that is, selecting a star QAM modulation model with good performance
  • selecting a star QAM modulation model with good performance is a key to QAM modulation applied to wireless mobile communication, especially wireless high-speed mobile communication.
  • the maximum phase tolerance of traditional rectangular QAM modulation is not good, which leads to its unsatisfactory anti-fading performance in high-speed mobile communication channels. It can be proved that the improved star QAM modulation method has better performance in wireless communication systems.
  • the traditional rectangular QAM modulation method has good anti-fading performance in a mobile communication channel, especially a high-speed mobile communication system, and has a good adaptability to the moving speed of a mobile terminal. Take 16QAM modulation as an example to compare the advantages of improved QAM modulation over traditional QAM modulation.
  • the improved 16QAM modulation method uses two 8-phase star constellation diagrams as shown in Figure 6 (a), and Figure 6 (b) is a 16QAM rectangular constellation diagram with the same minimum distance.
  • This star 16QAM can be considered as a combination of amplitude modulation and phase modulation. It differs from the rectangular 16QAM in that it has two amplitudes and eight phases.
  • the input information is divided into two parts: one part performs baseband amplitude modulation and the other part performs phase modulation.
  • Two 8-phase star 16QAM signals Each symbol consists of four bits. It is divided into two parts: the first bit and the last three bits. The former is used to determine the signal amplitude. When the input bit is "0", the signal amplitude is 2.6131a, and when the input bit is "1", the signal amplitude is 4.6131a, a is determined by the average power of the signal. The last three bits are used to select a signal phase: one of [0, ⁇ / 4, ⁇ / 2, 3 ⁇ / 4, ⁇ , 5/4, 3 ⁇ / 2, 7 ⁇ / 4].
  • the minimum signal distance of two 8-phase star 16QAM and rectangular 16QAM is 2a, then Their noise immunity is the same.
  • the average signal transmission power is:
  • 16 means that the average signal power differs by 1.47dB. It can be seen that in an additive white Gaussian noise (AWGN) channel, the signal-to-noise ratio required for two 8-phase star 16QAMs is higher than that of a rectangle under the same bit error rate 16QAM is 1.47dB higher. However, the optimal constellation map under the AWGN channel is not necessarily optimal under the fading channel.
  • the star 16QAM improves the arrangement of the rectangular 16QAM constellation, reduces the number of amplitudes and phases, and increases the maximum tolerable phase error.
  • the traditional rectangular 16QAM constellation diagram has three amplitude values and twelve phase values, and its maximum tolerance phase error is only 13.3. As shown in Table 1.
  • the improved 16QAM modulation can also use four 4-phase star 16QAM constellations as shown in Figure 8. You can also use the two 8-phase constellations and four 4-phase constellations described above.
  • the corresponding constellation diagram after the map is mathematically transformed, for example, the constellation diagram obtained by rotating each signal point of two 8-phase star 16QAM constellation diagrams by ⁇ / 8.
  • QAM modulation methods For other QAM modulations, corresponding improved QAM modulation methods can be similarly obtained.
  • 64QAM two 32-phase star 64QAM, four 16-phase star 64QAM, 8 8-phase star 64QAM, and so on can be used.
  • the first step is to adopt effective anti-fading methods, such as maximum ratio combining, Rake, according to the capacity and spectrum efficiency requirements of the wireless mobile communication system or the requirements of high-speed data transmission services and the fading environment and Doppler frequency shift range of the system.
  • the second step is to improve the signal-to-interference ratio of the decision front-end by using technologies such as equalization, channel coding, diversity, and spread spectrum based on the interference of the system, such as MAI, ACI, and ISI, so that it can meet the threshold information required by the corresponding service requirements. Interference ratio.
  • the sender modulates the signal to be transmitted according to the constellation diagram selected in the first step, as shown in FIG. 2.
  • the receiver selects the star QAM constellation map consistent with the sender according to the first step to demodulate and judge the received signal.
  • FIG. 5 is a QAM solution transmitted through a fading channel. Tuning block diagram.
  • the channel estimation can use channel estimation methods such as decision feedback, linear interpolation, Gaussian interpolation, and continuous pilot.
  • the channel compensation can use channel compensation methods such as phase compensation, amplitude compensation, and RAKE reception.
  • the first and second embodiments are performed on the COSSAP simulation platform of SY OPSYS Company in the United States. All simulation work is based on the assumption that chip synchronization and carrier synchronization have been achieved on the uplink and downlink.
  • the simulation work of this embodiment is divided into two parts: AWGN channel and Rayleigh fading channel.
  • the system adopts LAS code spread spectrum, and adopts rectangular and star 16QAM modulation respectively.
  • the channel model is additive white Gaussian channel. At this time, channel estimation and compensation loop are not needed. Only the adverse effects of additive white Gaussian noise exist in the channel.
  • the minimum Euclidean distance decision scheme shown in Figure 5 is used for demodulation and decision, and the source information is Gray coded, as shown in Figure 9.
  • Figure 10 shows the error curves of the two constellation diagrams in the AWGN channel obtained by simulation.
  • the simulation of the fading channel is generated using the three-path channel model in the IS95 library provided in COSSAP.
  • the delay spread parameters and power allocation of the three-path channel are shown in Figure 11.
  • the three-path Rayleigh fading is delayed at equal intervals and has equal power, that is, the simulation uses a uniform delay power spectrum as shown in Figure 12.
  • This type of channel model is called a HRTVC Homogeneous Random Time Variable Channel (HRTVC) model.
  • HRTVC Homogeneous Random Time Variable Channel
  • the purpose of LAS-CDMA system simulation using this channel model is to find the most unfavorable situation in the chip synchronization process to test the performance of the synchronization loop. It has no influence on the selection of modulation mode, the simulation of fading channel estimation and compensation.
  • the frame structure used by the system in this embodiment is shown in FIG. 13, where the broadcast channel
  • broadcast Channel Broadcast Channel
  • Access Channel complete the initial synchronization of the uplink and downlink.
  • the broadcast channel also has automatic gain control (AGC) and automatic power control.
  • AGC automatic gain control
  • APC automatic frequency correction
  • AFC automatic frequency correction
  • the service channel consists of nine service sub-frames, and each service sub-frame includes two parts, pilot and service data.
  • the service channel uses 16QAM modulation (rectangular or star), and the pilot symbol sends a known signal bit stream "1000", that is, it is transmitted at the maximum power and is used to provide 16QAM The required starting amplitude and phase reference for demodulation.
  • the receiver uses a five-path RAKE receiver, as shown in Figure 14.
  • APC automatic gain control
  • ADC automatic delay control
  • the I and Q correlators and channel estimation loops (IQC & CAE) on each rake of the RAKE receiver first compare the performance of rectangular 16QAM and star 16QAM under fading channels when using decision feedback channel estimation paths.
  • the first embodiment is mainly based on a large area synchronous CDMA (LAS-CDMA) system.
  • This system uses LAS spreading code spreading.
  • the simulation of the fading channel is generated by using the three-path channel model in the IS95 library provided in COSSAP.
  • the parameters of the channel delay extension and power allocation are used. Rec.ITU-RM.1225 Parameters specified in Vehicle environment A.
  • Channel estimation uses a continuous pilot estimation method.
  • the RAKE receiver, maximum ratio combining, and the like are the same as those in the first embodiment.
  • the error curves of rectangular 64QAM and star 64QAM modulations at different vehicle speeds are shown in Figure 18.
  • the above two embodiments can fully prove that applying the star QAM modulation method to a wireless communication system not only has good anti-fading performance, but also has good adaptability to the moving speed of a mobile terminal.
  • the system's decision front-end signal-to-interference ratio must be greater than the threshold signal-to-noise ratio of the required bit error rate of the corresponding service corresponding to QAM modulation (such as voice service 1.0e-3, data service 1.0e-6).
  • the system has better anti-fading performance. For different channel environments and different vehicle moving speeds (which essentially correspond to different Doppler frequency shifts), the system can provide high-quality services.
  • the above two embodiments only satisfy the second condition.
  • the following two methods can be adopted: 1) Reduce interference. Reduce intersymbol interference (ISI), adjacent cell and adjacent channel interference (ACI), multiple access interference (MAI), etc., which are present in mobile communication systems.
  • the CDMA system uses a spreading code with a small MAI and ACI, such as a LAS-CDMA system; for example, equalization and other technologies are used to reduce inter-symbol interference (ISI).
  • ISI inter-symbol interference
  • Rake receiver Rake receiver
  • diversity spread spectrum and other technologies to improve the signal-to-noise ratio of the decision front end.
  • Embodiment three uses channel coding technology as an example to further describe the change of the signal-to-noise ratio of the system's decision front end after channel coding is added.
  • This embodiment uses the Turbo Coding coding technology.
  • This embodiment combines Turbo Coding technology with this improved QAM modulation technology to improve the signal-to-noise ratio (C / I) of the decision front end.
  • Turbo Coding is a high-performance channel coding method proposed by Claude Berrou, Alain Glaemper, Punya Thitimajshima, etc. in "Near Shannon Limit Error Correcting Coding and Decoding: Turbo Codes" in 1993.
  • This embodiment is implemented by a recursive encoder with feedback, and the polynomials used are as follows:
  • the encoder has a coding efficiency of 1/2.
  • the Turbo Coding internal interleaver uses a pseudo-interleaver (Pseudo-random interleaver).
  • the interleaving length is 4096 bits.
  • the input decoder is hard-decision information.
  • the number of decoding iterations is 8 times.
  • the four 16-phase QAM constellation diagrams shown in FIG. 17 are used, and the others are the same as those in the second embodiment. The obtained simulation results are shown in FIG. 19.
  • the method of the present invention adopts improved and optimized QAM modulation, which can improve its phase blur tolerance and amplitude blur tolerance, and have good adaptability to different Doppler frequency shifts, so that the system has Good anti-fading performance.
  • the system can provide high-quality services.
  • the signal-to-noise ratio of wireless communication transmission can be significantly improved, and the quality of wireless communication is higher.

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  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
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Abstract

L'invention se rapporte à un procédé d'application d'une modulation d'amplitude en quadrature à un système de radiocommunication, plus particulièrement à un système de radiocommunication mobile haute vitesse. Le procédé consiste à : (a) sélectionner un procédé approprié de réduction d'évanouissement conformément aux conditions requises du système de radiocommunication mobile et sélectionner simultanément une constellation Star QAM et l'optimiser ; (b) conformément au degré d'interférence du système, améliorer le rapport frontal signal-interférence afin de réduire l'interférence du système ; (c) faire en sorte que l'émetteur utilise la constellation QAM sélectionnée et améliorée à l'étape (a) afin de moduler le signal à émettre avec QAM ; (d) à faire en sorte que le récepteur utilisant la constellation QAM sélectionnée et améliorée à l'étape (a) et correspondant à l'émetteur démodule le signal reçu avec QAM. Grâce à ce procédé, le système de communication mobile est en mesure de réduire l'évanouissement et d'adapter le terminal mobile tout en offrant un service de qualité et en assurant l'efficacité pour chaque voie et à différentes vitesses du terminal mobile.
PCT/CN2001/000804 2001-05-17 2001-05-17 Procede d'application d'une modulation d'amplitude en quadrature sur un systeme de radiocommunication WO2002093861A1 (fr)

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CN01812972.2A CN1443416A (zh) 2001-05-17 2001-05-17 一种将正交振幅调制运用于无线移动通信系统的方法
PCT/CN2001/000804 WO2002093861A1 (fr) 2001-05-17 2001-05-17 Procede d'application d'une modulation d'amplitude en quadrature sur un systeme de radiocommunication

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WO2008040088A1 (fr) * 2006-10-05 2008-04-10 Cohda Wireless Pty Ltd Amélioration des performances de récepteur dans un réseau de communication
CN100558096C (zh) * 2007-07-25 2009-11-04 北京天碁科技有限公司 一种应用于通信系统的正交幅度调制解调方法和装置
CN106850499B (zh) * 2017-04-13 2023-03-24 桂林电子科技大学 一种角度差分qam解调方法和解调器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5828695A (en) * 1991-06-03 1998-10-27 British Telecommunications Public Limited Company QAM system in which the constellation is modified in accordance with channel quality
US5838728A (en) * 1994-11-23 1998-11-17 At&T Wireless Services, Inc. High rate reed-solomon concatenated trellis coded 16 star QAM system for transmission of data over cellular mobile radio

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5828695A (en) * 1991-06-03 1998-10-27 British Telecommunications Public Limited Company QAM system in which the constellation is modified in accordance with channel quality
US5838728A (en) * 1994-11-23 1998-11-17 At&T Wireless Services, Inc. High rate reed-solomon concatenated trellis coded 16 star QAM system for transmission of data over cellular mobile radio

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