Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567396
O. Ata
Linearisation of a radio base station amplifier using a third order and a fifth order predistortion scheme is studied. Adaptive predistortion using a third order predistorter improved the amplifiers intermodulation distortion (IMD) by between 6.5 dB and 30 dB as measured by a two tone test. The variation in improvement is due to changes in the input power level. Improvement increases as the input power is backed off from the 1 dB compression point. A fifth order predistorter will give an IMD improvement of between 9 dB and 48 dB if properly adjusted. For a nine-tone test (with uniformly distributed random phase), a fifth order predistorter, if properly adapted will give an IMD improvement of between 8.5 dB and 40 dB from the worst IMD level, provided by the raw nonlinear amplifier.
{"title":"Predistort-linearisation method for future basestation amplifiers of cellular radio","authors":"O. Ata","doi":"10.1109/PIMRC.1996.567396","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567396","url":null,"abstract":"Linearisation of a radio base station amplifier using a third order and a fifth order predistortion scheme is studied. Adaptive predistortion using a third order predistorter improved the amplifiers intermodulation distortion (IMD) by between 6.5 dB and 30 dB as measured by a two tone test. The variation in improvement is due to changes in the input power level. Improvement increases as the input power is backed off from the 1 dB compression point. A fifth order predistorter will give an IMD improvement of between 9 dB and 48 dB if properly adjusted. For a nine-tone test (with uniformly distributed random phase), a fifth order predistorter, if properly adapted will give an IMD improvement of between 8.5 dB and 40 dB from the worst IMD level, provided by the raw nonlinear amplifier.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130078564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.568462
M. Bui, H. Azad, H. Aghvami
Different channel estimation algorithms for direct-sequence code-division multiple-access (DS/CDMA) communications systems using binary phase-shift-keying (BPSK) modulation and a RAKE receiver are evaluated under fading multipath conditions. Two strategies are considered: the transmission of a pilot signal in the downlink and the block organization of the data in the uplink. The performance degradation of the system is due mainly to inaccurate estimation of the complex amplitudes rather than the delays; it remains low when using pilot signals with averaging filters or combining preamble information with symbol estimation.
{"title":"Channel estimation algorithms for DS/BPSK-CDMA communications systems","authors":"M. Bui, H. Azad, H. Aghvami","doi":"10.1109/PIMRC.1996.568462","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.568462","url":null,"abstract":"Different channel estimation algorithms for direct-sequence code-division multiple-access (DS/CDMA) communications systems using binary phase-shift-keying (BPSK) modulation and a RAKE receiver are evaluated under fading multipath conditions. Two strategies are considered: the transmission of a pilot signal in the downlink and the block organization of the data in the uplink. The performance degradation of the system is due mainly to inaccurate estimation of the complex amplitudes rather than the delays; it remains low when using pilot signals with averaging filters or combining preamble information with symbol estimation.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134123771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567439
K. Wesołowski
Application of linear predictors is considered for maximum likelihood sequence estimation of digital signals corrupted by intersymbol interference and colored noise. After general derivation of the cost function a few receiver versions are presented. The simulation results for trellis coded signals transmitted over a two-path channel introducing deep selective fade are presented. The proposed receivers when applied in mobile TDMA radio are aimed to cope with intercell and interchannel interference which in case of many interferers can be modeled as colored Gaussian noise.
{"title":"ML sequence estimation for data signals corrupted by intersymbol interference and colored noise","authors":"K. Wesołowski","doi":"10.1109/PIMRC.1996.567439","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567439","url":null,"abstract":"Application of linear predictors is considered for maximum likelihood sequence estimation of digital signals corrupted by intersymbol interference and colored noise. After general derivation of the cost function a few receiver versions are presented. The simulation results for trellis coded signals transmitted over a two-path channel introducing deep selective fade are presented. The proposed receivers when applied in mobile TDMA radio are aimed to cope with intercell and interchannel interference which in case of many interferers can be modeled as colored Gaussian noise.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134320459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567440
R. Vaughan
The Rayleigh-like distributed envelopes encountered in mobile communications occupy a wide dynamic range, typically 10 dB above the local mean to 40 dB below the local mean, with the range decreasing for increasing bandwidth. The local mean varies owing to shadow fading, by tens of dB, and on top of this, the inverse-distance loss can vary by some 50 dB within a cell. In characterizing the Rayleigh-like fading in real-world channels, measuring equipment needs to be expensive to cover such a dynamic range or else signal limiting occurs. For diversity channel evaluation, the correlation coefficient between channels is required in order to establish the potential diversity gain. This paper gives a statistical formulation for the effect of soft- and hard-clipped envelopes used for the correlation coefficient. It is shown that even hard-clipped envelopes are useful for diversity channel evaluation using the correlation coefficient.
{"title":"Signal limiting in envelope correlations for diversity channel evaluation: a statistical approach","authors":"R. Vaughan","doi":"10.1109/PIMRC.1996.567440","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567440","url":null,"abstract":"The Rayleigh-like distributed envelopes encountered in mobile communications occupy a wide dynamic range, typically 10 dB above the local mean to 40 dB below the local mean, with the range decreasing for increasing bandwidth. The local mean varies owing to shadow fading, by tens of dB, and on top of this, the inverse-distance loss can vary by some 50 dB within a cell. In characterizing the Rayleigh-like fading in real-world channels, measuring equipment needs to be expensive to cover such a dynamic range or else signal limiting occurs. For diversity channel evaluation, the correlation coefficient between channels is required in order to establish the potential diversity gain. This paper gives a statistical formulation for the effect of soft- and hard-clipped envelopes used for the correlation coefficient. It is shown that even hard-clipped envelopes are useful for diversity channel evaluation using the correlation coefficient.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131616845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567543
W. Wong, E. Sousa
We propose a wireless multimedia DS-CDMA system with dynamic power assignment (DPA) for adaptive traffic control. The system supports service groups with different quality of service (QoS) requirements specified in terms of both transmission bit rate and bit error rate (BER). The optimal received power level for each service group is obtained by minimizing a cost function consisting of the weighted sum of the blocking rates of different service groups subject to their QoS requirements. The performance is compared to a similar system with fixed power assignment (FPA) in which the received power level for each service group is assigned based only on its transmission bit rate. Simulation results show that DPA algorithm can support much higher offered traffic loads, on merit of the blocking probability. By implementing the cost function with different weighting coefficients, we can assign different blocking probabilities to different service groups to cope with the demands in the system. The DPA algorithm therefore plays the role of a "movable blocking boundary" in the system which can accommodate multimedia traffic and priority-based capacity access.
{"title":"Power assignment strategies and traffic control for wireless multimedia DS-CDMA systems","authors":"W. Wong, E. Sousa","doi":"10.1109/PIMRC.1996.567543","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567543","url":null,"abstract":"We propose a wireless multimedia DS-CDMA system with dynamic power assignment (DPA) for adaptive traffic control. The system supports service groups with different quality of service (QoS) requirements specified in terms of both transmission bit rate and bit error rate (BER). The optimal received power level for each service group is obtained by minimizing a cost function consisting of the weighted sum of the blocking rates of different service groups subject to their QoS requirements. The performance is compared to a similar system with fixed power assignment (FPA) in which the received power level for each service group is assigned based only on its transmission bit rate. Simulation results show that DPA algorithm can support much higher offered traffic loads, on merit of the blocking probability. By implementing the cost function with different weighting coefficients, we can assign different blocking probabilities to different service groups to cope with the demands in the system. The DPA algorithm therefore plays the role of a \"movable blocking boundary\" in the system which can accommodate multimedia traffic and priority-based capacity access.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131293405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567546
J. Brázio, F. Velez
A model was presented for the design tradeoffs between reuse distance D and coverage length R for cellular planning of a linear coverage situation. This model allows the determination of (R,D) pairs satisfying given raw bit error rate constraints. A "net cost model" was also presented, and the dependence of the cost on the reuse distance was studied. The existence of profitable cell configurations for the system were discussed. The noise/interference, cost, and revenue models used consisted of simple linear functions, but the approach followed is general in the sense that the same steps can be used if more complex models are used.
{"title":"Design of cell size and frequency reuse for a millimeterwave highway coverage cellular communications system","authors":"J. Brázio, F. Velez","doi":"10.1109/PIMRC.1996.567546","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567546","url":null,"abstract":"A model was presented for the design tradeoffs between reuse distance D and coverage length R for cellular planning of a linear coverage situation. This model allows the determination of (R,D) pairs satisfying given raw bit error rate constraints. A \"net cost model\" was also presented, and the dependence of the cost on the reuse distance was studied. The existence of profitable cell configurations for the system were discussed. The noise/interference, cost, and revenue models used consisted of simple linear functions, but the approach followed is general in the sense that the same steps can be used if more complex models are used.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114806820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.568391
Y. P. Zhang, Y. Hwang, P. Ching
We propose an imperfect waveguide model to represent empty curved tunnels. We use the field configuration in an optical dielectric guide together with the surface impedance boundary condition for the walls to simplify the complexity of derivation of the propagation modal equations. The curvature of the tunnels is assumed to be gentle. Our results show that increased propagation loss is almost linearly proportional to frequency and inversely proportional to the radius of curvature.
{"title":"Characterization of UHF radio propagation channel in curved tunnels","authors":"Y. P. Zhang, Y. Hwang, P. Ching","doi":"10.1109/PIMRC.1996.568391","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.568391","url":null,"abstract":"We propose an imperfect waveguide model to represent empty curved tunnels. We use the field configuration in an optical dielectric guide together with the surface impedance boundary condition for the walls to simplify the complexity of derivation of the propagation modal equations. The curvature of the tunnels is assumed to be gentle. Our results show that increased propagation loss is almost linearly proportional to frequency and inversely proportional to the radius of curvature.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"14 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114504604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567555
Sau-Mou Wu, Jeng-Rern Yang, Tzen-Yi Liu
A novel batteryless, self-powered transponder design as well as its chip layout is presented. The transponder operates in two phases. First, the chip is energized by rectifying the electromagnetic energy from the interrogating RF field from the RFID base station; the extracted energy is temporarily stored and is thereafter used to power the whole circuitry. Second, the transponder starts to transmit coded data by FSK modulation back to the base station. The major part of the design uses a digital CMOS circuit, thus it is simple and easy to implement. The circuit is designed such that the output frequencies are independent of the load of the antenna; the simulation results show that the tolerance of the antenna variation is within /spl plusmn/10%. The design is compatible with the TIRIS system, a popular RFID product designed by Texas Instruments. It operates in the 134.2 and 123.2 kHz frequency bands. The layout occupies about 0.8 um/spl times/0.8 um area.
{"title":"A transponder IC for wireless identification systems","authors":"Sau-Mou Wu, Jeng-Rern Yang, Tzen-Yi Liu","doi":"10.1109/PIMRC.1996.567555","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567555","url":null,"abstract":"A novel batteryless, self-powered transponder design as well as its chip layout is presented. The transponder operates in two phases. First, the chip is energized by rectifying the electromagnetic energy from the interrogating RF field from the RFID base station; the extracted energy is temporarily stored and is thereafter used to power the whole circuitry. Second, the transponder starts to transmit coded data by FSK modulation back to the base station. The major part of the design uses a digital CMOS circuit, thus it is simple and easy to implement. The circuit is designed such that the output frequencies are independent of the load of the antenna; the simulation results show that the tolerance of the antenna variation is within /spl plusmn/10%. The design is compatible with the TIRIS system, a popular RFID product designed by Texas Instruments. It operates in the 134.2 and 123.2 kHz frequency bands. The layout occupies about 0.8 um/spl times/0.8 um area.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114680647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567544
M. Andersin, Z. Rosberg
We study the transmission power control in a cellular network where users' mobility results in a time varying gain matrix. A framework for evaluating the channel quality is specified, and an asymptotic representation of the link gain evolution in time is obtained. Then, a time variant distributed constrained power control (TVPC) which copes with user mobility is derived. The algorithm is compared to a classical distributed constrained power control (DCPC), as well as to a constant-received power control and constant-transmitted power. The comparison reveals that the classical DCPC exhibits an outage probability close to one, unless some counter-measures are taken. The TVPC algorithm however, copes well with users' mobility and provides a close to optimal scale up factor for the signal to interference ratio (SIR) target.
{"title":"Time variant power control in cellular networks","authors":"M. Andersin, Z. Rosberg","doi":"10.1109/PIMRC.1996.567544","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567544","url":null,"abstract":"We study the transmission power control in a cellular network where users' mobility results in a time varying gain matrix. A framework for evaluating the channel quality is specified, and an asymptotic representation of the link gain evolution in time is obtained. Then, a time variant distributed constrained power control (TVPC) which copes with user mobility is derived. The algorithm is compared to a classical distributed constrained power control (DCPC), as well as to a constant-received power control and constant-transmitted power. The comparison reveals that the classical DCPC exhibits an outage probability close to one, unless some counter-measures are taken. The TVPC algorithm however, copes well with users' mobility and provides a close to optimal scale up factor for the signal to interference ratio (SIR) target.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117134123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-10-15DOI: 10.1109/PIMRC.1996.567422
C. Despins, Gaingar Djelassem, V. Roy
This paper presents a comparative evaluation of code-division-multiple access (CDMA) and frequency-division time-division-multiple-access (FD-TDMA) system capacities as a function of the radio link capacity (i.e. Shannon bound). This bound is first evaluated over time-varying frequency-selective fading channels by treating this information theoretic value of the capacity as a random variable. The total system sum-of-rates capacity is then evaluated for both multiple-access schemes using a multi-cell simulator and the 99% reliability level of the radio link capacity. System capacity is compared as a function of the number of cells per cluster and the use of power control in the FD-TDMA system, the spreading gain in the CDMA system, the receiver space diversity level, the number of channel multipath components as well as large-scale propagation parameters such as the shadowing standard deviation and the path-loss exponent. According to this methodology, it is observed that CDMA system capacity can be but is not always superior to FD-TDMA capacity. The spectral efficiency advantage (in terms of capacity per unit bandwidth) of CDMA over FD-TDMA systems is however much larger for larger spreading gains.
{"title":"Comparative evaluation of CDMA and FD-TDMA cellular system capacities with respect to radio link capacity","authors":"C. Despins, Gaingar Djelassem, V. Roy","doi":"10.1109/PIMRC.1996.567422","DOIUrl":"https://doi.org/10.1109/PIMRC.1996.567422","url":null,"abstract":"This paper presents a comparative evaluation of code-division-multiple access (CDMA) and frequency-division time-division-multiple-access (FD-TDMA) system capacities as a function of the radio link capacity (i.e. Shannon bound). This bound is first evaluated over time-varying frequency-selective fading channels by treating this information theoretic value of the capacity as a random variable. The total system sum-of-rates capacity is then evaluated for both multiple-access schemes using a multi-cell simulator and the 99% reliability level of the radio link capacity. System capacity is compared as a function of the number of cells per cluster and the use of power control in the FD-TDMA system, the spreading gain in the CDMA system, the receiver space diversity level, the number of channel multipath components as well as large-scale propagation parameters such as the shadowing standard deviation and the path-loss exponent. According to this methodology, it is observed that CDMA system capacity can be but is not always superior to FD-TDMA capacity. The spectral efficiency advantage (in terms of capacity per unit bandwidth) of CDMA over FD-TDMA systems is however much larger for larger spreading gains.","PeriodicalId":206655,"journal":{"name":"Proceedings of PIMRC '96 - 7th International Symposium on Personal, Indoor, and Mobile Communications","volume":"471 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116413601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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