In this work, a wavelet-based multiple access system, STCDMA (scale-time-code-division multiple access), which is based on the scale, time, and code orthogonality has been described and its performance has been analyzed for synchronous transmission in an AWGN channel. In a synchronous AWGN channel, Hadamard codebased PN sequences keep their orthogonality and hence STCDMA achieves optimum single-user BPSK performance by using a conventional single-user detector for each user. It also supports a larger number of users than conventional DS-CDMA (six or seven times more than DS-CDMA) if the first (coarsest) scale is thought to be traditional DS-CDMA. When we use other wavelets than the Haar wavelet, or the signature waveforms exhibit some correlation in other environments such as asynchronous AWGN channel and the multipath propagation medium, the system will have multiple access interference.
{"title":"Scale-time-code-division multiple access (STCDMA)","authors":"O. Kucur, G. Atkin","doi":"10.1109/TCC.1996.561117","DOIUrl":"https://doi.org/10.1109/TCC.1996.561117","url":null,"abstract":"In this work, a wavelet-based multiple access system, STCDMA (scale-time-code-division multiple access), which is based on the scale, time, and code orthogonality has been described and its performance has been analyzed for synchronous transmission in an AWGN channel. In a synchronous AWGN channel, Hadamard codebased PN sequences keep their orthogonality and hence STCDMA achieves optimum single-user BPSK performance by using a conventional single-user detector for each user. It also supports a larger number of users than conventional DS-CDMA (six or seven times more than DS-CDMA) if the first (coarsest) scale is thought to be traditional DS-CDMA. When we use other wavelets than the Haar wavelet, or the signature waveforms exhibit some correlation in other environments such as asynchronous AWGN channel and the multipath propagation medium, the system will have multiple access interference.","PeriodicalId":398935,"journal":{"name":"Proceedings of the 1996 Tactical Communications Conference. Ensuring Joint Force Superiority in the Information Age","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126821681","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}
The current literature contains many algorithms for determination of the number of emitters and their parameters when the emitter signals are all present over the observation period of the receiver. In the problem considered, emissions are of short duration, and interference between emissions at the receiver is a rare event. The receiver estimates the angle, frequency, amplitude, and time of arrival for each emission assuming that no other emissions are present. These estimates are then collected for some time interval and passed to a sorting method that estimates the number of emitters and the parameters associated with each. Two methods are presented. These methods are ad-hoc, although the 3D method resembles the Parzen with a normal kernel for estimating a probability density function and the maximum a posteriori method for estimating the parameters. The 2D method is a modification to the 3D that trades off performance for speed of execution. Both methods were evaluated using over 100 data sets. The data varies from sparse, containing 50 or less hits over the collection interval, to dense, with over 1000 hits. In sparse environments both methods produce about the same emitter reports. In dense environments, the 2D method sometimes misses emitters that the 3D method detects.
{"title":"Sorting methods for estimating the number of emitters and their parameters","authors":"R. Kenefic","doi":"10.1109/TCC.1996.561125","DOIUrl":"https://doi.org/10.1109/TCC.1996.561125","url":null,"abstract":"The current literature contains many algorithms for determination of the number of emitters and their parameters when the emitter signals are all present over the observation period of the receiver. In the problem considered, emissions are of short duration, and interference between emissions at the receiver is a rare event. The receiver estimates the angle, frequency, amplitude, and time of arrival for each emission assuming that no other emissions are present. These estimates are then collected for some time interval and passed to a sorting method that estimates the number of emitters and the parameters associated with each. Two methods are presented. These methods are ad-hoc, although the 3D method resembles the Parzen with a normal kernel for estimating a probability density function and the maximum a posteriori method for estimating the parameters. The 2D method is a modification to the 3D that trades off performance for speed of execution. Both methods were evaluated using over 100 data sets. The data varies from sparse, containing 50 or less hits over the collection interval, to dense, with over 1000 hits. In sparse environments both methods produce about the same emitter reports. In dense environments, the 2D method sometimes misses emitters that the 3D method detects.","PeriodicalId":398935,"journal":{"name":"Proceedings of the 1996 Tactical Communications Conference. Ensuring Joint Force Superiority in the Information Age","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116622050","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}
A new method is described for routing multimedia traffic in a frequency-hop (FH) store-and-forward packet radio network. The new routing protocol is an extension of least-resistance routing (LRR), which bases route selection on the resistances for the routes from the source to the destination. The link resistance for LRR is a measure of the interference environment and other conditions that affect the probability that a FH radio can receive and forward a packet. For multimedia least-resistance routing (MMLRR), the link resistance for a given type of packet also accounts for the service requirements of that packet. MMLRR is illustrated for two types of traffic, each type having its own constraints on the number of errors and the delay. A typical application is the routing of voice and data packets in a multiple-hop network. In such an application, the voice packets cannot tolerate much delay, but they are allowed to contain a small number of errors. The data packets must be delivered error-free, even if a moderate delay is required to do so. The performance of MMLRR is measured by the throughput, end-to-end success probability, and delay which are obtained by computer simulation of a multiple-hop network of FH radios.
{"title":"Measuring the link qualities in a frequency-hop packet radio network for use in the routing of multimedia packets","authors":"M. Pursley, H. Russell, P. E. Staples","doi":"10.1109/TCC.1996.561094","DOIUrl":"https://doi.org/10.1109/TCC.1996.561094","url":null,"abstract":"A new method is described for routing multimedia traffic in a frequency-hop (FH) store-and-forward packet radio network. The new routing protocol is an extension of least-resistance routing (LRR), which bases route selection on the resistances for the routes from the source to the destination. The link resistance for LRR is a measure of the interference environment and other conditions that affect the probability that a FH radio can receive and forward a packet. For multimedia least-resistance routing (MMLRR), the link resistance for a given type of packet also accounts for the service requirements of that packet. MMLRR is illustrated for two types of traffic, each type having its own constraints on the number of errors and the delay. A typical application is the routing of voice and data packets in a multiple-hop network. In such an application, the voice packets cannot tolerate much delay, but they are allowed to contain a small number of errors. The data packets must be delivered error-free, even if a moderate delay is required to do so. The performance of MMLRR is measured by the throughput, end-to-end success probability, and delay which are obtained by computer simulation of a multiple-hop network of FH radios.","PeriodicalId":398935,"journal":{"name":"Proceedings of the 1996 Tactical Communications Conference. Ensuring Joint Force Superiority in the Information Age","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123875835","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}
Spread spectrum packet radio networks are being proposed to support tactical communications in highly mobile battlefield environments. Direct sequence packet radio waveforms offer certain benefits that provide antijamming (A/J) and LPI protection while reducing the effects of multipath and providing rapid acquisition. However, near/far interference restricts the performance of a direct sequence type waveforms in a tactical network where the relative power of each transmitting node cannot be centrally controlled. This paper reviews the implementation and analysis of adaptive power control for a spread spectrum waveform within a hierarchical packet radio network. The adaptive power control algorithm operates in conjunction with a receiver directed/reservation-based channel access protocol that uses a sequence of short synchronization and acknowledgment bursts to reserve the channel and adapt the transmit power for the exchange of direct sequence modulated data packets. The waveform, channel access protocol and power control algorithm operate within a hierarchical packet radio network that supports 400 or more radio nodes within a Brigade size area of 20/spl times/30 km. The network of radio nodes is divided into clusters that communicate locally. Clusterheads within each cluster form, a virtual backbone for intercluster packet exchange. This paper presents an overview of the waveform, protocols and power control algorithm that support the packet exchange process. Modeling results are presented to show the relative throughput, delay and reliability performance of the network versus various adaptive power control parameters.
{"title":"Evaluation of adaptive power control algorithms for a hierarchical packet radio network","authors":"T. Dempsey, C. Langford, R. Martin, J. McChesney","doi":"10.1109/TCC.1996.561102","DOIUrl":"https://doi.org/10.1109/TCC.1996.561102","url":null,"abstract":"Spread spectrum packet radio networks are being proposed to support tactical communications in highly mobile battlefield environments. Direct sequence packet radio waveforms offer certain benefits that provide antijamming (A/J) and LPI protection while reducing the effects of multipath and providing rapid acquisition. However, near/far interference restricts the performance of a direct sequence type waveforms in a tactical network where the relative power of each transmitting node cannot be centrally controlled. This paper reviews the implementation and analysis of adaptive power control for a spread spectrum waveform within a hierarchical packet radio network. The adaptive power control algorithm operates in conjunction with a receiver directed/reservation-based channel access protocol that uses a sequence of short synchronization and acknowledgment bursts to reserve the channel and adapt the transmit power for the exchange of direct sequence modulated data packets. The waveform, channel access protocol and power control algorithm operate within a hierarchical packet radio network that supports 400 or more radio nodes within a Brigade size area of 20/spl times/30 km. The network of radio nodes is divided into clusters that communicate locally. Clusterheads within each cluster form, a virtual backbone for intercluster packet exchange. This paper presents an overview of the waveform, protocols and power control algorithm that support the packet exchange process. Modeling results are presented to show the relative throughput, delay and reliability performance of the network versus various adaptive power control parameters.","PeriodicalId":398935,"journal":{"name":"Proceedings of the 1996 Tactical Communications Conference. Ensuring Joint Force Superiority in the Information Age","volume":"423 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126713308","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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