Pub Date : 1982-10-01DOI: 10.1109/MILCOM.1982.4806008
P. Sass
The analysis and prediction of UHF spread spectrum communications system performance in tactical environments has revealed a great deal of uncertainty relating to the applicability of narrowband propagation models and the effects of terrain irregularity and vegetation on broadband signals. This paper presents an overview of an ongoing Army program utilizing wideband pulse response measurements to characterize ground-to-ground, tactical, UHF spread spectrum propagation channels. Recently acquired experimental data is used to demonstrate the potential of this program for improving available tools for prediction and analysis of tactical UHF spread spectrum systems employing bandwidths of hundreds of MHz.
{"title":"Propagation Measurements for UHF Spread Spectrum Communications","authors":"P. Sass","doi":"10.1109/MILCOM.1982.4806008","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806008","url":null,"abstract":"The analysis and prediction of UHF spread spectrum communications system performance in tactical environments has revealed a great deal of uncertainty relating to the applicability of narrowband propagation models and the effects of terrain irregularity and vegetation on broadband signals. This paper presents an overview of an ongoing Army program utilizing wideband pulse response measurements to characterize ground-to-ground, tactical, UHF spread spectrum propagation channels. Recently acquired experimental data is used to demonstrate the potential of this program for improving available tools for prediction and analysis of tactical UHF spread spectrum systems employing bandwidths of hundreds of MHz.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"250 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116475062","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805941
R. Larosa, S. J. Kerbel, T. L. Fowler, Patrick M. Corcoran
At proposed design of an all-SAW programmable matched filter for a pseudorandom-coded direct sequence waveform is described. The 200 MHz bandwidth is split into 8 bands 50 MHz wide on 25 MHz centers. Each band is converted down to 100 MHz where the 270 microsecond signal is processed by five cascaded SAW tapped delay lines. Each of the 750-tap transducers in each channel is matched to a segment of a noise-like waveform. Tap polarities are switched by integrated circuit chips. A thick film resistor matrix connects groups of taps with proper weighting to 24 doppler summing lines. After up-conversion, the channel outputs are combined to provide real time outputs on 24 doppler channels. This study was supported by the RADC Electromagnetic Sciences Division, Air Force Systems Command, Hanscom AFB, MA 01731.
{"title":"Bandwidth Partitioned Programmable Matched Filter for 54,000 Time-Bandwidth Product Direct Sequence","authors":"R. Larosa, S. J. Kerbel, T. L. Fowler, Patrick M. Corcoran","doi":"10.1109/MILCOM.1982.4805941","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805941","url":null,"abstract":"At proposed design of an all-SAW programmable matched filter for a pseudorandom-coded direct sequence waveform is described. The 200 MHz bandwidth is split into 8 bands 50 MHz wide on 25 MHz centers. Each band is converted down to 100 MHz where the 270 microsecond signal is processed by five cascaded SAW tapped delay lines. Each of the 750-tap transducers in each channel is matched to a segment of a noise-like waveform. Tap polarities are switched by integrated circuit chips. A thick film resistor matrix connects groups of taps with proper weighting to 24 doppler summing lines. After up-conversion, the channel outputs are combined to provide real time outputs on 24 doppler channels. This study was supported by the RADC Electromagnetic Sciences Division, Air Force Systems Command, Hanscom AFB, MA 01731.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123534604","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805932
S. Davidovici, L. Milstein, D. Schilling
This paper describes a new technique to achieve rapid acquisition in a direct sequence spread spectrum communication system. It is based in part on an upper bound for the partial correlation function of a PN sequence, and hence it is a fairly general procedure, applicable to a wide variety of systems.
{"title":"A Fast PN Acquisition Scheme","authors":"S. Davidovici, L. Milstein, D. Schilling","doi":"10.1109/MILCOM.1982.4805932","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805932","url":null,"abstract":"This paper describes a new technique to achieve rapid acquisition in a direct sequence spread spectrum communication system. It is based in part on an upper bound for the partial correlation function of a PN sequence, and hence it is a fairly general procedure, applicable to a wide variety of systems.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127292371","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4806013
J. Westcott, J. Jubin
In this paper, we will present the need for distributed network control in a packet radio environment, the criteria used for its evaluation, and an overview of the network algorithms chosen to maintain routing information and to route user traffic. The routing algorithm, known as tiered rings, functions by building a distributed tree of shortest path routes to each packet radio in the network. The information kept by each node grows only linearly as the network expands. The design uses the radio channel efficiently by providing shortest path routing and by taking advantage of the information available in a broadcast environment.
{"title":"A Distributed Routing Design for a Broadcast Environment","authors":"J. Westcott, J. Jubin","doi":"10.1109/MILCOM.1982.4806013","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4806013","url":null,"abstract":"In this paper, we will present the need for distributed network control in a packet radio environment, the criteria used for its evaluation, and an overview of the network algorithms chosen to maintain routing information and to route user traffic. The routing algorithm, known as tiered rings, functions by building a distributed tree of shortest path routes to each packet radio in the network. The information kept by each node grows only linearly as the network expands. The design uses the radio channel efficiently by providing shortest path routing and by taking advantage of the information available in a broadcast environment.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129979446","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805911
A. Budreau
This paper describes a compact synthesizer developed* for an Air Force spread-spectrum system. The prototype from TRW (ref. 1) covers the 1280-1535 MHz range in integral MHz steps, with a hopping speed of approximately 25 nanoseconds. As all the output frequencies are obtained by multiple mixing of only two clock-referenced input tones, the long-term stability of the output is as good as that of the clock. The overall architecture is that of an iterative synthesizer, with four identical stages of divide-and-mix. A 1×4 switch at each stage chooses the additional tone to be mixed in. Use of four identical modules facilitates the use of custom RF LSI chips, leading to the achievement of small size and low cost.
{"title":"Compact Fast-Hopping Frequency Synthesizer for Spread-Spectrum Systems","authors":"A. Budreau","doi":"10.1109/MILCOM.1982.4805911","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805911","url":null,"abstract":"This paper describes a compact synthesizer developed* for an Air Force spread-spectrum system. The prototype from TRW (ref. 1) covers the 1280-1535 MHz range in integral MHz steps, with a hopping speed of approximately 25 nanoseconds. As all the output frequencies are obtained by multiple mixing of only two clock-referenced input tones, the long-term stability of the output is as good as that of the clock. The overall architecture is that of an iterative synthesizer, with four identical stages of divide-and-mix. A 1×4 switch at each stage chooses the additional tone to be mixed in. Use of four identical modules facilitates the use of custom RF LSI chips, leading to the achievement of small size and low cost.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126680871","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805907
E. Chandler, G. Cooper
This study was motivated by a desire to minimize the required input signal-to-noise ratio at the receiver as a first step in optimizing the anti-intercept (AI) performance of a spread spectrum system. In the absence of error correction coding, specification of the message bit rate, the transmitted signal bandwidth, and the required bit error probability can yield a required signal-to-noise ratio for each type of SS system. Error correction coding can be used to reduce the required signal-to-noise ratio. When coding is employed, lower and upper bounds on the reduction of required signal-to-noise ratio can be determined in terms of the required bit error probability and code complexity. These performance bounds are evaluated as functions of the restricted code complexity.
{"title":"Error Correction Coding Performance Bounds for Spread Spectrum Systems","authors":"E. Chandler, G. Cooper","doi":"10.1109/MILCOM.1982.4805907","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805907","url":null,"abstract":"This study was motivated by a desire to minimize the required input signal-to-noise ratio at the receiver as a first step in optimizing the anti-intercept (AI) performance of a spread spectrum system. In the absence of error correction coding, specification of the message bit rate, the transmitted signal bandwidth, and the required bit error probability can yield a required signal-to-noise ratio for each type of SS system. Error correction coding can be used to reduce the required signal-to-noise ratio. When coding is employed, lower and upper bounds on the reduction of required signal-to-noise ratio can be determined in terms of the required bit error probability and code complexity. These performance bounds are evaluated as functions of the restricted code complexity.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113965403","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805977
J. Modestino, V. Eyuboglu
An optimum receiver structure is described for maximum-likelihood estimation of a linearly modulated binary data sequence received in the presence of spatially distributed interference by a multi-element antenna array. The optimum structure consists of an interference suppression spatial filter followed by a matched filter sampled at the baud rate, and a recursive nonlinear processor employing the Viterbi algorithm to perform maximum-likelihood sequence estimation. This receiver provides an extension of known results for single-element digital communication systems to the case where a multi-element array capability is available and results in a practically implementable optimum spatial/temporal processor.
{"title":"Adaptive Multi-Element Receiver Structure for Maximum-Likelihood Sequence Estimation in a Spatially Distributed Interference Channel","authors":"J. Modestino, V. Eyuboglu","doi":"10.1109/MILCOM.1982.4805977","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805977","url":null,"abstract":"An optimum receiver structure is described for maximum-likelihood estimation of a linearly modulated binary data sequence received in the presence of spatially distributed interference by a multi-element antenna array. The optimum structure consists of an interference suppression spatial filter followed by a matched filter sampled at the baud rate, and a recursive nonlinear processor employing the Viterbi algorithm to perform maximum-likelihood sequence estimation. This receiver provides an extension of known results for single-element digital communication systems to the case where a multi-element array capability is available and results in a practically implementable optimum spatial/temporal processor.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121851880","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805982
Hal Feinstein, Paul L. Rinaldo
Spread spectrum techniques have been used by the military for years. Civil applications of spread spectrum have been slow to develop due to perceived high cost, insufficiency of data for the civil environment and other factors. The Amateur Radio Service is being used as a test bed for spread spectrum experimentation using volunteer experimenters. Results thus far demonstrate that spread spectrum systems can be built economically, operate effectively and share frequency bands with existing users employing narrow-band communications techniques.
{"title":"Spread Spectrum Experiments for Civil Applications","authors":"Hal Feinstein, Paul L. Rinaldo","doi":"10.1109/MILCOM.1982.4805982","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805982","url":null,"abstract":"Spread spectrum techniques have been used by the military for years. Civil applications of spread spectrum have been slow to develop due to perceived high cost, insufficiency of data for the civil environment and other factors. The Amateur Radio Service is being used as a test bed for spread spectrum experimentation using volunteer experimenters. Results thus far demonstrate that spread spectrum systems can be built economically, operate effectively and share frequency bands with existing users employing narrow-band communications techniques.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125239546","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805943
A. Viterbi
It is well known [Refs 1, 2] that a tone or partial-band noise jammer can so choose his jamming strategy as to cause the bit error rate of a frequency-hopped MFSK transmission system, to be an inverse linear function of Eb/No = (W/R)/(J/S), where W is the total available bandwidth available to the communicator, R is the bit rate and J/S is the jammer-to-signal power margin. This situation can be greatly improved by the use of coding, but with hard decisions, performance is still significantly worse than in additive Gaussian noise, unless sufficient time diversity (hops/bit) are employed to thwart such jammers - but at a cost in performance due to coherence loss. This paper investigates use of a simple robust technique which generates a "quality" bit based on the ratio of the maximum filter output to the second largest filter output. This improves coded system performance by as much as 6 dB for a tone jammer and makes lower redundancy (time diversity) more desirable. Performance is determined for both tone and partial band noise jamming and the two are shown to be almost equal and only slightly worse than for full-band Gaussian noise in a coded system.
{"title":"A Robust Ratio-Threshold Technique to Mitigate Tone and Partial Band Jamming in Coded MFSK Systems","authors":"A. Viterbi","doi":"10.1109/MILCOM.1982.4805943","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805943","url":null,"abstract":"It is well known [Refs 1, 2] that a tone or partial-band noise jammer can so choose his jamming strategy as to cause the bit error rate of a frequency-hopped MFSK transmission system, to be an inverse linear function of Eb/No = (W/R)/(J/S), where W is the total available bandwidth available to the communicator, R is the bit rate and J/S is the jammer-to-signal power margin. This situation can be greatly improved by the use of coding, but with hard decisions, performance is still significantly worse than in additive Gaussian noise, unless sufficient time diversity (hops/bit) are employed to thwart such jammers - but at a cost in performance due to coherence loss. This paper investigates use of a simple robust technique which generates a \"quality\" bit based on the ratio of the maximum filter output to the second largest filter output. This improves coded system performance by as much as 6 dB for a tone jammer and makes lower redundancy (time diversity) more desirable. Performance is determined for both tone and partial band noise jamming and the two are shown to be almost equal and only slightly worse than for full-band Gaussian noise in a coded system.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130327309","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 : 1982-10-01DOI: 10.1109/MILCOM.1982.4805987
R. W. Nettleton
This paper describes the common structure of a large class of frequency-hopping multiple-access address sequences of the so-called "one-coincidence" type. We show methods for expanding the address sets to great size without compromising performance, and compare frequency and phase modulation methods. We also describe methods for dealing with unsynchronizable signalling alphabets, which arise as a result of expanding the MFSK sets.
{"title":"Addressing and Modulation for Frequency-Hopping Multiple Access","authors":"R. W. Nettleton","doi":"10.1109/MILCOM.1982.4805987","DOIUrl":"https://doi.org/10.1109/MILCOM.1982.4805987","url":null,"abstract":"This paper describes the common structure of a large class of frequency-hopping multiple-access address sequences of the so-called \"one-coincidence\" type. We show methods for expanding the address sets to great size without compromising performance, and compare frequency and phase modulation methods. We also describe methods for dealing with unsynchronizable signalling alphabets, which arise as a result of expanding the MFSK sets.","PeriodicalId":179832,"journal":{"name":"MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116543706","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：