An investigation of measured and simulated wideband channels with applications to 1.25 MHz and 5 MHz CDMA systems

Abstract

, J-E. (1998). An investigation of measured and simulated wideband channels with applications to 1.25 MHz and 5 MHz CDMA systems. In 48th IEEE Vehicular Technology Conference, 1998. VTC 98. (Vol. 1, pp. 562-566). DOI: 10.1109/VETEC.1998 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal An Investigation of Measured and Si ulated Wideband Channels with Applications to 1.25 MHz and 5 MHz CDMA SystemsHenrik Asplund, Andres Alayon Glazunov and Jan-Erik BergEricsson Radio Systems AB S-16480 Stockholm SwedenAbstract -Fading of the wideband radio channel and its implications for CDMA RAKE receiver operation has been investigated using measured wideband impulse responses and simulations with an exponentially shaped channel model. The emphasis has been on systems with 1.25 MHz and 5 MHz bandwidth, and the reduction in fading variations as well as the increased complexity in terms of required RAKE correlator branches when increasing the bandwidth has been studied. An analysis of the consequences of fast power control has also been performed.

Efficient Rate-Power Allocation for OFDM in a Realistic Fading Environment

“…The transmission channel data used was obtained by Ericsson Radio Systems AB of Stockholm, Sweden and was initially described in [2]. The first set of measurements was taken in Kista, an environment that may be described as having a mix of urban and suburban characteristics; the second set was captured in central Stockholm, an urban environment with areas of open water.…”

“…The median noise level was also assessed and all received samples less than 6dB above this level were set to zero in a manner similar to [12]. Additional details of the data acquisition process are presented in [2].…”

“…The data provided for this analysis was obtained as result of an evaluation performed of mobile wireless transmission in two locations in Stockholm, and was kindly made available to us by Ericsson Radio Systems AB: this data is from the same dataset used by [2]. LMS filtration [11] is applied to predict the CSI at the future instant of symbol transmission: this prediction horizon will be exploited to perform the transmission optimisation.…”

“…The resulting solution is therefore quite robust to certain transient channel quality degradation yet the generous safety tolerances render it unable to exploit other transient transmission quality improvements We seek to overcome the problems associated with this approach by applying a theoretically sound novel adaptive resource allocation framework to actual broadband wireless channel development data. The allocation framework is derived from the optimal OFDM allocation scheme for a known channel [1]: the channel development data is obtained from actual measurement of a broadband wireless mobile environment [2]. Prediction techniques are employed to overcome the time lag between channel assessment and symbol transmission.…”