Abstract: It is proposed a receiver comprising receiving means for receiving a preamble signal (26) that comprises a long PN sequence (33) being a combination of a plurality of short PN sequences (29, 30, 31,32), wherein said short PN sequences (29, 30, 31,32) are selected on the basis of their auto-correlation and/or cross-correlation properties. At least one of said short PN sequences (29, 30, 31,32) referred to as a coarse timing short PN sequence (PN1) is adapted to perform a coarse timing synchronization, extracting means (41) for extracting said coarse timing short PN sequence (PN1) from said long PN sequence (33), first auto-correlating means (42, 43, 44, 45) for performing a coarse timing synchronization using said coarse timing short PN sequence (PN1), and second auto-correlating means (52, 53, 54, 55) for performing a fine timing synchronization using said long PN sequence (33).

Abstract: A heterogeneous wireless network topology suited for low-power, short-range and ubiquitous ad-hoc communication. The network topology integrates different wireless transmission technologies, in particular to a wireless sensor network including different node types and communication technologies. The network is highly heterogeneous and can be operated according to the master-slave principle. The nodes can have different wireless communication means tailored to their individual role in the network and other constraints, thus allowing different communication patterns.

Abstract: The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna means, respectively.

Abstract: The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna mean, respectively.

Abstract: The invention relates to a wireless optical data transmission system and a method for wireless optical transmission of data. The system comprises a data stream generator for generating at least two parallel data streams (18.1, 18.2, 18.3). The parallel data streams are transmitted by a number of separate optical transmitting devices (8, 9, 10) separately by emitting first optical signals. The system further comprises a corresponding number of detectors (19, 20, 21) for detecting the first optical signals and converting them into respective second signals (26.1, 26.2, 26.3) and an error correction unit (31) for correcting the amended second signals. Within a predistortion (29) unit each second signal (26.1, 26.2, 26.3) is amended individually with respect to a transmission channel used.

Abstract: The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna means, respectively.

Abstract: A transmitting device for transmitting data symbols and pilot symbols in an OFDM transmission system; the device comprising symbol generating means for generating said data symbols and said pilot symbols, means for transmitting said data symbols and pilot symbols respectively by using a plurality of subcarriers of said OFDM transmission system, wherein said symbol generating means is designed to selectively generate a first type pilot symbol and a second type pilot symbol being orthogonal to said first type pilot symbol so that a pilot symbol pattern in the frequency dimension comprises at least said first type pilot symbol to be transmitted by using a predefined subcarrier and second type pilot symbol to be transmitted by using other predefined subcarrier, and wherein said pilot symbol pattern has a different pattern from a succeeding pilot symbol pattern in time dimension.

Abstract: The present patent application is directed to a communication system 0 comprising a first station 1 with a first narrow beam antenna 31 and a second station 2 comprising a second narrow beam antenna 41, wherein the first and second stations 1, 2 are adapted to establish a first communication path 7a for wireless communication via said first and second narrow beam antennas 31, 41, respectively. It is a disadvantage with such a communication system that communication via said first communication path might be disturbed by randomly appearing obstacles. In consequence, the data transmission rate is reduced. According to the present invention said first and second stations 1, 2 are adapted to automatically establish at least one alternative communication path 7b, 7c for wireless communication via said first and second narrow beam antennas 31, 41, said alternative communication path 7b, 7c being spatially different from said first communication path 7a.

Abstract: The present invention relates to a frequency-shift-keying demodulator (1, 1?) comprising a phase shifter 2 for shifting the phase of an input signal i(t) by a predetermined degree and for outputting a shifted signal Id(t), a combining unit (3, 4; 31, 32, 33, 41, 42) for combining the input signal i(t) and the shifted signal Id(t) output by the phase shifter 2 and for outputting a corresponding signal r(t) and a low-pass filter 5 for filtering the signal r(t) output by the combining unit (3, 4; 31, 32, 33, 41, 42), and for outputting a low-pass filtered signal rLP(t) the bandwidth of said low-pass filter 5 being matched with the bandwidth of a data signal contained in said input signal i(t).

Abstract: The present invention relates to a device (10) for receiving signals in a wireless orthogonal frequency division multiplex (OFDM) system and to a channel estimation method in such a system. The data symbols and pilot symbols are transmitted in frequency subcarriers and timeslots, whereby pilot symbols are transmitted in a continuous stream within at least one frequency subcarrier. A channel estimation for a data symbol is performed on the basis of received pilot symbols using a filter including a common phase error correction value from the continuous stream pilot symbol in the same timeslot as the data symbol to be channel estimated. The present invention thereby enables a correct and efficient channel estimation including a common phase error correction to be performed.

Abstract: In a backscatter interrogator reception method, a continuous carrier signal (P1) with a frequency fc is sent from an interrogator (100) to a tag device (110) over a wireless link, the tag device (110) transmits data to the interrogator (100) using a modulated backscatter (P2) signal, and the received modulated backscatter signal (P2) is demodulated by the interrogator (100) to retrieve the data transmitted from the tag device (110). According to the present invention, the interrogator (100) estimates the phase and the amplitude of an inband interferer signal contained in the received modulated backscatter signal (P2), generates a cancellation signal having the opposite phase and the same amplitude as the estimation of the inband interferer signal, and combines said cancellation signal with the received backscatter signal (P2) in order to reduce the influence of the inband interferer signal. In addition, a two-stage interferer cancellation scheme is proposed.

Abstract: The invention proposes a device for generating, from incoming signal values (Xi,n), soft-values (Yi,n) to be input into a channel decoder of a communication device for use in a wireless communication system, comprising truncation means (24, 26, 28) for truncating the incoming signal values (Xi,n) such as to fall within a predetermined limit value range, and normalization means (30, 32) for normalizing the truncated signal values (Xti,n) such as to fit to an input range of the decoder. According to the invention, the truncation means (24, 26, 28) are adapted to determine the boundaries of the limit value range in dependence on information representative of a signal-to-noise ratio of the incoming signal values (Xi,n). The truncated signal values (Xti,n), after normalization, then are output as said soft-values (Yi,n).

Abstract: The present invention relates to a cellular communication system for wireless telecommunication on the basis of an OFDM scheme, comprising a plurality of base stations B, whereby at least one base station B is allocated to each cell C of the communication system and whereby information communicated from the base stations comprises data parts and pilot parts. The present invention further relates to a method for operating such a cellular communication system. The present invention is characterised in that the frequency reuse factor of the data parts is different from a frequency reuse factor of the pilot parts. Hereby, an optimisation between high capacity and reliable and correct channel estimation on the basis of the pilot parts can be achieved.

Abstract: The present invention relates to a device (10) for receiving signals in a wireless orthogonal frequency division multiplex (OFDM) system and to a channel estimation method in such a system. The data symbols and pilot symbols are transmitted in frequency subcarriers and timeslots, whereby pilot symbols are transmitted in a continuous stream within at least one frequency subcarrier. A channel estimation for a data symbol is performed on the basis of received pilot symbols using a filter including a common phase error correction value from the continuous stream pilot symbol in the same timeslot as the data symbol to be channel estimated.

Abstract: The present invention relates to a cellular communication system for wireless telecommunication on the basis of an OFDM scheme, comprising a plurality of base stations B, whereby at least one base station B is allocated to each cell C of the communication system and whereby information communicated from said base stations comprises data parts and pilot parts. The present invention further relates to a method for operating such a cellular communication system. The present invention is characterised in that the frequency reuse factor of the data parts is different from a frequency reuse factor of the pilot parts. Hereby, an optimisation between high capacity and reliable and correct channel estimation on the basis of the pilot parts can be achieved.

Abstract: The invention proposes a device for generating, from incoming signal values (Xi,n), soft-values (Yi,n) to be input into a channel decoder of a communication device for use in a wireless communication system, comprising truncation means (24, 26, 28) for truncating the incoming signal values (Xi,n) such as to fall within a predetermined limit value range, and normalization means (30, 32) for normalizing the truncated signal values (Xti,n) such as to fit to an input range of the decoder. According to the invention, the truncation means (24, 26, 28) are adapted to determine the boundaries of the limit value range in dependence on information representative of a signal-to-noise ratio of the incoming signal values (Xi,n). The truncated signal values (Xti,n), after normalization, then are output as said soft-values (Yi,n).

Abstract: The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna means, respectively.

Abstract: The present invention relates to a device for receiving signals in a wireless cellular OFDM system, in which data symbols are transmitted in frequency subcarriers and timeslots. The present invention further relates to a method for channel estimation in such a device. According to the present invention, a channel estimation on the basis of received pilot symbols is performed, whereby the channel estimation for data symbols between pilot symbols is performed by means of a filter, said filter being selected from a set of filters on the basis of an interference reference value.

Abstract: A code division multiple access (CDMA) receiver for receiving an encoded CDMA signal is disclosed, the receiver comprising an analog to digital converter for sampling a received signal and passing the thus sampled and digitized signal to a CDMA decoder, the converter receiving a sampling clock signal at a sampling frequency, the phase of the clock signal being adjustable. The CDMA decoder includes a plurality of sets of correlators, each set having a different base delay, each base delay being adjustable.