TH73708A - Interference management for soft forwarding and broadcasting services in wireless frequency hopping communication systems. - Google Patents

Abstract

DC60 (21/09/47) Various techniques have been prepared to handle interference for soft forwarding and broadcasting services in wireless frequency hop communication systems (e.g., OFDMA systems). These techniques may be applied for both forward and backward links. In the first scheme, the fH function fsho(r,T) is applied to users of soft forwarding. The fH function fsi(k,T) is applied to users not in soft forwarding. In each sector, Si and the fH function fsi(k,T) are modified to be perpendicular to the fH function fsho(r,T) if and where necessary. In the second scheme, the fH function fsho(r,T) is applied to users. The soft forward function is set to be orthogonal to or have a low correlation with the fH function fsi(k,T) used for non-soft forward users in each sector si; therefore, modification of the fH function fsi(k,T) is not necessary. The fH function fsi(k,T) for each sector may be set to pseudo-random relative to the fH function fsi(k,T) for other sectors. Various techniques are provided to handle interference for soft forward and broadcast services in wireless frequency hop communication systems (e.g., OFDMA systems). These techniques may be applied for forward and backward links. In the first scheme, the fH function fsho(r,T) is used for soft forward users. The fH function fsi(k,T) is used for non-soft forward users in each sector si, and the fH function fsi(k,T) is modified to be orthogonal to the fH function fsho(r,T) if and when necessary. In the second scheme... The fH function fsho(r,T) used for the user of the soft forward is assigned orthogonal to, or has a low correlation, to the fH function fsi(k,T) used for the non-soft forward user in each sector si; therefore, no modification to the fH function fsi(k,T) is required. The fH function fsi(k,T) for each sector may be assigned pseudo-random relative to the fH function fsi(k,T) for other sectors.

Claims (30)

1. The method for handling interference in a wireless frequency hop (FH) communication system includes: obtaining the first FH function; obtaining an identifier for the first traffic channel assigned by that first FH function; modifying the second FH function based on the first FH function, and the identifier for the first traffic channel to obtain the modified second FH function. The second FH function is modified so that the second traffic channel assigned by the modified second FH function and the first traffic channel are orthogonal and have low correlation, and the second traffic channel is used for data transmission. 2. The method of Claim 1 where the first FH function is implemented for users in soft forwarding with at least two base stations in that system, and where the second FH function is implemented for users not in soft forwarding and communicating with one of at least two base stations. 3. The method of claim 1 whereby the first FH function shall be for the first base station in that system, and the second FH function shall be for the second base station in that system. 4. The method of claim 1 in which the first FH function is used for broadcasting by at least two base stations in the system, and in which the first traffic channel is used to transmit broadcast data. 5. The method of claim 1 is further incorporated: the acquisition of an identifier for the third traffic channel assigned by the second FH function, where the third traffic channel is associated with the first traffic channel, and where the second FH function is further modified on the basis of the identifier for the third traffic channel. 6. Method of claim 5 where the modified second FH function is defined as: (chemical formula) in other words, where r is the identifier for traffic channel one, k is the identifier for traffic channel two, v is the identifier for traffic channel three, T is the system time pointer, f1(r,T) is the first FH function defining the specific subband to be used for traffic channel r at time T, f2(k,T) is the second FH function, and f2(k,T) is the modified second FH function. 7. The method of claim number 5, whereby the identifiers for the first, second and third traffic channels are obtained by means of a signal transmitted over the air. 8. The method of claim 1 whereby the first traffic channel is associated with the first order of the subband determined by the first FH function and the identifier for the first traffic channel, and whereby the second traffic channel is associated with the second order of the subband determined by the second modified FH function and the identifier for the second traffic channel. 9. The method of claim 1, where the first and second FH functions are determined by the first and second time shifts, respectively, of the pseudo-random number (PN) code. 10. Method of Claim 1 in which a second traffic channel will be used for transmitting data on the front link from the base station to the terminal. 11. The method of claim 1 in which a second traffic channel will be used for transmitting data on a backward link from the terminal to the base station. 12. Method of Claim 1 where the wireless communication system is a Orthogonal Frequency Division Multiple Access (OFDM) communication system. 13. The components of a wireless frequency hop (FH) communication system consist of: a path for acquiring the first FH function; a path for acquiring the identifier for the first traffic channel assigned by the first FH function; a path for modifying the second FH function based on the first FH function and the identifier for the first traffic channel in order to obtain a modified second FH function, where the second FH function is modified so that the second traffic channel assigned by the modified second FH function and the first traffic channel are orthogonal and have low correlation; and a path for using the second traffic channel for data transmission. 14. The components of a wireless frequency hop (FH) communication system include: a processor that operates to obtain the first FH function and identifier for the first traffic channel assigned by that first FH function; modifies the second FH function based on the first FH function and identifier for the first traffic channel to obtain the modified second FH function; and prepares the FH sequence for the second traffic channel assigned by the modified second FH function, where the second FH function is modified so that the second and first traffic channels are orthogonal or have low correlation; and a switch that operates to determine a specific subband of a given frequency subband to be used in each frequency hop period based on the FH sequence for the second traffic channel. 15. The instrument of claim 14 is further comprised of: a modulator which operates to modulate data for the second traffic channel and provides the modulation symbol, and where a switch operates to provide the modulation symbol to the subband considered to be determined by the FH sequence for the second traffic channel. 16. The instrument of claim 14 is further comprised of: a demodulator which operates to obtain from the switch the modulation symbol received on the subband considered by the FH sequence for the second traffic channel and to demodulate the received modulation symbol in order to provide demodulated data for the second traffic channel. 17. Terminal equipment incorporating the equipment of claim 14. 18. Base station comprising the equipment under claim 14. 19. A processor-readable medium for storing executable instructions to: obtain the first frequency hop (FH) function; obtain the identifier for the first traffic channel assigned by that first FH function; and modify the second FH function based on the first FH function and the identifier for the first traffic channel in order to obtain the modified second FH function, where the second FH function is modified so that the second traffic channel assigned by the modified second FH function and the first traffic channel are orthogonal and have low correlation, and where the second traffic channel is used for forward or backward link transmission. 20. Methods for handling interference in wireless frequency hop (FH) communication systems include: receiving the assignment of the first traffic channel, assigned by FH function one; using the first traffic channel for communication with the first base station; receiving the assignment of the second traffic channel, assigned by FH function two, where FH functions one and two are orthogonal and have low correlation; and using the second traffic channel for communication between the first and second base stations. 21. The method of claim 20 whereby the second base station is made relevant to the third FH function for determining the third traffic channel adopted for communication with the second base station, whereby the second and third FH functions are orthogonal and have low correlation, and whereby the first FH function is pseudo-random with respect to the third FH function. 22. The method of claim 20, in which the first and second FH functions are determined by the first and second time shifts, respectively, of pseudo-random number (PN) codes. 23. The method of claim 20 whereby the first traffic channel shall be used to transmit the first transmission on the link-to-link from the first base station to the terminal, and whereby the second traffic channel shall be used to transmit the second transmission on the link-to-link from the first and second base stations to the terminals. 24. The method of claim 20 whereby the first traffic channel shall be used to transmit the first transmission on the backward link from the terminal to the first base station, and whereby the second traffic channel shall be used to transmit the second transmission on the backward link from the terminal to the first and second base stations. 25. Method of Claim 20 where the wireless communication system is a Orthogonal Frequency Division Multiple Access (OFDM) communication system. 26. The components of a wireless frequency hop (FH) communication system include: a path for receiving the assignment of the first traffic channel, assigned by FH function one; a path for using the first traffic channel for communication with base station one; a path for receiving the assignment of the second traffic channel, assigned by FH function two, where FH functions one and two are orthogonal and have low correlation; and a path for using the second traffic channel for communication between base station one and base station two. 27. The components of a wireless frequency hop (FH) communication system consist of: a processor that operates to receive the assignment of the first traffic channel, assigned by the FH function one, and prepares the FH sequence one for the first traffic channel, which is then used for communication with the first base station; and a switch that operates to determine a specific subband of a certain frequency subband to be used for each period of the first frequency hop based on the FH sequence one for the first traffic channel; and where the processor further operates to receive the assignment of the second traffic channel, assigned by the FH function two, and prepares the FH sequence two for the second traffic channel, which is then used for communication with the first and second base stations; and where the switch further operates to determine a specific subband of a certain frequency subband to be used for each period of the second frequency hop based on the FH sequence two for the second traffic channel. The second figure. 28. The methods for handling interference in wireless frequency hop (FH) communication systems include: the first transmission/receipt on traffic channel one from base station one, where traffic channel one is assigned by FH function one relative to base station one; and the second transmission/receipt on traffic channel two from base station one and base station two, where traffic channel two is assigned by FH function two, where FH function three relative to base station two, where FH function two is orthogonal to or has a lower correlation with both FH functions one and three, and where FH function one is pseudo-random with respect to FH function three. 29. The method of claim 28 in which the second transmission shall include broadcast information. 30. A wireless frequency hop (FH) communication system consists of: a first transmit/receive path on traffic channel one from base station one, where traffic channel one is assigned by FH function one relative to base station one, and a second transmit/receive path on traffic channel two from base station one and base station two, where traffic channel two is assigned by FH function two, where FH function three relative to base station two, where FH function two is orthogonal to or has low correlation with both FH functions one and three, and where FH function one is pseudo-random with respect to FH function three.