Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/04—TPC
  • H04W52/06—TPC algorithms
  • H04W52/14—Separate analysis of uplink or downlink
  • H04W52/143—Downlink power control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/04—TPC
  • H04W52/18—TPC being performed according to specific parameters
  • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
  • H04W52/243—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account interferences
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/04—TPC
  • H04W52/06—TPC algorithms
  • H04W52/14—Separate analysis of uplink or downlink
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/04—TPC
  • H04W52/06—TPC algorithms
  • H04W52/14—Separate analysis of uplink or downlink
  • H04W52/146—Uplink power control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
  • H04W52/04—TPC
  • H04W52/18—TPC being performed according to specific parameters
  • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters

Definitions

• This invention relates generally to a system for minimizing co-channel interference and more particularly, to a system for minimizing co-channel interference utilizing geographic separation of signals and transmission power control.
• a radio telephone communication system In general, the purpose of a radio telephone communication system is to transmit information-bearing signals from a source, located at one point to a user destination, located at a point some distance away.
• a radio telephone communication system generally includes three basic components: transmitter, radio communication channel, and receiver.
• Time Division Multiplexing In Time Division Multiplexing ("TDM”), a wideband channel is subdivided into several narrowband channels by allocating the use of the wideband channel to the different narrowband channels during different time slots. Each of these narrowband channels is assigned to different users to allow for contemporaneous utilization of the wideband channel resources by many users.
• Time Division Multiple Access (“TDMA”) is a technique by which a large population of subscribers with a low individual probability of becoming active get access to the channel resources. This technique relies on a dynamic TDM slot allocation.
• FDMA Frequency Division Multiple Access
• FDM Frequency Division Multiplexing
• May 27, 1993 discloses a multiple access communications system in which a measure of co-channel interference in a first radio communication channel being used in a first geographic area is determined. The system reacts to the measure exceeding a predetermined level to switch the user to a second radio communication channel in the same geographic area. This system does not address the problem of co-channel interference by minimizing such interference but reacts to the problem after the interference is detected.
• the foregoing objects are attained by the invention, which provides a method of and apparatus for minimizing co-channel interference by geographic separation of signals and transmission power control in a combined Frequency Hopping/TDMA radio telephone system.
• the invention includes a first sector divided into geographic zones, and an adjoining second sector divided into the same number of geographic zones. Time slots are selectively allocated to each of the different geographic zones in the first sector and the same time slots are allocated to the geographic zones in the second sector but in a different order. Thus, every user located within a particular geographic zone within a sector is assigned the same time slot. In addition, each time zone has an up-link and down-link transmission power associated with it.
• FIG. 1 depicts a diagram of three adjoining sectors in a combined Frequency
• Hopping/TDMA radio telephone system in which a system for minimizing co-channel interference operates in accordance with the invention; showing each sector divided into different geographic zones;
• FIG. 2 depicts the sectors of FIG. 1, showing time slot allocations and transmission overlap between the different sectors;
• FIG. 3 depicts a base station and mobile receivers; showing a transmitter, a receiver in a base station, a transmitter in the mobile receivers and showing the up ⁇ link and down-link transmissions.
• FIG. 1 is a diagram of three sectors in a combined Frequency Hopping /
• TDMA radio telephone system in which an embodiment of the invention operates, showing three sectors SI, S2 and S3 each adjoining the other two, wherein each sector is divided into three geographic zones Zll, Z12 Z13, Z21, Z22 Z23, Z31, Z32 and Z33.
• Fig. 2 is a diagram of the three sectors of FIG. 1 showing the different geographic zones Zll, Z12 Z13, Z21, Z22 Z23, Z31, Z32 and Z33 having corresponding TDM time frame time slot allocations Tl, T2 and T3, transmission fields 1-1, 2-2 and 3-3 of the different antennas Al, A2 and A3 and the areas of transmission overlap ⁇ 1 2 , F x _ 3 and F 2 . 3 between transmission fields 1-1, 2-2 and 3-3.
• FIG. 3 is a diagram of the relationship between base station 10 and a mobile receiver 12 during down-link transmission and during up-link transmission.
• transmitter 16 can generate a signal to transmit to a particular sector.
• transmitter 14 can generate a signal to transmit from mobile receiver 12.
• Base station 10 is also capable of assigning time slots to users located in the various geographic zones.
• Fig. 2 illustrates what may occur with a three time slot repeat pattern in each sector, and roughly the same frequency capacity in each sector.
• Sector SI is split into three geographic zones Zll, Z12 and Z13, each zone Zll, Z12 and Z13 being determined by a corresponding time slot Tl, T2 and T3.
• Sectors S2 and S3 are each divided into an equal number of geographic zones as sector SI (in this configuration three), Z21, Z22, Z23, Z31, Z32 and Z33 such that each zone Z21, Z22, Z23, Z31, Z32 and Z33 is determined based upon a corresponding time slot Tl, T2 and T3 associated with it.
• the sequences of the time slots Tl, T2 and T3 in sectors S2 and S3 are dictated from the order of the time slots Tl, T2 and T3 in sector SI.
• the geographic zones Z21 and Z31 located along the fringes F 1.2 , and F x _ 3 respectively, of sectors S2 and S3 should be allocated the same time slot as the central time zone in sector SI (in this case Tl).
• the central geographic zones Z22, and Z33 in sectors S2 and S3 respectively, should be allocated the same time slots as the geographic zones in sector SI located adjacent to the respective sectors S2 and S3 (i.e. geographic zone Z22 should be allocated time slot T2 as is zone Z12 and zone Z33 should be allocated time slot T3 as is zone Z13).
• Transmissions during each time slot Tl, T2 and T3 have transmission power stipulations associated with them for transmission during up-link and down-link.
• a transmission in time slot Tl in sector SI has a down-link transmission power associated with it that is lower than the transmission power associated with time slots Tl in sectors S2 and S3, but the transmission power during up-link is normal.
• Transmissions in time slots T2 and T3 in sector SI both have normal down-link transmission power associated with them, but they both have up-link transmission power associated with them that is lower than the up-link power associated with the corresponding time slots in the adjoining sectors.
• time slots Tl, T2 and T3 in sectors SI, S2 and S3 respectively are allocated to mobile transmitters located in the central geographic zones Zll, Z22 and Z33 respectively.
• use of the radio channels during time slots that have transmissions which have lower down-link transmission power associated with them is allocated to users in the central geographic zones (i.e. in SI the set of users in Zll would get Tl, in S2 the set of users in Z22 would get T2 and in S3 the set of users in Z33 would get T3), while time slots that have transmissions which have lower up-link transmission power associated with them are allocated to users located near the fringe of the sector (i.e. in SI the set of users in Z12 or Z13 would get T2 or T3 respectively, in S2 the set of users in Z21 or Z23 would get Tl or T3 respectively and in S3 the set of users in Z31 or Z32 would get Tl or T2 respectively).
• This arrangement minimizes the possibility of co-channel interference by geographically separating the users and by controlling the transmission power.
• the areas of transmission overlap F ⁇ _ 2 , F ⁇ and F 2 . 3 decrease, and the power of the interfering signal (i.e. the signal from S2 during time T2 in sectors SI and S3) is very weak as compared to the signal coming from the proper sector antenna (i.e. the signal from antenna Al during time T2 will be much stronger in sector SI during time T2 than the signal in sector SI from antenna A2).
• the overlapping signal will not interfere with the actual signal.
• the transmission power from any region is determined by the requirements for the received signal strength. Subscriber units which are located in regions in which the transmission power needs enhancement, can transmit at higher power levels than that required for transmissions from subscriber units which are located in locations in which the transmissions get no co-channel interference. Communications are not being degraded for some subscriber units to increase quality for other subscriber units, rather communications are being improved for subscriber units located in problem areas.
• the invention efficiently attains the objects set forth above, among those made apparent from the preceding description.
• the invention provides a system for minimizing co-channel interference in a combined

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11065601

Family Applications (1)

Country Status (7)

Cited By (11)

Citations (6)

• 1993
  • 1993-12-16 IL IL10805693A patent/IL108056A/en active IP Right Revival
• 1994
  • 1994-12-16 CA CA002156071A patent/CA2156071A1/en not_active Abandoned
  • 1994-12-16 WO PCT/US1994/014562 patent/WO1995017048A1/en not_active Application Discontinuation
  • 1994-12-16 KR KR1019940035457A patent/KR950022259A/ko not_active Application Discontinuation
  • 1994-12-16 EP EP95906655A patent/EP0685128A1/en not_active Withdrawn
  • 1994-12-16 JP JP7516983A patent/JPH08509111A/ja active Pending
• 1995
  • 1995-03-07 TW TW084102643A patent/TW266360B/zh active

Patent Citations (8)

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