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
  • H04W52/30—TPC using constraints in the total amount of available transmission power
  • H04W52/32—TPC of broadcast or control channels
  • H04W52/325—Power control of control or pilot channels
• • 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
  • H04W52/16—Deriving transmission power values from another channel
• • 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
  • H04W52/28—TPC being performed according to specific parameters using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
  • H04W52/288—TPC being performed according to specific parameters using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission taking into account the usage mode, e.g. hands-free, data transmission, telephone
• • 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
  • H04W52/38—TPC being performed in particular situations
  • H04W52/50—TPC being performed in particular situations at the moment of starting communication in a multiple access environment

Definitions

• This invention relates to the field of wireless digital communications, and more particularly to gain factors.
• Wireless communications facilitates the delivery of information between the transmitter and the receiver without a physical wired connection.
• Such advantage translates to the freedom of mobility for the users and to the savings of wiring nuisance for the users.
• spectrum has become scarce resource as the usage of wireless communications for various applications becomes more popular. Therefore the efficiency of using spectrum presents challenges for the wireless industry.
• various multiple access methods have been proposed to achieve the goal.
• First generation cellular communications systems Advanced Mobile Phone
• AMPS Frequency Division Multiple Access
• FDMA Frequency Division Multiple Access
• FDMA Frequency Division Multiple Access
• CDMA Code Division Multiple Access
• Second generation cellular communications systems improved the spectrum efficiency by using more digital processing of signals and employed Time Division Multiple Access (TDMA) method in GSM and IS-136 systems and Code Division Multiple Access (CDMA) method in IS-95 systems. While second generation systems typically provide two to five times voice capacity over the first generation systems, data capabilities of second-generation systems are very limited. Recent rapid commercial development of Internet and multimedia applications has created a strong demand for wireless cellular systems capable of providing sufficient bandwidth. In addition, further improvement of voice capacity in spectrum efficiency is in great demand as the spectrum allocated for service is very limited. This scarcity results in high licensing fees for the available spectrum.
• the present invention is a method and system to determine the gain factors for the uplink and downlink Dedicated Physical Control Channel (DPCC) and Dedicated Physical Data Channel (DPDC).
• DPCC uplink and downlink Dedicated Physical Control Channel
• DPDC Dedicated Physical Data Channel
• FIG. 1 is a functional block diagram.
• the present invention is equally well suited for both uplink of WCDMA as well as other similar systems like CDMA2000.
• One feature of the present invention is a method and system to determine the gain factors for the uplink and downlink DPDCH and DPCCH. This method and system is equally well suited for Physical Random
• PRACH Physical Access Channel
• DPCCH Downlink Dedicated Physical Control Channel
• DPDCH Dedicated Physical Data Channel
• the gain factors ⁇ c and ⁇ d are important to 3GPP WCDMA system performance like capacity.
• the initial uplink DPCCH transmit power is set by higher layers. Subsequently the uplink transmit power control procedure simultaneously controls the power of a
• the relative transmit power offset between DPCCH and DPDCHs is determined by the network and is computed using the gain factors signaled to the User Equipment (UE) using higher layer signaling.
• UE User Equipment
• TFCs Transport Format Combinations
• Combinations of the two above methods may be used to associate ⁇ c and ⁇ d values to all TFCs in the TFCS.
• the operation of the inner power control loop adjusts the power of the DPCCH and DPDCHs by the same amount, provided there are no changes in gain factors. Additional adjustments to the power of the DPCCH associated with the use of compressed mode.
• Any change in the uplink DPCCH transmit power shall take place immediately before the start of the pilot field on the DPCCH.
• the change in DPCCH power with respect to its previous value is derived by the User Equipment and is denoted by ⁇ DPCC H (in dB).
• the previous value of DPCCH power shall be that used in the previous slot, except in the event of an interruption in transmission due to the use of compressed mode, when the previous value shall be that used in the last slot before the transmission gap.
• the User Equipment transmit power shall not exceed a maximum allowed value which is the lower out of the maximum output power of the terminal power class and a value which may be set by higher layer signaling. Uplink power control shall be performed while the User Equipment transmit power is below the maximum allowed output power. If the User Equipment transmit power is below the required minimum output power [as defined in TS 25.101] and the derived value of ⁇ DPCCH is less than zero, the User Equipment may reduce the magnitude of ⁇ D PC CH- The User Equipment shall scale the total transmit power of the DPCCH and
• DPDCH(s) such that the DPCCH output power follows the changes required by the power control procedure with power adjustments of ⁇ DPCCH dB, unless this would result in a User Equipment transmit power above the maximum allowed power.
• the User Equipment shall scale the total transmit power so that it is equal to the maximum allowed power.
• the gain factors during compressed frames are based on the nominal power relation defined in normal frames.
• the gain factors ⁇ c and ⁇ are signaled by higher layers for a certain TFC, the signaled values are used directly for weighting of DPCCH and DPDCH(s).
• the variable A j called the nominal power relation is then computed as:
• each TFC has a unique data rate connected with a unique pair of gain factors for the DPCCH and DPDCH.
• the change of gain factors for DPCCH and DPDCH are performed to keep constant the transmitted bit energy E D (before coding) on the DPDCH, independent of the data rate.
• the DPCCH power is kept constant to avoid affecting the transmit power control (TPC). If the power ratio between DPDCH and DPCCH goes wrong, the TPC loop operating based on DPCCH will degrade the WCDMA system performance.
• the present invention provides a method and system to determine the gain factors for the uplink DPDCH and DPCCH.
• Equation 2 A key concept of the present invention is to link up the nominal power relation in Equation 1 with both system and radio channel parameters through the closed form relationship given by Equation 2.
• Fig. 1 there can be seen an illustration of the use of the present invention in the form of a functional block diagram to set up the normalized reference power ratio.
• Step 102 we use the corresponding reference power ratio for voice (Most times the system parameters are optimized for voice performance and for a WCDMA system the initial focus is voice applications) as the initial value of Po.
• step 104 The data rate in step 104 is given.
• step 106 the necessary system and radio channel parameters necessary for Equation 2 are given.
• the normalized reference power ratio is determined in step 110.
• Steps 104 through 110 are dynamically repeated for new data rate.
• the dynamic nature of the radio channel is directly related to the dynamic nature of the DPDCH data channel. Therefore the present invention responds quickly to the radio channel of the air interface while the mobile terminal is moving around. No simple scheme in power settings can be accurate without dynamic response to the real-time radio channel being experienced by the DPDCH data channel and the DPCCH channel.
• this scheme can be regarded as the adaptive scheme for the system to set up the resources to make certain that the WCDMA system works at an optimal state.
• the significance of this method is the speed of the quick convergence. Although it may not be so accurate for some working conditions, the method is Fig. 1 dynamically adjust the nominal power relation quickly. Thus the system is always working at the quasi-optimal system settings.
• One result of the net advantages of this method is that the system resource or system power is not wasted and thus the interference is minimized.
• CDMA2000 One feature of the present invention is a method and system to determine the gain factors for the uplink and downlink DPDCH and DPCCH. This method and system is equally well suited for Physical Random Access Channel (PRACH) message part. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Details of the structure may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications, which come within the scope of the appended claim, is reserved.
• PRACH Physical Random Access Channel

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

Applications Claiming Priority (3)

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• 2001
  • 2001-12-21 WO PCT/US2001/050552 patent/WO2002052757A1/en not_active Application Discontinuation
  • 2001-12-21 CA CA002436042A patent/CA2436042A1/en not_active Abandoned
  • 2001-12-21 EP EP01992407A patent/EP1354433A1/de not_active Withdrawn

Non-Patent Citations (1)

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