Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
  • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
  • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
  • H04B7/2603—Arrangements for wireless physical layer control
  • H04B7/2609—Arrangements for range control, e.g. by using remote antennas

Definitions

• This invention relates to wireless microcell distribution systems and more particularly to a reverse path autogain control system which generates shortened reduced-amplitude gain tones.
• each microcell has a transceiver and
• integrators are summed and coupled to a head end interface converter which, among other things,
• the head end interface converter sends a message to the cable microcell integrator to adjust attenuators at the cable microcell integrator to bring the signals that arrive at the head end
• each cable microcell integrator has a primary and diversity
• antenna the purpose of which is to compensate for the effects of fading or phase cancellation at
• gain tone generators were provided to inject gain control signals
• the duration of the gain tones were such as to compete with the telephony signals. The longer the duration of the gain
• tone amplitude is reduced.
• each cable microcell integrator is instructed
• the head end interface converter to turn on its respective gain tone generators simultaneously.
• the head end interface converter After receipt of a sufficient amount of gain tone, the head end interface converter then instructs
• the gain tones for the primary and diversity paths independently, such that the gain tone for the
• the gain tones is reduced to 100 milliseconds each. What this means is that the gain tones rather
• the amplitude of the gain tones is pre-set below the cumulative level for the
• the cumulative permissible level is -93dBm.
• one embodiment is set lOdB down from this -93dBm level. It will be appreciated that for the subject purposes, while signals from six cable microcell integrators are described, the number of
• the gain tone amplitudes can be reduced to minimize interference.
• the duration of the gain tones can be reduced to minimize interference.
• each of the cable microcell integrators is provided with a timer which times the start and stop of each gain tone, with the head end interface converter providing a message to
• the cable microcell integrator as to when to start each of the tones and when to stop them.
• the timing for the gain control tones is controlled at the cable microcell integrator upon receipt of
• a robust, automatic reverse path gain control system is provided to be able to level adjust the reverse path transmissions from the cable microcell integrators to prevent
• the gain tones for the primary and diversity receive
• each of the gain tones is limited
• Gain tone measurement is likewise done on an independent basis
• each of the gain tones only need to be on for that portion of the measurement period
• the shortened gain tones are injected after the first down-conversion stages so that the power
• Figure 1 is a diagrammatic illustration of the coverage area of multiple microceUs and the
• FIG. 2 is a block diagram of a wireless microcell distribution system in which signals
• Figure 3 is a block diagram illustrating the injection of gain tones on the signals from the
• the cable microcell integrator to adjust attenuators in the primary and diversity paths such that
• Figure 4 is a waveform diagram showing the generation of gain tones in a prior system in
• Figure 5 is a waveform diagram in the frequency domain for the carriers and gain tones of
• Figure 6 is a waveform diagram of the generation of the gain tones for the subject system indicating that the gain tones are generated independently and sequentially, with the gain tones
• Figure 7 is a waveform diagram in the frequency spectrum of the generation of the gain
• Figure 8 is a schematic diagram of the combined amplitudes of the carriers from six cable
• microcell integrators indicating that the gain tones in the subject invention are to be below the maximum level, in one embodiment by lOdB, to reduce potential interference with the associated
• Figure 9 is a block diagram of the subject system indicating that it is the head end interface converter which provides a message to a given cable microcell integrator to turn on the
• Figure 10 is a waveform diagram illustrating the measurement window at the head end
• Figure 11 is a block diagram illustrating the utilization of a temperature sensor at each
• the head end interface converter having a temperature compensation table so as to alter the message sent to the attenuators in a cable microcell integrator such that these attenuators can be set taking into account the temperature sensed at the microcell;
• Figure 12 is a block diagram of the circuit utilized in a cable microcell integrator for
• microceUs 10, 12 and 14 functioning as cell sites provide signals back on a reverse path to a summation unit 16 which is coupled to a head end interface converter 18 for providing the
• each microcell includes a cable microcell integrator.
• each cable microcell integrator, solar shading or varying wind conditions can provide
• FIG. 2 a wireless microcell distribution system is depicted in which a number of cable microcell integrators 40, 42, 44 and 46 each having respective primary and
• diversity antennas 48 and 50 provide signals back to a summation point 52 along a reverse path.
• illustrated at 53 is a carrier from each of these cable microcell integrators.
• cable microcell integrator 40 is provided with gain tone
• gain control generators are provided to respective transceivers 64 and 66, CDMA receivers in one embodiment, and thence through adjustable attenuators 68 and 70 back to head
• This provides gain tones, the amplitudes of which are measured by the head end interface converter.
• these gain tone carries the appropriate gain tone, here illustrated at 78 and 80. In one embodiment, these gain
• tones are offset from the center frequency of the primary and diversity channels by 400 KHz and
• tones are sampled as illustrated by waveforms 86 and 88 respectively, the gain tones are on
• sampling is done at the time illustrated by arrow 98, whereas in
• tones is such that both are on all the time during the combined sampling window.
• the gain tone for the primary reverse path is limited to 100
• microcell integrators are coupled to a summation point, then the total amplitude as illustrated by
• carrier level 120 is set to be no more than -93dBm. It has been found by utilizing the subject system that gain tone 122 can be set 10 dB down
• converter 54 is provided with message generators 124 and 126 which control the gain tone
• cable microcell integrator 40 is provided with a decoder for decoding the messages from the head
• the decoded messages are provided to units 132
• the head end interface converter sends a message to the cable microcell integrator to turn on its respective gain tones. Thereafter, units 132 and 134 activate the gain
• tone generators to provide for the start and stop of each gain tone at the appropriate time.
• the generation of the gain tones is timed at the cable microcell integrator in response to a
• microcell integrator generated gain tone is nominally set at 120 milliseconds, with the head end
• interface converter is provided with a programmable delay 144 which can be set so as not to miss
• a temperature sensor 150 is provided in one embodiment.
• cable microcell integrator 40 which senses the temperature on a real time basis and provides it
• measurement unit measures the absolute amplitude and generates a message at 156 which is then sent back to the attenuators 158 within the cable microcell integrator.
• the message sent is altered from that established by the absolute amplitude measured at
• a local oscillator 168 is coupled to a splitter 170 which provides signals
• gain tones are injected before down-conversion, typically at 2 GHz, then
• couplers 176 and 178 are applied respectively to saw filters and amplifiers
• Attenuators 184 and 186 for each of the paths control the
• Attenuation control is provided by attenuator 202.
• pri_gain_delta + (cmi_db [gain_cmi_num] [gain_cmi_sec ] . upstr_pri_att - PRI_NOMINAL) ; ⁇
• Initial_Comb cmi_db[gain_cmi_num] [gain_cmi_sec] .upstr_comb_att;
• Initial_Pri cmi_db[gain_cmi_num] [gain_cmi_sec] .upstr_pri_att;
• Initial_Div cmi_db [gain_cmi_num] [gain_cmi_sec] . upstr_div_att ;
• US_Counter US_COUNTER_MAX; /* don't allow second pass */ ⁇ /* end else if (adjust combined, primary, and diversity attenuators ) * /
• Pri_Raw_Noise_Floor Measure_US_Power (gain_cmi_sec, 0x00) ;
• Gain_Tone_Searches GAIN_TONE_SEARCHES_MAX; ⁇ /* end elseif (ag_status) */
• PCSC-056 Measure US power with Primary & Diversity Gain Tones up one at a time */ void US_ ith_Gain_Tone (unsigned int gain_cmi_num, unsigned int gain_cmi_sec)
• ⁇ lw_msg_out.dat.raw.dat [2] PULSE_PRIMARY; ⁇ else /* 2nd pass: Turn PRIMARY GT OFF & turn DIVERSITY GT ON */ ⁇ lw_msg_out.dat. raw.
• PCSC-288 Need to send 100ms delay so CMI Gain tone can settle before it */
• Pri_Raw_Gain_Tone Measure_US_Power (gain_cmi_sec, 0x00);
• 0x1; /* CMI_HIC_GAIN message successfully sent to CMI
• Gain_Tone_Searches GAIN_TONE_SEARCHES_MAX; break; ⁇ J * end elseif (ag_status) */
• Pri_Raw_Gain_Tone Pri_Raw_Noise_Floor
• Pri_Pwr_from_LUT conv_us_pwr (Pri_Pwr_Gain_Tone) ; /* Primary pwr from look up table */
• Div_Pwr_from_LUT conv_us_pwr (Div_Pwr_Gain_Tone) ; /* Diversity pwr from look up table */
• noise measurement convert to dBm(raw noise measurement) ;
• Gain_Mute ( MST_GAIN_MUTE_BOTH,DFLT_GT_OFFSET ) ; /* mutes gain tones AND */
• Pulse_Gain_Tone (unsigned char choice, unsigned char offset )
• PB_US_GT_MUTE_ADR port_val;
• This routine calculates the LO frequency necessary for tunning * the Gain Tone and invokes the necessary routines to set the PLL
• gain_tone_val * INPUTS: gain_tone_val :
• Tune_Cntl_Freq (unsigned char pri_freq_code, unsigned char div_freq_code) ⁇ t define _1MHZ 1000 /* 1 MHz in KHz*/ unsigned long pll3_freq, cntl_freq, pll4_freq;
• pll3_freq (div_freq_code * _250KHZ) + REV_1ST_IF_FREQ ; /* in KHz */
• pll4_freq pll3_freq - cntl_freq; /* in KHz */
• port_val (port_B_save & BTH_MSK)

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

Applications Claiming Priority (3)

Publications (1)

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• 2000
  • 2000-05-19 CA CA002371496A patent/CA2371496A1/en not_active Abandoned
  • 2000-05-19 WO PCT/US2000/013886 patent/WO2000072475A1/en not_active Application Discontinuation
  • 2000-05-19 AU AU51481/00A patent/AU5148100A/en not_active Abandoned
  • 2000-05-19 JP JP2000620761A patent/JP2003500978A/ja active Pending
  • 2000-05-19 IL IL14635800A patent/IL146358A0/xx unknown
  • 2000-05-19 EP EP00936120A patent/EP1179234A1/de not_active Withdrawn
  • 2000-05-19 KR KR1020017014785A patent/KR20010113973A/ko not_active Application Discontinuation

Non-Patent Citations (1)

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