Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04H—BROADCAST COMMUNICATION
  • H04H20/00—Arrangements for broadcast or for distribution combined with broadcast
  • H04H20/65—Arrangements characterised by transmission systems for broadcast
  • H04H20/67—Common-wave systems, i.e. using separate transmitters operating on substantially the same frequency
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/851—Dispositions of multiple connectors or interconnections
  • H10W72/853—On the same surface
  • H10W72/865—Die-attach connectors and bond wires
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/851—Dispositions of multiple connectors or interconnections
  • H10W72/874—On different surfaces
  • H10W72/884—Die-attach connectors and bond wires
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W90/00—Package configurations
  • H10W90/701—Package configurations characterised by the relative positions of pads or connectors relative to package parts
  • H10W90/751—Package configurations characterised by the relative positions of pads or connectors relative to package parts of bond wires
  • H10W90/756—Package configurations characterised by the relative positions of pads or connectors relative to package parts of bond wires between a chip and a stacked lead frame, conducting package substrate or heat sink

Definitions

• This invention relates in general to simulcast communication systems, and more specifically to a method of synchronizing one or more receivers prior to receiving a simulcast transmission.
• transmitter simulcasting is frequently utilized to expand the geographic area in which receivers may receive an information signal.
• existing simulcast systems have not fully addressed the effects of differential delay of the received simulcast signals. Differential delay arises when a receiver receives simulcast signals from multiple transmitters that are substantially identical in composition, but are shifted (in time) with respect to one another.
• the acceptable differential delay between signals received from multiple transmitters is reduced and tolerance to timing error minimized. Accordingly, a need exists to compensate for differential delay effects in a simulcast communication system without unduly impeding information throughput .
• receivers synchronize to signals sequentially transmitted from several transmitters prior to receiving a signal simulcast by the transmitters .
• FIG. 1 is a block diagram of a simulcast communication system suitable for use with the present invention.
• FIG. 2 is a transmitter coverage map in accordance with the present invention.
• FIG. 3 is a timing diagram illustrating the signal transmission process in accordance with the present invention.
• FIG. 4 is a timing diagram illustrating the bit- sampling process in accordance with the present invention.
• FIG. 5 is a flow diagram in accordance with the present invention.
• a block diagram of a simulcast communication system comprises at least two transmitter sites, each transmitter site comprising a transmitter and an antenna such as a transmitter A 103 and an antenna 104 and a transmitter B 113 and an antenna 114.
• Radio frequency signals are sent from the transmitter sites over the air to at least one selective call receiver (SCR) such as a SCR 112.
• SCR selective call receiver
• the radio frequency signals are typically modulated by a digital signal comprised of: (a) a synchronization signal portion for the purpose of synchronizing the SCR's in the system and (b) an address and message data portion.
• a typical SCR 112 receives the modulated radio frequency signals from the air through an antenna 105.
• the signals are conducted to a receiver 106, where the address and data portions are recovered and provided to a microprocessor 10 .
• the recovered address is compared to one or more addresses stored in a memory 108. If there is a match, the message data is stored in the memory 108, and an alert 109 is activated to inform the SCR user of a received message.
• the stored message may then be displayed on a display 111 either automatically or by actuation of one or more controls 110.
• a transmitter coverage map in accordance with the present invention comprises an arrangement of a plurality of transmitter coverage areas, each represented in FIG. 2 by a circle and a number at the center.
• a transmitter such as the transmitter A 103 or transmitter B 113 is located at the center of each of the circular areas to provide radio frequency coverage for each particular area.
• the transmitters and their coverage areas comprise a predetermined number of groups; in FIG. 2, the predetermined number of groups is four, although it may be a different number.
• Typical coverage areas 201, 202, 203, and 204 are shown for transmitters within group one (1), group two (2), group three (3), and group four (4), respectively.
• the groups of transmitters are arranged in a manner that prevents simultaneous receipt of more than one signal from any particular group. In other words, in FIG. 2, like circles never intersect.
• a timing diagram illustrating the signal transmission process comprises signals from each of the four groups of transmitters.
• the signals include a sequential calibration 301 and a simulcast transmission 302.
• the four transmitter groups sequentially broadcast a calibration signal over the air to the SCR's in the system.
• the calibration signal may comprise a synchronization signal portion for time-synchronizing the SCR's.
• the calibration signal may also be used to determine which signals are of sufficient strength to be further considered by a particular SCR. If, for example, a particular SCR is located within the geographical area 205, the SCR may, following the sequential calibration 301, determine that the received calibration signals from transmitter groups three and four are weak relative to those from transmitter groups one and two. The SCR may, then, decide to consider only the signals from transmitter groups one and two for the simulcast transmission 302.
• the simulcast transmission 302 may comprise, for all of the transmitter groups in the system, an identical address and message data portion that may include addresses of and data messages for particular ones of the
• a timing diagram illustrating the bit-sampling process comprises typical sequential calibration signals received by a selective call receiver from transmitter groups one (1) 401 and two (2) 402.
• signal 402 is delayed by an additional amount of time y due to delay dispersion, which may be due to the SCR being located closer to a group one transmitter than a group two transmitter. It is assumed in the example of FIG. 4 that the signals from transmitter groups three and four are very weak relative to signals 401 and 402 and are, therefore, rejected by the SCR.
• the arrows shown indicate sampling positions as determined by the received signals 401 and 402.
• the process then proceeds to step 502 in which the sequential calibration signal is received from transmitter group N.
• step 503 the signal strength and bit timing for the group N transmitter are determined.
• the signal strength and bit timing information for the group N transmitter is stored in the memory 108 of the SCR 112, step 504, and the counter N is checked to see if it is equal to four (4), step 505.
• the predetermined level in step 506 may comprise a level relative to the strongest received signal or, alternatively, an absolute signal strength level.
• step 507. the bit timing of the remaining groups is compared and the sampling reference for the following simulcast transmission is determined, step 507. The simulcast transmission is then received and sampled, step 508, and the process returns to step 501.

Landscapes

• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
• Lead Frames For Integrated Circuits (AREA)
• Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=23768015

Family Applications (1)

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Cited By (3)

Families Citing this family (13)

Citations (6)

• 1989
  • 1989-12-04 US US07/445,210 patent/US5054113A/en not_active Expired - Lifetime
• 1990
  • 1990-11-23 WO PCT/US1990/006755 patent/WO1991008620A1/en not_active Ceased
  • 1990-12-21 JP JP2404833A patent/JPH0590451A/ja active Pending
• 1991
  • 1991-11-02 TW TW080108610A patent/TW242687B/zh active

Patent Citations (6)

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