JP5620484B2 - Method and apparatus for wireless communication - Google Patents

Description

<Cross-reference to related applications>
This application claims the benefit of US Provisional Patent Application No. 61 / 223,162, filed July 6, 2009. The contents of that application are hereby incorporated by reference in their entirety.

  This application claims the benefit of US Provisional Patent Application No. 61 / 078,505, filed July 7, 2008, US Provisional Patent Application No. 61 / 223,162, filed July 6, 2009, Partial continuation of this application (serial number pending) resulting from conversion under 37 CFR 37, section 1.53 (c) (3). The contents of the provisional application are hereby incorporated by reference in their entirety.

<Field of Invention>
The present invention relates generally to wireless communications, and more particularly to methods and apparatus related to handover in wireless communications.

  Non-Patent Document 1 (“IEEE802.16e standard”) defines various standards for broadband wireless access systems, which are hereby incorporated by reference in their entirety. For example, the IEEE 802.16e standard defines various protocols for handing over a mobile station from an anchor base station to a target base station. Although considerations regarding when a mobile station performs a handover procedure from an anchor base station to a target base station are outside the scope of the IEEE 802.16e standard, in general, a mobile station communicates with an anchor base station over a period of time. Initiate a handover procedure from the anchor base station to the target base station, after which the mobile station communicates with the target base station instead. This is done, for example, when the mobile station moves to a position where communication with the target base station is more effective than communication with the anchor base station.

IEEE Standard for Local and metropolitan area networks, Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems, Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1, February 28, 2006 Sun ("IEEE802.16e standard")

  The IEEE 802.16e standard has several drawbacks. For example, before a mobile station can complete a handover to a target base station, the mobile station requests some system configuration information (SCE) about the target base station and such system configuration of the target base station The protocol defined by the IEEE 802.16e standard for communicating information to mobile stations can be cumbersome and can cause undesirable delays during handover. Also, a mobile station typically sends various media access control (MAC) messages (sometimes referred to simply as “control messages”) to initiate a handover procedure. The .16e standard does not include a satisfactory protocol for facilitating reception of such MAC messages at various base stations that may be the target base station for handover. Further, before the mobile station can complete the handover to the target base station, it may be desirable for the mobile station to obtain data representing the distance between the mobile station and the target base station. The mobile station can transmit uplink signals at a time calculated to cause the signals to be received at the target base station at a time allocated for uplink signals from the base station; This is to avoid interference with uplink signals from other mobile stations. However, the protocol defined by the IEEE 802.16e standard for obtaining such data can be cumbersome and can cause unnecessary delays during handover. Further, the IEEE 802.16e standard does not stipulate an acknowledgment by the anchor base station that the mobile station performs handover from the anchor base station to the target base station. Thus, if the anchor base station does not receive the indicator or receives the wrong indicator, the anchor base station will continue to communicate with the base station after the base station has completed handover to the target base station. To do. This can cause unnecessary interference and congestion. In addition, when the anchor base station does not receive the indicator, the anchor base station may not have notified the target base station that the mobile station will perform a handover to the target base station. In that case, the target base station may not be ready to communicate with the mobile station, which may cause communication interruption.

  According to an example embodiment, a method is provided that facilitates handover of a mobile station from an anchor base station to a target base station. The method includes receiving a handover indicator signal from the mobile station at the anchor base station indicating that the mobile station performs a handover from the anchor base station to the target base station; Transmitting a receipt confirmation signal for receiving and confirming receipt of the handover indicator signal.

  According to another exemplary embodiment, a base station apparatus is provided that includes an interface that facilitates radio communication with a mobile station and a processor that communicates with the interface. The processor receives from the interface a handover indicator signal from the mobile station indicating that the mobile station performs a handover from the base station to the target base station; Is operatively configured to transmit an acknowledgment signal for receiving and confirming receipt of the handover indicator signal.

  According to another exemplary embodiment, the base station apparatus receives a handover indicator signal from a mobile station indicating that the mobile station performs a handover from the base station to the target base station. A provision for transmitting to the mobile station a confirmation signal for receiving and confirming that the base station has received the handover indicator signal.

  According to another exemplary embodiment, by a mobile station in radio communication with an anchor base station, between the mobile station and a base station included in an active set of base stations in radio communication with the mobile station A method is provided that facilitates obtaining data representing distance. The active set includes a subset of neighboring base stations of the anchor base station. The method: transmits a ranging resource signal identifying a reference code and a reference time associated with the mobile station from an anchor base station to each other base station of the active set; The base station of the active set is transmitted at a time corresponding to the reference time, and each base station of the active set receives the ranging signal at a respective time; From each base station of the active set, a respective offset signal is received that identifies a respective temporal difference between the reference time and each time the base station of the active set receives the ranging signal. Transmitting a ranging control signal corresponding to each of the offset signals to the mobile station.

  The method may further include generating the reference code from a pseudo-randomly generated code.

  Transmitting the ranging control signal transmits a ranging signal that represents an average of the respective temporal differences between the reference time and the respective times at which each base station of the active set received the ranging signal. May include.

  Transmitting the ranging control signal may include transmitting a plurality of ranging control signals. Each of the plurality of ranging control signals is associated with a respective base station of the active set, between the reference time and each time the base station of the active set receives a ranging signal. Each time difference is expressed.

  The active set may further include an anchor base station.

  According to another exemplary embodiment, a base station apparatus: a first interface facilitating radio communication with a mobile station; at least one included in an active set for radio communication with the mobile station An apparatus is provided that includes a second interface that facilitates communication with two neighboring base stations; and a processor in communication with the first and second interfaces. The processor causes the second interface to transmit a ranging resource signal identifying a reference code and a reference time associated with the mobile station to the at least one neighboring base station included in the active set. Instructing the mobile station to transmit a ranging signal including the reference code to each base station included in the active set at a time corresponding to the reference time. Transmitting a ranging command signal so that each base station included in the active set receives the ranging signal at a respective time; from the second interface, from each neighboring base station of the active set; Each offset signal is received, and each offset signal includes the reference time, Identifying a respective temporal difference between each of the neighboring base stations included in the active set and the time when the ranging signal has been received; It is configured to be operable to transmit a ranging control signal corresponding to the offset signal.

  The processor may further be configured to be operable to generate the reference code from a pseudo-randomly generated code.

  The ranging control signal may represent an average of respective temporal differences between the reference time and respective times when each base station included in the active set receives the ranging signal.

  The ranging control signal may include a plurality of ranging control signals. Each of the plurality of ranging control signals is associated with a respective base station of the active set, and a respective time between the reference time and a respective time at which each base station receives the ranging signal. Difference.

  The active set may further include the device, the processor further: receiving a ranging signal from the mobile station from the first interface; the reference time, and the device from the mobile station Calculating a temporal difference between the time when the ranging signal is received; the ranging control signal for the mobile station to the first interface; the reference time; and the device ranging from the mobile station. It may be configured to be operable to transmit according to a time difference from the time when the signal is received.

  According to another exemplary embodiment, a base configured for radio communication with a mobile station and for communication with at least one neighboring base station included in an active set in radio communication with the mobile station. A station device is provided. The apparatus includes: a ranging resource signal identifying a reference code and a reference time associated with the mobile station to the at least one neighboring base station included in the active set; Transmitting a ranging command signal instructing a base station included in the active set to transmit a ranging signal including the reference code to a station at a time corresponding to the reference time; and Provisions for each base station included in a set to receive the ranging signal at respective times; provisions for receiving a respective offset signal from each base station included in the active set. Each offset signal is a ranging signal generated by the reference station and a base station included in the active set. Identifying respective time differences between the respective received time, with a; to the mobile station, and a provision for transmitting a ranging control signal corresponding to the respective offset signal.

  According to another exemplary embodiment, a method for delivering base station system configuration information is provided. The method comprises: from a first mobile station having a first active set of base stations, a first active indicating that the first mobile station has added the base station to the first active set Receiving an aggregate signal; transmitting a system configuration information signal including system configuration information of the base station to the first mobile station in response to receiving the first active aggregate signal; including.

  The base station system configuration information may include one or more of the following groups of information: an identifier of the base station; an identifier of a preamble index of the base station; a subchannel of the base station; Index identifier; frequency allocation information of the base station; time / frequency synchronization indicator associated with the base station; uplink channel information for the base station; downlink channel information for the base station; Trigger reference indicator associated with the base station; equivalent isotropically radiated power of the base station; handover information for the base station; scheduling service information for the base station; supported for the base station Mobility function information; relevant to the base station Paging group identifier; base station channel bandwidth identifier; base station cyclic prefix identifier; base station frame duration identifier; base station fast Fourier transform size identifier; and Operating mode for starting subchannelization of base station frame and channel numbers.

  The method further includes: from a second mobile station having a second active set of base stations, a second mobile station indicating that the second mobile station has added the base station to the second active set. Receiving an active aggregate signal. The step of transmitting a system configuration information signal to the first mobile station includes transmitting the system configuration information signal to the first and second mobile stations in response to receiving the first and second indicator signals. It may include multicasting the signal.

  According to another exemplary embodiment, a base station apparatus: an interface that facilitates radio communication with a first mobile station having a first active set of base stations; There is provided an apparatus comprising: a computer readable memory having a storage unit for storing system configuration information; and a processor in communication with the interface and the computer readable memory. The processor: from the interface, a first from the first mobile station indicating that the first mobile station has added one of the plurality of base stations to the first active set. Receiving an active aggregate signal; and in response to receiving the first active aggregate signal, the interface to the first mobile station and the one of the plurality of base stations. Transmitting a system configuration information signal including system configuration information of the base station.

  The base station system configuration information may include one or more of the following groups of information: an identifier of the base station; an identifier of a preamble index of the base station; a subchannel index of the base station Identifier of the base station; frequency allocation information of the base station; time / frequency synchronization indicator associated with the base station; uplink channel information about the base station; downlink channel information about the base station; Associated trigger reference indicator; Equivalent isotropically radiated power of the base station; Handover information for the base station; Scheduling service information for the base station; Supported for the base station Mobility function information; associated with the base station Paging group identifier; channel bandwidth identifier of the base station; cyclic prefix identifier of the base station; frame duration identifier of the base station; fast Fourier transform size identifier of the base station; and the base Mode of operation for starting subchannelization of station frame and channel number.

  The processor further includes: from the interface, from a second mobile station having a second active set of base stations, wherein the second mobile station transfers the one of the plurality of base stations to the second May be configured to receive a second active set signal indicating that the active set has been added. The processor is further operable to cause the interface to multicast the system configuration signal to the first and second mobile stations in response to receiving the first and second indicator signals. May be configured.

  According to another exemplary embodiment, there is a base station apparatus: provision for storing system configuration information of a plurality of base stations; from a mobile station having an active set, the mobile station For receiving an active set signal indicating that one of the base stations has been added to the active set; in response to receiving the active set signal, for the mobile station; And a provision for transmitting a system configuration information signal including system configuration information of the one base station of the plurality of base stations.

  According to another exemplary embodiment, a method for controlling a mobile station in radio communication with a plurality of base stations through an uplink control channel is provided. The method includes receiving a channel condition signal from each of the plurality of base stations, each channel condition signal being transmitted from the mobile station through the uplink control channel in the one of the plurality of base stations. Indicating a respective channel condition of the received control signal; determining an uplink control channel power parameter according to the respective channel condition signal; and providing the mobile station with the uplink control channel power parameter. Transmitting a power control signal including.

  Each channel condition may include a signal to noise ratio.

  Determining the uplink control channel power parameter includes: a threshold signal to noise ratio and a signal to noise for each of the control signals received from the mobile station through the uplink control channel at each of the plurality of base stations. Determining a ratio with the smallest of the ratios may be included.

  According to another exemplary embodiment, a base station apparatus: a first interface facilitating radio communication with a mobile station; at least one included in an active set for radio communication with the mobile station; An apparatus is provided that includes a second interface that facilitates communication with two neighboring base stations; and a processor in communication with the first and second interfaces. The processor: receiving, from the second interface, a respective channel condition signal from each neighboring base station of the active set, wherein each channel condition signal is received at the neighboring base station of the active set. Indicating a respective channel condition of a control signal received from the mobile station through an uplink control channel; and a channel condition of the control signal received from the mobile station through the uplink control channel and the active signal in the apparatus Determining an uplink control channel power parameter in response to the respective channel condition signal received from the at least one neighboring base station of the set; to the mobile station on the first interface; Power including link control channel power parameters Operatively configured to perform the step of transmitting a control signal.

  Each channel condition may include a signal to noise ratio.

  The processor includes: the uplink control channel power parameter, a threshold signal to noise ratio, a signal to noise ratio of the control signal received from the mobile station through the uplink control channel in the apparatus, and the active set Each neighboring base station may be configured to be operable to determine a control signal received from the mobile station through the uplink control channel according to a ratio of a signal-to-noise ratio of the control signal that is the smallest. .

  According to another exemplary embodiment, a base configured for radio communication with a mobile station and for communication with at least one neighboring base station included in an active set in radio communication with the mobile station. A station device is provided. The apparatus comprises: for receiving a respective channel condition signal from each neighboring base station of the active set, wherein each channel condition signal is transmitted through the uplink control channel at the neighboring base station of the active set. Indicating a respective channel condition of a control signal received from the mobile station; and at least one of the channel condition of the control signal received from the mobile station through the uplink control channel and the active set in the apparatus. Provision for determining an uplink control channel power parameter in response to the respective channel condition signals received from two neighboring base stations; a power control signal including the uplink control channel power parameter for the mobile station; For preparing to transmit.

  According to another exemplary embodiment, a method for transmitting control signals to a plurality of base stations included in an active set of mobile stations is provided. The method includes: for each base station included in the active set, transmitting the control signal to the base station on a respective control channel.

  According to another exemplary embodiment, a mobile station apparatus: an interface that facilitates radio communication with a plurality of base stations included in an active set of the apparatus, communicating with the interface, and An apparatus is provided that includes a processor operatively configured to transmit a control signal to each base station included in the active set on a respective control channel.

  According to another exemplary embodiment, a mobile station apparatus comprising: provision for facilitating radio communication with a plurality of base stations included in an active set of the apparatus; An apparatus is provided that includes provisions for transmitting on a respective control channel to each base station included in the active set.

  Other aspects and features of the present invention will become apparent to those skilled in the art upon review of the following description of the individual embodiments in connection with the accompanying drawings.

Embodiments of the present application will now be described by way of example only with reference to the accompanying drawings.
The present invention further provides, for example:
(Item 1)
A method for facilitating mobile station handover from an anchor base station to a target base station, comprising:
Receiving a handover indicator signal from the mobile station at the anchor base station indicating that the mobile station performs a handover from the anchor base station to the target base station;
Transmitting to the mobile station an acknowledgment signal for receiving and confirming that the anchor base station has received the handover indicator signal.
Method.
(Item 2)
A base station apparatus having an interface that facilitates radio wave communication with a mobile station, and a processor that communicates with the interface, wherein the processor:
Receiving, from the interface, a handover indicator signal from the mobile station indicating that the mobile station performs a handover from the base station apparatus to the target base station;
The interface is configured to be operable to cause the mobile station to transmit a reception confirmation signal for receiving and confirming that the base station apparatus has received the handover indicator signal.
Base station device.
(Item 3)
Means for receiving a handover indicator signal from the mobile station indicating that the mobile station performs a handover from the base station device to the target base station;
Means for transmitting to the mobile station a reception confirmation signal for receiving and confirming that the base station apparatus has received the handover indicator signal;
Base station device.
(Item 4)
Facilitates acquisition of data representing the distance between the mobile station and the base stations included in the active set of base stations that are in radio communication with the mobile station by the mobile station in radio communication with the anchor base station The active set is a neighbor base station of the anchor base station.
Including a subset, the method is:
Transmitting a ranging resource signal identifying a reference code and a reference time associated with the mobile station from the anchor base station to each other base station of the active set;
The mobile station transmits a ranging signal including the reference code to each base station of the active set at a time corresponding to the reference time, and each base station of the active set transmits the ranging signal. To receive at each time;
From each base station of the active set, a respective offset signal identifying a respective temporal difference between the reference time and each time the base station of the active set received the ranging signal. Receive;
Transmitting a ranging control signal corresponding to the respective offset signal to the mobile station,
Method.
(Item 5)
The method of claim 4, further comprising generating the reference code from a pseudo-randomly generated code.
(Item 6)
Transmitting the ranging control signal includes a ranging signal representing an average of respective temporal differences between the reference time and respective times when each base station of the active set receives the ranging signal. Item 5. The method according to Item 4, comprising transmitting.
(Item 7)
Transmitting the ranging control signal includes transmitting a plurality of ranging control signals, each of the plurality of ranging control signals being associated with a respective base station of the active set, and the reference time And a respective temporal difference between the active set of base stations and the respective times at which the ranging signals are received.
(Item 8)
The method of item 4, wherein the active set further includes the anchor base station.
(Item 9)
Base station equipment:
A first interface that facilitates radio communication with a mobile station;
A second interface facilitating communication with at least one neighboring base station included in an active set in radio communication with the mobile station;
A processor in communication with the first and second interfaces, the processor comprising:
Causing the second interface to transmit a ranging resource signal identifying a reference code and a reference time associated with the mobile station to the at least one neighboring base station included in the active set;
Instructing the first interface to transmit a ranging signal including the reference code to the mobile station at a time corresponding to the reference time to each base station included in the active set. Transmitting a ranging command signal to cause each base station included in the active set to receive the ranging signal at a respective time;
Respective offset signals from each neighboring base station of the active set are received from the second interface, and each offset signal is received by the neighboring base station included in the active set by the ranging. Identify each temporal difference between each time the signal was received;
The first interface is configured to be operable to cause the mobile station to transmit a ranging control signal corresponding to the respective offset signal.
apparatus.
(Item 10)
The apparatus of claim 9, wherein the processor is further configured to be operable to generate the reference code from a pseudo-randomly generated code.
(Item 11)
10. The ranging control signal according to item 9, wherein the ranging control signal represents an average of respective temporal differences between the reference time and each time when each base station included in the active set receives the ranging signal. apparatus.
(Item 12)
The ranging control signal includes a plurality of ranging control signals, each of the plurality of ranging control signals is associated with a respective base station of the active set, and the reference time and each base station is configured with the ranging Item 10. The apparatus of item 9, which represents a respective temporal difference between each time a signal is received.
(Item 13)
The active set further includes the device, and the processor further includes:
Receiving the ranging signal from the mobile station from the first interface;
Calculating a temporal difference between the reference time and a time at which the apparatus receives the ranging signal from the mobile station;
The ranging control signal is sent to the first interface for the mobile station according to a temporal difference between the reference time and the time when the apparatus receives the ranging signal from the mobile station. Item 10. The device of item 9, configured to be operable to transmit.
(Item 14)
A base station device configured for radio communication with a mobile station and for communication with at least one neighboring base station included in an active set for radio communication with the mobile station:
Means for transmitting a ranging resource signal identifying a reference code and a reference time associated with the mobile station to the at least one neighboring base station included in the active set;
Transmitting a ranging command signal instructing the mobile station to transmit a ranging signal including the reference code to each base station included in the active set at a time corresponding to the reference time; Means for causing each base station included in the active set to receive the ranging signal at a respective time;
Means for receiving a respective offset signal from each base station included in the active set, each offset signal receiving the ranging signal by the reference time and the base station included in the active set; Means to identify each temporal difference between each time measured;
Means for transmitting a ranging control signal to the mobile station according to the respective offset signals;
apparatus.
(Item 15)
A method of delivering base station system configuration information comprising:
A first active set signal is received from a first mobile station having a first active set of base stations indicating that the first mobile station has added the base station to the first active set. And the stage of
In response to receiving the first active aggregate signal, transmitting a system configuration information signal including system configuration information of the base station to the first mobile station.
Method.
(Item 16)
16. The method according to item 15, wherein the system configuration information of the base station includes: an identifier of the base station; an identifier of a preamble index of the base station; an identifier of a subchannel index of the base station; Frequency allocation information; time / frequency synchronization indicator associated with the base station; uplink channel information for the base station; downlink channel information for the base station; trigger reference indicator associated with the base station; Equivalent isotropic radiated power of the base station; handover information for the base station; scheduling service information for the base station; supported mobility function information for the base station; paging associated with the base station Group identifier: Channel band of the base station The base station's cyclic prefix identifier; the base station's frame duration identifier; the base station's fast Fourier transform size identifier; and the base station's frame and channel number starting subchannelization mode of operation. A method comprising one or more of the group of information consisting of:
(Item 17)
16. The method of item 15, further comprising: from a second mobile station having a second active set of base stations, the second mobile station adds the base station to the second active set. Receiving a second active set signal indicating that the step of transmitting a system configuration information signal to the first mobile station is responsive to receiving the first and second indicator signals Multicasting the system configuration information signal to the first and second mobile stations.
(Item 18)
Base station equipment:
An interface that facilitates radio communication with a first mobile station having a first active set of base stations;
A computer readable memory having a storage unit for storing system configuration information of a plurality of base stations;
An apparatus having a processor in communication with the interface and the computer readable memory, the processor comprising:
From the interface, a first active set signal from the first mobile station indicating that the first mobile station has added one of the plurality of base stations to the first active set. Receiving, and
In response to receiving the first active set signal, the interface includes system configuration information of the one base station of the plurality of base stations for the first mobile station in the interface. Configured to perform the step of transmitting a configuration information signal;
apparatus.
(Item 19)
The system configuration information of the base station is: an identifier of the base station; an identifier of a preamble index of the base station; an identifier of a subchannel index of the base station; a frequency allocation information of the base station; Time / frequency synchronization indicator; uplink channel information for the base station; downlink channel information for the base station; trigger reference indicator associated with the base station; equivalent isotropic radiated power of the base station; Handover information for the base station; scheduling service information for the base station; supported mobility capability information for the base station; paging group identifier associated with the base station; channel bandwidth of the base station Width identifier; cyclic prefix of the base station A base station frame duration identifier; a base station fast Fourier transform size identifier; and a base station frame and channel number start subchannelization mode of operation. Item 19. The device of item 18, comprising one or more.
(Item 20)
The processor further includes:
From the interface, the second mobile station from a second mobile station having a second active set of base stations causes the one of the plurality of base stations to become the second active set. Configured to receive a second active aggregate signal indicating the addition,
The processor is further operable to cause the interface to multicast the system configuration signal to the first and second mobile stations in response to receiving the first and second indicator signals. Composed of,
Item 19. The apparatus according to Item 18.
(Item 21)
Base station equipment:
Means for storing system configuration information of a plurality of base stations;
Means for receiving, from a mobile station having an active set, an active set signal indicating that the mobile station has added one of the plurality of base stations to the active set;
Means for transmitting a system configuration information signal including system configuration information of the one of the plurality of base stations to the mobile station in response to receiving the active set signal. ,
apparatus.
(Item 22)
A method for controlling a mobile station that communicates with multiple base stations through an uplink control channel.
There:
Receiving each channel condition signal from each of the plurality of base stations, wherein each channel condition signal is received from the mobile station through the uplink control channel in the one of the plurality of base stations. A stage indicating each channel condition of the signal;
The uplink control channel power parameter is determined according to the respective channel condition signals.
A stage to determine;
Transmitting a power control signal including the uplink control channel power parameter to the mobile station,
Method.
(Item 23)
24. The method of item 22, wherein each channel condition comprises a signal to noise ratio.
(Item 24)
Determining the uplink control channel power parameter includes: a threshold signal to noise ratio and a signal to noise for each of the control signals received from the mobile station through the uplink control channel at each of the plurality of base stations. 24. The method of item 23, comprising determining a ratio of the ratio to the smallest one.
(Item 25)
Base station equipment:
A first interface that facilitates radio communication with a mobile station;
A second interface facilitating communication with at least one neighboring base station included in an active set in radio communication with the mobile station;
A processor in communication with the first and second interfaces;
Rosesa:
Receiving a respective channel condition signal from each neighboring base station of the active set from the second interface, wherein each channel condition signal is transmitted to the uplink control channel in the neighboring base station of the active set. Indicating the respective channel conditions of the control signal received from the mobile station through;
An uplink according to a channel condition of a control signal received from the mobile station through the uplink control channel in the apparatus and the respective channel condition signal received from the at least one neighboring base station of the active set. Determining control channel power parameters;
Causing the first interface to transmit a power control signal including the uplink control channel power parameter to the mobile station.
apparatus.
(Item 26)
26. The apparatus of item 25, wherein each channel condition includes a signal to noise ratio.
(Item 27)
The processor: the uplink control channel power parameter, a threshold signal-to-noise ratio, a signal-to-noise ratio of the control signal received from the mobile station through the uplink control channel in the apparatus, and the active set An item operatively configured to determine according to a ratio of a respective signal-to-noise ratio of the control signal received from the mobile station through the uplink control channel in each neighboring base station according to a ratio to the smallest one. 26. The apparatus according to 26.
(Item 28)
A base station device configured for radio communication with a mobile station and for communication with at least one neighboring base station included in an active set for radio communication with the mobile station:
Means for receiving a respective channel condition signal from each neighboring base station of the active set, wherein each channel condition signal is received from the mobile station via the uplink control channel at the neighboring base station of the active set. Means for indicating respective channel conditions of the control signals;
An uplink according to a channel condition of a control signal received from the mobile station through the uplink control channel in the apparatus and the respective channel condition signal received from the at least one neighboring base station of the active set. Means for determining a control channel power parameter;
Means for transmitting a power control signal including the uplink control channel power parameter to the mobile station;
apparatus.
(Item 29)
A method for transmitting a control signal to a plurality of base stations included in an active set of mobile stations, comprising:
For each base station included in the active set, transmitting the control signal to the base station on a respective control channel;
Method.
(Item 30)
A mobile station device:
An interface that facilitates radio communication with a plurality of base stations included in the active set of the device;
An apparatus configured to communicate with the interface and to be configured to transmit the control signal to each base station included in the active set on a respective control channel.
(Item 31)
A mobile station device:
Means for facilitating radio communication with a plurality of base stations included in the active set of devices;
Means for transmitting the control signal to each base station included in the active set on a respective control channel.

1 is a block diagram of an exemplary cellular communication system. FIG. 2 is a block diagram of an exemplary base station shown in FIG. FIG. 2 is a block diagram of an exemplary mobile station shown in FIG. FIG. 2 is a block diagram of an exemplary relay station shown in FIG. FIG. 3 is a block diagram of a logical configuration of an exemplary OFDM transmitter of the base station of FIG. FIG. 4 is a block diagram of a logical configuration of an exemplary OFDM receiver of the wireless terminal of FIG. 3. FIG. 2 is a schematic diagram corresponding to FIG. 1 of IEEE 802.16m-08 / 003r1, showing a network structure implemented by the cellular communication system of FIG. FIG. 5 is a schematic diagram illustrating the structure of the relay station of FIG. 4 and corresponding to FIG. 2 of IEEE802.16m-08 / 003r1. It is the schematic corresponding to FIG. 3 of IEEE802.16m-08 / 003r1 which shows the system reference model of the cellular communication system of FIG. FIG. 5 is a schematic diagram corresponding to FIG. 4 of IEEE802.16m-08 / 003r1, showing a protocol structure based on IEEE802.16m. It is a figure corresponding to FIG. 5 of IEEE802.16m-08 / 003r1 which shows the processing flow of the MS / BS data plane based on IEEE802.16m. It is a figure corresponding to FIG. 6 of IEEE802.16m-08 / 003r1 which shows the processing flow of the MS / BS control plane based on IEEE802.16m. FIG. 8 is a schematic diagram illustrating a protocol structure for supporting a multi-carrier system and corresponding to FIG. 7 of IEEE802.16m-08 / 003r1. FIG. 3 is a schematic diagram of an exemplary control system of the base station of FIG. 2. FIG. 4 is a schematic diagram of an exemplary control system for the mobile station of FIG. 3. FIG. 15 is a schematic diagram of an exemplary preamble index message sent by the base station control system of FIG. 14. FIG. 16 is a schematic diagram of an exemplary active set message sent by the mobile station control system of FIG. 15. FIG. 15 is a block diagram of an exemplary system configuration information delivery code executed by the microprocessor of the base station control system of FIG. FIG. 15 is a schematic diagram of an exemplary system control information message sent by the base station control system of FIG. 14. FIG. 15 is a block diagram of exemplary power control code executed by the microprocessor of FIG. FIG. 15 is a schematic diagram of an exemplary channel condition request message sent by the base station control system of FIG. 14. FIG. 15 is a schematic diagram of an exemplary channel condition message sent by the base station control system of FIG. 14. FIG. 15 is a schematic diagram of an exemplary power control message sent by the base station control system of FIG. 14. FIG. 15 is a block diagram of an exemplary control assignment code executed by the microprocessor of FIG. FIG. 15 is a schematic diagram of an exemplary control channel assignment message sent by the base station control system of FIG. 14. FIG. 16 is a block diagram of exemplary uplink control code executed by the microprocessor of FIG. FIG. 15 is a block diagram of exemplary ranging start code executed by the microprocessor of FIG. FIG. 15 is a schematic diagram of an exemplary ranging resource message sent by the base station control system of FIG. 14. FIG. 15 is a schematic diagram of an exemplary ranging command message sent by the base station control system of FIG. FIG. 16 is a block diagram of exemplary ranging code executed by the microprocessor of FIG. FIG. 15 is a schematic diagram of an exemplary offset message sent by the base station control system of FIG. FIG. 15 is a schematic diagram of an exemplary single ranging parameter ranging control message sent by the base station control system of FIG. 14. FIG. 15 is a schematic diagram of an exemplary multiple ranging parameter ranging control message sent by the base station control system of FIG. 14. FIG. 16 is a block diagram of an exemplary handover code executed by the microprocessor of FIG. FIG. 16 is a schematic diagram of an exemplary handover indicator message sent by the mobile station control system of FIG. 15. FIG. 15 is a block diagram of exemplary handover acknowledgment code executed by the microprocessor of FIG. FIG. 15 is a schematic diagram of an exemplary handover receipt confirmation message sent by the base station control system of FIG. 14. Similar reference numerals are used in different figures to indicate similar elements.

  Referring to the drawings, FIG. 1 shows a base station controller (BSC) 10 that controls wireless communications within a plurality of cells 121, 123, 124, 125, 127, 128 and 129. These cells are served by corresponding base stations (BS) 141, 143, 144, 145, 147, 148 and 149, respectively. In some configurations, each cell is further divided into multiple sectors 13 or zones (not shown). In general, each base station 141, 143, 144, 145, 147, 148 and 149 is a mobile station (MS) in one of cells 121, 123, 124, 125, 127, 128 and 129. And / or facilitate communication with wireless terminals 161, 162, 163, 164 and 165 using Orthogonal Frequency-Division Multiplexing (OFDM).

  As mobile stations 161, 162, 163, 164 and 165 move relative to base stations 141, 143, 144, 145, 147, 148 and 149, significant variations in channel conditions may occur. As shown, base stations 141, 143, 144, 145, 147, 148 and 149 and mobile stations 161, 162, 163, 164 and 165 include multiple antennas to provide spatial diversity for communication. May be. In some configurations, a relay station (RS) 15 assists in communication between base stations 141, 143, 144, 145, 147, 148 and 149 and mobile stations 161, 162, 163, 164 and 165. May be. Mobile stations 161, 162, 163, 164 and 165 are cells 121, 123, 124, 125, 127, 128 and 129, sector 13, zone (not shown), base stations 141, 143, 144, 145, 147, 148. And 149 or any of relay stations 15 from cells 121, 123, 124, 125, 127, 128 and 129, sector 13, zone (not shown), base stations 141, 143, 144, 145, 147 148 and 149 or another of relay stations 15 can be handed off. In some configurations, base stations 141, 143, 144, 145, 147, 148 and 149 are connected to each other and to another network (such as a core network or the Internet not shown) through backhaul network 11. ). In some configurations, the base station controller 10 is not required.

< Base station >
Referring to FIG. 2, a base station 141 is shown. Base stations 143, 144, 145, 147, 148 and 149 are substantially the same as base station 141. Base station 141 generally includes a control system 20, a baseband processor 22, a transmit circuit 24, a receive circuit 26, a plurality of transmit antennas 28, and a network interface 30. The receiving circuit 26 is from one or more remote transmitters provided by the mobile stations 161, 162, 163, 164 and 165 (mobile station 161 is shown in FIG. 3) and the relay station 15 (shown in FIG. 4). A radio frequency signal carrying information is received. A low noise amplifier and filter (not shown) may cooperate to amplify the received signal for processing and remove broadband interference from the signal. A down conversion and digitization circuit (not shown) then down converts the filtered received received signal to an intermediate or baseband frequency signal, which is then digitized to produce one or more digital signals. To be streamed.

  Baseband processor 22 processes the digitized stream and extracts information or data bits that are conveyed in the received signal. This process typically includes demodulation, decoding and error correction operations. Thus, the baseband processor 22 is typically implemented in one or more digital signal processors (DSPs) or application-specific integrated circuits (ASICs). Said information is then sent over the wireless network directly or with the assistance of one of the relay stations 15, or one of the base stations 141, 143, 144, 145, 147, 148 and 149 or It is transmitted to one of the mobile stations 161, 162, 163, 164 and 165 served by a plurality. Thus, network interface 30 facilitates communication with base stations 143, 144, 145, 147, 148 and 149, for example.

  To perform the transmission function, the baseband processor 22 receives digitized data, which may represent voice, data or control information, from the network interface 30 under the control of the control system 20 and encodes it for transmission. Generated data. The encoded data is output to the transmitter circuit 24 where it is modulated by one or more carrier signals having the desired transmission frequency (s). A power amplifier (not shown) amplifies the modulated carrier signal to an appropriate level for transmission and delivers the modulated carrier signal to the transmit antenna 28 through a matching network (not shown). Thus, the antenna 28 functions as an interface for facilitating radio wave communication with one or more of the mobile stations 161, 162, 163, 164, and 165. Details of the modulation and processing are described in more detail below.

  Referring to FIG. 14, a control system 20 is schematically shown. The control system 20 in the illustrated embodiment includes a microprocessor 170 and includes a program memory 172, a data memory 174, and a clock 176, each in communication with the microprocessor 170. Microprocessor 170 also includes a baseband processor interface 178 for communicating with baseband processor 22 (shown in FIG. 2). Thus, in the illustrated embodiment, the control system 20 communicates with the other base and mobile stations shown in FIG. 1 through the baseband processor interface 178, through the baseband processor 22, and through the antenna 28 or network interface. Communicate through 30. In the illustrated embodiment, the program memory 172 is a known computer readable memory and generally includes code for instructing the microprocessor 170 to perform various functions of the control system 20. Data memory 174 is also a known computer readable memory and generally stores data related to the function of control system 20. Clock 176 stores the current time value and, in the illustrated embodiment, is synchronized with the corresponding clock of base stations 143, 144, 145, 147, 148 and 149. Although the control system 20 is shown in the illustrated embodiment as including a microprocessor 170, a program memory 172, a data memory 174, and a clock 176, those skilled in the art will appreciate that alternative embodiments are different components or components. It will be understood that different combinations may be included.

< Mobile station >
Referring to FIG. 3, a mobile station 161 is shown. Mobile stations 162, 163, 164 and 165 are substantially the same as mobile station 161. Similar to the base station 141, the mobile station 161 includes a control system 32, a baseband processor 34, a transmission circuit 36, a reception circuit 38, a plurality of reception antennas 40, and a user interface circuit 42. The receiving circuit 38 receives radio frequency signals carrying information from one or more of the base stations 141, 143, 144, 145, 147, 148 and 149 and the relay station 15. A low noise amplifier and filter (not shown) may cooperate to amplify the signal for processing and remove broadband interference from the signal. A down conversion and digitization circuit (not shown) then down converts the filtered received signal to an intermediate or baseband frequency signal, which is then digitized into one or more digital streams. The

  Baseband processor 34 processes the digitized stream and extracts information or data bits that are conveyed in the signal. This process typically includes demodulation, decoding and error correction operations. Baseband processor 34 is typically implemented in one or more digital signal processors (DSPs) and application-specific integrated circuits (ASICs).

  For transmission, the baseband processor 34 receives digitized data from the control system 32 that may represent voice, video, data or control information and encodes it for transmission. The encoded data is output to transmitter circuit 36 where it is used by the modulator to modulate one or more carrier signals at the desired transmission frequency (s). A power amplifier (not shown) amplifies the modulated carrier signal to an appropriate level for transmission and delivers the modulated carrier signal to the receiving antenna 40 through a matching network (not shown). Various modulation and processing techniques available to those skilled in the art include mobile stations 161, 162, 163, 164 and 165 and base stations 141, 143, 144, 145, 147, 148 and 149, either directly or via relay stations. Used for signal transmission between. As described above, the antenna 40 functions as an interface for facilitating radio wave communication with one or more of the base stations 141, 143, 144, 145, 147, 148 and 149.

  Referring to FIG. 15, the control system 32 is schematically shown. The control system 32 includes a microprocessor 180 and includes a program memory 182, a data memory 184 and a clock 186, each in communication with the microprocessor 180. Microprocessor 180 also includes a baseband processor interface port 188 for communicating with baseband processor 34 (shown in FIG. 3). Accordingly, in the illustrated embodiment, the control system 32 communicates with the base station shown in FIG. 1 through the baseband processor interface 188, through the baseband processor 34, and through the antenna 40. In the illustrated embodiment, the program memory 182 is a known computer readable memory and generally includes code for instructing the microprocessor 180 to perform various functions of the control system 32. Data memory 184 is also a known computer readable memory and generally stores data related to the function of control system 32. The clock 186 stores a value representing the current time, and in the illustrated embodiment, the corresponding clock of the mobile stations 162, 163, 164, and 165, the clock 176 of the base station 141 (shown in FIG. 14), and the base station Synchronized with the corresponding clocks at 143, 144, 145, 147, 148 and 149. Although the control system 32 is shown in the illustrated embodiment as including a microprocessor 180, a program memory 182, a data memory 184, and a clock 186, those skilled in the art will recognize that alternative embodiments are different components or components. It will be understood that different combinations may be included.

< OFDM modulation >
In OFDM modulation, the transmission band is divided into a plurality of orthogonal carriers. Each carrier is modulated according to the digital data to be transmitted. Since OFDM divides the transmission band into multiple carriers, the bandwidth per carrier decreases and the modulation time per carrier increases. Since multiple carriers are transmitted in parallel, the transmission rate of digital data or symbols on any given carrier is lower than when a single carrier is used.

  OFDM modulation involves using an inverse fast Fourier transform (IFFT) on the information to be transmitted. For demodulation, fast Fourier transform (FFT) is performed on the received signal to recover the transmitted information. In practice, IFFT and FFT are provided by digital signal processing related to Inverse Discrete Fourier Transform (IDFT) and Discrete Fourier Transform (DFT), respectively. Thus, a characteristic that characterizes OFDM modulation is that orthogonal carriers are generated for multiple bands in the transmission channel. The modulated signal is a digital signal that has a relatively low transmission rate and can remain within the respective band. Individual carriers are not directly modulated by digital signals. Instead, all carriers are modulated at once by IFFT processing.

  In operation, OFDM is preferably used for at least downlink transmission from base stations 141, 143, 144, 145, 147, 148 and 149 to mobile stations 161, 162, 163, 164 and 165. Each of the base stations 141, 143, 144, 145, 147, 148 and 149 is provided with “n” (n ≧ 1) of the transmitting antennas 28, and the mobile stations 161, 162, 163, 164 and 165 Each is provided with “m” (m ≧ 1) of the receiving antennas 40. In particular, each antenna can be used for both reception and transmission with an appropriate duplexer or switch, and is labeled for clarity only.

  When using relay station 15, OFDM is preferably from base stations 141, 143, 144, 145, 147, 148 and 149 to relay station 15 and from relay station 15 to mobile stations 161, 162, 163, 164 and 165. Used for downlink transmission.

< Relay station >
Referring to FIG. 4, an exemplary relay station 15 is shown. Similar to the base station 141 and the mobile station 161, the relay station 15 includes a control system 132, a baseband processor 134, a transmission circuit 136, a reception circuit 138, a plurality of antennas 130 and a relay circuit 142. The relay circuit 142 allows the relay station 15 to assist in communication between one of the base stations 141, 143, 144, 145, 147, 148 and 149 and one of the mobile stations 161, 162, 163, 164 and 165. . The receiving circuit 138 receives radio frequency signals carrying information from one or more of the base stations 141, 143, 144, 145, 147, 148 and 149 and the mobile stations 161, 162, 163, 164 and 165. A low noise amplifier and filter (not shown) may cooperate to amplify the signal for processing and remove broadband interference from the signal. A down conversion and digitization circuit (not shown) then down converts the filtered received signal to an intermediate or baseband frequency signal, which is then digitized into one or more digital streams. The

  Baseband processor 134 processes the digital stream to extract information or data bits conveyed in the signal. This process typically includes demodulation, decoding and error correction operations. Baseband processor 134 is typically implemented in one or more digital signal processors (DSPs) and application-specific integrated circuits (ASICs).

  For transmission, the baseband processor 134 receives digitized data from the control system 132 that may represent voice, video, data, or control information and encodes the data for transmission. The encoded data is output to the transmission circuit 136 where it is used by the modulator to modulate one or more carrier signals at the desired transmission frequency (s). A power amplifier (not shown) amplifies the modulated carrier signal to an appropriate level for transmission, and delivers the modulated carrier signal to antenna 130 through a matching network (not shown). As described above, various modulation and processing techniques available to those skilled in the art include mobile stations 161, 162, 163, 164 and 165 and base stations 141, 143, 144, directly or indirectly via relay stations. 145, 147, 148 and 149 can be used for signal transmission.

<OFDM transmission>
The logical OFDM transmission architecture will be described with reference to FIG. Referring to FIG. 1, first, the base station controller 10 transmits data to be transmitted to various mobile stations 161, 162, 163, 164, and 165 directly or with the assistance of one of the relay stations 15. To the base stations 141, 143, 144, 145, 147, 148 and 149. Base stations 141, 143, 144, 145, 147, 148 and 149 schedule the data for transmission and select an appropriate encoding and modulation scheme for transmitting the scheduled data. Channel quality indicators (CQI) associated with the mobile stations 161, 162, 163, 164 and 165 may be used. CQI may be provided directly by mobile stations 161, 162, 163, 164 and 165, or determined by base stations 141, 143, 144, 145, 147, 148 and 149 based on information provided by the mobile stations. May be. In any case, the CQI for each mobile station 161, 162, 163, 164 and 165 is a function of the degree to which the channel amplitude (or response) varies through the OFDM frequency band.

< Scheduled data transmission to mobile station >
Referring to FIGS. 1 and 5, scheduled data 44 is a stream of bits that is scrambled using data scrambling logic 46 in a manner that reduces the peak-to-average power ratio for the data. . A cyclic redundancy check (CRC) additional logic 48 is used to determine a cyclic redundancy check (CRC) for the scrambled data and append it to the scrambled data. Channel encoding is then performed using channel encoder 50 to effectively add redundancy to the data to facilitate recovery and error correction at mobile stations 161, 162, 163, 164 and 165. Is done. The channel coding for a particular one of mobile stations 161, 162, 163, 164 and 165 is based on the CQI associated with that particular mobile station. In some implementations, channel encoder 50 uses known turbo encoding techniques. The encoded data is then processed by rate matching logic 52 to compensate for the data expansion associated with the encoding.

  Bit interleaver logic 54 systematically rearranges the bits in the encoded data to minimize the loss of consecutive data bits. The reordered data bits are systematically mapped by mapping logic 56 to corresponding symbols depending on the chosen baseband modulation. Preferably, quadrature amplitude modulation (QAM) or quadrature phase shift key (QPSK) modulation is used. The degree of modulation is preferably selected based on the CQI associated with a particular mobile station. To further enhance the security of transmitted data against periodic data loss caused by frequency selective fading, symbol interleaver logic 58 may be used to systematically reorder symbols. Good.

  At this point, the group of bits has been mapped to a symbol representing the position in the amplitude and phase configuration diagram (constellation). When spatial diversity is desired, the block of symbols is then processed by a space-time block code (STC) encoder logic 60. This modifies the symbols in a way that makes the transmitted signal more resistant to interference and more easily decoded by the mobile stations 161, 162, 163, 164 and 165. STC encoder logic 60 processes incoming symbols and provides “n” outputs corresponding to the number of transmit antennas 28 for base stations 141, 143, 144, 145, 147, 148 and 149. Control system 20 and / or baseband processor 22 described above with respect to FIG. 5 provides mapping control signals for controlling STC encoding. At this point, assume that the symbols for “n” outputs represent data that can be recovered by the mobile stations 161, 162, 163, 164, and 165 to be transmitted.

  For the present example, assume that the mobile station (141 in FIG. 1) has two transmit antennas 28 (n = 2) and that the STC encoder logic 60 provides two output streams of symbols. Each of the output symbol streams is sent to a corresponding output path 61, 63 which is illustrated separately for ease of understanding. One skilled in the art will recognize that one or more processors can be used to provide such digital signal processing alone or in combination with other processes described herein. In each output path, IFFT processor 62 operates on a given symbol to perform an inverse Fourier transform. The output of IFFT processor 62 provides time domain symbols. This time domain signal, also known as an OFDM symbol, is organized into frames by assigning prefixes by the prefix insertion function 64. The resulting frame is up-converted to an intermediate frequency in the digital domain via a corresponding digital up-conversion (DUC) and digital-to-analog (D / A) conversion circuit 66. And converted into an analog signal. The resulting (analog) signal from each output path is then simultaneously modulated and amplified at the desired RF frequency via RF circuit 68 and transmit antenna 28, and mobile stations 161, 162, 163, 164 and 165 is transmitted. In particular, a pilot signal known by the intended mobile station among the mobile stations 161, 162, 163, 164 and 165 is distributed among the subcarriers. Mobile stations 161, 162, 163, 164 and 165, discussed in detail later, use the pilot signals for channel estimation.

< Receiving signal at mobile station >
Here, the transmitted signal is received by the mobile station 161 directly from one of the base stations (such as the base station 141 of FIG. 1) or with the assistance of one of the relay stations (15 of FIG. 1). Reference is made to FIG. When the transmitted signal arrives at each of the receiving antennas 40 of one of the mobile stations 161, 162, 163, 164 and 165, each signal is demodulated and amplified by the corresponding RF circuit 70. For simplicity, only one of the two receive paths will be described and illustrated in detail. An analog-to-digital (A / D) converter / down conversion circuit 72 digitizes and down-converts the analog signal for digital processing. The resulting digitized signal may be used by automatic gain control circuitry (AGC) 74 to control the gain of the amplifier in RF circuit 70 based on the received signal level.

  Initially, the digitized signal is provided to synchronization logic, generally indicated at 76. Synchronization logic 76 includes coarse synchronization logic 78 that buffers several OFDM symbols and calculates the autocorrelation between two successive OFDM symbols. The resulting time index corresponding to the maximum of the correlation results determines the fine synchronization search window. Fine synchronization logic 80 uses this search window to determine a precise framework start position based on the header. The output of fine synchronization logic 80 facilitates frame acquisition by frame alignment logic 84. Proper framework alignment is important so that subsequent FFT processing gives an accurate transformation from the time domain to the frequency domain. The fine synchronization algorithm is based on the correlation between the received pilot signal carried by the header and a local copy of the known pilot data. Once frame alignment acquisition occurs, the OFDM symbol prefix is removed by prefix removal logic 86 and the resulting samples are sent to frequency offset / correction logic 88. The frequency offset / correction logic 88 compensates for system frequency offsets caused by mismatched local oscillators at the transmitter and receiver. Preferably, the synchronization logic 76 includes frequency offset and clock estimation logic 82. This uses the header to estimate frequency and clock offsets in the transmitted signal and provides such estimation to frequency offset / correction logic 88 to properly process the OFDM symbols.

  At this point, the OFDM symbol in the time domain is ready for conversion to the frequency domain by the FFT processing function 90. The result is a set of frequency domain symbols that are sent to the processing function 92. The processing function 92 uses the distributed pilot extraction function 94 to extract the interspersed pilot signal, and uses the channel estimation function 96 to determine a channel estimate based on the extracted pilot signal, and a channel reconfiguration function 98. Is used to provide the channel response for all subcarriers. In order to determine the channel response for each of the subcarriers, the pilot signal is essentially a plurality of pilot symbols distributed among the data symbols through the OFDM subcarriers in a known pattern in both time and frequency. It is.

  Continuing with FIG. 6, processing logic compares the received pilot symbols with the expected pilot signal on a subcarrier at some point in time, and the channel response for the subcarrier that contained the transmitted pilot symbols. To decide. The result is interpolated to estimate the channel response for most if not all of the remaining subcarriers that were not given pilot symbols. The actual channel response and the interpolated channel response are used to estimate the overall channel response. The overall channel response includes the channel response for most if not all of the subcarriers in the OFDM channel.

  Frequency domain symbols and channel reconfiguration information derived from the channel response for each received path are provided to the STC decoder 100. The STC decoder 100 provides STC decoding on both reception paths to recover the transmitted symbols. The channel reconfiguration information provides the STC decoder 100 with equalization information sufficient to remove the effects of the transmission channel when processing each frequency domain symbol.

  The recovered symbols are returned to their original order using symbol deinterleaver logic 102 corresponding to transmitter symbol interleaver logic 58. The de-interleaved symbols are then demodulated or de-mapped using de-mapping logic 104 into the corresponding bit stream. Those bits are then deinterleaved using bit deinterleaver logic 106 corresponding to the bit interleaver logic 54 of the transmitter architecture. The deinterleaved bits are then processed by the rate dematching logic 108 and submitted to the channel decoder logic 110 for recovering the originally scrambled data and CRC checksum. Thus, CRC logic 112 removes the CRC checksum, inspects the scrambled data in a traditional manner, and unscrambles the data using a known base station descrambling code. Provided to descrambling logic 114 for reproduction as 116.

  Continuing with FIG. 6, in parallel with restoring data 116, there is sufficient information to generate CQI or CQI at least at each of base stations 141, 143, 144, 145, 147, 148 and 149, respectively. It is determined and transmitted to each base station. As described above, CQI may be a function of the carrier-to-interference ratio (CR) and the degree to which the channel response varies through various subcarriers in the OFDM frequency band. For this embodiment, the channel gain for each subcarrier in the OFDM frequency band being used to transmit information is compared against each other to determine the degree to which the channel gain varies through the OFDM frequency band. . Many techniques are available to measure the degree of variation, but one technique calculates the standard deviation of the channel gain for each subcarrier through the OFDM frequency band used to transmit the data. That is.

  In some embodiments, the relay station may operate in a time division manner using only one radio wave, or may include multiple radio waves.

< Active set >
Referring back to FIG. 1, each of base stations 141, 143, 144, 145, 147, 148 and 149 generally has a plurality of neighboring base stations. Neighboring base stations are generally base stations with neighboring cells. Referring to FIG. 1 as an example, base station 143 has neighboring base stations 141, 144, 145, 147, 148 and 149.

  Mobile stations 161, 162, 163, 164 and 165 each define an active set of base stations and / or relay stations, as appropriate. In the illustrated embodiment, each active set is one or more of the base stations 141, 143, 144, 145, 147, 148 and 149 and / or one of the relay stations 15 under the control of the respective base station. Contains one or more. In the illustrated embodiment, each of these active sets includes an anchor base station with which the mobile station communicates as described above. Further, these active sets may not include one, or some, or all of the neighboring base stations of the anchor base station. Thus, such an active set generally includes the anchor base station and a subset of neighboring base stations of the anchor base station. For example, in the illustrated embodiment, mobile station 161 may have an active set that includes only base station 141, and mobile station 162 may have an active set that includes base stations 141 and 145. . As another example, neighboring base stations of mobile station 163 can be one or more of base stations 141, 143 and 145 and relay stations, but due to signal propagation conditions or other circumstances, mobile station 163 The active set may include only base stations 141 and 143. In alternative embodiments, the active set may exclude the anchor base station and instead include one of the anchor base station's neighboring base stations and / or one or more relay stations. , Some or all.

  When one of the mobile stations 161, 162, 163, 164 and 165 is in one of the cells 121, 123, 124, 125, 127, 128 or 129, for example, the mobile station is powered on or the cells 121, 123, When entering the region defined by 124, 125, 127, 128, and 129, the mobile station is in contact with one of the base stations 141, 143, 144, 145, 147, 148 and 149 that are within the communication range of the mobile station. Start communication. In the illustrated embodiment, the base station is the initial anchor base station for the mobile station. At this point, the anchor base station transmits information including the preamble index of the neighboring base station of the anchor base station to the mobile station. This is so that the mobile station can identify, for example, each neighboring base station and measure its signal strength.

  In the illustrated embodiment, the anchor base station transmits the preamble index of each of its neighboring base stations to the mobile station using a preamble index message (190 discussed below). Referring to FIG. 1 as an example, base station 143 transmits the preamble index of its neighboring base stations 141, 144, 145, 147, 148 and 149 to the mobile station using a preamble index message (190). .

  Referring to FIG. 16, an exemplary preamble index message is indicated generally at 190. Preamble index message 190 includes a base station identifier field 192 that stores the identifier of the base station, and a preamble index field 194 that stores the preamble index of the base station identified by base station identifier field 192. In the illustrated embodiment, when the mobile stations 161, 162, 163, 164 and 165 are in the network shown in FIG. 1, the base stations 141, 143, 144, 145, 147, 148 and 149 are used as anchor base stations. A functioning base station transmits a preamble index message 190 for each of the base stations 141, 143, 144, 145, 147, 148 and 149 that are neighbors to the base station. More generally, the anchor base station in the illustrated embodiment transmits a preamble index message 190 for every base station in the vicinity of the anchor base station to a mobile station that joins the network for the anchor base station. These messages may be in the same or different OFDM frames based on the IEEE 802.16e standard. In other embodiments, the preamble indexes of the various base stations may be combined in a single message.

  Referring back to FIG. 15, the data memory 184 stores a preamble storage unit 196 that stores the preamble index and associated base station identifier received in the preamble index message 190 (shown in FIG. 16). In addition, the control system 32 stores the preamble index that the mobile station 161 receives in various preamble index messages (190) from time to time in the preamble storage unit 196.

  Still referring to FIG. 15, the program memory 182 determines which base station identified by the base station identifier in the preamble storage unit 196 is to be maintained in the active set of base stations for the mobile station 161. , A code for an active set manager 198 that stores a list of base station identifiers of base stations included in the active set in the active set storage 200 in the data memory 184. The criteria applied by the active set manager 198 varies in various embodiments, but in general, for example, base station signal conditions, set elements recommended by the anchor base station, services offered by the base station, and network operation of the base station One or more of the persons. Since the base stations included in the active set of the mobile station 161 change from time to time, the mobile station 161 sends an active set signal containing an active set message (202, discussed below) to the anchor base station. , Notify the base stations included in the active set.

  Referring to FIG. 17, an exemplary active set message is indicated generally at 202. The active set message 202 includes a base station number field 204 that stores the number of base stations included in the active set, and one or more base station identifier fields equal to the number stored in the base station number field 204. 206. In the illustrated embodiment, the mobile station 161 sends an active set message 202 to an anchor base station (such as base station 141) when the base station in the mobile station's 161 active set changes. In an alternative embodiment, the mobile station 161 may send a MOB_BSHO-RSP message (defined in the IEEE 802.16e standard) to the anchor base station, and the diversity set field ( The active set may be communicated to the anchor base station using diversity set field.

  Referring back to FIG. 14, data memory 174 stores a list of active sets of various mobile stations 161, 162, 163, 164 and / or 165 for which base station 141 serves as an anchor base station. Including the active set storage unit 208, the control system 20 stores a list of active sets that the base station 141 receives in various active set messages from time to time in the active set storage unit 208.

< System configuration information delivery >
Still referring to FIG. 14, the data memory 174 includes a system configuration information (SCI) storage unit 210 that stores system configuration information of the base station 141 and neighboring base stations of the base station 141. In the illustrated embodiment, the neighboring base stations are base stations 143, 145 and 147. Although different types of system configuration information may be stored in various embodiments, in the illustrated embodiment, the system configuration information stored in the system configuration information storage unit 210 includes information about the base station 141 and each neighboring base station. For 143, 145 and 147, include: base station identifier; base station preamble index; base station uplink channel information; and base station downlink channel information. However, in an alternative embodiment, the base station system configuration information may include one or more of the following: an identifier of the base station; an identifier of the preamble index of the base station; Station subchannel index identifier; base station frequency allocation information; time / frequency synchronization indicator associated with the base station; uplink channel information for the base station; downlink channel for the base station Information; trigger reference indicator associated with the base station; equivalent isotropically radiated power of the base station; handover information for the base station; scheduling service information for the base station; Supported mobility feature information about the station Paging group identifier associated with the base station; channel bandwidth identifier of the base station; cyclic prefix identifier of the base station; frame duration identifier of the base station; fast Fourier transform size of the base station The mode of operation of the starting subchannelization of the identifier and the frame and channel number of the base station.

  With continued reference to FIG. 14, the program memory 172 includes code for the system configuration information distributor 212. Referring to FIG. 18, a system configuration information distributor 212 is schematically shown. One of the mobile stations 161, 162, 163, 164 and 165 (hereinafter referred to as “first mobile station” in FIG. 18). In response to receiving the active set message 202 (shown in FIG. 17) from 214.

  The system configuration information distributor 212 proceeds to block 216 which blocks the base station in the active set message 202 (shown in FIG. 17) received from the first mobile station by the microprocessor 170 (shown in FIG. 14). The base station identified by the identifier field 206 is compared with the active set list stored in the active set storage unit 208 (shown in FIG. 14) for the first mobile station, and the active set of the first mobile station Command to determine if there is a new base station added.

  The system configuration information distributor 212 proceeds to block 218 for each new base station included in the active set of first mobile stations identified in block 216. Block 218 indicates to microprocessor 170 (shown in FIG. 14) that the system configuration information for the new base station in the active set of first mobile stations is the first of mobile stations 161, 162, 163, 164 and 165. Command to determine whether it should also be sent to one other than the mobile station (referred to below and in FIG. 18 as “second mobile station”). As background, the system configuration information distributor 212 may be executed asynchronously, so that the base station 141 receives the respective active set message 202 (shown in FIG. 17) from the first and second mobile stations. The active set messages may include the same new base station in each set of first and second mobile stations. The microprocessor (shown in FIG. 14) responds to the active set message (202) from the first mobile station before reaching block 218 in response to the active set message (202) from the second mobile station. The code at block 218 can then be reached. In such a situation, at block 218, the microprocessor (170) determines that the new base station's system configuration information may be sent to both the first and second mobile stations. In that case, the system configuration information distributor 212 continues to block 220, which is in response to the microprocessor (170) receiving active set messages (202) from the first and second mobile stations, Commands the first and second mobile stations to multicast a system configuration signal including a system configuration message (222, discussed below). Then, the system configuration information distributor 212 ends.

  Referring to FIG. 19, an exemplary system configuration information message is indicated generally at 222 and generally includes a system configuration information store 210 (see FIG. 14) for a new base station in an active set of mobile stations. System configuration information stored in (shown). In the illustrated embodiment, the system configuration information message includes a base station identifier field 224, a preamble index field 226, a downlink channel field 228 and an uplink channel field 230. However, in various embodiments, the system configuration information message 222 may include different information, and in some embodiments includes information delivered in, for example, a MOB_NBR-ADV message defined in the IEEE 802.16e standard. You may go out.

  Referring back to FIG. 18, if, at block 218, the microprocessor (170) determines that the new base station system configuration information does not need to be sent to any second mobile station, the system configuration information distributor 212. Continues to block 232 which sends system configuration information to the first mobile station, including system configuration information message 222 (shown in FIG. 19), to the first mobile station. To do. Then, the system configuration information distributor 212 ends.

  Referring back to FIG. 15, the data memory 184 includes a system configuration information storage unit 233 that stores system configuration information received from the system configuration information message 222 (shown in FIG. 19). The system configuration information storage unit 233 stores the system configuration information received by the mobile station 161 in various system configuration information messages (222) as needed.

  In general, the system configuration information distributor 212 only transmits system configuration information of the base station to the mobile station when the base station is added to the active set of mobile stations. The delivery method can be more efficient than other protocols that deliver system configuration information.

< Control channel >
In OFDM modulation and other modulation techniques, mobile stations (such as mobile stations 161, 162, 163, 164 and 165 shown in FIG. 1) and base stations (eg, base stations 141, 143, 144 shown in FIG. 1). Control channels may be established to transmit control messages to and from such as 145, 147, 148 and 149. Examples of such control messages include a preamble index message 190 (shown in FIG. 16), an active set message 202 (shown in FIG. 17), and a system configuration information message 222 (shown in FIG. 19). Other examples of such control messages include MAC messages defined in the IEEE 802.16e standard.

  Referring back to FIGS. 14 and 15, the base station 141 and mobile station 161 in the illustrated embodiment can operate in either a single control channel mode or a multiple control channel mode. Accordingly, the data memory 174 includes a control channel mode storage 234 that stores an indicator of whether the base station 141 is in single control channel mode or multiple control channel mode, and the data memory 184 includes A control channel mode storage unit 236 that stores an indicator of whether the mobile station 161 is in the single control channel mode or the multiple control channel mode is included. The control channel mode storage units 234 and 236 may be configured in advance, or may be configured at any time to change the control channel mode of the base station 141 and the mobile station 161.

  Referring back to FIG. 14, program memory 172 includes code for power controller 238. The power controller 238 in the illustrated embodiment may be implemented for mobile stations 161, 162, 163, 164, and 165 for which the base station 141 is the anchor base station. When the mobile station on which the base station 141 and the power controller 238 are executed is in the single control channel mode, the power controller 238 controls the power level of the mobile station through the uplink control channel.

  Referring to FIG. 20, the power controller 238 code is shown schematically and begins at 240. The power controller 238 may be run periodically or in response to encountering a problem with respect to the power level used by the mobile station on the uplink control channel, eg, signal interference or poor reception of control messages. May be executed.

  The power controller 238 continues to block 242, which blocks the microprocessor 170 (shown in FIG. 4) from the active set storage 208 (shown in FIG. 14) of the target mobile station on which the power controller 238 is being executed. Obtain the identifier of the base station included in the active set and send a channel condition request message (244 discussed below) to each base station included in the active set of mobile stations for which the power controller 238 is executing Command.

  Referring to FIG. 21, an exemplary channel condition request message is indicated generally at 244 and includes a mobile station identifier field 246 that identifies the mobile station for which the power controller 238 is executing.

  Referring back to FIG. 14, the data memory 174 provides a condition value representing the channel condition of the control signal received by the base station 141 from various of the mobile stations 161, 162, 163, 164 and 165. A channel condition storage unit 248 for storing is included. The base station 141 periodically updates the value in the channel condition storage unit 248, and in the illustrated embodiment, various values of the mobile stations 161, 162, 163, 164, and 165 are measured at the base station 141 from time to time. Maintain a regularly updated channel condition value that reflects the signal-to-noise ratio for the thing.

  One of the base stations 141, 143, 144, 145, 147, 148 and 149 receives a condition request message 244 (shown in FIG. 21) from another one of the base stations 141, 143, 144, 145, 147, 148 and 149. When receiving, the base station that received the condition request message (244) returns a channel condition signal that includes the channel condition message (250, discussed below) to the base station that sent the condition request message (244).

  With reference to FIG. 22, an exemplary channel condition message is indicated generally at 250. Channel condition message 250 includes a mobile station identifier field 252. This includes the mobile station identifier from the mobile station identifier field 246 of the channel condition request message 244 (shown in FIG. 21) to which the channel condition message 250 is responding. Channel condition message 250 also includes a signal to noise ratio field 254. This stores the signal-to-noise ratio of the mobile station identified by the mobile station identifier field 252 from the channel condition store 248 (shown in FIG. 14).

  Referring back to FIG. 20, power controller 238 continues to block 256, which blocks microprocessor 170 (shown in FIG. 14) into the active set of mobile stations for which power controller 238 is being executed. Commands included to receive a channel condition message 250 from each base station other than the base station executing the power controller 238.

  The power controller 238 continues to block 258 which blocks the microprocessor 170 (shown in FIG. 14) from the channel condition storage 248 of the base station 141 to the channel condition of the target mobile station on which the power controller 238 is being executed. To receive Thus, the codes in blocks 256 and 258 collectively cause the microprocessor (170) to receive channel condition signals from all base stations included in the active set of mobile stations for which the power controller 238 is executing.

  The power controller 238 continues to block 260, which instructs the microprocessor (170) to determine the uplink control channel power parameters for the mobile station for which the power controller 238 is executing. In the illustrated embodiment, the data memory 174 includes a channel condition threshold storage 262 (shown in FIG. 14) that stores the threshold signal-to-noise ratio. The threshold signal to noise ratio is the minimum preferred signal to noise ratio for receiving a control signal from the mobile station. In the illustrated embodiment, the code in block 260 causes the microprocessor (170) to receive the signal-to-noise ratio received in blocks 256 and 258 from base stations included in the active set on which the power controller 238 is executing. The lowest of the levels is determined, and the lowest of the threshold signal-to-noise ratios stored in the channel condition threshold storage unit (262) and the signal-to-noise ratio levels received in blocks 256 and 258 Command to calculate the ratio to. Thus, in the illustrated embodiment, the uplink control channel power parameter is the base station in which the control signal from the mobile station is included in the active set of the base station in the target mobile station on which the power controller 238 is executing. All are scaling factors required for the power level to be received with at least the threshold signal-to-noise ratio stored in the channel condition threshold storage 262.

  Referring back to FIG. 20, the power controller 238 continues to block 264, which blocks the microprocessor (170) from the power control message (described below) to the target mobile station on which the power controller 238 is executing. Command to transmit a power control signal including 266) discussed. Then, the power controller 238 ends.

  Referring to FIG. 23, an exemplary power control message is indicated generally at 266 and includes a power control parameter field 268 that stores the power control parameter determined at block 260 (shown in FIG. 20). .

  Referring back to FIG. 15, the data memory 184 stores the power level for transmitting control signals on the uplink control channel when the control channel mode of the mobile station 161 is the single channel mode. A control channel power storage unit 270. In response to receiving the power control message 266, the mobile station 161 in the illustrated embodiment includes the control channel power in the control channel power storage 270 in the power control parameter field 268 (shown in FIG. 23). The control channel power stored in the control channel power storage unit 270 is adjusted by multiplying the power control parameters. Therefore, in the illustrated embodiment, when the power control parameter is greater than 1, the control channel power in the control channel power storage unit 270 is increased by the scaling factor expressed in the power control parameter, and the power control parameter is 1 Otherwise, the control channel power in the control channel power storage 270 is reduced by a scaling factor expressed in the power control parameter.

  The power controller 238 provides a single parameter to the mobile station that can be used by the mobile station to facilitate reception of control messages sent by the mobile station at all base stations included in the active set of mobile stations. Cause the transmission of. This advantageously reduces additional transmissions associated with the mobile station that may be required in processing protocols or known protocols for power control at the mobile station.

< Multiple control channel mode >
Referring back to FIG. 14, program memory 172 includes code for control channel and allocator 272. If the control channel mode storage unit 234 indicates that the control channel mode is a multiple control channel mode, the microprocessor 170 may determine the mobile station 161, 162, 163, 164, or 165 for the mobile station. For each base station included in the active set, a control channel assigner 272 for assigning a respective control channel is executed.

  Referring to FIG. 24, a control channel allocator 272 is shown schematically and in response to receiving an active set message 202 (shown in FIG. 17) from a mobile station, a control channel mode store Begins at 274 when (234) indicates that the control channel mode is a multiple control channel mode.

  Control channel allocator 272 follows block 276, which was added to the active set of mobile stations that sent the active set message (202) received at 274 to microprocessor 170 (shown in FIG. 4). Commands to determine if there is a new base station. Thus, the code for block 276 is substantially the same as the code for block 216 shown in FIG.

  With continued reference to FIG. 24, the control channel allocator 272 performs blocks 278 and 280 for each new base station identified in block 276. The code in block 280 assigns a control channel from among a plurality of available control channels for the mobile station to transmit an uplink control signal to the new base station included in the active set of mobile stations. The code at block 280 then causes the microprocessor (170) to transmit a control channel assignment message (282, discussed below) to the mobile station.

  Referring to FIG. 25, an exemplary control channel assignment message is indicated generally at 282 and has a base station identifier field 284 that stores the identifier of the new base station added to the active set of mobile stations. And a channel identifier field 286 for storing an identifier of a channel assigned to the mobile station for transmitting an uplink control signal to the base station identified by the base station identifier in the base station identifier field 284.

  Referring back to FIG. 24, once the control channel allocator 272 performs blocks 278 and 280 for each new base station identified at block 276, the control channel allocator 272 ends.

  Referring back to FIG. 15, data memory 184 includes a control channel assignment storage 288 for storing control channel assignments received in control assignment message 282 (shown in FIG. 25), and control system 32 provides The control channel assignment storage unit 288 stores the control channel assignment received in the control assignment message (282) as needed.

  Still referring to FIG. 15, the program memory 182 controls the uplink for controlling transmission of the uplink control command when the control mode storage unit 236 indicates that the control channel mode is the multiple control channel mode. Contains code for controller 290.

  Referring to FIG. 26, an uplink controller 290 is shown schematically and begins at 292 in response to receiving a control message. The control message received at 292 may be any control message transmitted from the mobile station 161 to a base station included in the active set of the mobile station 161. For example, it may be a normal MAC message.

  For each base station included in the active set (identified in the active set store 200 shown in FIG. 15), the uplink controller 290 executes the codes of blocks 294 and 296. The code in block 294 instructs the microprocessor 180 (shown in FIG. 15) to identify the control channel assigned to the base station identified in the control channel assignment store 288. The code in block 296 instructs the microprocessor (180) to send a control message to the base station on the assigned control channel identified by the code in block 294. The uplink controller 290 then ends.

  Advantageously, the mobile station 161 may determine a respective power level for each of the control channels identified in the control channel assignment storage unit 288. These respective power levels may be adapted to the specific circumstances associated with each base station included in the active set of mobile stations 161, such as distance, noise conditions and other interference. Accordingly, the various control channels identified in the control channel assignment store 288 facilitate sending control channels at respective power levels that can be identified for each base station included in the active set.

< Ranging >
Referring to FIG. 1, as described above, the mobile stations 161, 162, 163, 164, or 165 have the mobile stations and base stations 141, 143, 144, 145, included in the active set of the mobile stations. Data representing the distance between one or more of 147, 148 and 149 may be obtained. Since mobile stations are generally at different distances from the base stations included in the mobile station's active set, uplink signals from the mobile station are transmitted before reaching the various base stations included in the active set. Proceed with different distances, thus arriving at different times at different base stations included in the active set. Such a time difference may cause interference. For example, a signal from one mobile station may arrive at the base station earlier or later than intended, thus interfering with a previous or subsequent signal from another mobile station, for example.

  Referring to FIG. 14, program memory 172 includes code for ranging initiator 298 that may be executed for a mobile station for which base station 141 is an anchor base station. Referring to FIG. 27, ranging starter 298 is shown schematically and begins at 300. Ranging initiator 298 may be periodically executed by a microprocessor (shown in FIG. 14), or because, for example, the mobile station has added a new base station to its active set, or the mobile station often has other mobile This may be performed in response to an indication that the mobile station needs new or updated ranging information because it has caused interference with the signal from the station.

  The ranging initiator 298 continues to block 302, which instructs the microprocessor 170 (shown in FIG. 14) to determine a reference code (which may be referred to as a “ranging code”). In the illustrated embodiment, the reference code generated at block 302 is a pseudo-random binary number. However, in other embodiments, the reference code may be a predetermined code for each mobile station, for example.

  The ranging initiator 298 continues to block 304, which instructs the microprocessor (170) to determine a reference time for the mobile station to transmit a signal including the reference code determined in block 302. As discussed above with reference to FIGS. 14 and 15, clocks 176 and 186 of base station 141 and mobile station 161 and base stations 143, 144, 145, 147, 148 and 149 and mobile stations 162, 163, respectively, The corresponding clocks at 164 and 165 are synchronized in the illustrated embodiment, and these clocks define temporal sequential frames for transmission of data. The code in block 304 instructs the microprocessor (170) to determine the reference time. The reference time is, in the illustrated embodiment, a specific OFDM frame determined by the synchronized clock described above.

  With continued reference to FIG. 27, the ranging initiator 298 continues to block 306 which causes the microprocessor (170) to send a ranging resource signal including a ranging resource message (308, discussed below) to the ranging initiator 298. Commands to be transmitted to other base stations included in the active set of target mobile stations being executed.

  Referring to FIG. 28, an exemplary ranging resource message is indicated generally at 308. The ranging resource message 308 includes a mobile station identifier field 309 that stores the identifier of the target mobile station on which the ranging initiator 298 is being executed, and a reference code that stores the reference code determined in block 302 (shown in FIG. 27). It includes a field 310 and a reference time field 312 that stores the reference time determined in block 304 (shown in FIG. 27).

  Referring back to FIG. 27, the ranging initiator 298 continues to block 314, which sends a ranging command signal including a ranging command message (316 discussed below) to the microprocessor (170), The ranging starter 298 commands transmission to the target mobile station being executed.

  Referring to FIG. 29, an exemplary ranging command message is indicated generally at 316. The ranging command message 316 includes a reference code field 318 that stores the reference code determined in block 302 (shown in FIG. 27) and a reference that stores the reference time determined in block 304 (shown in FIG. 27). And a time field 320.

  Referring back to FIG. 15, the program memory 182 includes code for a ranger 322. Referring to FIG. 30, a ranger 322 is shown schematically and reaches the reference time specified by the reference time field 320 of the ranging command message 316 (shown in FIG. 29) received by the mobile station 161. Will start at 324. Ranger 322 follows block 326, which provides the microprocessor 180 (shown in FIG. 15) with a ranging signal that includes a reference code specified by the reference code field 318 of the ranging command message (shown in FIG. 29). To the base stations included in the active set of mobile stations 161. Ranger 322 then ends. In an alternative embodiment, the ranger 322 receives the ranging signal at base stations included in the active set of mobile stations 161 closer in time to the reference time specified by the reference time field (320). To do so, it may begin at a specific time period before the reference time specified by the reference time field (320). This particular time period is expected signal transmission, for example based on estimated distances to base stations included in the active set or based on previously acquired data reflecting such distances. Time may be reflected.

  Accordingly, the base stations included in the active set of mobile stations 161 receive ranging signals including ranging codes transmitted in response to the code of block 326, each of these base stations receiving ranging signals. Receive at each time. Referring back to FIG. 27, the ranging initiator 298 continues to block 328 which blocks the microprocessor 170 (shown in FIG. 14), the reference time determined in block 304, and block 326 (shown in FIG. 30). The base station 141 is instructed to calculate a time difference between the time when the base station 141 receives the ranging signal transmitted from the mobile station in response to the code).

  Each of the other base stations included in the active set of mobile stations 161 also receives a reference time and a ranging signal in response to the code in block 326 (shown in FIG. 30) when the base station included in the active set receives it. Calculate the time difference between and. These other base stations send respective offset signals to the base station 141, including respective offset messages (330 discussed below) that identify respective temporal differences calculated at that base station.

  Referring to FIG. 31, an exemplary offset message is indicated generally at 330 and includes a base station identifier field 332 identifying the base station for which the time difference was calculated, and the target mobile station for which the time difference was calculated. Mobile station identifier field 334 and a time difference field 336 identifying the calculated time difference.

  Referring back to FIG. 27, the ranging initiator 298 continues to block 338 which blocks the microprocessor 170 (shown in FIG. 14) the active mobile station active for which the ranging initiator 298 is being executed. Commands to receive various offset messages 330 (shown in FIG. 31) from other base stations included in the set. The ranging initiator 298 then continues to block 340, which provides the microprocessor (170) with a ranging control signal including a ranging control message (344 or 348 discussed below) on which the ranging initiator 298 is being executed. To send to the mobile station.

  Referring back to FIG. 14, the data memory 174 includes a ranging mode storage unit 342 that stores an indicator of the ranging mode of the base station 141. The ranging mode indicated by the ranging mode storage unit 342 in the illustrated embodiment may be a single ranging parameter mode or a multiple ranging parameter mode. The ranging mode identified by the ranging mode storage unit 342 may be preconfigured or may be configured at any time.

  Referring to FIG. 32, a single ranging parameter ranging control message is indicated generally at 344 and includes an average time difference field 346. If the ranging mode store (342) indicates a single ranging parameter ranging mode, the code in block 340 is sent to the microprocessor (170) by the time difference received in blocks 328 and 338 (shown in FIG. 27). And the average is stored in the average time difference field 346 of the single ranging parameter ranging control message 344, and the single ranging parameter ranging control message 344 is the target for which the ranging initiator 298 is executed. Command to transmit to mobile station.

  Alternatively, if the ranging mode storage unit 342 indicates multiple ranging parameter ranging mode, the code in block 340 (shown in FIG. 27) sends a multiple ranging parameter ranging control message to the microprocessor (170). Command to generate. An exemplary multiple ranging parameter ranging control message is indicated generally at 348 in FIG. Referring to FIG. 33, the multiple ranging parameter ranging control message 348 includes at least one base station identifier that identifies each base station included in the active set of mobile stations for which the ranging initiator 298 is being executed. 350 and a plurality of time difference fields 352. Each time difference field corresponds to one of the base station identifiers 350 and stores the time difference associated with that base station received at blocks 328 and 338 (shown in FIG. 27). If the ranging mode storage unit 342 indicates multiple ranging parameter ranging mode, the code in block 340 (shown in FIG. 27) generates a multiple ranging parameter ranging control message 348 to the microprocessor (170). The multiple ranging parameter ranging control message is commanded to be transmitted to the target mobile station on which the ranging initiator 298 is being executed.

  As described above, in alternative embodiments, the active set excludes anchor base stations and does not include neighboring base stations and / or one or more relay stations of the anchor base station. Or all of them. In these embodiments, the code of block 328 may be omitted and the code of block 340 may exclude the time difference received at block 328.

  Referring back to FIG. 15, data memory 184 stores ranging data for storing ranging data received from ranging control messages (344 and 348) transmitted at block 340 (shown in FIG. 27). A storage unit 354 is included. The mobile station 161 refers to the ranging data stored in the ranging data storage unit 354, and the transmission of the uplink signal is based on the ranging data in various base stations included in the active set of the mobile station 161. Facilitates reception at a point in time and facilitates signal reception near the time that may be assigned, thereby avoiding interference with uplink signals from other mobile stations. Advantageously, the above process is periodically updated in the ranging data store 354 of the mobile station 161 for the base stations that the mobile station 161 has identified in the active set store 200 for its active set. Maintaining ranging data, thereby facilitating efficient handover of the mobile station from the anchored base station to the target base station in the active set of base stations.

< Handover receipt confirmation >
Referring back to FIG. 1, as described above, one of the mobile stations 161, 162, 163, 164 and 165 can initiate a handover from its anchor base station to another base at any time. In various embodiments, various criteria may be involved in determining when a mobile station initiates a handover from its anchor base station to the target base station, but these criteria are often determined by the anchor base station and the target base station. Including relative signal strength, services available from the anchor base station and target base station, and recommended target base stations transmitted by the anchor base station. In one embodiment based on the IEEE 802.16e standard, the mobile station and base station may control various information such as MOB_BSHO-REQ, MOB_MSHO-REQ, MOB_BSHO-RESP and MOB_HO-IND messages to communicate information and decisions regarding handover. Exchange messages.

  Referring back to FIG. 15, the program memory 182 generally provides for determining when to initiate a handover from the current anchor base station to the target base station and for performing such a determination. Contains code for the handover handler 356.

  Referring to FIG. 34, the handover handler 356 is shown schematically and begins at block 358. Block 358 includes code that instructs microprocessor 180 (shown in FIG. 15) to determine that a handover is to be performed from the anchor base station of mobile station 161 to the target base station. The code in block 358 may implement one or more of the above criteria or other criteria for determining that a handover will occur.

  The handover handler 356 continues to block 360. Block 360 commands the microprocessor (180) to send an indicator signal to the anchor base station that includes a handover indication message (362, discussed below) that the handover determined in block 358 will occur. .

  Referring to FIG. 35, an exemplary handover indication message is indicated generally at 362 and a target base station identifier field that stores the identifier of the target base station determined at block 358 (shown in FIG. 34). 364.

  Referring back to FIG. 14, program memory 172 includes code for handover receipt confirmer 366. Referring to FIG. 36, a handover receipt confirmer 366 is schematically shown, and the base station 141 transmits a handover indication message 362 (FIG. 35) transmitted from the mobile station in block 360 (shown in FIG. 34). Starts at 368. Handover receipt confirmer 366 continues to block 370. Block 370 sends a handover acknowledgment signal including a handover acknowledgment message (372, discussed below) to microprocessor 170 (shown in FIG. 14) to the mobile station that sent the handover indication message received at 368. Command to send.

  With reference to FIG. 37, an exemplary handover acknowledgment message is shown schematically at 372 and includes an acknowledgment field 374. In the illustrated embodiment, the acknowledgment field is set to 1 if the handover indication message received at 368 is received without error, and the handover indication message received at 368 was received with some error. Contains a binary flag that is set to 0 in some cases.

  Referring back to FIG. 34, the handover handler 356 continues to block 376. Block 376 instructs microprocessor 180 (shown in FIG. 15) to perform the handover determined in block 358. Handover can be implemented by one of many known protocols, for example, protocols established in the IEEE 802.16e standard.

  The handover handler 356 continues to block 378. Block 378 determines to the microprocessor (180) whether the mobile station 161 has received the handover acknowledgment message 372 (shown in FIG. 37) transmitted by the anchor base station 141 in block 370 (shown in FIG. 36). To do. If so, the handover handler 356 ends. If not, the handover handler 356 continues to block 380. Block 380 instructs the microprocessor (180) to resend the handover indication message sent in block 360 and wait a predetermined time before returning to block 378. Blocks 378 and 380 are thus repeated until the mobile station 161 confirms that the base station 141 has received the handover indication message. Blocks 378 and 380 are performed after block 376, but in other embodiments block 376 may be performed after blocks 378 and 380 so that the handover receives an acknowledgment from the anchor base station. Postponed until The handover indicator message retransmitted at block 378 may continue to cause the anchor base station 141 to attempt to communicate with the base station 161 after the base station 161 completes the handover to the target base station. This may be prevented. This can advantageously prevent unwanted interference and congestion. The handover indication message retransmitted at block 378 may also ensure that the anchor base station notifies the target base station that the mobile station will perform a handover to the target base station. This advantageously prevents communication interruptions that may occur if the target base station is not ready to communicate with the mobile station because the anchor base station has not received the handover instruction message.

Although the above provides a specific example of a communication system in which embodiments of the present invention are implemented, the embodiments of the present invention have an architecture different from this specific example, but the implementation described herein. It should be understood that a communications system that operates in a manner consistent with the implementation of the form can be implemented.

  While particular embodiments of the present invention have been described and illustrated, such embodiments are merely illustrative of the invention and are not intended to limit the invention as construed according to the appended claims. Should be considered.

Claims (11)

A method for facilitating handover of a mobile station from an anchor base station to a target base station, the method comprising:
The anchor base station transmitting a ranging resource signal identifying a reference code and reference time associated with the mobile station to each base station of the active set of base stations, the base station of the active set; Comprises a subset of neighboring base stations of the anchor base station;
The mobile station transmitting a ranging signal including the reference code to each base station of the active set of base stations in a time to respond to the reference time, wherein each of the base stations of the active set The base station receives the ranging signal at each time; and
The anchor base station receiving a respective offset signal from each base station of the active set of base stations, wherein each of the offset signals includes the reference time and the active set of base stations; Identifying a respective temporal difference between a respective time at which each base station received the ranging signal;
The anchor base station transmitting a ranging control signal to the mobile station in response to the respective offset signal;
The anchor base station, the method comprising: receiving a handover indication signal indicating that said mobile station performs a handover to the anchor base station or rata Getto base station from the mobile station, the target base station Is one of the active set of base stations;
The anchor base station, and transmitting an acknowledgment signal the anchor base station acknowledgment of the reception of the handover indication signal to the mobile station, the method. A base station device,
A first interface that facilitates radio communication with mobile stations;
A second interface that facilitates communication with at least one neighboring base station in the active set of base stations, wherein the active set of base stations is in radio communication with the mobile station; Interface,
A processor in communication with the first interface and the second interface ;
Wherein the processor is,
Causing the second interface to transmit a ranging resource signal identifying a reference code and a reference time associated with the mobile station to the at least one neighboring base station in the active set of base stations. When,
A ranging command signal for instructing the mobile station to transmit a ranging signal including the reference code to each base station in the active set of base stations at a time in response to the reference time. Transmitting to the first interface, each base station in the active set of base stations receiving the ranging signal at a respective time; and
Receiving from the second interface a respective offset signal from each neighboring base station in the active set of base stations, wherein each respective offset signal includes the reference time and the active set of Identifying a respective temporal difference between a respective time at which each neighboring base station in the base station receives the ranging signal;
Causing the first interface to transmit a ranging control signal to the mobile station in response to each of the respective offset signals;
The method comprising the mobile station receives from the handover indication signal the first interface from the mobile station indicating to perform a handover to the target base station from the base station apparatus, the target base station Being one of the active set of base stations;
And possible to perform sending a receipt confirmation signal by the base station apparatus receives confirmation that it has received the handover indication signal to the mobile station to the first interface
Operably Ru configured Tei, the base station apparatus to perform. A base station apparatus configured for radio communication with a mobile station and communication with at least one neighboring base station in an active set of base stations , wherein the active set of base stations is the mobile station Radio communication with a station, the base station device
Means for transmitting a ranging resource signal identifying a reference code and a reference time associated with the mobile station to the at least one neighboring base station in the active set of base stations;
A ranging command signal for instructing the mobile station to transmit a ranging signal including the reference code to each base station in the active set of base stations at a time in response to the reference time. Means for transmitting, wherein each base station in the active set of base stations receives the ranging signal at a respective time;
Means for receiving a respective offset signal from each base station in the active set of base stations, wherein each respective offset signal includes the reference time and each neighbor in the active set of base stations; Means for identifying respective temporal differences between respective times at which a base station receives the ranging signal;
Means for transmitting a ranging control signal to the mobile station in response to each of the respective offset signals;
And means for the mobile station receives a handover indication signal from the mobile station indicating to perform a handover to the target base station from the base station apparatus, the target base station, the base of the active set Means of one of the stations;
And means for transmitting the acknowledgment signal by the base station apparatus receives confirmation that it has received the handover indication signal to the mobile station, the base station apparatus. Further comprising the method of claim 1 in that the anchor base station, generates the reference code from the code generated pseudorandom. Transmitting the ranging control signal includes a ranging signal representing an average of respective temporal differences between the reference time and respective times when each base station of the active set receives the ranging signal. The method of claim 1, comprising transmitting. Transmitting the ranging control signal includes transmitting a plurality of ranging control signals, each of the plurality of ranging control signals being associated with a respective base station of the active set, and the reference time The method of claim 1, wherein the respective temporal differences between the active set and the respective times at which the respective base stations of the active set received the ranging signal. Wherein the active set, further comprises the anchor base station, the method according to claim 1. Wherein the processor, Ru Tei is further operatively configured to generate the reference code from the code generated pseudo-random, according to claim 2. The ranging control signal represents an average of each temporal difference between the reference time and a respective time at which each base station in the active set received the ranging signal. 2. The apparatus according to 2 . The ranging control signal includes a plurality of ranging control signals, each of the plurality of the ranging control signal, said is associated with each of the base stations in the active set, and the reference time, the respective base station The apparatus according to claim 2, wherein each apparatus represents a respective temporal difference from a respective time at which the ranging signal is received. Wherein the active set, further comprises the device, the processor,
And receiving the ranging signal from the mobile station from said first interface,
Calculating a temporal difference between the reference time and a time at which the device receives the ranging signal from the mobile station ;
In response to the time difference between the reference time and the time at which the apparatus receives the ranging signal from the mobile station, the first interface is configured to transmit the ranging control signal to the mobile station. What to do and
The Ru further operably configured Tei to perform, according to claim 2.

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