JP5559175B2 - Adaptive transmit (Tx) / receive (Rx) pulse shaping filters for femtocell base stations and mobile stations in a network - Google Patents

Description

RELATED APPLICATIONS This application is incorporated herein by reference, filed on August 20, 2008, “Adaptive Transmission (Tx) / Reception (Rx) Pulse Shaping Filter For Access Point Base Stations And Mobile Stations Within A Network” And claims priority to US patent application Ser. No. 61 / 090,569.

  The present disclosure relates generally to communication systems. More particularly, this disclosure relates to adaptive transmit (Tx) / receive (Rx) pulse shaping filters for femtocell base stations and mobile stations in a network.

  Wireless communication systems have become an important means for enabling many people around the world to communicate. A wireless communication system may perform communication for a number of mobile stations, and each mobile station may be served by a base station.

  As used herein, the term “mobile station” refers to an electronic device that may be used for voice and / or data communication via a wireless communication system. Examples of mobile stations include cellular phones, personal digital assistants (PDAs), wireless modems, laptop computers and the like. A mobile station may alternatively be referred to as an access terminal, mobile terminal, subscriber station, remote station, user terminal, terminal, subscriber unit, mobile device, wireless device, user equipment, or some other terminology.

  The term “base station” refers to a wireless communication station installed at a fixed location and used to communicate with a mobile station. A base station may alternatively be referred to as an access point, Node B, evolved Node B, or some other similar terminology.

  A mobile station may be able to communicate with one or more base stations via transmissions on the uplink and downlink. The uplink (or reverse link) refers to the communication link from the mobile station to the base station, and the downlink (or forward link) refers to the communication link from the base station to the mobile station.

  A femtocell base station is a small cellular base station that is typically designed for use in a residential or small business environment. The femtocell base station connects to the service provider's network via broadband (such as DSL or cable). The femtocell base station allows service providers to extend service coverage, especially indoors where access would otherwise be restricted or unavailable. A femtocell base station may alternatively be referred to as an access point base station, home node B (HNB), home evolved node B (HeNB), femto node, and so on.

  The coverage area of a femtocell base station may be referred to herein as a femtocell. A typical base station coverage area may be referred to herein as a macro cell, and a typical base station may be referred to herein as a macro cell base station.

  Adjacent channel interference is interference caused by extraneous power from signals in adjacent channels. Adjacent channel interference may occur between two mobile stations, one of the mobile stations receiving service from the femtocell base station and the other mobile station receiving service from the macrocell base station. Two mobile stations are operating on adjacent carriers. The present disclosure relates in particular to reducing adjacent channel interference where interference channels are involved in femtocell base stations and macrocell bases.

1 illustrates a wireless communication system configured to support a number of users. FIG. The figure which shows the wireless communication system containing a femtocell base station and a macrocell base station. 1 illustrates a wireless communication system including a first mobile station and a second mobile station where adjacent channel interference may occur. FIG. The figure which shows the transmitter and receiver in a wireless communication system. The figure which shows the system by which a femtocell base station uses a narrow-band transmission pulse shaping filter, and the macrocell base station in a system uses a standard transmission pulse shaping filter. The figure which shows the system by which a femtocell base station uses a narrow-band transmission pulse shaping filter, and the macrocell base station in a system uses a standard transmission pulse shaping filter. FIG. 7 illustrates a method that can be performed by a mobile station in the systems of FIGS. 5 and 6 when it detects that a handoff from a macrocell base station to a femtocell base station has occurred. FIG. 7 illustrates a method that can be performed by a mobile station in the system of FIGS. 5 and 6 when it detects that a handoff from a femtocell base station to a macrocell base station has occurred. The figure which shows the means plus function block corresponding to the method of FIG. The figure which shows the means plus function block corresponding to the method of FIG. The femtocell base station uses a narrowband transmission pulse shaping filter, the macrocell base station in the system uses a standard transmission pulse shaping filter, and the first mobile station and the second mobile station are located in the femtocell. The figure which shows another system. FIG. 4 illustrates some components that may be included within a wireless device.

  A femtocell base station configured to limit adjacent channel interference is disclosed. The femtocell base station includes a transmitter for transmitting a downlink signal to the first mobile station. The first mobile station is located in the femtocell. The femtocell base station also includes a narrowband transmit pulse shaping filter. The narrowband transmit pulse shaping filter is configured such that the bandwidth of the downlink signal transmitted by the femtocell base station is smaller than the bandwidth of the downlink signal transmitted to the second mobile station by the macrocell base station. Is done.

  The femtocell base station may also include a receiver for receiving uplink signals from the first mobile station. The femtocell base station may also include a narrowband receive pulse shaping filter that matches the narrowband transmit pulse shaping filter at the first mobile station. The narrowband transmission pulse shaping filter in the first mobile station is configured so that the bandwidth of the uplink signal transmitted by the first mobile station is greater than the bandwidth of the uplink signal transmitted by the second mobile station to the macrocell base station. Can also be configured to be smaller.

  As described above, the present femtocell base station includes a narrowband transmission pulse shaping filter. The narrowband receive pulse shaping filter at the first mobile station may be able to match the narrowband transmit pulse shaping filter at the femtocell base station.

  The macro cell base station may be able to cover the macro cell. A femto cell may be located within a macro cell. The second mobile station may also be located in the femtocell.

  A mobile station configured to limit adjacent channel interference is disclosed. The mobile station includes a transmitter for transmitting an uplink signal. The mobile station also includes a transmit pulse shaping filter that limits the bandwidth of the uplink signal transmitted by the mobile station. The mobile station also includes a narrowband transmission pulse shaping filter that limits the bandwidth of the uplink signal transmitted by the mobile station to a degree greater than the transmission pulse shaping filter.

  The mobile station may also include a switching mechanism for switching between a transmission pulse shaping filter and a narrowband transmission pulse shaping filter. As an example, the switching mechanism can be configured to switch from a transmission pulse shaping filter to a narrowband transmission pulse shaping filter in response to detecting that a handoff from a macrocell base station to a femtocell base station has been performed. . The switching mechanism can be configured to switch from the narrowband transmit pulse shaping filter to the transmit pulse shaping filter in response to detecting that a handoff from the femtocell base station to the macrocell base station has been performed. Of course, other switching mechanisms are possible within the scope of this disclosure.

  The mobile station can further include a receiver for receiving a downlink signal. The mobile station may also include a receive pulse shaping filter that matches the transmit pulse shaping filter at the macrocell base station. The mobile station may also include a narrowband receive pulse shaping filter that matches the narrowband transmit pulse shaping filter at the femtocell base station. The mobile station may further include a switching mechanism for switching between a received pulse shaping filter and a narrowband received pulse shaping filter. As an example, the switching mechanism can be configured to switch from a received pulse shaping filter to a narrowband received pulse shaping filter in response to detecting that a handoff from a macrocell base station to a femtocell base station has been performed. . The switching mechanism can be configured to switch from the narrowband received pulse shaping filter to the received pulse shaping filter in response to detecting that a handoff from the femtocell base station to the macrocell base station has been performed. Of course, other switching mechanisms are possible within the scope of this disclosure.

  A method for increasing signal to noise ratio (SNR) for a received signal and limiting adjacent uplink channel interference is disclosed. The method is implemented by a mobile station. The method includes detecting that a handoff from the macrocell base station to the femtocell base station has occurred. The method also includes switching from a received pulse shaping filter to a narrowband received pulse shaping filter. The method also includes using a narrowband receive pulse shaping filter to receive downlink transmissions from the femtocell base station.

  The method may also include switching from a transmit pulse shaping filter to a narrowband transmit pulse shaping filter. The method may also include using a narrowband transmit pulse shaping filter to send uplink transmissions to the femtocell base station.

  The method may further include detecting that a handoff from the femtocell base station to the macrocell base station has occurred. The method or may include switching from a narrowband receive pulse shaping filter to a receive pulse shaping filter. The method may also include using a receive pulse shaping filter to receive a downlink transmission from the macrocell base station. The method may also include switching from a narrowband transmit pulse shaping filter to a transmit pulse shaping filter. The method may further include using a transmit pulse shaping filter to send an uplink transmission to the macrocell base station.

  Disclosed is an apparatus configured to increase a signal to noise ratio (SNR) for a received signal and limit adjacent uplink channel interference. The apparatus includes means for detecting that a handoff from a macrocell base station to a femtocell base station has occurred. The apparatus also includes means for switching from the received pulse shaping filter to the narrowband received pulse shaping filter. The apparatus also includes means for using a narrowband receive pulse shaping filter to receive downlink transmissions from the femtocell base station.

  A computer program product for increasing the signal to noise ratio (SNR) for a received signal and limiting adjacent uplink channel interference is disclosed. The computer program product includes a computer readable medium having instructions thereon. The instructions include code for detecting that a handoff from the macrocell base station to the femtocell base station has occurred. The instructions also include code for switching from the received pulse shaping filter to the narrowband received pulse shaping filter. The instructions also include code for using a narrowband receive pulse shaping filter to receive downlink transmissions from the femtocell base station.

  FIG. 1 illustrates a wireless communication system 100 configured to support a number of users. System 100 communicates for a plurality of macro cells 102 (eg, macro cells 102a-c), and each macro cell 102 is served by a corresponding macro cell base station (BS) 104 (eg, macro cell BS 104a-c). Mobile stations 106 (eg, mobile stations 106a-n) may be distributed at various locations throughout the system 100 over time. Each mobile station (MS) 106 may be on the uplink and / or downlink at a given time depending on, for example, whether the MS 106 is active and whether the MS 106 is in soft handoff. It may be possible to communicate with one or more macrocell base stations 104. The wireless communication system 100 may be able to provide service over a large geographic area.

  FIG. 2 shows a wireless communication system 200 that includes a femtocell BS 210 and a macrocell BS 204. The coverage area of the femtocell BS 210 may be referred to as a femtocell 208, and the coverage area of the macrocell BS 204 may be referred to herein as a macrocell 202. Macrocell 202 may be significantly wider than femtocell 208. For example, the radius of the macrocell 202 can be on the order of several kilometers, and the femtocell 208 can cover a home or small building. The femtocell 208 can be thought of as a small separate coverage area located within the macrocell 202.

  Femtocell BS 210 may be coupled to wide area network 218 (eg, the Internet) and mobile operator core network 216 via a DSL router, cable modem, wireless link, or other connectivity means. Macrocell BS 204 may also be coupled to core network 216.

  The MS 206 may be able to receive services from the femtocell BS 210 and may be able to receive services from the macrocell BS 204. For example, femtocell BS 210 may be able to provide service to MS 206 when MS 206 is located in femto cell 208. When the MS 206 moves out of the femtocell 208 but is still located within the macrocell 202, the macrocell BS 204 may be able to serve the MS206.

  FIG. 3 shows a wireless communication system 300 in which a first MS 306 a and a second MS 306 b are located in a femto cell 308 located in the macro cell 302. The first MS 306 a receives service from the femtocell BS 310. The first MS 306a sends data to the femtocell BS 310 via the uplink 312a and receives data from the femtocell BS 310 via the downlink 314a. However, even though the second MS 306b is located in the femtocell 308, the second MS 306b is receiving service from the macrocell BS 304. For example, a femtocell BS 310 may be located in an individual's home, and the second MS 306b is visiting that individual's home but is authorized to receive services from the femtocell BS 310. You can not belong to someone. The second MS 306b sends data to the macro cell BS 304 via the uplink 312b and receives data from the macro cell BS 304 via the downlink 314b.

  The second MS 306b may be located relatively close to the femtocell BS 310. As a result, transmissions from the second MS 306b on the uplink 312b to the macro cell BS 304 may be received at the femto cell BS 310, thus interfering with transmissions from the first MS 306a to the femto cell BS 310 on the uplink 312a. obtain. If adjacent carriers are used for uplink 312a, 312b, this interference may be referred to as adjacent uplink channel interference.

  Similarly, transmissions from the femtocell BS 310 on the downlink 314a to the first MS 306a may be received at the second MS 306b, thus interfering with transmissions from the macro cell BS 304 to the second MS 306b on the downlink 314b. Can do. If adjacent carriers are used for downlink 314a, 314b, this interference may be referred to as adjacent downlink channel interference.

  In FIG. 3, the second MS 306b is located in the femtocell 308, but adjacent uplink channel interference and adjacent downlink channel interference occur even when the second MS 306b is located outside the femtocell 308. There is. The methods disclosed herein may be utilized regardless of whether the second MS 306b is located within the femtocell 308 or outside the femtocell 308.

  FIG. 4 shows a transmitter 420 and a receiver 422 in the wireless communication system 400. The transmitter 420 accepts digital data, converts it to a modulated radio frequency (RF) signal, and transmits the signal to the receiver 422. Receiver 422 receives the RF signal and demodulates it to recover the data.

  Digital data provided to transmitter 420 may be modulated by a modulator 424 to generate a sequence of modulated samples representing symbols according to a certain modulation format. The modulated samples may be filtered by a transmitter (Tx) pulse shaping filter 426 to generate a filtered sequence of samples. The Tx pulse shaping filter 426 is a digital filter that can be implemented as a finite impulse response (FIR) filter.

  Tx front end 428 may be able to process the output of Tx pulse shaping filter 426. The Tx front end 428 may be able to perform functions such as interpolation, predistortion and / or other filtering operations. The filtered samples can be provided to a digital-to-analog converter (DAC) 430 that generates an analog signal that represents a modulated and filtered sample sequence at its input. The analog signal may then be upconverted to a suitable radio frequency by upconverter (UC) 432 and amplified by power amplifier (PA) 434. The RF signal can then be transmitted via transmit antenna 436.

  Receive antenna 438 may receive the transmitted signal and provide it to downconverter 440, which downconverts the signal from RF to a suitable intermediate frequency (IF) or baseband analog signal. The analog signal may be digitized by an analog-to-digital converter (ADC) 442 that generates a digitized sequence of samples. The digitized samples can be processed by a receiver (Rx) front end 444 that can perform functions such as decimation, automatic gain control (AGC) and / or other adaptive filtering operations. The sample can then be filtered by an Rx pulse shaping filter 446. The Rx pulse shaping filter 446 is a digital filter that can be implemented as an FIR filter. The samples at the output of the Rx pulse shaping filter 446 can be demodulated by a demodulator 448 that reproduces and outputs the data provided to the transmitter 420.

  The spectral responses of Tx pulse shaping filter 426 and Rx pulse shaping filter 446 can significantly affect the performance of communication system 400. For example, the Tx pulse shaping filter 426 limits the spectral bandwidth of the transmitted signal, which often determines the level of adjacent channel interference and other spurious emissions generated by the transmitter 420. When transmitter 420 complies with a particular communication standard, the bandwidth of the transmitted signal is generally specified in that standard, often using a spectral mask that must not be exceeded.

  The Tx pulse shaping filter 426 and the Rx pulse shaping filter 446 must match each other. For example, Tx pulse shaping filter 426 and Rx pulse shaping filter 446 can be implemented such that they each have a root raised cosine (RRC) response and their combined spectral response is a raised cosine (RC) spectral response. obtain. Of course, RRC is given as an example only, and Tx pulse shaping filter 426 and Rx pulse shaping filter 446 need not be implemented such that they each have an RRC response. However, they must have the same response so that the Rx pulse shaping filter 446 matches the Tx pulse shaping filter 426 so as to maximize the signal to noise ratio (SNR).

  Femto cell BS 310, macro cell BS 304, and MS 306a, 306b in system 300 of FIG. 3 may each include a transmitter and receiver configured similarly to transmitter 420 and receiver 422 shown in FIG.

  5 and 6 illustrate one possible technique for reducing adjacent channel interference of the type described above with respect to FIG. In the illustrated approach, the femtocell BS 510 in the wireless communication system 500 utilizes a narrowband Tx pulse shaping filter 550a, while the macro cell BS 504 in the system 500 utilizes a standard Tx pulse shaping filter 526a. The term “narrowband” in this context means that the Tx pulse shaping filter 550a utilized by the femtocell BS 510 is more restrictive than the Tx pulse shaping filter 526a limits the spectral bandwidth of the downlink 514b signal transmitted by the macrocell BS 504. To a greater extent, it means limiting the spectral bandwidth of the downlink 514a signal transmitted by the femtocell BS 510. For example, in one possible implementation, the 3 dB bandwidth of narrowband Tx pulse shaping filter 550a may be 90% of the 3 dB bandwidth of standard Tx pulse shaping filter 526a. However, this value is given merely as an example and should not be used to limit the scope of the present disclosure.

  The MS 506 in the system 500 includes both a narrowband Rx pulse shaping filter 552b that matches the narrowband Tx pulse shaping filter 550a of the femtocell BS510, and a standard Rx pulse shaping filter 546b that matches the standard Tx pulse shaping filter 526a of the macrocell BS504. including.

  The MS 506 includes both a narrowband Tx pulse shaping filter 550b and a standard Tx pulse shaping filter 526b. Narrowband Tx pulse shaping filter 550a has a spectral band of uplink 512a signal transmitted by MS 506 to an extent that the spectral bandwidth of uplink 512b signal transmitted by MS 506 is greater than that limited by standard Tx pulse shaping filter 526b. Limit the width. The femtocell BS 510 includes a narrow band Rx pulse shaping filter 552a that matches the narrow band Tx pulse shaping filter 550b of the MS 506. Macrocell BS 504 includes a standard Rx pulse shaping filter 546a that matches MS 506 standard Rx pulse shaping filter 546b.

  The MS 506 can operate in at least two different configurations. In the first configuration, the MS 506 uses a narrowband Tx pulse shaping filter 550b and a narrowband Rx pulse shaping filter 552b. In the second configuration, the MS 506 uses a standard Tx pulse shaping filter 526b and a standard Rx pulse shaping filter 546b. The MS 506 also includes a switching mechanism 554 for switching between the first configuration and the second configuration.

  FIG. 5 shows the MS 506 located within the femtocell 508. MS 506 is in communication with femtocell BS 510 via uplink 512a and downlink 514a. The MS 506 is the first configuration described above, ie, a narrowband Tx pulse shaping filter 550b (which matches the narrowband Rx pulse shaping filter 552a used by the femtocell BS510) and (used by the femtocell BS510). A narrow band Rx pulse shaping filter 552b (which matches the narrow band Tx pulse shaping filter 550a).

  FIG. 6 shows the MS 506 located outside the femtocell 508 but still located within the macrocell 502. The MS 506 is in communication with the macro cell BS 504 via the uplink 512b and the downlink 514b. The MS 506 is the second configuration described above, ie, a standard Tx pulse shaping filter 526b (which matches the standard Rx pulse shaping filter 546a used by the macro cell BS 504), and a standard Tx pulse shaping (used by the macro cell BS 504). And a standard Rx pulse shaping filter 546b (which matches filter 526a).

  More specifically, referring to FIG. 7, when the MS 506 detects that a handoff from the macro cell BS 504 to the femto cell BS 510 has been performed (756), the MS 506 switches to the narrowband Tx pulse shaping filter 550b (758); It may be possible to switch 760 to the narrowband Rx pulse shaping filter 552b. The MS 506 then uses the narrowband Tx pulse shaping filter 550b to send the transmission to the femtocell BS 510 on the uplink 512a (762) and receives the transmission from the femtocell BS 510 on the downlink 514a. An Rx pulse shaping filter 552b may be used (764).

  Referring now to FIG. 8, when the MS 506 detects that a handoff from the femtocell BS 510 to the macro cell BS 504 has been performed (866), the MS 506 switches to the standard Tx pulse shaping filter 526b (868) and standard Rx pulses. It can be switched 870 to the shaping filter 546b. The MS 506 then uses the standard Tx pulse shaping filter 526b to send the transmission to the macro cell BS 504 on the uplink 512b (872) and receives the transmission from the macro cell BS 504 on the downlink 514b. 546b may be used (874).

  In the above description, it is assumed that the MS 506 detects whether the MS 506 is being served by the macro cell BS 504 or the femto cell BS 510 and the MS 506 automatically switches to the appropriate pulse shaping filter. Alternatively or additionally, when MS 506 is serviced by femtocell BS 510, femto cell BS 510 may instruct MS 506 to switch to narrowband Tx pulse shaping filter 550b and narrowband Rx pulse shaping filter 552b. it can.

  The method 700 of FIG. 7 described above may be performed by various hardware (s) and / or software components and / or modules corresponding to the means plus function block 900 shown in FIG. In other words, the blocks 756 to 764 shown in FIG. 7 correspond to the means plus function blocks 956 to 964 shown in FIG.

  Similarly, the method 800 of FIG. 8 described above may be performed by various hardware (s) and / or software components and / or modules corresponding to the means plus function block 1000 shown in FIG. In other words, the blocks 866 to 874 shown in FIG. 8 correspond to the means plus function blocks 1066 to 1074 shown in FIG.

  FIG. 11 illustrates a system 1100 that is similar to the system 300 described above with respect to FIG. Specifically, FIG. 11 shows a system 1100 in which a first MS 1106a and a second MS 1106b are located in a femto cell 1108 located in a macro cell 1102. Like the system 300 described above with respect to FIG. 3, the first MS 1106a is receiving service from the femtocell BS 1110. The first MS 1106a sends data to the femtocell BS 1110 via the uplink 1112a and receives data from the femtocell BS 1110 via the downlink 1114a. The second MS 1106b is receiving service from the macrocell BS 1104 even though the second MS 1106b is located in the femtocell 1108. The second MS 1106b sends data to the macro cell BS 1104 via the uplink 1112b and receives data from the macro cell BS 1104 via the downlink 1114b.

  In system 300 described above with respect to FIG. 3, femtocell BS 310, macro cell BS 304, and MS 306a, 306b each utilize the same Tx pulse shaping filter 426 and the same Rx pulse shaping filter 446. In contrast, in system 1100 shown in FIG. 11, femtocell BS 1110, macrocell BS 1104, and MS 1106a, 1106b do not utilize the same Tx pulse shaping filter and the same Rx pulse shaping filter.

  The femtocell BS 1110 uses a narrow band Tx pulse shaping filter 1150a, while the macro cell BS 1104 uses a standard Tx pulse shaping filter 1126a. Narrowband Tx pulse shaping filter 1150a receives the downlink 1114a signal transmitted by femtocell BS 1110 to the extent that the spectral bandwidth of downlink signal 1114b transmitted by macrocell BS 1104 is greater than that limited by standard Tx pulse shaping filter 1126a. Limit the spectral bandwidth of. The first MS 1106a matches the narrowband Tx pulse shaping filter 1150a of the femtocell BS 1110 (for use when the first MS 1106a is located in the femtocell 1108 and is receiving service from the femtocell BS 1110) Of the narrowband Rx pulse shaping filter 1152b and the standard Tx pulse shaping filter 1126a of the macro cell BS 1104 (the first MS 1106a is located outside the femto cell 1108 but located within the macro cell 1104 and is served by the macro cell BS 1104) And a standard Rx pulse shaping filter 1146b (for use when receiving). The second MS 1106b includes a standard Rx pulse shaping filter 1146b 'that matches the standard Tx pulse shaping filter 1126a of the macrocell BS 1104.

  The first MS 1106a includes a narrowband Tx pulse shaping filter 1150b (for use when the first MS 1106a is located in the femtocell 1108 and is receiving service from the femtocell BS 1110); The MS 1106a of the MS1106a utilizes both the standard Tx pulse shaping filter 1126b (for use when receiving services from the macrocell BS 1104) located outside the femtocell 1108 but within the macrocell 1104. The second MS 1106b includes a standard Tx pulse shaping filter 1126b '. The narrowband Tx pulse shaping filter 1150b is configured so that the uplink 1112b signal transmitted by the second MS 1106b is more limited than the standard Tx pulse shaping filter 1126b limits the spectral bandwidth of the uplink signal transmitted by the first MS 1106a. Limit the spectral bandwidth of the uplink 1112a signal transmitted by the first MS 1106a to a greater extent than the standard Tx pulse shaping filter 1126b ′ limits. The femtocell BS 1110 includes a narrowband Rx pulse shaping filter 1152a that matches the narrowband Tx pulse shaping filter 1150b of the first MS 1106a. The macrocell BS 1104 includes a standard Rx pulse shaping filter 1146a that matches the standard Tx pulse shaping filter 1126b of the first MS 1106a and the standard Tx pulse shaping filter 1126b 'of the second MS 1106b.

  As with the system 300 described above with respect to FIG. 3, the second MS 1106b may be located relatively close to the femtocell BS 1110. As a result, transmissions from the second MS 1106b on the uplink 1112b to the macro cell BS 1104 may be received at the femtocell BS 1110, thus interfering with transmissions from the first MS 1106a to the femtocell BS 1110 on the uplink 1112a. obtain. If adjacent carriers are used for uplink 1112a, 1112b, this interference may be referred to as adjacent uplink channel interference. However, because the first MS 1106a utilizes a narrowband Tx pulse shaping filter 1150b, the adjacent uplink channel interference that occurs in the system 1100 of FIG. 11 is greater than the adjacent uplink channel interference that occurs in the system 300 of FIG. Can be significantly smaller. Also, the femtocell BS 1110 uses a narrowband Rx pulse shaping filter 1152a, which increases the signal to noise ratio (SNR) for the received signal.

  Similarly, transmissions from the femtocell BS 1110 on the downlink 1114a to the first MS 1106a may be received at the second MS 1106b, thus interfering with transmissions from the macro cell BS 1104 to the second MS 1106b on the downlink 1114b. obtain. If adjacent carriers are used for downlink 1114a, 1114b, this interference may be referred to as adjacent downlink channel interference. However, because the femtocell BS 1110 utilizes a narrowband Tx pulse shaping filter 1150a, the adjacent downlink channel interference that occurs in the system 1100 of FIG. 11 is greater than the adjacent downlink channel interference that occurs in the system 300 of FIG. Can be significantly less. Also, the first MS 1106a uses a narrowband Rx pulse shaping filter 1152b, which increases the SNR for the received signal.

  FIG. 12 illustrates some components that may be included within the wireless device 1201. The wireless device 1201 may be a mobile station or a base station.

  The wireless device 1201 includes a processor 1203. The processor 1203 may be a general purpose single or multi-chip microprocessor (eg, ARM), special purpose microprocessor (eg, digital signal processor (DSP)), microcontroller, programmable gate array, and the like. The processor 1203 may be referred to as a central processing unit (CPU). Although only a single processor 1203 is shown in the wireless device 1201 of FIG. 12, in an alternative configuration, a combination of processors (eg, ARM and DSP) can be used.

  Wireless mobile 1201 also includes memory 1205. Memory 1205 may be any electronic component capable of storing electronic information. The memory 1205 includes a random access memory (RAM), a read-only memory (ROM), a magnetic disk storage medium, an optical storage medium, a flash memory device in the RAM, an on-board memory included in the processor, an EPROM memory, an EEPROM memory, a register, etc. , And combinations thereof.

  Data 1207 and instructions 1209 may be stored in the memory 1205. Instruction 1209 may be executable by processor 1203 to implement the methods disclosed herein. Executing instructions 1209 may include use of data 1207 stored in memory 1205. A certain amount of data 1207a and instructions 1209a may be loaded into the processor 1203.

  Wireless device 1201 may also include a transmitter 1211 and a receiver 1213 to allow transmission and reception of signals between wireless device 1201 and a remote location. Transmitter 1211 and receiver 1213 may be collectively referred to as transceiver 1215.

  If the wireless device 1201 is a mobile station 506, the transmitter 1211 may include both a narrowband Tx pulse shaping filter 550b and a standard Tx pulse shaping filter 526b, and the receiver 1213 may include a narrowband Rx pulse shaping filter 552b. Both standard Rx pulse shaping filters 546b may be included. If the wireless device 1201 is a femtocell base station 510, the transmitter 1211 may include a narrowband Tx pulse shaping filter 550a and the receiver 1213 may include a narrowband Rx pulse shaping filter 552a. If the wireless device 1201 is a macrocell base station 504, the transmitter 1211 may include a standard Tx pulse shaping filter 526a and the receiver 1213 may include a standard Rx pulse shaping filter 546a.

  Antenna 1217 can be electrically coupled to transceiver 1215. The wireless device 1201 may also include multiple transmitters, multiple receivers, multiple transceivers, and / or multiple antennas (not shown).

  The various components of the wireless device 1201 may be coupled together by one or more bus systems that may include a power bus, a control signal bus, a status signal bus, a data bus, etc. For clarity, the various buses are shown as bus system 1219 in FIG.

  The term “processor” should be broadly construed to encompass general purpose processors, central processing units (CPUs), microprocessors, digital signal processors (DSPs), controllers, microcontrollers, state machines, and the like. Under some circumstances, a “processor” may refer to an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), and the like. The term “processor” refers to a combination of processing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors associated with a DSP core, or other such configuration. Can be.

  The term “memory” should be construed broadly to encompass any electronic component capable of storing electronic information. The term memory refers to random access memory (RAM), read only memory (ROM), non-volatile random access memory (NVRAM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable It may refer to various types of processor readable media such as PROM (EEPROM), flash memory, magnetic or optical data storage, registers, and the like. A memory is said to be in electronic communication with a processor if the processor can read information from and / or write information to the memory. Memory that is integral to a processor is in electronic communication with the processor.

  The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement (s). For example, the terms “instructions” and “code” may refer to one or more programs, routines, subroutines, functions, procedures, and the like. “Instructions” and “code” may comprise a single computer-readable statement or a number of computer-readable statements.

  The functions described herein may be implemented in hardware, software, firmware, or combinations thereof. If implemented in software, the functions may be stored on a computer-readable medium as one or more instructions. The term “computer-readable medium” refers to any medium that can be accessed by a computer. By way of example, and not limitation, computer-readable media can be RAM, ROM, EEPROM, CD-ROM, or other optical disk storage device, magnetic disk storage device or other magnetic storage device, or desired program in the form of instructions or data structures. Any other medium that can be used to carry or store the code and that can be accessed by a computer can be provided. In this specification, a disk and a disc are a compact disc (CD), a laser disc (disc), an optical disc (disc), a digital versatile disc (DVD), a floppy (registered). (Trademark) disk and Blu-ray (registered trademark) disk, in which case the disk normally reproduces data magnetically, and the disk optically reproduces the data with a laser. To play.

  Software or instructions may also be transmitted over a transmission medium. For example, the software can use a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology such as infrared, wireless, and microwave, from a website, server, or other remote source When transmitted, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of transmission media.

  The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and / or actions may be interchanged with one another without departing from the scope of the claims. That is, unless a specific order of steps or actions is required for proper operation of the methods described herein, the order and / or use of specific steps and / or actions is within the scope of the claims. Can be corrected without departing from the above.

  Further, modules and / or other suitable means for performing the methods and techniques described herein, such as those illustrated by FIGS. 7 and 8, may be downloaded and / or otherwise obtained by the device. I want to understand what I can do. For example, a device can be coupled to a server to allow transfer of means for performing the methods described herein. Alternatively, the various methods described herein may include storage means (e.g., random access memory) so that the device can acquire various methods when coupling or providing the storage means to the device. (RAM), read-only memory (ROM), physical storage medium such as a compact disc (CD) or floppy disk, etc.). Further, any other suitable technique for providing the devices with the methods and techniques described herein may be utilized.

It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the systems, methods, and apparatus described herein without departing from the scope of the claims.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[C1]
A femtocell base station configured to limit adjacent channel interference comprising:
A transmitter for transmitting a downlink signal to a first mobile station located in the femtocell;
Narrowband transmission pulse configured such that the bandwidth of the downlink signal transmitted by the femtocell base station is smaller than the bandwidth of the downlink signal transmitted by the macrocell base station to the second mobile station Shaping filter and
A femtocell base station.
[C2]
A receiver for receiving an uplink signal from the first mobile station;
A narrowband receive pulse shaping filter that matches the narrowband transmit pulse shaping filter in the first mobile station;
The femtocell base station according to C1, further comprising:
[C3]
The narrowband transmission pulse shaping filter in the first mobile station is configured such that the bandwidth of the uplink signal transmitted by the first mobile station is transmitted to the macro cell base station by the second mobile station. The femtocell base station according to C2, configured to be smaller than a bandwidth of the link signal.
[C4]
The femtocell base station according to C1, wherein a narrowband reception pulse shaping filter in the first mobile station matches the narrowband transmission pulse shaping filter.
[C5]
The femtocell base station according to C1, wherein the macrocell base station covers a macrocell, and the femtocell is located in the macrocell.
[C6]
The femtocell base station according to C1, wherein the second mobile station is also located in the femtocell.
[C7]
A mobile station configured to limit adjacent channel interference comprising:
A transmitter for transmitting an uplink signal;
A transmit pulse shaping filter that limits the bandwidth of the uplink signal transmitted by the mobile station;
A narrowband transmission pulse shaping filter that limits the bandwidth of the uplink signal transmitted by the mobile station to a degree greater than the transmission pulse shaping filter;
A mobile station comprising:
[C8]
The mobile station according to C7, further comprising a switching mechanism for switching between the transmission pulse shaping filter and the narrowband transmission pulse shaping filter.
[C9]
The switching mechanism is configured to switch from the transmission pulse shaping filter to the narrowband transmission pulse shaping filter in response to detecting that a handoff from the macro cell base station to the femto cell base station has been performed. A mobile station according to C8.
[C10]
The switching mechanism is configured to switch from the narrowband transmission pulse shaping filter to the transmission pulse shaping filter in response to detecting that a handoff from the femtocell base station to the macrocell base station has been performed. A mobile station according to C8.
[C11]
A receiver for receiving a downlink signal;
A reception pulse shaping filter that matches the transmission pulse shaping filter in the macrocell base station;
A narrowband receive pulse shaping filter that matches the narrowband transmit pulse shaping filter in a femtocell base station;
The mobile station according to C7, further comprising:
[C12]
The mobile station according to C11, further comprising a switching mechanism for switching between the reception pulse shaping filter and the narrowband reception pulse shaping filter.
[C13]
The switching mechanism is configured to switch from the received pulse shaping filter to the narrowband received pulse shaping filter in response to detecting that a handoff from the macro cell base station to the femto cell base station has been performed. The mobile station according to C12.
[C14]
The switching mechanism is configured to switch from the narrowband received pulse shaping filter to the received pulse shaping filter in response to detecting that a handoff from the femtocell base station to the macro cell base station has been performed. The mobile station according to C12.
[C15]
A method for increasing a signal to noise ratio (SNR) for a received signal and limiting adjacent uplink channel interference, wherein the method is performed by a mobile station, the method comprising:
Detecting a handoff from a macrocell base station to a femtocell base station;
Switching from a receive pulse shaping filter to a narrowband receive pulse shaping filter;
Using the narrowband receive pulse shaping filter to receive a downlink transmission from the femtocell base station;
A method comprising:
[C16]
The method of C15, wherein the narrowband receive pulse shaping filter matches a narrowband transmit pulse shaping filter at the femtocell base station.
[C17]
Switching from a transmit pulse shaping filter to a narrowband transmit pulse shaping filter;
Using the narrowband transmit pulse shaping filter to send an uplink transmission to the femtocell base station;
The method of C15, further comprising:
[C18]
The method of C17, wherein the narrowband transmit pulse shaping filter limits the bandwidth of the uplink transmission to a greater extent than the transmit pulse shaping filter.
[C19]
Detecting that a handoff from the femtocell base station to the macrocell base station has been performed;
Switching from the narrowband received pulse shaping filter to the received pulse shaping filter;
Using the received pulse shaping filter to receive a downlink transmission from the macrocell base station;
The method of C15, further comprising:
[C20]
Switching from a narrowband transmit pulse shaping filter to a transmit pulse shaping filter;
Using the transmit pulse shaping filter to send an uplink transmission to the macrocell base station;
The method of C19, further comprising:
[C21]
An apparatus configured to increase a signal to noise ratio (SNR) for a received signal and limit adjacent uplink channel interference,
Means for detecting that a handoff from the macrocell base station to the femtocell base station has been performed;
Means for switching from a received pulse shaping filter to a narrowband received pulse shaping filter;
Means for using the narrowband receive pulse shaping filter to receive downlink transmissions from the femtocell base station;
An apparatus comprising:
[C22]
The apparatus of C21, wherein the narrowband receive pulse shaping filter matches a narrowband transmit pulse shaping filter at the femtocell base station.
[C23]
Means for switching from a transmission pulse shaping filter to a narrowband transmission pulse shaping filter;
Means for using the narrowband transmit pulse shaping filter to send an uplink transmission to the femtocell base station;
The apparatus according to C21, further comprising:
[C24]
The apparatus of C23, wherein the narrowband transmit pulse shaping filter limits the bandwidth of the uplink transmission to a degree greater than the transmit pulse shaping filter.
[C25]
Means for detecting that a handoff has been performed from the femtocell base station to the macrocell base station;
Means for switching from the narrowband received pulse shaping filter to the received pulse shaping filter;
Means for using the received pulse shaping filter to receive a downlink transmission from the macrocell base station;
The apparatus according to C21, further comprising:
[C26]
Means for switching from a narrowband transmit pulse shaping filter to a transmit pulse shaping filter;
Means for using the transmit pulse shaping filter to send an uplink transmission to the macrocell base station;
The apparatus according to C25, further comprising:
[C27]
A computer program product for increasing signal-to-noise ratio (SNR) for received signals and limiting adjacent uplink channel interference, said computer program product comprising a computer-readable medium having instructions thereon, said instructions But,
A code for detecting a handoff from the macrocell base station to the femtocell base station;
A code for switching from a reception pulse shaping filter to a narrowband reception pulse shaping filter;
A code for using the narrowband receive pulse shaping filter to receive a downlink transmission from the femtocell base station;
A computer program product comprising:
[C28]
A code for switching from a transmission pulse shaping filter to a narrowband transmission pulse shaping filter;
A code for using the narrowband transmit pulse shaping filter to send an uplink transmission to the femtocell base station;
The computer program product according to C27, further comprising:
[C29]
A code for detecting that a handoff from the femtocell base station to the macrocell base station has been performed;
A code for switching from the narrowband received pulse shaping filter to the received pulse shaping filter;
A code for using the received pulse shaping filter to receive a downlink transmission from the macrocell base station;
The computer program product according to C27, further comprising:
[C30]
A code for switching from a narrowband transmission pulse shaping filter to a transmission pulse shaping filter;
A code for using the transmit pulse shaping filter to send an uplink transmission to the macrocell base station;
The computer program product according to C29, further comprising:

Claims (25)

A femtocell base station configured to limit adjacent channel interference comprising:
A transmitter for transmitting a downlink signal to a first mobile station located in the femtocell;
Narrowband transmission pulse configured such that the bandwidth of the downlink signal transmitted by the femtocell base station is smaller than the bandwidth of the downlink signal transmitted by the macrocell base station to the second mobile station Shaping filters ,
A receiver for receiving an uplink signal from the first mobile station;
A femtocell base station comprising: a narrowband reception pulse shaping filter that matches a narrowband transmission pulse shaping filter in the first mobile station. The narrowband transmission pulse shaping filter in the first mobile station is configured such that the bandwidth of the uplink signal transmitted by the first mobile station is transmitted to the macro cell base station by the second mobile station. The femtocell base station according to claim 1 , wherein the femtocell base station is configured to be smaller than a bandwidth of a link signal.   The femtocell base station according to claim 1, wherein the narrowband reception pulse shaping filter in the first mobile station matches the narrowband transmission pulse shaping filter.   The femtocell base station according to claim 1, wherein the macrocell base station covers a macrocell, and the femtocell is located in the macrocell.   The femtocell base station according to claim 1, wherein the second mobile station is also located in the femtocell. A mobile station configured to limit adjacent channel interference comprising:
A transmitter for transmitting an uplink signal;
A transmit pulse shaping filter that limits the bandwidth of the uplink signal transmitted by the mobile station;
A narrowband transmission pulse shaping filter that limits the bandwidth of the uplink signal transmitted by the mobile station to a degree greater than the transmission pulse shaping filter;
A switching mechanism for switching between the transmission pulse shaping filter and the narrowband transmission pulse shaping filter,
The switching mechanism is configured to switch from the transmission pulse shaping filter to the narrowband transmission pulse shaping filter in response to detecting that a handoff from the macro cell base station to the femto cell base station has been performed. , Mobile station. The switching mechanism is configured to switch from the narrowband transmission pulse shaping filter to the transmission pulse shaping filter in response to detecting that a handoff from the femtocell base station to the macrocell base station has been performed. The mobile station according to claim 6 . A receiver for receiving a downlink signal;
A reception pulse shaping filter that matches the transmission pulse shaping filter in the macrocell base station;
The mobile station according to claim 6 , further comprising a narrowband reception pulse shaping filter that matches a narrowband transmission pulse shaping filter in the femtocell base station. The mobile station according to claim 8 , further comprising a switching mechanism for switching between the reception pulse shaping filter and the narrowband reception pulse shaping filter. The switching mechanism is configured to switch from the received pulse shaping filter to the narrowband received pulse shaping filter in response to detecting that a handoff from the macro cell base station to the femto cell base station has been performed. The mobile station according to claim 9 . The switching mechanism is configured to switch from the narrowband received pulse shaping filter to the received pulse shaping filter in response to detecting that a handoff from the femtocell base station to the macro cell base station has been performed. The mobile station according to claim 9 . A method for increasing a signal to noise ratio (SNR) for a received signal and limiting adjacent uplink channel interference, wherein the method is performed by a mobile station, the method comprising:
Detecting a handoff from a macrocell base station to a femtocell base station;
Switching from a reception pulse shaping filter to a narrow band reception pulse shaping filter, which matches the narrow band transmission pulse shaping filter in the femtocell base station ;
Using the narrowband receive pulse shaping filter to receive downlink transmissions from the femtocell base station. Switching from a transmit pulse shaping filter to a narrowband transmit pulse shaping filter;
13. The method of claim 12 , further comprising using the narrowband transmit pulse shaping filter to send an uplink transmission to the femtocell base station. 14. The method of claim 13 , wherein the narrowband transmit pulse shaping filter limits the uplink transmission bandwidth to a greater extent than the transmit pulse shaping filter. Detecting that a handoff from the femtocell base station to the macrocell base station has been performed;
Switching from the narrowband received pulse shaping filter to the received pulse shaping filter;
13. The method of claim 12 , further comprising using the received pulse shaping filter to receive a downlink transmission from the macrocell base station. Switching from a narrowband transmit pulse shaping filter to a transmit pulse shaping filter;
16. The method of claim 15 , further comprising using the transmit pulse shaping filter to send an uplink transmission to the macrocell base station. An apparatus configured to increase a signal to noise ratio (SNR) for a received signal and limit adjacent uplink channel interference,
Means for detecting that a handoff from the macrocell base station to the femtocell base station has been performed;
Means for switching from a received pulse shaping filter to a narrowband received pulse shaping filter , consistent with the narrowband transmitted pulse shaping filter in the femtocell base station ;
Means for using the narrowband receive pulse shaping filter to receive downlink transmissions from the femtocell base station. Means for switching from a transmission pulse shaping filter to a narrowband transmission pulse shaping filter;
18. The apparatus of claim 17 , further comprising means for using the narrowband transmit pulse shaping filter to send an uplink transmission to the femtocell base station. The apparatus of claim 18 , wherein the narrowband transmit pulse shaping filter limits a bandwidth of the uplink transmission to a degree greater than the transmit pulse shaping filter. Means for detecting that a handoff has been performed from the femtocell base station to the macrocell base station;
Means for switching from the narrowband received pulse shaping filter to the received pulse shaping filter;
18. The apparatus of claim 17 , further comprising means for using the received pulse shaping filter to receive a downlink transmission from the macrocell base station. Means for switching from a narrowband transmit pulse shaping filter to a transmit pulse shaping filter;
21. The apparatus of claim 20 , further comprising means for using the transmit pulse shaping filter to send an uplink transmission to the macrocell base station. A computer program product for increasing signal-to-noise ratio (SNR) for received signals and limiting adjacent uplink channel interference, said computer program product comprising a computer-readable medium having instructions thereon, said instructions But,
A code for detecting a handoff from the macrocell base station to the femtocell base station;
A code for switching from the reception pulse shaping filter to the narrow band reception pulse shaping filter, which matches the narrow band transmission pulse shaping filter in the femtocell base station ;
And a code for using the narrowband receive pulse shaping filter to receive a downlink transmission from the femtocell base station. A code for switching from a transmission pulse shaping filter to a narrowband transmission pulse shaping filter;
23. The computer program product of claim 22 , further comprising code for using the narrowband transmit pulse shaping filter to send an uplink transmission to the femtocell base station. A code for detecting that a handoff from the femtocell base station to the macrocell base station has been performed;
A code for switching from the narrowband received pulse shaping filter to the received pulse shaping filter;
23. The computer program product of claim 22 , further comprising code for using the received pulse shaping filter to receive a downlink transmission from the macrocell base station. A code for switching from a narrowband transmission pulse shaping filter to a transmission pulse shaping filter;
25. The computer program product of claim 24 , further comprising code for using the transmit pulse shaping filter to send an uplink transmission to the macrocell base station.

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