Patent Publication Number: US-2007110011-A1

Title: Mobile communication apparatus for operation in a wireless local area network

Description:
TECHNICAL FIELD OF THE INVENTION  
      The present invention relates to a mobile communication apparatus and a method for operation in a wireless local area network.  
     DESCRIPTION OF RELATED ART  
      Many standard protocols for short-range wireless communication in e.g. wireless local area networks (WLAN) are becoming popular. These standard protocols may include protocols such as IEEE 802.11, home RF, Bluetooth, etc. These protocols provide requirements for devices to communicate wirelessly within a local area network. For example, a wireless local area network may be based on a cellular architecture sub-divided into so-called Basic Service Sets (BSS), where each BSS is controlled by an Access Point (AP). The AP may be connected to a Distribution System (DS), which could e.g. be the Ethernet standard IEEE 802.3.  
      Furthermore, it is becoming more and more popular to provide a portable device, such as a mobile telephone or a portable computer, with a WLAN transceiver. Portable devices may, for example, communicate with each other within the wireless local area network according to any of the above-mentioned protocols, e.g. IEEE 802.11, home RF, Bluetooth. Furthermore, a portable device may communicate with a wired network via an AP of the wireless local area network. The maximum transmission length in a wireless local area network may be limited to a range of approximately 10 to 15 meters. Also, the maximum transmission length may in some cases be even more limited when the portable device has a limited output power, such as a mobile telephone. The above-mentioned range is, however, generally less than the coverage range required in places where the WLAN technology is to be utilized. These places include e.g. home environments, office environments and public places such as hotels, cafes, airport lounges, university campuses, etc. As distances in the area of coverage increase, the wireless system performance typically decreases.  
     SUMMARY OF THE INVENTION  
      According to a first aspect, a mobile communication apparatus for operation in a wireless local area network is provided. The mobile communication apparatus comprises a transceiver adapted to communicate data intended for the mobile communication apparatus. Furthermore, the mobile communication apparatus comprises a repeater adapted to receive at least one data packet received by the transceiver, wherein the data packet is intended for another communication device, and forward the data packet via the transceiver to the communication device.  
      The repeater may be adapted to receive the data packet from a first communication device, the data packet being intended for a second communication device, and determine whether the data packet is to be forwarded to the second communication device based on data packets communicated from the first communication device or from the second communication device.  
      The repeater may be adapted to determine whether an identifier comprised in the data packet corresponds to a pre-defined identifier stored in the mobile communication apparatus and determine that the data packet is to be forwarded only if the identifier corresponds to the pre-defined identifier. The repeater may be adapted to determine whether a first data packet received by the repeater corresponds to a second data packet received by the repeater, wherein the first data packet is received prior to the second data packet, and determine that the first data packet or the second data packet is to be forwarded only if the first data packet corresponds to the second data packet. The repeater may be adapted to determine whether a second data packet received by the repeater from the second communication device comprises an ACK message (ACKnowledge message) as a response to a first data packet, wherein the first data packet is received from the first communication device prior to the second data packet, and determine that the first data packet is not to be forwarded if the second data packet comprises the ACK message. The repeater may be adapted to determine whether a second data packet received by the repeater from the second communication device comprises a NACK message (Negative-ACKnowledge message) as a response to a first data packet, wherein the first data packet is received from the first communication device prior to the second data packet, and determine that the first data packet is to be forwarded if the second data packet comprises the NACK message.  
      The mobile communication apparatus may also comprise a power monitoring unit adapted to control the repeater in dependence of a remaining charge of a battery included in the mobile communication apparatus.  
      The mobile communication apparatus may, for example, be a portable or handheld mobile radio communication device, a mobile radio terminal, a mobile telephone, a cellphone, a pager, a communicator, an electronic organizer, a smartphone, a computer, or a portable computer.  
      According to a second aspect, a method performed by a mobile communication apparatus for operation in a wireless local area network is provided. The mobile communication apparatus has a transceiver adapted to communicate data intended for the mobile communication apparatus. The method comprises the steps of receiving by means of a repeater at least one data packet received by the transceiver, wherein the data packet is intended for another communication device, and forwarding the data packet by means of the repeater via the transceiver to the communication device.  
      The step of receiving may comprise receiving the data packet from a first communication device, the data packet being intended for a second communication device, and determining whether the data packet is to be forwarded to the second communication device based on data packets communicated from the first communication device or the second communication device.  
      The step of determining may comprise determining whether an identifier comprised in the data packet corresponds to a pre-defined identifier stored in the mobile communication apparatus, and determining that the data packet is to be forwarded only if the identifier corresponds to the pre-defined identifier. The step of determining may comprise determining whether a first data packet corresponds to a second data packet, wherein the first data packet is received prior to the second data packet, and determining that the first data packet or the second data packet is to be forwarded only if the first data packet corresponds to the second data packet. The step of determining may comprise determining whether a second data packet received from the second communication device comprises an ACK message as a response to a first data packet, wherein the first data packet is received from the first communication device prior to the second data packet, and determining that the first data packet is not to be forwarded if the second data packet comprises the ACK message. The step of determining may comprise determining whether a second data packet received from the second communication device comprises a NACK message as a response to a first data packet, wherein the first data packet is received from the first communication device prior to the second data packet, and determining that the first data packet is to be forwarded if the second data packet comprises the NACK message.  
      The method may also comprise controlling the repeater in dependence of a remaining charge of a battery included in the mobile communication apparatus.  
      According to a third aspect, a computer program product is provided. The computer program product comprises computer program code means for executing the method according to the second aspect, when said computer program code means are run by an electronic device having computer capabilities.  
      According to a fourth aspect, a computer readable medium is provided. The computer readable medium has stored thereon a computer program product comprising computer program code means for executing the method according to the second aspect, when said computer program code means are run by an electronic device having computer capabilities.  
      Further embodiments of the invention are defined in the dependent claims.  
      Embodiments of the invention may allow for an increase of the coverage of a wireless local area network.  
      It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Further objects, features and advantages of embodiments of the invention will appear from the following detailed description, reference being made to the accompanying drawings, in which:  
       FIG. 1  is a schematic view of a local area network including a mobile communication apparatus wirelessly connected to a first and a second communication device;  
       FIG. 2  is a schematic view of a local area network including three mobile communication apparatuses;  
       FIG. 3  is a block diagram illustrating an embodiment of a packet configuration of a data packet;  
       FIG. 4  is a block diagram illustrating some components of an embodiment of a mobile communication apparatus;  
       FIG. 5  is a block diagram illustrating some components of another embodiment of a mobile communication apparatus; and  
       FIG. 6  is a flowchart illustrating an embodiment of a method performed by a mobile communication apparatus for operation in a wireless local area network.  
       FIG. 7  is a flowchart illustrating an embodiment of a method performed by a mobile communication apparatus for operation in a wireless local area network. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       FIG. 1  illustrates a wireless local area network  1  including a mobile communication apparatus  100 . The mobile communication apparatus  100  may be adapted to wirelessly communicate, over a link  102 , with a first communication device  200  according to a short-range wireless communication standard. Also, the mobile communication apparatus  100  may be adapted to wirelessly communicate, over a link  103 , with a second communication device  300  according to a short-range wireless communication standard. Furthermore, a connection  301 , which may be an Ethernet connection, a T1 line, a wideband wireless connection or any other electrical connection providing data communications, may be connected to the second communication device  300 . Moreover, the first communication device  200  may be adapted to wirelessly communicate, over a link  203 , with the second communication device  300  according to a short-range wireless communication standard.  
      In  FIG. 1 , the mobile communication apparatus  100  is exemplified as a mobile telephone. However, for convenience and for simplicity of presentation reference will be made to a mobile communication apparatus  100  in the following. This should not be interpreted restrictively, but rather as an example. The mobile communication apparatus  100  may be a portable or handheld mobile radio communication device, a mobile radio terminal, a cellphone, a pager, a communicator, an electronic organizer, a smartphone, or a portable computer. Furthermore, the first communication device  200  may e.g. be a computer (such as a portable computer) or a mobile telephone. Moreover, the second communication device  300  may be an Access Point (AP).  
      The first and second communication devices  200 ,  300  may be separated at a distance, which is larger than the maximum transmission length in the wireless local area network  1 . Thus, the first communication device  200  and the second communication device  300  may be out-of-range of each other for direct communication over the link  203 . Providing a repeater functionality in the mobile communication apparatus  100  may allow for the first communication device  200  to connect wirelessly to the second communication device  300  via the mobile communication apparatus  100 , even though the first and second communication devices  200  and  300  are out-of-range for direct communication. The mobile communication apparatus  100  is movable and may be located in between the first and the second communication devices  200 ,  300 . Hence, in comparison to the first communication device  200 , the mobile communication apparatus  100  may be located closer to the intended second communication device  300 . Accordingly, the mobile communication apparatus  100  may be in a better position to wirelessly connect to the second communication device  300 . In other words, providing repeater functionality in the mobile communication apparatus  100  may allow for the provision of an operable wireless link  102 - 103  between the first and second communication devices  200 ,  300  via the mobile communication apparatus  100 . Consequently, the mobile communication apparatus  100  equipped with the repeater functionality may allow for an enhancement of the coverage of the wireless local area network  1 .  
      The mobile communication apparatus  100  according to embodiments of the invention comprises a transceiver  110  operatively connected to a repeater  111  ( FIG. 4 ). The transceiver  110  may be adapted to communicate data intended for the mobile communication apparatus  100 . Furthermore, the transceiver  110  is adapted to communicate data packets according to one or several short-range wireless communication standards. The short-range wireless communication standard may e.g. be any IEEE 802.11 standard, such as 802.11b (Wi-Fi) or 802.11g (Wi-Fi), or any Bluetooth standard, such as Bluetooth 1.0. Both IEEE 802.11 standards and Bluetooth standards may be used for wireless short-range communication between any of the mobile communication apparatus  100 , and the first and second communication devices  200  and  300 . The transceiver  110  may be adapted to receive any data packet transmitted from the first communication device  200  intended for the second communication device  300 , or vice versa. The transceiver  110  may also, but does not need to, be configured for communication with a mobile telecommunications network according to any communication technology such as GSM, UMTS, CDMA2000, PDS, or PDC.  
      The repeater  111  is adapted to receive at least one data packet received by the transceiver  110  and forward the data packet via the transceiver  100 . The data packet may be a data packet received from the first communication device  200  and being intended for the second communication device  300 . The repeater  110  may e.g. be adapted to determine whether the data packet is to be forwarded to the second communication device  200  based on the traffic of data packets transmitted from the first communication device  200  to the intended second communication device  300 . Moreover, the repeater  111  may be adapted to forward the data packet via the transceiver  110  to the second communication device  300  if it is determined that the data packet received by the repeater  111  is to be forwarded.  
      Yet further, the repeater  111  may be adapted to repeatedly forward the data packet until the repeater  111  determines that a data packet received by the repeater  111  includes an ACK from the second communication device  300  as a response to the forwarded data packet. For example, when the repeater  111  has determined that a data packet received by the repeater  111  includes an ACK from the second communication device  300  as a response to the forwarded data packet, it may be possible to establish and maintain a wireless connection  102 - 103  between the first and second communication devices  200 ,  300  via the mobile communication apparatus  100 .  
       FIG. 2  illustrates a wireless local area network  2  including three mobile communication apparatuses  100   a,    10   b,    100   c.  Each of the mobile communication apparatuses  10   a,    100   b,    100   c  is adapted to operate in accordance with the description of the mobile communication apparatus  100  hereinabove. It is to be noticed that the respective repeater of the mobile communication apparatuses  100   a,    10   b,    100   c  may be adapted to forward a data packet via the respective transceiver either directly to an intended communication device  200 ,  300  or indirectly to the intended communication device  200 ,  300  via one or several proximate mobile communication apparatuses  100   a,    100   b,    10   c.  Thus, providing repeater functionality in a mobile communication apparatus  100   a,    100   b,    100   c  may allow for the first communication device  200  to connect wirelessly to the second communication device  300  via one or more of the mobile communication apparatuses  100   a,    100   b,    100   c.  This may be accomplished even though the first and second communication devices  200  and  300  are separated by a relatively large distance. Consequently, several mobile communication apparatuses  100   a,    100   b,    100   c  equipped with repeater functionality may allow for an increase of the coverage of the existing wireless local area network  2  over large areas.  
      It should be noticed that a wireless local area network including several mobile communication apparatuses  100  and/or several communication devices  200 ,  300  may require collision handling or a mechanism to either prevent collisions of data packets altogether or to recover from collisions when they do occur. This may, for instance, be accomplished according to known principles in accordance with the short-range wireless communication standard utilized in the wireless local area network.  
       FIG. 3  illustrates an example of a configuration of a data packet that may be communicated between the mobile communication apparatus  100 , the first communication device  200 , and the second communication device  300  in  FIGS. 1 and 2 . For example, the data packet may be part of the ongoing WLAN transactions between the mobile communication apparatus  100 , the first communication device  200 , and the second communication device  300 .  FIG. 3  shows an example of a configuration of a data packet governed by the above-mentioned short-range wireless communication standards. Note, however, that the data packet shown in  FIG. 3  is only one example. It should be appreciated that there are several other data packets embedded in e.g. the 802.11 standard.  
      The data packet  3  may comprise an ID element  31  for identifying the transmitting communication device  100 ,  200 ,  300  of the data packet  3 . The ID element  300  may comprise data concerning a subscriber identity of the transmitting communication device  100 ,  200 ,  300 . Furthermore, the data packet  3  may comprise an address element  32  including information regarding the intended recipient of the data packet  3 . Moreover, the data packet  3  may comprise a length element  33  for indicating the variable length of an information element  34 . The information element  34  includes information. This information may include speech and/or data. Furthermore, the data packet may comprise a data packet status field  35 . The data packet status field  35  may e.g. include data for keeping track of communicated data packets and the corresponding ACKs/NACKs.  
       FIG. 4  illustrates certain components, which may be integrated in a mobile communication apparatus  100  described above with reference to  FIGS. 1 and 2 . The mobile communication apparatus comprises a transceiver  110  operatively connected to a repeater  111 . The transceiver may be operatively connected to an antenna  112 . The repeater  111  may comprise a memory device  113 . Moreover, the repeater  111  may be operatively connected to a processor  114 , which may e.g. be a Central Processing Unit (CPU). The processor  114  may be operatively connected to the transceiver  110 . Furthermore, the processor may be operatively connected to a memory unit  115 . The repeater  111  and the processor  114  are shown as separate units in  FIG. 4 . However, a CPU could alternatively provide the repeater  111  by running software designed for performing the functions of the repeater  111 .  
      The transceiver  110  may be configured to include an 802.11-transceiver. Additionally, or alternatively, the transceiver  110  may be configured to include a Bluetooth transceiver. The transceiver  110  may thus be adapted to communicate data packets ( FIG. 3 ), via the antenna  112 , according to one or more of the short-range wireless communication standards mentioned above, e.g. IEEE 802.11 standards or Bluetooth standards. The transceiver  110  may be adapted to listen to or sense the traffic of data packets transmitted from the first and second communication devices  200  and  300  ( FIG. 1 ). Accordingly, the transceiver  110  may be adapted to detect any data packets that are transmitted between the first and second communication devices  200  and  300 . Furthermore, the transceiver  110  is adapted to receive any data packets from the first communication device  200  intended for the second communication device  300 . Similarly, the transceiver  110  is adapted to receive any data packets from the second communication device  300  that are intended for the first communication device  200 .  
      The transceiver  110  is operatively connected to the repeater  111 . The repeater  111  may be adapted to receive at least one data packet received by the transceiver  110 . Consequently, the repeater  111  may be adapted to receive any data packet from the first communication device  200  intended for the second communication device  300 , or vice versa. Furthermore, the repeater  111  may comprise a memory device  113  for temporarily storing any received data packet. The memory device  113  may be adapted to only store data packets intended for use of the repeater  111 . Data intended for the mobile communication apparatus  100  itself may be stored in another memory unit, e.g. memory unit  115 , of the mobile communication apparatus  100 . Providing a memory device  113  within the repeater  111  in which only content not intended for the mobile communication apparatus  100  may be stored may e.g. allow for a mobile communication apparatus  100  with low risk for intrusion of e.g. viruses.  
      Furthermore, the repeater  111  may be adapted to forward the at least one received data packet via the transceiver  110 . The forwarding of the at least one data packet may comprise repeating or re-generating the at least one received data packet. The repeater  111  may be adapted to determine whether any received data packet is to be forwarded. For example, the repeater  111  may be adapted to receive from the first communication device  200  a data packet intended for the second communication device  300 , and determine whether this data packet is to be forwarded to the intended second communication device  300  based on data packets communicated from the first communication device  200  or from the second communication device  300 .  
      The determination of whether any received data packet is to be forwarded or not performed by the repeater  111  may be accomplished in different ways. In one embodiment, the repeater  111  is adapted to determine whether the ID element  31  of a received data packet  3  corresponds to a pre-defined ID element. The pre-defined ID element may be pre-loaded or stored in the memory device  113  of the repeater  111 . Alternatively, a pre-defined ID element may be pre-loaded or stored in another memory unit, e.g. memory unit  115 , comprised in the mobile communication apparatus  100 . The repeater  111  may be adapted to determine that a received data packet is to be forwarded only when it is determined that the ID element  31  of the received data packet corresponds to a pre-defined ID element. Thus, the repeater  111  may be adapted to selectively forward data packets to an intended communication device  200 ,  300 . This may e.g. allow for the user of a mobile communication apparatus  100  to pre-define rules for which data packets to forward. As one example, in a home environment the user could select that only data packets from communication devices authorized by the user should be forwarded. As another example, in an office environment the user could authorize that only data packets from communication devices managed by colleagues in the user&#39;s organization should be forwarded. Having pre-defined rules for which data packets to forward may allow for minimizing the total traffic of data packets within a local area network. Furthermore, this may allow for reducing the total power consumption necessary for forwarding data packets.  
      In an embodiment, the repeater  111  is adapted to determine whether a first data packet received by the repeater  111  corresponds to a second data packet received by the repeater  111 , where the first data packet is received prior to the second data packet. In this embodiment, the repeater  111  may thus be adapted to compare two data packets received at different instants of time. The repeater  111  may be adapted to determine that the first data packet or the second data packet is to be forwarded only if the first data packet corresponds to the second data packet. The repeater  111  may thus be adapted to forward data packets to an intended communication device only when necessary. For example, if the first communication device  200  retries to send the same data packet one or more times for establishing a wireless link with the second communication device  300 , the repeater  111  according to this embodiment may be capable of determining that corresponding data packets have been transmitted to the intended second communication device  300  several times. Accordingly, the repeater  111  may receive at least a first data packet and a second data packet, respectively. The first and the second data packet would be identical. Then, the repeater  111  would be capable of determining that the first data packet corresponds to the second data packet. Hence, the first data packet or the second data packet would be forwarded to the intended second communication device  300 . The forwarding of the first data packet or the second data packet may e.g. be accomplished after a pre-defined number of retries by the first communication device  200 . Forwarding a data packet only when the first communication device  200  has retried to connect wirelessly to an intended second communication device  300  one or more times may allow for minimizing the total traffic of data packets within a local area network.  
      In an embodiment, the repeater  111  is adapted to determine whether a second data packet received by the repeater comprises an ACK from the second communication device  300  as a response to a first data packet. Note that the first data packet is received from the first communication device  200  before the second data packet is received from the second communication device  300 . Furthermore, in this embodiment the repeater  111  is adapted to determine that the first data packet is not to be forwarded if the second data packet comprises the ACK. In other words, the repeater  111  is adapted to refrain from forwarding an initially received data packet received from the first communication device  200  if it is determined that a subsequent data packet received later from the second communication device  300  comprises an ACK as a response to the initially received data packet. For example, if the first communication device  200  receives a data packet comprising an ACK from the second communication device  300  it is determined that the first communication device  200  may establish and maintain a wireless link with the second communication device  300 . Thus, it is not necessary forward any received data packet. Similar to the previous embodiment, this embodiment may allow for the provision of a mobile communication apparatus  100  that is adapted to forward data packets to an intended communication device only when necessary.  
      In an embodiment, the repeater  111  is adapted to determine whether a second data packet received by the repeater comprises an NACK from the second communication device  300  as a response to a first data packet. Note that the first data packet is received from the first communication device  200  before the second data packet is received from the second communication device  300 . Furthermore, in this embodiment the repeater  111  is adapted to determine that the first data packet is to be forwarded if the second data packet comprises the NACK. For example, if the first communication device  200  has been successful in establishing a wireless connection over link  203  with the second communication device  300  (FIG.  1 ), the wireless connection  203  may even so be relatively bad, for example, due to the fact that the first and second communication devices  200 ,  300  are separated are separated from each other at a distance which is substantially equal to or slightly above the maximum transmission length in the wireless local area. In this example, the second communication device  300  would transmit a NACK message to the first communication device  200 , thus informing the first communication device  200  that the wireless connection is relatively bad. When the repeater  111  receives the NACK from the second communication device  300  as a response to the first data packet, the repeater is capable of determining that the earlier received first data packet should be forwarded to the intended second communication device. Compared to the first communication device  200 , the mobile communication apparatus  100  may be located closer to the intended second communication device  300 . Thus, the mobile communication apparatus  100  may be in a better position to wirelessly connect to the second communication device  300 .  
       FIG. 5  illustrates another embodiment of the mobile communication apparatus  100 . Besides what is described below with reference to  FIG. 5 , the elements of  FIG. 5  having corresponding reference signs in  FIG. 4  may operate and interact similarly to the description with reference to  FIG. 4 . The mobile communication apparatus  100  of  FIG. 5  differs from the mobile communication apparatus  100  described with reference to.  FIG. 4  in that it further includes a power monitoring unit  516 . The power monitoring unit  516  may be configured to monitor the remaining charge of a battery (not shown) included in the mobile communication apparatus  100 . The obtaining of the remaining charge of the battery may be accomplished according to known principles and will not be further explained here. As is illustrated in  FIG. 5 , the repeater  111  may be operatively connected to the power monitoring unit  516 . The power monitoring unit  516  may be adapted to control the repeater  111  in dependence of the remaining charge of the battery. Thus, forwarding of a data packet may e.g. be performed only when the remaining charge of the battery is above a certain pre-defined level. Forwarding any received data packet to an intended communication device only when the remaining power in the battery is over a pre-defined value may provide for the avoidance of draining the battery.  
       FIG. 6  illustrates an embodiment of a method performed by a mobile communication apparatus  100  suitable for operation in a wireless local area network. The mobile communication apparatus  100  comprises a transceiver  110  adapted to communicate data intended for the mobile communication apparatus  100 . In step  601 , a first initial data packet that has been received by the transceiver  110  is received by means of a repeater  111  of the mobile communication apparatus. The initial data packet may e.g. be received from a first communication device  200  and being intended for a second communication device  300 . In step  602 , it is determined whether the initially received data packet is to be forwarded to the second communication device  300  or not. The determination in step  602  may be based on data packets communicated from the first communication device  200  or from the second communication device  300 .  
      In step  602   a,  it is determined whether an identifier comprised in the initially received data packet corresponds to a pre-defined identifier that is stored in the mobile communication apparatus  100 . If the identifier comprised in the received data packet does not correspond to a pre-defined identifier, the procedure is ended. If the identifier comprised in the received data packet corresponds to a pre-defined identifier, the procedure proceeds to step  602   b.  In step  602   b,  it is determined whether a second data packet comprises an ACK from the second communication device  300  as a response to the initial data packet. It is to be noted that the initial data packet is received from the first communication device  200  before the second data packet is received from the second communication device  300 . If it is determined that the second data packet comprises the ACK it is also determined that the initial data packet is not to be forwarded to the second communication device. If so, the procedure is ended. If it is determined that the second data packet does not comprise any ACX, the procedure proceeds to step  602   c.  In step  602   c,  it is determined whether the initial data packet corresponds to a second data packet, wherein the initial data packet has been received prior to the second data packet. Hence, the initially received data packet is compared with another data packet received later. In step  602   c,  it may also be determined that the initial data packet is to be forwarded only if the initially received data packet corresponds to another data packet that has been received later. If the initially received data packet does not correspond to another data packet that has been received later, the procedure is ended. However, if it is determined in step  602   c  that the initial data packet is to be forwarded, the procedure proceeds to step  603 . In step  603 , the initial data packet may be forwarded by means of the repeater  111  via the transceiver  110  to the second communication device  300 . In one embodiment, the step of forwarding in step  603  may be performed in dependence of the remaining charge of a battery included in the mobile communication apparatus.  
      Not all steps illustrated in  FIG. 6  are necessary for carrying out the method according to embodiments of the invention. For example, step  602   a  is not necessary in all embodiments as the determination of whether a received data packet is to be forwarded may e.g. be applied by one or more of the steps  602   b  and  602   c  without carrying out step  602   a.  It should be appreciated that the method steps  602   a,    602   b,  and  602   c,  respectively, may be varied in different combinations for carrying out the determination of whether a received data packet is to be forwarded.  
       FIG. 7  illustrates an embodiment of a method performed by a mobile communication apparatus  100  suitable for operation in a wireless local area network. Besides what is described below with reference to  FIG. 7 , the steps of  FIG. 7  having corresponding reference signs in  FIG. 6  may be carried out similarly to the description with reference to  FIG. 6 . The method shown in  FIG. 7  differs from the method described with reference to  FIG. 6  in that it includes a step  702   d.  In step  702   d,  it is determined whether a second data packet comprises a NACK from the second communication device  300  as a response to the initial data packet, whereby the initial data packet has been received from the first communication device  200  before the second data packet is received from the second communication device  300 . If it is determined that the second data packet comprises the NACK, the procedure may continue to step  603 . If it is determined that the second data packet does not comprise the NACK, the procedure may continue to step  602   c.    
      Not all steps illustrated in  FIG. 7  are necessary for carrying out the method according to embodiments of the invention. For example, step  602   a  is not necessary in all embodiments as the determination of whether a received data packet is to be forwarded may e.g. be applied by one or more of the steps  702   d  and  602   c  without carrying out step  602   a.  It should be appreciated that the method steps  602   a,    702   d,  and  602   c  may be varied in different combinations for carrying out the determination of whether a received data packet is to be forwarded.  
      The present invention may be embedded in a computer program product, which enables implementation of the method and functions described herein. The invention may be carried out when the computer program product is loaded and run in a system having computer capabilities. Computer program, software program, program product, or software, in the present context mean any expression, in any programming language, code or notation, of a set of instructions intended to cause a system having a processing capability to perform a particular function directly or after conversion to another language, code or notation.  
      Embodiments of the present invention may allow for an extension of an existing wireless local area network. A mobile communication apparatus, such as a mobile telephone, equipped with a repeater according to embodiments of the invention may hence extend the range of an existing wireless local area network. Furthermore, implementing a repeater into the mobile communication apparatus  100  may allow for utilizing the existing transceiver of the mobile communication apparatus  100 . The additional manufacturing costs of implementing the repeater in the mobile communication apparatus  100  may be relatively low. Furthermore, a synergy effect can be obtained in that the mobile communication apparatus  100  can be used not only for its specific purpose but also at the same time act as an extension of an existing wireless local area network. Moreover, a repeater implemented in a mobile communication apparatus may allow for a temporary extension of an existing wireless local area network. The functionality of the repeater may be used in mobile communication apparatuses for operation in a wireless local area network in e.g. a public place, etc. When several mobile communication apparatus having repeater functionality according to embodiments of the invention are located in such a public place, they may together allow for the provision of a virtual wireless local area network by forwarding data packets to each other. This may allow for an extension of the existing wireless local area network over large areas. Moreover, embodiments of the invention may allow for the extension of an existing wireless local area network without installing additional access points. Accordingly, no additional network investment is required for extending the range of the wireless local area network.  
      The present invention has been described above with reference to specific embodiments. However, other embodiments than the above described are equally possible within the scope of the invention. Different method steps than those described above, performing the method by hardware or software or a combination of hardware and software, may be provided within the scope of the invention. The different features and steps of the invention may be combined in other combinations than those described. The scope of the invention is only limited by the appended patent claims.