Abstract:
To provide high-data-rate wireless communication in both directions between a pair of nodes, the present invention provides for operating at least two asymmetric wireless connections in parallel but in reverse directions between the nodes. One of the asymmetric wireless connections will provide a high-data-rate forward link in one direction between the nodes, while the other asymmetric wireless connection will concurrently provide a high-data-rate forward link in the other direction between the nodes. The lower-data-rate reverse links provided by the asymmetric wireless connections can then be used to carry overhead control data or can be used to supplement the primary high-data-rate communication provided by the forward links. Preferably, 1xEV-DO will be used for both asymmetric wireless data links, but other asymmetric air interface protocols could be used instead.

Description:
FIELD OF THE INVENTION 
     The present invention relates to wireless communications and more particularly to providing high speed wireless data communication. The invention can be usefully employed to provide improved wireless backhaul communication between a pair of network nodes. 
     BACKGROUND 
     In a typical cellular radio communications system (wireless communication system), an area is divided geographically into a number of cell sites and sectors, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS) antenna. The base station antennae in the cells are in turn coupled to a base station controller (BSC), which is then coupled to a telecommunications switch or gateway, such as a mobile switching center (MSC) or packet data serving node (PDSN) for instance. The switch or gateway may then be coupled with a transport network, such as the Public Switched Telephone Network (PSTN) or a packet-switched network (e.g., the Internet). 
     When a mobile station (i.e., any wirelessly equipped client device (whether movable or in fixed position), such as a cellular telephone, pager, or appropriately equipped portable computer or personal digital assistant, for instance) is positioned in a cell, the mobile station communicates via an RF air interface with the BTS antenna of the cell. Consequently, a communication path can be established between the mobile station and the transport network, via the air interface, the BTS, the BSC and the switch or gateway. 
     Data communications over the air interface between a mobile station and a base station generally proceed according to a designated air interface protocol, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), or any other air interface protocol now known or later developed. Air interface communications from the base station to the mobile station constitute “forward link” or “downlink” communications, while those from the mobile station to the base station constitute “reverse link” or “uplink” communications. 
     The speed or rate at which data is transmitted between a base station and a mobile station can vary from protocol to protocol and can further vary based on a number of factors, such as propagation loss, building and landscape obstructions, and multi-path fading for instance. 
     Certain air interface protocols provide for largely symmetric communication between a base station and a mobile station, in that the data rate provided on the forward link is substantially similar to the data rate provided on the reverse link. CDMA 1xRTT (1xRTT) is an example of such a symmetric protocol. 
     As defined by well known industry standards such as IS-2000 for instance, 1xRTT allows multiple mobile stations in a cell sector to communicate on the same frequency and at the same time as each other. Communications between the base station and a given mobile station are distinguished from those between the base station and other mobile stations by modulating the communications with one or more codes unique to the mobile station. Each forward link traffic channel, for instance, is defined in part by modulating with a “Walsh Code” assigned for use by the mobile station. And each reverse link traffic channel is defined in part by modulating with a “long code” associated with the mobile station. Fundamental traffic channels under 1xRTT generally support up to 9.6 kbps or 14.4 kbps respectively on both the forward link and reverse link, although supplemental traffic channels can also be used (on both the forward link and reverse link) to moderately increase the data rate. 
     Other air interface protocols, in contrast, provide for largely asymmetric communication of data, by providing a substantially higher data rate on the forward link than on the reverse link. Such air interface protocols leverage the fact that, with most IP traffic, the forward link carries a heavier load than the reverse link (as users tend to download far more than they upload). CDMA 1xEV-DO (EV-DO) is an example of such an asymmetric protocol. 
     In a EV-DO system, as defined by well known industry standard IS-856 for instance, the forward link uses time division multiplexing, in order to allocate all of the transmission power in a sector to a given mobile station at any moment, while the reverse link retains largely the traditional 1xRTT code division multiplexing format, albeit with the addition of a “data rate control” (DRC) channel used to indicate the supportable data rate and best serving sector for the forward link. The end result is that an EV-DO forward link data rate can theoretically support from 38.4 kbps to 3.1 Mbps, while the EV-DO reverse link is limited to the lower data rate more typically provided by 1xRTT. In addition, EV-DO provides an “always on” connection, in which a mobile station can quickly engage in wireless data communications. This “always on” connection mode, combined with EV-DO&#39;s high speed forward link, makes EV-DO an attractive alternative to more traditional wireline data communications. 
     While wireless data communications are most often used to facilitate communication between end-user devices (such as cell phones) and base stations, the industry has also recognized that wireless data communications can be advantageously used to provide wireless backhaul communications between network components. By way of example, rather than incurring the expense of installing and maintaining a T1 line or other landline connection extending from a BSC to a BTS, a wireless carrier can set up a wireless data connection such as a 1xRTT or EV-DO connection from the BSC to the BTS. To do so, the wireless carrier may equip the BSC with an antenna and circuitry to function largely like a base station, and the carrier may equip the BTS with circuitry (and another antenna, if necessary) to function largely like a mobile station (albeit fixed). Backhaul data (including bearer traffic and overhead control data) can then flow wirelessly between the BSC and the BTS. Similarly, a wireless backhaul connection can be provided to extend coverage from a BTS out to a remote BTS or distributed antenna system (DAS), by setting up the remote BTS or DAS to function largely like a mobile station so as to receive data wirelessly from the serving BTS. 
     SUMMARY 
     The present invention stems from a realization that, in certain situations, it would be desirable to provide high data rate wireless communications bi-directionally between a pair of nodes. 
     A prime example of such a situation is where backhaul data needs to be carried bi-directionally between an aircraft and a ground base station, to support use of cell phones or other mobile stations within the aircraft. As envisioned by the industry, to provide aircraft-based cellular communication service, a wireless transceiver may be mounted to the belly of an airplane and set to interface (i) with a “pico-BTS” within the aircraft or directly with mobile stations within the aircraft and (ii) wirelessly with conventional ground-based BTSs. In practice, the transceiver could then receive data transmitted by aircraft-based mobile stations and forward that data over the air interface to a currently-serving ground-based BTS, and the transceiver could similarly receive data over the air interface from the ground-based BTS and forward that data into the aircraft for receipt by one or more mobile stations. 
     Another, analogous situation is where backhaul data needs to be carried between a BTS and a remotely located DAS (which may essentially include a pico-BTS). Like the scenario described above, a wireless transceiver can be provided at the DAS and can be set to interface (i) with the DAS or directly with mobile stations served by the DAS and (ii) over an air interface with the serving BTS. That way, the transceiver can receive data transmitted by DAS-based mobile stations and forward that data over the air interface to the serving BTS, and the transceiver can similarly receive data over the air interface from the serving BTS and forward that data into the DAS for receipt by one or more mobile stations. 
     Unfortunately, existing symmetric air interface protocols such as 1xRTT can be too restrictive for this type of application, because such protocols typically provide a relatively low data rate on both the forward and reverse links. On the other hand, asymmetric air interface protocols such as EV-DO are also restrictive for this type of application, because such protocols are, by their very nature, designed to provide high data rate communications on only the forward link and to provide a relative low data rate on the reverse link. 
     To provide high-data-rate wireless communication in both directions between a pair of nodes, the present invention provides for operating at least two asymmetric wireless connections in parallel but in reverse directions between the nodes. One of the asymmetric wireless connections will provide a high-data-rate forward link in one direction between the nodes, while the other asymmetric wireless connection will concurrently provide a high-data-rate forward link in the other direction between the nodes. The lower-data-rate links provided by the asymmetric wireless connections can then be used to carry overhead control data or can be used to supplement the primary high-data-rate communication provided by the forward links. 
     An exemplary embodiment of the invention may thus take the form of a method that includes (i) providing a first asymmetric wireless data link between a first node and a second node, the first asymmetric wireless data link defining a first high-data-rate link extending from the first node to the second node and a first low-data-rate link extending from the second node to the first node, (ii) providing a second asymmetric wireless data link between the second node and the first node, the second asymmetric wireless data link defining a second high-data-rate link extending from the second node to the first node and a second low-data-rate link extending from the first node to the second node, and (iii) concurrently operating the first asymmetric wireless data link and the second asymmetric wireless data link so as to provide bi-directional high-data-rate wireless communication between the first node and the second node. 
     In another respect, the exemplary embodiment can take the form of a method that includes (i) providing a first asymmetric wireless data link between a first node and a second node, the first asymmetric wireless data link defining a first link that extends from the first node to the second node and a second link that extends from the second node to the first node, the first link defining a higher data rate than the second link, (ii) providing a second asymmetric wireless data link between the second node and the first node, the second asymmetric wireless data link defining a third link that extends from the second node to the first node and a fourth link that extends from the first node to the second node, the third link defining a higher data rate than the fourth link, and (iii) concurrently operating the first asymmetric wireless data link and the second asymmetric wireless data link so as to provide bi-directional high-data-rate wireless communication between the first node and the second node. 
     Further, in another respect, the exemplary embodiment can take the form of a bi-directional wireless data communication system that includes (i) a first node having a first cell-site-modem and a first mobile-station-modem and (ii) a second node having a second cell-site-modem and a second mobile-station-modem. Oppositely directed asymmetric wireless data links are then provided between the first node and the second node. In particular, the first cell-site-modem is arranged to send data to the second mobile-station-modem via a first wireless data link, and the second mobile-station-modem is arranged to send data to the first cell-site-modem via a second wireless data link, with the first wireless data link defining a higher data rate than the second wireless data link. In addition, the second cell-site-modem is arranged to send data to the first mobile-station-modem via a third wireless data link, and the first mobile-station-modem is arranged to send data to the second cell site modem via a fourth wireless data link, with the third wireless data link defining a higher data rate than the fourth wireless data link. 
     These as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings. Further, it should be understood that this summary and the description provided below are intended to describe the claimed invention by way of example only. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is block diagram of a communication arranged to operate in accordance with the exemplary embodiment. 
         FIG. 2  is a block diagram depicting cell site modems and mobile station modems set to establish dual asymmetric wireless data links in accordance with the exemplary embodiment. 
         FIG. 3  is a block diagram of a cellular wireless communication system arranged to support wireless packet data communications. 
         FIG. 4  is an illustration depicting use of dual asymmetric wireless data links to extend high speed wireless service to mobile stations in an aircraft. 
         FIG. 5  is an illustration depicting use of dual asymmetric wireless data links to extend high speed wireless service to mobile stations in a distributed antenna system. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings,  FIG. 1  is a generalized block diagram depicting a communication system set to operate in accordance with the exemplary embodiment. As shown in  FIG. 1 , the communication system includes two nodes  12 ,  14 , which are to engage in bi-directional wireless data communication. (As used herein, the term “data communication” can refer to communication of non-real-time data or alternatively to communication of data representing real-time media such as voice or video.) Two asymmetric wireless data connections  16 ,  18  are then provided between these nodes. Asymmetric wireless data connection  16  provides a high-data-rate forward link  20  from node  12  to node  14  and a low-data-rate reverse link  22  from node  14  to node  12 . Asymmetric wireless data connection  18 , on the other hand, provides a high-data-rate forward link  24  from node  14  to node  12  and a low-data-rate reverse link  26  from node  12  to node  14 . 
     With this arrangement, nodes  12  and  14  can engage in bi-directional high-data-rate wireless communication with each other, with forward link  20  providing high-data-rate communication from node  12  to node  14 , and forward link  24  providing high-data-rate communication from node  14  to node  12 . Preferably, the high-data-rate on forward link  20  will be substantially the same as the high-data-rate on forward link  24 , by employing the same air interface protocol for both asymmetric wireless data connections. However, the forward link data rates can differ from each other. In any event, by definition, the forward link of each asymmetric wireless data connection will provide for higher speed data communication than the corresponding reverse link of that connection. 
     In the preferred embodiment, the forward links of the respective asymmetric wireless data connections can be used to carry the bulk of data communications bi-directionally between nodes  12  and  14 . The reverse links of the asymmetric wireless data connections can then be used to supplement the forward link data communications, such as to carry overhead control data. For instance, reverse link  22  of asymmetric wireless data connection  16  can be used to supplement data communications on forward link  20  from node  14  to node  12 . Similarly, reverse link  26  of asymmetric wireless data connection  18  can be used to supplement data communications on forward link  24  from node  12  to node  14 . Circuitry and/or program logic at the nodes can be programmed to send certain data on a forward link and to send other data on the reverse link. Which data is sent on which link is a matter of design choice. 
     To provide the arrangement of  FIG. 1  in practice, each of nodes  12  and  14  can be equipped to function both as a base station (wireless server) and as a mobile station (wireless client). In this regard, a conventional mobile station is commonly equipped with a “mobile station modem” chipset such as one of the various “MSM” chipsets available from Qualcomm Incorporated, and a base station is commonly equipped with a “cell site modem” chipset such as one of the various “CSM” chipsets available from Qualcom Incorporated. In a manner well known in the art, the mobile station modem and cell site modem chipsets, together with other circuitry and antennas, enable a mobile station and base station to engage in air interface communication with each other according to a designated air interface protocol. As presently contemplated, in order to make each of nodes node  12  and  14  function as both a base station and a mobile station, each node can be equipped with both a cell site modem and a mobile station modem. This arrangement is illustrated generally by  FIG. 2 . 
     As shown in  FIG. 2 , node  12  is equipped with a cell site modem  28  and a mobile station modem  30 , and node  14  is equipped with a cell site modem  32  and a mobile station modem  34 . With this arrangement, cell site modem  28  and mobile station modem  34  will communicate with each other to define asymmetric wireless data connection  16 , providing high-data-rate forward link  20  from node  12  to node  14  and low-data-rate reverse link  22  from node  14  to node  12 . Further, cell site modem  32  and mobile station modem  30  will communicate with each other to define asymmetric wireless data connection  18 , providing high-data-rate forward link  24  from node  14  to node  12 , and low-data-rate reverse link  26  from node  12  to node  14 . 
     The bulk of useful data communications in this arrangement will preferably occur over the forward links provided between the nodes. To facilitate this, each node will include control circuitry (not shown) such as a programmed microprocessor or a DSP, that will pass outgoing data communications to the node&#39;s cell site modem for transmission to the other node and that will receive incoming data communications transmitted to the node&#39;s mobile station modem from the other node. Each node&#39;s control circuitry can further provide for exchange of supplemental data, such as overhead control information for instance, over the respective reverse links, receiving such data via the reverse link into its cell site modem, and transmitting such data via the reverse link from its mobile station modem. 
     The asymmetric air interface protocol used for connection  16  and connection  18  can be any asymmetric air interface protocol desired, including any now known or later developed. Further, the asymmetric air interface protocol used for connection  16  can differ from that used for connection  18 . In a preferred embodiment, however, both connections will use the well known EV-DO protocol, which has been defined by TIA/EIA IS-856 and is also known as the “high rate packet data (HRPD) system.” Thus, both cell site modems  28 ,  32  will be cell site modems arranged to support EV-DO communication, and both mobile station modems  30 ,  34  will be mobile station modems arranged to support EV-DO communications. By way of example, each cell site modem can be a Qualcomm CSM6800™ chipset, and each mobile station modem can be an MSM6800™ chipset. Both the CSM6800™ chipset and MSM6800™ chipset have EV-DO operating modes (e.g., 1xEV-DO Rev. 0 or Rev. A), and each chipset can be programmatically set to operate in that mode. 
     Under EV-DO, as noted above, the forward link uses time division multiplexing (TDM) in order to allocate all of the sector&#39;s forward link power to a given mobile station at any given moment, while the reverse link retains the code division multiplexing (CDM) format of 1xRTT, albeit with the addition of a “data rate control” (DRC) channel used to indicate the supportable data rate and best serving sector for the forward link. 
     The EV-DO forward link is divided into time slots of length 2048 chips, and each time slot is further time division multiplexed to carry various channels, including a pilot channel, a Medium Access Control (MAC) channel, and, if any traffic exists, a forward traffic channel and a “control” channel. Each EV-DO sector is further defined by a PN offset, and the pilot channel carries an indication of the sector&#39;s PN offset. A mobile station operating under EV-DO monitors the pilot signal emitted by various sectors as a basis to facilitate handoff from one sector to another. 
     With EV-DO, a mobile station communicates with the network on just a single “best” sector at any given time. Generally, the mobile station will maintain an “active set” list of sectors and will monitor the strength of pilot signals received from the active set sectors. The mobile station will then select the “best” of those sectors, typically the sector having the strongest detected pilot strength, and the mobile station will then include an indication of that sector in its DRC on the reverse link. Only that sector will then serve the mobile station with forward link packets. 
       FIG. 3  is a simplified block diagram of a typical network arranged to implement EV-DO. As a basic matter, in the arrangement of  FIG. 3 , a mobile station  40  communicates over an air interface  42  with a BTS  44 , which is then coupled or integrated with a BSC  46 . (The BTS and BSC may be referred to separately or in combination as a “base station.”) BSC  46  is coupled with a PDSN  48 , which provides connectivity with a packet-switched network  50  such as the Internet and/or a wireless carrier&#39;s private core packet-network. In a typical arrangement, sitting as nodes on network  50  may then be a remote computer  52 , an authentication, authorization, and accounting (AAA) server  54 , and a mobile-IP home agent (HA)  56 . In basic operation, after the mobile station  40  is authenticated by AAA server  54 , HA  56  may assign an IP address for use by the mobile station  12 , and the mobile station  12  may then engage in packet-data communications with entities such as remote computer  52 , via a communication path comprising air interface  42 , BTS  44 , BSC  46 , PDSN  48 , and network  50 . 
     In operation, when a mobile station enters the coverage area of an EV-DO base station, the mobile station will detect a pilot signal emitted by the base station. In response, the mobile station will then transmit on the reverse link to the base station a Universal Access Terminal Identifier (UATI) request. In response to the UATI request, the BSC will then transmit on the forward link to the mobile station an International Mobile Station Identifier (IMSI), which the mobile station can then use to identify itself in subsequent communications with the BSC. In turn, the mobile station will then send a EV-DO Connection-Request to the base station, and the base station will responsively invoke a process to authenticate the mobile station and to have the mobile station acquire a radio link (traffic channel), a data link, and an IP address. 
     In particular, after authenticating the mobile station, the BSC will then assign radio resources for data communication, by directing the mobile station to operate on a particular time slot of the TDM forward link and by establishing that the mobile station will communicate with a particular long code on the reverse link. Further, the BSC will signal to the PDSN, and the PDSN and mobile station will then negotiate with each other to establish a data link, such as a point-to-point protocol (PPP) session. In addition, the mobile station will send a Mobile-IP registration request (MIP RRQ) message to the PDSN, which the PDSN will forward to the HA, and the HA will assign a mobile-IP address for the mobile station to use. The mobile station  12  may then engage in packet-data communications with entities such as remote computer  52 , via a communication path comprising air interface  42 , BTS  44 , BSC  46 , PDSN  48 , and network  50 . 
     With the arrangement presently contemplated, node  12  of  FIG. 2  can be constructed as a modified version of an existing base station, such as a modified version of the BTS  44  and/or BSC  46  shown in  FIG. 3 . Conveniently, BTS  44  would already include the cell site modem  28  shown in node  12  of  FIG. 2  and would thus already be configured to transmit data on EV-DO forward link  20  to one or more mobile stations and to receive data from one or more mobile stations on EV-DO reverse link  22 . Node  14  (i.e., mobile station modem  34 ) would be one such mobile station. 
     To function as node  12 , the base station will be modified to further include the mobile station modem  30  shown in  FIG. 2 , so that the base station can receive data from node  14  on EV-DO forward link  24  and can transmit data to node  14  on EV-DO reverse link  26 . The mobile station modem  30  added to the base station could be co-located with the base station&#39;s existing cell site modem  28 , such as in a common equipment cabinet at the base of the antenna tower. Further, the mobile station modem  30  can be set to share antennas with the cell site modem  28  or to use separate antennas. 
     Node  14 , on the other hand, can advantageously be a node to which a wireless carrier wishes to extend EV-DO coverage, such as a node that is located remotely from BTS  44  and that itself serves or provides connectivity for multiple mobile stations. Examples of such remotely located nodes include (i) a wireless transceiver on an aircraft, (ii) a pico-BTS or other wireless transceiver serving a multi-passenger vehicle or located in some other place, and (iii) a wireless transceiver at a distributed antenna system hub. Node  14  can take other forms as well, however, and may even take the form of a handheld mobile station (such as a cell phone or wirelessly equipped PDA or computer). 
     Node  14  will preferably be configured with the cell site modem  32  shown in  FIG. 2 , so that node  14  can transmit data on the EV-DO forward link  24  to the mobile station modem  30  of node  12 , and so that node  14  can receive data on the EV-DO reverse link  26  from the mobile station modem  30  of node  12 . Further, node  14  will preferably be configured with the mobile station modem shown in  FIG. 2 , so that node  14  can receive data on the EV-DO forward link  20  from the cell site modem  28  of node  12 , and so that node  14  can transmit data on the EV-DO reverse link  22  to the cell site modem  28  of node  12 . 
     To avoid interference between air interface communications on asymmetric wireless data connections  16 ,  18 , nodes  12  and  14  will preferably be arranged to use different carrier frequencies for their EV-DO communications on the various links. In particular, they can be set to communicate on one carrier frequency (e.g., one 1.25 MHz channel) for forward link  20  of connection  16 , another carrier frequency for reverse link  22  of connection  16 , still another carrier frequency for forward link  24  of connection  18 , and yet another carrier frequency for the reverse link  26  of connection  18 . Alternatively, other arrangements for avoiding interference can be provided. 
     In the event node  14  is literally mobile, such as if node  14  is mounted on the belly of an aircraft in flight or on some other moving vehicle, multiple nodes  12  can be provided to serve and be served by node  14  as node  14  moves. Each such node  12  would include both a cell site modem  28  and a mobile station modem  30 , and a process would be put in place to transfer communications between node  14  and nodes  12  as node  14  moves out of communication with one node  12  and into communication with another node  12 . 
     The conventional handoff process can govern handoff of mobile station modem  34  as node  14  moves out of the coverage of one node  12  and into the coverage of another node  12 . In particular, BSC  46  or another entity controlling the cell site modems  28  of the various nodes  12  can control handoff of mobile station modem  34  from one cell site modem  28  to another. 
     Further, in response to mobile station modem  34  handing off from the cell site modem  28  of one node  12  to the cell site modem of another node  12 , control logic at both ends will preferably also transfer the other asymmetric wireless data connection accordingly. In particular, control logic at node  14  will preferably direct cell site modem  32  to begin communicating with the mobile station modem  30  of the new node  12 , and control logic at node  12  (e.g., BSC  46 ) will preferably direct the mobile station modem  30  of the new node  12  to begin communicating with the cell site modem  32  of node  14 . To facilitate this, nodes  12  and  14  can use asymmetric wireless data link  16  to exchange radio link parameters needed for set up of the new asymmetric wireless data link  18 . 
     In the preferred embodiment, if node  14  communicates with only one node  12  at a time, node  14  need not employ the complex scheduling algorithm that is commonly employed to manage the EV-DO forward link. Rather, the cell site modem  32  of node  14  can keep its EV-DO forward link open at all times and, as node  14  receives data to transmit to node  12 , node  14  can simply transmit that data along the open EV-DO forward link to node  12 . 
     Similarly, if node  12  communicates with only one node  14  at a time, node  12  need not employ the complex scheduling algorithm that is commonly employed to manage the EV-DO forward link. Rather, the cell site modem  28  of node  12  can similarly keep its EV-DO forward link open at all times and, as node  12  receives data to transmit to node  14 , node  12  can simply transmit that data along the open EV-DO forward link to node  14 . 
       FIG. 4  next illustrates how the exemplary embodiment can be implemented to provide bi-directional high-data-rate wireless service for mobile stations within an aircraft. As shown in  FIG. 4 , an aircraft  70  is configured (internally and/or externally) with a node  14 , arranged to include a cell site modem  32  and a mobile station modem  34  as in  FIG. 2 . The cell site modem  32  and mobile station modem  34  are then connected with a controller  72 , which is in turn coupled with a pico-BTS  74  within the aircraft passenger compartment. (Note that, while the aircraft is shown as an airplane, any sort of flying vehicle, or any other sort of vehicle could just as well be provided in its place.) The pico-BTS  74  may then serve a plurality of mobile stations operated by passengers or others within the aircraft. 
       FIG. 4  further illustrates a ground-based BTS  44 , which is arranged to include a cell site modem  28  and a mobile station modem  30 . The cell site modem  28  and mobile station modem  30  of ground-based BTS  44  are then connected with a ground-based BSC  46 , which is in turn coupled with PDSN  48  as in  FIG. 3 , so as to provide a connection with packet-switched network  50 . As shown, BTS  44  and BSC  46  may cooperatively define a ground-based node  12 . 
     With this arrangement, dual asymmetric wireless data links  16 ,  18  are provided between ground-based BTS  44  and node  14 . In particular, asymmetric wireless connection  16  is provided between the cell site modem  28  of ground-based BTS  44  and the mobile station modem  34  of node  14 , and asymmetric wireless connection  18  is provided between the cell site modem  32  of node  14  and the mobile station modem  30  of ground-based BTS  44 . Control and bearer data communication may thus pass bi-directionally over high-data rate forward links between the aircraft and the ground. 
     In operation, for instance, ground-based BTS  44  may transmit a pilot signal to node  14  on either forward link  20  or reverse link  26 , controller  72  of node  14  may then forward the pilot signal to pico-BTS  74 , and pico-BTS  74  may then broadcast the pilot signal for receipt by the mobile stations within the aircraft. Upon detecting the pilot signal, one or more of the mobile stations may then acquire packet-data connectivity in the manner described above, beginning by sending a UATI request, which pico-BTS  74  would forward to node  14 , and node  14  would transmit to ground-based BTS  44  on either forward link  24  or reverse link  22 , and carrying on with further communication to acquire radio links, data links, and mobile-IP addresses for communication on network  50 . 
     Once the mobile stations have acquired packet-data connectivity, the mobile stations may then send packet-data destined to particular IP addresses. As the mobile stations transmit such packet-data, pico-BTS  74  would receive the packet-data and forward the packet-data to node  14 , and node  14  would transmit the packet-data on high-data-rate forward link  24  to ground-based BTS  44 . Ground-based BTS  44  would then pass the packet-data to BSC  46 , BSC  46  would pass it to PDSN  48 , and PDSN  48  would route it on network  50  to its destination. 
     Similarly, as BSC  46  receives packet-data destined for the IP address of any of the mobile stations on the aircraft, BSC  46  may pass the packet-data to ground-based BTS  44 , and ground-based BTS  44  would transmit the packet-data on high-data-rate forward link  20  to aircraft-based node  14 . Node  14  would then pass the packet-data along to pico-BTS  74 , and pico-BTS  74  would broadcast the packet-data for receipt by the destination mobile station. 
     Finally,  FIG. 5  illustrates how the exemplary embodiment can be implemented to provide bi-directional high-data-rate wireless service for mobile stations within a distributed antenna system (DAS). This situation is analogous to that the scenario depicted in  FIG. 4 , except that here, node  14  serves a DAS. (In fact, the arrangement of  FIG. 4  can be considered to be an aircraft-based DAS as well, but it is shown and described separately here for clarity.) 
     The DAS of  FIG. 5  is shown within an enclosure  80  such as a building. The DAS includes a DAS hub  82 , which is connected to a plurality of remotely located DAS antenna units  84 . This arrangement thus serves to extend wireless communications within the enclosure, to mobile stations positioned within the coverage of the various DAS antenna units  84 . A DAS such as this can be set to operate in a manner well known in the art, either passively repeating communications between DAS hub  82  and the various antenna units  84  or actively routing communications between the DAS hub  82  and certain ones of the antenna units  84 . 
     In the arrangement of  FIG. 5 , DAS hub  82  is shown coupled with a node  14 , which is arranged like the node  14  in  FIG. 4  to include a cell site modem  32 , a mobile station modem  34 , and a controller  72 . Further,  FIG. 5  illustrates a macro BTS  44 , which is arranged as in  FIG. 4  to include a cell site modem  28  and a mobile station modem  30 . The cell site modem  28  and mobile station modem  30  are then connected with a BSC  46 , which is in turn coupled with PDSN  48  as in  FIG. 3 , so as to provide a connection with packet-switched network  50 . As in  FIG. 4 , BTS  44  and BSC  46  may cooperatively define a node  12 . 
     With this arrangement, BTS  44  may transmit a pilot signal to node  14  on either forward link  20  or reverse link  26 , controller  72  of node  14  may then forward the pilot signal to DAS hub  82 , DAS hub  82  may forward the pilot signal to the various DAS antenna units  84 , and the antenna units  84  may broadcast the pilot signal for receipt by mobile stations within the building  80 . Upon detecting the pilot signal, one or more of the mobile stations may then acquire packet-data connectivity in the manner described above, and packet-data may then flow between node  14  and BTS  44  in the manner described above. 
     Still other example scenarios are possible within the scope of the invention as claimed. For example, dual asymmetric wireless data links can similarly be provided as an improved backhaul connection between the various elements shown in  FIG. 3 , such as between BTS  44  and BSC  46 , or between BSC  46  and PDSN  48 , for instance. As another example, dual asymmetric wireless data links can be provided as an improved backhaul connection between base stations and wireless repeaters, between base stations and other base stations, or between various other entities. 
     An exemplary embodiment of the present invention has been described above. Those skilled in the art will understand, however, that changes and modifications may be made to this embodiment without departing from the true scope and spirit of the present invention, which is defined by the claims.