WO2011124744A1

WO2011124744A1 - Radio performance policy extraction based on spectrum sensing

Info

Publication number: WO2011124744A1
Application number: PCT/FI2010/050278
Authority: WO
Inventors: Mikko Olavi VÄÄRÄKANGAS; Aarno Tapio PÄRSSINEN
Original assignee: Nokia Corporation
Priority date: 2010-04-08
Filing date: 2010-04-08
Publication date: 2011-10-13

Abstract

According to one general aspect, a method may include determining a set of statistical properties of at least a portion of a communications channel. The method may also include performing spectrum sensing by utilizing the set of statistic properties of the portion of the communications channel for signal detection, wherein the spectrum sensing 5 may attempt to detect one or more hidden nodes. The method may further include adjusting the operating parameters of a transceiver based at least partly on the spectrum sensing results.

Description

RADIO PERFORMANCE POLICY EXTRACTION BASED ON SPECTRUM

SENSING

TECHNICAL FIELD

[0001] This description relates to communications, and more specifically to the detection of communication channel condition information and the allocation of resources based, in part, upon the information

BACKGROUND

[0002] Modern society has quickly adopted, and become reliant upon, handheld devices for wireless communication. For example, cellular telephones continue to proliferate in the global marketplace due to technological improvements in both the communication quality and device functionality. These wireless communication devices have become common for both personal and business use, allowing users to transmit and receive voice, text and graphical data from a multitude of geographic locations. Likewise, computers (e.g., laptops, desktops, smart-phones, etc.) have become common in personal and business use, allowing computers to network and communicate in a wireless and mobile fashion. The communication networks utilized by these devices span different frequencies and cover different transmission distances, each having strengths desirable for various applications.

[0003] Wireless Local Area Network (WLAN) is a telecommunications technology often aimed at providing wireless data over shorter distances (e.g., meters or tens of meters) in a variety of ways, from point-to-point links to full mobile cellular type access. A network based upon the WLAN standard is occasionally also referred to by the common or marketing name "WiFi" (or "Wi-Fi") from Wireless Fidelity; although it is understood that WLAN may include other shorter ranged technologies. WiFi often includes a network that is substantially in compliance with the IEEE 802.11 standards, their derivatives, or predecessors (hereafter, "the 802.11 standard"). Institute of Electrical and Electronics Engineers, IEEE Standard for Information Technology— Telecommunications and Information Exchange between Systems— Local and Metropolitan Area Network— Specific Requirements— Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, IEEE Std. 802.11 -2007. SUMMARY

[0004] According to one general aspect, a method may include determining a set of statistical properties of at least a portion of a communications channel. The method may also include performing spectrum sensing by utilizing the set of statistical properties of the portion of the communications channel for signal detection, wherein the spectrum sensing may attempt to detect one or more hidden nodes. The method may further include adjusting the operating parameters of a transceiver based at least partly on the spectrum sensing results.

[0005] According to another general aspect, an apparatus may include a transceiver, a spectrum sensor, and a controller. In one embodiment, the transceiver may be configured to transmit and receive, based upon a set of operating parameters, signals via a wireless communications channel. The spectrum sensor may be configured to determine a set of statistical properties of at least a portion of the communications channel and utilize the set of statistical properties of the portion of the communications channel for signal detection via spectrum sensing. The controller may be configured to adjust the operating parameters of the transceiver based at least partly on the spectrum sensing results.

[0006] According to another general aspect, a computer program product for transmitting information may include executable code that, when executed, is configured to cause a mobile wireless communications apparatus to determine a set of statistical properties of at least a portion of a communications channel. The computer program product may also include code to cause the apparatus to perform spectrum sensing by utilizing the set of statistic properties of the portion of the communications channel for signal detection. The computer program product may further include code to cause the apparatus to adjust the operating parameters of a transceiver based at least partly on the spectrum sensing results. In various embodiments, the computer program product being tangibly embodied on a computer-readable medium.

[0007] The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

[0008] A system and/or method for communicating information, substantially as shown in and/or described in connection with at least one of the figures, as set forth more completely in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a block diagram of an example embodiment of a system in accordance with the disclosed subject matter.

[0010] FIG. 2 is a block diagram of an example embodiment of a system in accordance with the disclosed subject matter.

[0011] FIG. 3 is a block diagram of an example embodiment of an apparatus in accordance with the disclosed subject matter.

[0012] FIG. 4 is a block diagram of an example embodiment of operating parameters in accordance with the disclosed subject matter.

[0013] FIG. 5 is a block diagram of an example embodiment of a system in accordance with the disclosed subject matter.

[0014] FIG. 6 is a series of flow charts of example embodiments of techniques in accordance with the disclosed subject matter.

[0015] FIG. 7 is a flow chart of an example embodiment of a technique in accordance with the disclosed subject matter.

[0016] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0017] FIG. 1 is a block diagram of a wireless network 102 including a base station or an access point (AP) 104 and mobile nodes or stations (STAs) 106, 108, 110, according to an example embodiment. Each of the STAs 106, 108, 110 may be associated with AP 104, and may transmit data in an uplink direction to AP 104, and may receive data in a downlink direction from AP 104, for example. Although only one AP 104 and three mobile stations (STAs 106, 108 and 110) are shown, any number of access points and mobile stations may be provided in network 102. Also, although not shown, mobile stations 106, 108 and 110 may be coupled to AP 104 via relay stations or relay nodes, for example. The AP 104 may be connected via wired or wireless links to another network (not shown), such as a Local Area Network, a Wide Area Network (WAN), the Internet, etc.. In various embodiments, the AP 104 may be coupled or connected with the other network 120 via an access network controller (ASN) or gateway (GW) 112 that may control, monitor, or limit access to the other network. It is understood that even though some embodiments are described for WLAN, this may be applicable also to other radio technologies.

[0018] Fig. 2 is a block diagram of an example embodiment of a system 200 in accordance with the disclosed subject matter. In system 200, mobile nodes 106 and 108 are both connected or in communication with access point 104. Unfortunately, mobile node 106 is "hidden" from mobile node 108, and vice versa. In wireless networking, the hidden node problem occurs when a node (e.g., mobile node 106) is visible from a wireless access point (e.g., AP 104), but not from other nodes (e.g., mobile node 108)

communicating with said AP. For example, the signal power from mobile nodes 106's transmission and received by mobile node 108, may be under a certain threshold and, therefore, channel is assumed, by mobile node 108, to be free for transmission.

Subsequently, a transmission by node 108 may lead to radio packet collision when AP 104 is trying to receive packet from node 106.

[0019] AP 104 may generate a wireless networking signal with a range of 104r, which encompasses both STAs 106 and 108. STA 106 may generate a wireless networking signal with a range of 106r, which encompasses AP 104 but not STA 108. Therefore, STA 108 is "hidden" from STA 106. Likewise, STA 108 and its wireless range 108r, result in STA 106 being "hidden" from STA 108.

[0020] The problem aspect of the "hidden node problem" may occur when nodes 106 and 108 both start packets or data transmissions simultaneously to the access pointl04. Since node 106 and 108 cannot detect each other's existence, using received signal power based channel access scheme (e.g., Carrier Sense Multiple Access / Collision Detection (CSMA/CD)), packet collisions or other forms of interference may occur at or near the AP 104, where ranges 106r and 108r overlap. Such interference or collisions may cause the AP 104 to not receive or incorrectly receive the data sent by each STA 106 or 108.

[0021] In various embodiments, different actions may be taken to ameliorate this problem. In non-WiFi systems a form of resource block allocation or handshaking may occur in which the AP 104 orchestrates the transmission of data from the STAs to the AP 104. Alternatively, the AP 104 could take on the task of informing all associated STAs (e.g., STAs 106 and 108) of the existence of all the STAs associated with the AP 104.

However, the 802.11 standards do not provide for these forms of AP-managed solutions.

[0022] In another embodiment, the power of one of the STAs (e.g., STA 106) may be increased to increase the chance that STA 106's transmissions will be properly received by the AP 104. Such a system can be likened to shouting over STA 108 so that AP 104 can hear STA 106. In another embodiment, STA 106 and STA 108 may be configured to use different channels or frequencies for transmission, if the AP 104 is capable of handling multiple frequency usage.

[0023] FIG. 3 is a block diagram of an example embodiment of an apparatus 300 in accordance with the disclosed subject matter. In one embodiment, the communications device 300 may include a base station (BS), Access Point (AP) or a mobile station (MS or STA) such as that illustrated in Fig. 1. In one embodiment, the communications device 300 may include a transceiver 302, a controller 304, and a memory 306. In one embodiment, an apparatus 300 may comprise at least one processor 304 and at least one memory 306, which may include computer program code. The apparatus 300 may be a terminal or a chipset, etc..

[0024] In some embodiments, the transceiver 302 may include a wireless transceiver configured to operate based upon a wireless networking standard {e.g., WiMAX, WiFi, WLAN, etc). In other embodiments, the transceiver 302 may include a wired transceiver configured to operate based upon a wired networking standard {e.g., Ethernet, etc.). In various embodiments, the transceiver 302 may include a plurality of antennas (not shown). In some embodiments, the transceiver 302 may include a transmitter 301 and a receiver 303. The transmitter 301 and receiver 303 may be configured to operate on a plurality of frequencies, either operating on a selected frequency or multiple frequencies substantially simultaneously.

[0025] In various embodiments, the controller 304 may include a processor. In various embodiments, the memory 306 may include permanent {e.g., ROM, compact disc, etc.), semi- permanent {e.g., a hard drive, etc.), and/or temporary {e.g., volatile random access memory, etc.) memory. For example, some operations illustrated and/or described herein, may be performed by a controller 304, under control of software, firmware, or a combination thereof. In another example, some components illustrated and/or described herein, may be stored in memory 306.

[0026] In some embodiments, the communications device 300 may include at least one operating parameter 310 configured to store one or more settings to control the operation of the transceiver 302. The operating parameters may include, for example, settings which indicates minimum/maximum transmission power, minimum receiver performance, quality of service requirements, which channel or frequency to use when transmitting or receiving a signal, a set of modulations (e.g., Orthogonal frequency- division multiplexing (OFDM), Phase-Shift Keying (PSK), etc.) to use when transmitting or receiving a signal, a bit-rate to use when transmitting or receiving a signal, etc. In various embodiments, the operating parameters 310 may be stored by the memory 306.

[0027] FIG. 4 is a block diagram of an example embodiment of operating parameters 400 in accordance with the disclosed subject matter. In various embodiments, the operating parameters may include various sets of predefined operating parameters or policies for the transmitter 402 and a second series of sets of predefined policies for the receiver 404. In another embodiment, the sets of policies may be for the transceiver as a whole. In some instances these polices may be dynamically generated based upon historical data or previous policies used (e.g., the last 5 sets of operating parameters used by the apparatus, etc.). These dynamically generated policies may be generated based upon the conditions encountered or detected as part of the communications channel, or portion thereof, used to communicate between the apparatus and another device (e.g., an AP, or STA, etc.).

[0028] Further, the operating parameters 400 may also include a set 406 or sets (one for receiver and transmitter) of operating parameters or policies currently employed by the apparatus. In various embodiments, these predefined or dynamically defined sets of policies 402 and 404 may be referred to by a numerical identifier (ID) (e.g., 0001, 12,

DEADBEEF, etc.) or similar reference schemes. As such, the current policies portion may only include a reference to a policy stored within the transmitter policies 402 or receiver policies 406. As the communications policies or operating parameters of the apparatus are adjusted the current policies 406 may be updated to reflect or cause this adjustment.

Likewise, the transceiver, controller, or processor may consult the current policies 406 to control the transceiver as appropriate.

[0029] Returning to Fig. 3, the apparatus 300 may include a spectrum sensor 312. The spectrum sensor 312 may include a receiver device or circuit that utilizes statistical properties of target signals to detect the target signals even if the signals exist under the noise level. In various embodiments, the spectrum sensor 312 may be configured to listen to a communications channel or portion thereof, in order to determine a set of statistical properties of the communications channel. In various embodiments, the spectrum sensor 312 may acquire or determine the set of statistical properties of the communications channel, or portion thereof, by utilizing various techniques, such as, autocorrelation, matched filtering, cyclo stationary detection, energy detection, etc.; although, it is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited.

[0030] Once the statistical properties of the channel are determined, the spectrum sensor 312 or processing component of the apparatus 300 may proceed to attempting to detect a target signal. In one embodiment, the target signal may be a WLAN OFDM signal as standardized in the IEEE 802.11 specifications {e.g., 802.1 la, 802.1 lg, 802.1 In, etc.). Spectrum sensor may include a receiver device configured to utilize known or determined statistical properties of the target signal for signal detection.

[0031] FIG. 5 is a block diagram of an example embodiment of a system 500 in accordance with the disclosed subject matter. The STA 106 may be configured to transmit or receive a signal over a given range, depending upon power levels, etc.. Typical received signal strength indication (RSSI) or signal-to-noise ratio (SNR) detection may allow a STA 106 to detect a target signal within a certain range (SNR range 502). With typical SNR signal detection, a signal is received and measurements of the strength of the received signal and the noise coupled with the signal are made. Using this as a guide the

appropriate level of transmission strength is determined. This SNR range 502 is typically the range over which the STA 106 may be configured to transmit or receive a signal {e.g., range 106r of Fig. 2).

[0032] However, by employing a spectrum sensor {e.g., spectrum sensor 312) a signal or at least the existence of a signal may be detected over a greater range than the SNR range 502. This spectrum sensor (SS) detection range 504 may be the range over which the spectrum sensor of STA 106 may detect the existence of the target signal.

[0033] Using a spectrum sensor the detection range can be expanded to SS range 504. In a traditional situation every device {e.g., STA or AP, etc.) beyond SNR range 502 may be hidden from the STA 106. These hidden devices, as described above in reference to Fig. 2, may cause interference in the network because those hidden devices see the SNR or RSSI, with respect to the signals transmitted from STA 106, to be under these hidden nodes' respective thresholds that define a clear communication channel. For example, those hidden devices and STA 106 may employ the wrong signal power or frequencies, etc. when communicating with the shared AP or other device (again see Fig. 2).

[0034] For those wireless communications standards which make use of

transmission power as the primary means of addressing RSSI or SNR issues, as STA 106 reduces its transmission power (e.g., to conserve battery power, etc.) the SNR range 502 decreases. This increases the probably of, if not the number of, hidden nodes which may exist outside the traditional SNR detection range. Traditionally the way to combat this danger was to increase the transmission power or refrain from reducing the transmission power.

[0035] It is understood that power is merely an illustrative example of one of several signal operating parameters that may be adjusted or define the SNR range 502. Other operating parameters, as described above, may include frequency, symbol definition, etc.; although, it is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited. Herein where the term "power" is used in this document it is understood that this is not a required limitation of the disclosed subject matter, but merely one embodiment of the disclosed subject matter.

[0036] Retuning to Fig. 3, upon the detection of hidden nodes or the lack thereof by the spectrum sensor 312, the apparatus 300 may adjust the operating parameters 310 of the transceiver 302 based at least partly on the spectrum sensing results. In one embodiment, if a hidden node is not detected the power or other operating parameters 310 may be reduced or altered in order to conserve resources (e.g., battery life, spectrum, etc.).

[0037] Conversely, if a hidden node is detected, the power or other operating parameters 310 may be increased or altered to minimize the interference experienced by an access point and created in part by the hidden node. In the case of transmission, the apparatus 300 may change the way it transmit in order to reduce the signal interference occurring at the access point. Conversely, in the case of reception, the apparatus 300 may modify the receiver sensitivity in order to detect desired signals in spite of interference caused by the interference of the hidden node. For example, the transmission power may be increased, the transmission frequency or channel may be altered, etc.; although, it is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited. In another embodiment, if a hidden node is detected, the apparatus 300 may not alter or adjust the power or operating parameters 310 employed by the transceiver 302, but merely maintain the status quo. [0038] For example, the 802.1 lg standard specifies 14 separate frequencies (referred to in the 802.11 specification as "channels"). The apparatus 300 may perform spectrum sensing on each of the 14 separate frequencies or portions of the larger communications channel. In various embodiments, if a hidden node is detected in one or more of these portions of the larger communications channel, the operating parameters may be altered or adjusted to utilize another frequency or portion of the communications channel.

Specifically, in one embodiment, if a hidden node is detected on the 2.437 GHz frequency (802.1 lg channel 6), the apparatus 300 may be adjusted to transmit and receive using the 2.417 GHz frequency (802.1 lg channel 2). It is understood that the above is merely an illustrative example to which the disclosed subject matter is not limited.

[0039] In another embodiment, interference caused by a hidden node may be reduced if transmissions of the hidden node are predictable using some machine learning algorithm. In yet another embodiment, device to device ad-hoc networking may occur in which the devices or nodes are near-by. Transmission power and receiver sensitivity may be minimized in order to save energy or power. If the existence of hidden nodes is predicted using spectrum sensing there may be no means to use measured channel and/or reduce transmission power in order to save energy because more retransmissions will occur because of the interference caused by hidden nodes. In various embodiments, interference may be limited from this type of device-to-device communications to other networks, because interference may be predicted by comparing received signal strengths and sensor information.

[0040] In another embodiment, reduced sensitivity may be employed, when spectrum sensing information may be used to avoid interference to devices that using normal sensitivity would also detect. These cases may normally be avoided because the WLAN standard does not allow this kind of functionality, but there can be systems in future or different communication standards that can utilize this type of channel access scheme in order to avoid interference between legacy systems.

[0041 ] In various embodiments, the operating parameters 310 for the transmitter 301 may be adjusted separately from the operating parameters 310 of the receiver 303. As described above, these operating parameters may be grouped into various performance or operating policies (e.g., those of Fig. 4). Depending upon the detection of hidden nodes these operating policies may be adjusted to better allocate resources (e.g., reduce battery usage, increase transmission power, etc.).

[0042] FIG. 6 is a series of flow charts of example embodiments of techniques 600 and 601 in accordance with the disclosed subject matter. Technique 600 illustrates a simplified embodiment of the disclosed subject matter. Technique 601 illustrates a more complex embodiment of the disclosed subject matter.

[0043] Technique 600 illustrates a simplified embodiment of the disclosed subject matter. Block 602 illustrates that the apparatus may engage in a "normal" transceiver performance policy. In the illustrated embodiment, "current" is casually defined as the transceiver policy, or policies if the transmitter and receiver are considered separately, the apparatus is currently employing. In various embodiments, such a transceiver policy may not be the policy employed by the apparatus during standard or "normal" operation as dictated by a networking standard (for example, the Wi-Fi standard which make dictate an average "optimal" performance"); for example, in various embodiments, the apparatus may alter the "normal" Wi-Fi operating parameters to reduce power or energy, etc..

[0044] Block 606 illustrates that, in one embodiment, the apparatus may perform spectrum sensing in order to determine if any hidden nodes exist within the network used by the apparatus, as described above.

[0045] Block 608 illustrates that, in one embodiment, if one or more hidden nodes are not detected the apparatus may adjust the transceiver performance policy {e.g., changing from one policy to another, etc). In one embodiment, this may include decreasing the amount of power used by the transceiver. Conversely, if the hidden node is detected the apparatus may maintain its current transceiver policy.

[0046] Alternately, in various embodiments, the reactions to the detection of a hidden node may be switched. For example, if hidden nodes are detected, the apparatus may increase the amount of power employed by the transceiver or adjust other operating parameters. In another embodiment, this adjustment may include switching from a first communications channel, or portion thereof, used by the hidden node and to a second communications channel that is not used by the hidden node. It is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited. While, if a hidden node is detected, the apparatus may maintain its current transceiver policy settings.

[0047] Technique 601 illustrates a more complex embodiment of the disclosed subject matter. Block 602 illustrates that the apparatus may engage in a "normal" transceiver performance policy. Again the term "normal" is a relative term, as described above. As described above. Block 606 illustrates that a determination may be made as to whether or not a hidden node exists.

[0048] Regardless of the outcome of the detection of Block 606, Block 610 illustrates that the communications channel or link may be tested to determine the quality of the communications channel or link. In various embodiments, this may include performing the traditional SNR or RSSI detection. In this context, the definition of "poor" link quality may include a set of predetermined characteristics (e.g., error rate, SNR level, missed message receipt acknowledgements, etc.); although, it is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited.

[0049] In one embodiment, if a "poor" link quality is so detected, Block 612 illustrates that the apparatus may adjust the operating parameters or policy by incrementing or decrementing (depending upon the embodiment) the power of the transceiver. Again, it is understood that the use of "power" is merely an illustrative example to which the disclosed subject matter is not limited. It is understood that the in this illustrative example the term "power" refers to the transmission power employed by the device, and that this transmission power affects that amount of power drawn from a battery (or other power source) utilized by the apparatus. In this embodiment, the quality of the communication channel may be the determinative factor in deciding whether or not to positively adjust (e.g., increase power, etc.) the transceiver operating parameters.

[0050] In one embodiment, if neither a hidden node nor "poor" link quality is detected, Block 614 illustrates that the apparatus may adjust the operating parameters or policy by decreasing the power of the transceiver. Alternatively, if a hidden node is detected but no "poor" link quality is detected, Block 602 illustrates that the apparatus may maintain its current operating parameters or policy.

[0051] It is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited. Various other techniques or schemes for adjusting or maintaining the operating parameters or policy of the apparatus.

[0052] FIG. 7 is a flow chart of an example embodiment of a technique in accordance with the disclosed subject matter. In various embodiments, the technique 700 may be used or produced by the systems or apparatuses such as those of Figs. 1, 2, 3, or 5. Although, it is understood that the above are merely a few illustrative examples to which the disclosed subject matter is not limited. It is understood that the disclosed subject matter is not limited to the ordering of or number of actions illustrated by technique 700.

[0053] Block 702 illustrates that, in one embodiment, a set of statistical properties of at least a portion of a communications channel may be determined, as described above. In various embodiments, determining may include performing autocorrelation, matched filtering, eye lo stationary detection, or energy detection, etc. on the portion of the communications channel, as described above. In another embodiment, determining may include determining respective sets of statistical properties of a plurality of portions of a communications channel, as described above. In yet another embodiment, determining may include determining a set of statistical properties of a target signal, as described above. In various embodiments, one or more of the action(s) illustrated by this Block may be performed by the apparatuses or systems of Figs. 1, 2, 3, or 5, the transceiver 302 or spectrum sensor 312 of Fig. 3, as described above.

[0054] Block 704 illustrates that, in one embodiment, spectrum sensing may be performed by utilizing the set of statistic properties of the portion of the communications channel for signal detection, as described above. In one embodiment, performing spectrum sensing may include determining if hidden nodes are utilizing the portion of the communications channel, as described above. In another embodiment, performing may include spectrum sensing across a plurality of portions of a communications channel, as described above. In yet another embodiment, performing may include performing spectrum sensing over a greater range than signal-to-noise ratio signal detecting may be performed, as described above. In various embodiments, one or more of the action(s) illustrated by this Block may be performed by the apparatuses or systems of Figs. 1, 2, 3, or 5, the transceiver 302 or spectrum sensor 312 of Fig. 3, as described above.

[0055] Block 706 illustrates that, in one embodiment, an apparatus may adjust the operating parameters of a transceiver based at least partly on the spectrum sensing results, as described above. In one embodiment, adjusting may include adjusting the operating parameters of a transceiver based at least in part upon whether or not a hidden node is detected to be utilizing the portion of the communications channel, as described above. In some embodiments, adjusting may include instructing the transceiver to utilize a second portion of the communications channel, if a hidden node is not detected to be utilizing the portion of a first portion of the communications channel but not the second portion of the communications channel, as described above. In various embodiments, one or more of the action(s) illustrated by this Block may be performed by the apparatuses or systems of Figs. 1, 2, 3, or 5, the transceiver 302 or spectrum sensor 312 of Fig. 3, as described above.

[0056] Block 708 illustrates that, in one embodiment, adjusting may include includes reducing the amount of power used for either a receiver portion of the transceiver, a transmitter portion of the transceiver, or both the receiver portion and the transmitter portion of the transceiver, if a hidden node is not detected to be utilizing the portion of the communications channel, as described above. Block 710 illustrates that, in yet another embodiment, adjusting may include not adjusting the operating parameters of the transceiver if a hidden node is detected to be utilizing the portion of the communications channel, as described above. In various embodiments, one or more of the action(s) illustrated by this Block may be performed by the apparatuses or systems of Figs. 1, 2, 3, or 5, the transceiver 302 or spectrum sensor 312 of Fig. 3, as described above.

[0057] Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0058] Method steps may be performed by one or more programmable processors executing a computer program to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g. , an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). [0059] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto -optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non- volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or

incorporated in special purpose logic circuitry.

[0060] To provide for interaction with a user, implementations may be implemented on a computer having a display device, e.g., a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0061] Implementations may be implemented in a computing system that includes a back-end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front-end component, e.g. , a client computer having a graphical user interface or a Web browser through which a user can interact with an implementation, or any combination of such back-end, middleware, or front-end components. Components may be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN) and a wide area network (WAN), e.g., the Internet.

[0062] While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the scope of the embodiments.

Claims

WHAT IS CLAIMED IS:

1. A method comprising:

determining a set of statistical properties of at least a portion of a communications channel;

performing spectrum sensing by utilizing the set of statistic properties of the portion of the communications channel for signal detection; and

adjusting the operating parameters of a transceiver based at least partly on the spectrum sensing results.

2. The method of claim 1, wherein determining a set of statistical properties includes performing autocorrelation on the portion of the communications channel.

3. The method of claim 1, wherein performing spectrum sensing includes determining if one or more hidden nodes are utilizing the portion of the communications channel.

4. The method of claim 1, wherein adjusting the operating parameters of a transceiver includes adjusting the operating parameters of a transceiver based at least in part upon whether or not a hidden node is detected to be utilizing the portion of the communications channel.

5. The method of claim 1, wherein adjusting the operating parameters of a transceiver includes, if a hidden node is not detected to be utilizing the portion of the communications channel, reducing the amount of power used for either:

a receiver portion of the transceiver,

a transmitter portion of the transceiver, or

both the receiver portion and the transmitter portion of the transceiver.

6. The method of claim 1, wherein adjusting the operating parameters of a transceiver includes not adjusting the operating parameters of the transceiver if a hidden node is detected to be utilizing the portion of the communications channel.

7. The method of claim 1, wherein determining a set of statistical properties of at least a portion of a communications channel includes determining respective sets of statistical properties of a plurality of portions of a communications channel; and

wherein adjusting the operating parameters of a transceiver includes instructing the transceiver to utilize a second portion of the communications channel, if a hidden node is detected to be utilizing the portion of a first portion of the communications channel but not the second portion of the communications channel.

8. The method of claim 1, wherein determining a set of statistical properties of at least a portion of a communications channel includes determining a set of statistical properties of a target signal, and

wherein performing spectrum sensing include performing spectrum sensing over a greater range than signal-to-noise ratio signal detecting may be performed.

9. An apparatus comprising:

at least one processor; and

at least one memory including computer program code,

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform at least the following:

determine a set of statistical properties of at least a portion of a communications channel;

perform spectrum sensing by utilizing the set of statistic properties of the portion of the communications channel for signal detection; and

adjust the operating parameters of a transceiver based at least partly on the spectrum sensing results.

10. The apparatus of claim 9, wherein the apparatus is configured to perform eye lo stationary detection on the portion of the communications channel.

11. The apparatus of claim 9, wherein the apparatus is configured to determine if one or more hidden nodes are utilizing the portion of the communications channel.

12. The apparatus of claim 9, wherein the apparatus is configured to adjust the operating parameters of the transceiver based at least in part upon whether or not a hidden node is detected to be utilizing the portion of the communications channel.

13. The apparatus of claim 9, wherein the apparatus is configured to, if a hidden node is not detected to be utilizing the portion of the communications channel, reduce the amount of power used for either:

a receiver portion of the transceiver,

a transmitter portion of the transceiver, or

both the receiver portion and the transmitter portion of the transceiver.

14. The apparatus of claim 9, wherein the apparatus is configured to not adjust the operating parameters of the transceiver if a hidden node is detected to be utilizing the portion of the communications channel.

15. The apparatus of claim 9, wherein the apparatus is configured to determine respective sets of statistical properties of a plurality of portions of the communications channel; and

wherein the apparatus is configured to instruct the transceiver to utilize a second portion of the communications channel, if a hidden node is detected to be utilizing the portion of a first portion of the communications channel but not the second portion of the communications channel.

16. The apparatus of claim 9, wherein the apparatus is configured to:

determine a set of statistical properties of a target signal, and

perform spectrum sensing over a greater range than signal-to-noise ratio signal detecting may be performed.

17. A computer program product for transmitting information, the computer program product being tangibly embodied on a computer-readable medium and including executable code that, when executed, is configured to cause a mobile wireless communications apparatus to determine a set of statistical properties of at least a portion of a communications channel;

18. The computer program product of claim 17, wherein the executable code that, when executed, is configured to cause the mobile wireless communications apparatus to:

determine if one or more hidden nodes are utilizing the portion of the

communications channel; and

adjust the operating parameters of a transceiver based at least in part upon whether or not a hidden node is detected to be utilizing the portion of the communications channel.

19. The computer program product of claim 17, wherein the executable code that, when executed, is configured to cause the mobile wireless communications apparatus to: if a hidden node is not detected to be utilizing the portion of the communications channel, reducing the amount of power used for either:

a receiver portion of the transceiver,

a transmitter portion of the transceiver, or

both the receiver portion and the transmitter portion of the transceiver; and if a hidden node is detected to be utilizing the portion of the communications channel, not adjusting the amount of power used by the transceiver.

20. The computer program product of claim 17, wherein the executable code that, when executed, is configured to cause the mobile wireless communications apparatus to: determine a set of statistical properties of a target signal,

perform signal-to-noise ration signal detection over a first range; and

perform spectrum sensing over a second range that is greater than the first range.