Systems and methods for header compression

Systems, methods, and devices for communicating packets having a plurality of types are described herein. In some aspects, the packets include a compressed header. In one embodiment, a compression protocol is selected from a plurality of compression protocols to compress a first packet header. The packet may contain a second packet header, which may include information indicative of the compression protocol used to compress the first packet header. The packet may be transmitted, including the first packet header which is compressed using the selected compression protocol.

FIELD

The present application relates generally to wireless communications, and more specifically to systems, methods, and devices for compressing headers for communication.

BACKGROUND

The devices in a wireless network may transmit/receive information between each other. The information may comprise packets, which in some aspects may be referred to as data units or data frames. The packets may include overhead information (e.g., header information, packet properties, etc.) that helps in routing the packet through the network, identifying the data in the packet, processing the packet, etc., as well as data, for example user data, multimedia content, etc. as might be carried in a payload of the packet.

Accordingly, the header information is transmitted with packets. Such header information may comprise a large portion of a data packet. Accordingly, transmission of data in such packets may be inefficient due to the fact that much of the bandwidth for transmitting data may be used to transmit header information as opposed to the actual data. Thus, improved systems, methods, and devices for communicating packets are desired.

SUMMARY

The systems, methods, and devices of the invention each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention as expressed by the claims which follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this invention provide advantages that include allowing the use of compressed headers for packets, thereby reducing the overhead in transmitting payloads in data packets.

One aspect of this disclosure provides a method of communicating in a wireless network. The method comprises selecting, at a first apparatus, at least one compression protocol from a plurality of compression protocols to use for compressing a first header of a data packet communicated between the first apparatus and a second apparatus. The method comprises transmitting information indicative of the at least one compression protocol from the first apparatus to the second apparatus, the information included in a second header of the data packet. The method comprises transmitting the data packet, compressed based on the at least one compression protocol, from the first apparatus to the second apparatus.

Another aspect of this disclosure provides a first apparatus for communicating in a wireless network. The first apparatus comprises a processor configured to select at least one compression protocol from a plurality of compression protocols to use for compressing a first header of a data packet communicated between the first apparatus and a second apparatus. The first apparatus comprises a transmitter. The transmitter is configured to transmit information indicative of the at least one compression protocol to the second apparatus, the information included in a second header of the data packet. The transmitter is configured to transmit the data packet, compressed based on the at least one compression protocol, to the second apparatus.

Another aspect of this disclosure provides a first apparatus for communicating in a wireless network. The first apparatus comprises means for selecting at least one compression protocol from a plurality of compression protocols to use for compressing a first header of a data packet communicated between the first apparatus and a second apparatus. The first apparatus comprises means for transmitting information indicative of the at least one compression protocol from the first apparatus to the second apparatus, the information included in a second header of the data packet. The first apparatus comprises means for transmitting the data packet, compressed based on the at least one compression protocol, from the first apparatus to the second apparatus.

Another aspect of this disclosure provides a computer readable medium comprising instructions. The instructions when executed cause a first apparatus to select, at the first apparatus, at least one compression protocol from a plurality of compression protocols to use for compressing a first header of a data packet communicated between the first apparatus and a second apparatus. The instructions when executed cause the first apparatus to transmit information indicative of the at least one compression protocol from the first apparatus to the second apparatus, the information included in a second header of the data packet. The instructions when executed cause the first apparatus to transmit the data packet, compressed based on the at least one compression protocol, from the first apparatus to the second apparatus.

DETAILED DESCRIPTION

Popular wireless network technologies may include various types of wireless local area networks (WLANs). A WLAN may be used to interconnect nearby devices together, employing widely used networking protocols. The various aspects described herein may apply to any communication standard, such as WiFi or, more generally, any member of the IEEE 802.11 family of wireless protocols. For example, the various aspects described herein may be used as part of the IEEE 802.11ah protocol, which uses sub-1 GHz bands.

In some aspects, wireless signals in a sub-gigahertz band may be transmitted according to the 802.11ah protocol using orthogonal frequency-division multiplexing (OFDM), direct—sequence spread spectrum (DSSS) communications, a combination of OFDM and DSSS communications, or other schemes. Implementations of the 802.11ah protocol may be used for sensors, metering, and smart grid networks. Advantageously, aspects of certain devices implementing the 802.11ah protocol may consume less power than devices implementing other wireless protocols, and/or may be used to transmit wireless signals across a relatively long range, for example about one kilometer or longer.

In some implementations, a WLAN includes various devices which are the components that access the wireless network. For example, there may be two types of devices: access points (“APs”) and clients (also referred to as stations, or “STAB”). In general, an AP serves as a hub or base station for the WLAN and an STA serves as a user of the WLAN. For example, an STA may be a laptop computer, a personal digital assistant (PDA), a mobile phone, etc. In an example, an STA connects to an AP via a WiFi (e.g., IEEE 802.11 protocol such as 802.11ah) compliant wireless link to obtain general connectivity to the Internet or to other wide area networks. In some implementations an STA may also be used as an AP.

An access point (“AP”) may also comprise, be implemented as, or known as a NodeB, Radio Network Controller (“RNC”), eNodeB, Base Station Controller (“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver, or some other terminology.

A station “STA” may also comprise, be implemented as, or known as an access terminal (“AT”), a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, user equipment, or some other terminology. In some implementations an access terminal may comprise a cellular telephone, a cordless telephone, a Session Initiation Protocol (“SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, a headset, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a gaming device or system, a global positioning system device, or any other suitable device that is configured to communicate via a wireless medium.

As discussed above, certain of the devices described herein may implement the 802.11ah standard, for example. Such devices, whether used as an STA or AP or other device, may be used for smart metering or in a smart grid network. Such devices may provide sensor applications or be used in home automation. The devices may instead or in addition be used in a healthcare context, for example for personal healthcare. They may also be used for surveillance, to enable extended-range Internet connectivity (e.g. for use with hotspots), or to implement machine-to-machine communications.

FIG. 1illustrates an example of a wireless communication system100in which aspects of the present disclosure may be employed. The wireless communication system100may include an AP104, which communicates with STAs106.

A variety of processes and methods may be used for transmissions in the wireless communication system100between the AP104and the STAs106. For example, signals may be sent and received between the AP104and the STAs106in accordance with OFDM/OFDMA techniques. If this is the case, the wireless communication system100may be referred to as an OFDM/OFDMA system. Alternatively, signals may be sent and received between the AP104and the STAs106in accordance with CDMA techniques. If this is the case, the wireless communication system100may be referred to as a CDMA system.

A communication link that facilitates transmission from the AP104to one or more of the STAs106may be referred to as a downlink (DL)108, and a communication link that facilitates transmission from one or more of the STAs106to the AP104may be referred to as an uplink (UL)110. Alternatively, a downlink108may be referred to as a forward link or a forward channel, and an uplink110may be referred to as a reverse link or a reverse channel.

The AP104may provide wireless communication coverage in a basic service area (BSA)102. It should be noted that the wireless communication system100may not have a central AP104, but rather may function as a peer-to-peer network between the STAs106. Accordingly, the functions of the AP104described herein may alternatively be performed by one or more of the STAs106.

FIG. 2illustrates various components that may be utilized in a wireless device202that may be employed within the wireless communication system100. The wireless device202is an example of a device that may be configured to implement the various methods described herein. For example, the wireless device202may comprise the AP104or one of the STAs106.

When the wireless device202is implemented or used as a transmitting node, the processor204may be configured to select one of a plurality compression protocols for compressing headers, and to generate a packet having a compressed header associated with the selected compression protocol. Further, the processor204may generate and/or process request messages and/or response messages for negotiating use of a particular compression protocol with another wireless device.

When the wireless device202is implemented or used as a receiving node, the processor204may be configured to receive and process packets having compressed headers. Further, the processor204may generate and/or process request messages and/or response messages for negotiating use of a particular compression protocol with another wireless device.

The wireless device202may also include a housing208that may include a transmitter210and/or a receiver212to allow transmission and reception of data between the wireless device202and a remote location. The transmitter210and receiver212may be combined into a transceiver214. An antenna216may be attached to the housing208and electrically coupled to the transceiver214. The wireless device202may also include (not shown) multiple transmitters, multiple receivers, multiple transceivers, and/or multiple antennas.

The transmitter210may be configured to wirelessly transmit request messages and/or response messages for negotiating use of a particular compression protocol with another wireless device. Further, the transmitter210may be configured to wirelessly transmit packets having compressed headers.

The receiver212may be configured to wirelessly receive request messages and/or response messages for negotiating use of a particular compression protocol with another wireless device. Further, the transmitter210may be configured to wirelessly receive packets having compressed headers.

The wireless device202may also include a signal detector218that may be used in an effort to detect and quantify the level of signals received by the transceiver214. The signal detector218may detect such signals as total energy, energy per subcarrier per symbol, power spectral density and other signals. The wireless device202may also include a digital signal processor (DSP)220for use in processing signals. The DSP220may be configured to generate a packet for transmission. In some aspects, the packet may comprise a physical layer data unit (PPDU).

The wireless device202may further comprise a user interface222in some aspects. The user interface222may comprise a keypad, a microphone, a speaker, and/or a display. The user interface222may include any element or component that conveys information to a user of the wireless device202and/or receives input from the user.

The various components of the wireless device202may be coupled together by a bus system226. The bus system226may include a data bus, for example, as well as a power bus, a control signal bus, and a status signal bus in addition to the data bus. Those of skill in the art will appreciate the components of the wireless device202may be coupled together or accept or provide inputs to each other using some other mechanism.

Although a number of separate components are illustrated inFIG. 2, those of skill in the art will recognize that one or more of the components may be combined or commonly implemented. For example, the processor204may be used to implement not only the functionality described above with respect to the processor204, but also to implement the functionality described above with respect to the signal detector218and/or the DSP220. Further, each of the components illustrated inFIG. 2may be implemented using a plurality of separate elements.

For ease of reference, when the wireless device202is configured as a transmitting node, it is hereinafter referred to as a wireless device202t. Similarly, when the wireless device202is configured as a receiving node, it is hereinafter referred to as a wireless device202r. A device in the wireless communication system100may implement only functionality of a transmitting node, only functionality of a receiving node, or functionality of both a transmitting node and a receive node.

As discussed above, the wireless device202may comprise an AP104or an STA106, and may be used to transmit and/or receive communications having a plurality of MAC header types.

As discussed above, a wireless device202tmay communicate with a wireless device202r. For example, the wireless device202tmay transmit data packets to the wireless device202r. The wireless device202tmay be configured to transmit data packets of different types. In particular, the data packets may utilize an uncompressed header or a compressed header. The compressed header may be one of a plurality of types of compressed headers. Each header may be defined based on one of a plurality of compression protocols discussed further herein (e.g., an uncompressed protocol, a robust header compression (ROHC) over WiFi protocol, a flow based header compression protocol, a modified 6LoWPAN for WiFi protocol, etc.). Accordingly, for the wireless device202rto properly decode data packets transmitted by the wireless device202t, the wireless device202rmay need to determine which compression protocol the wireless device202tused in generating the header for the data packet (i.e., what type of header is in the data packet). In one aspect, in order to implement the compression protocols a compression layer is defined that is above the media access control (MAC) layer of the open systems interconnection (OSI) model used for communication. For example, the OSI model defines a hierarchy of layers starting at a lowest layer to a highest layer (i.e., a physical layer, a data link layer, a network layer, a transport layer, a session layer, a presentation layer, and an application layer). The MAC layer is a sublayer of the data link layer. Accordingly, the compression layer may be defined as a new layer or a sublayer that is above the MAC layer in the hierarch of layers. Accordingly, the compression layer specifies which compression protocol is to be used for a data packet, and the elements that are included in the compressed header.

In one aspect, the device202tand the device202rmay negotiate the use of a particular compression protocol for data packets communicated between the device202tand the device202r. The devices202tand202rmay negotiate by exchanging messages or signaling between each other that indicates the compression protocol to be used. In one aspect, such message exchange or signaling may occur at the MAC layer by defining mechanisms at the MAC layer (e.g., a 802.11 MAC layer).

In some aspects, the message exchange or signaling may occur through transmission of an information element. The information element may comprise one or more bits. The value of the information element may indicate which compression protocol(s) are to be used and/or parameters of the compression protocol. The device receiving the information element may further acknowledge receipt of the information element and use of the compression protocol(s) as defined by the information element.

Parameters may include header information that is static or semi static (e.g., does not change often) from one packet to another communicated between the wireless devices202tand202r. Accordingly, such header information may be exchanged and stored at each of the devices and used for decoding data packets having compressed headers. The compressed headers themselves may have only information that changes often. The information from the compressed header of the data packet may be used with the static or semi-static header information received in the message exchange or signaling to decode data packets.

In one aspect, the information element is transmitted from the wireless device202tto the wireless device202rand indicates which compression protocols are used for transmissions from the wireless device202tto the wireless device202r, but not from the wireless device202rto the wireless device202t. Further, the wireless device202rmay send a message acknowledging receipt of the information element and use of the compression protocol(s) as defined by the information element. In such an aspect, the wireless device202rmay transmit another information element to the wireless device202tthat indicates which compression protocols are used for transmissions from the wireless device202rto the wireless device202t. Further, the wireless device202tmay send a message acknowledging receipt of the information element and use of the compression protocol(s) as defined by the information element.

In another aspect, the information element is transmitted from the wireless device202tto the wireless device202rand indicates which compression protocols are used for transmissions from the wireless device202tto the wireless device202rand which compression protocols are used for transmissions from the wireless device202rto the wireless device202t. In such an aspect, the transmission in both directions may define use of the compression protocols in the same manner. Further, the wireless device202rmay send a message acknowledging receipt of the information element and use of the compression protocol(s) as defined by the information element.

In some aspects, the information element may be sent from the wireless device202tto the wireless device202rin a management frame. In one aspect, the information element may be sent as part of an existing management frame such as a MAC header. In another aspect, the information element may be sent in a new management frame, such as a compression request management frame. Further, the wireless device202rmay send a message acknowledging receipt of the information element and use of the compression protocol(s) as defined by the information element. For example, the acknowledgement may be sent in a new management frame, such as a compression response management frame.

As discussed above, the message exchange or signaling may indicate which compression protocol(s) are to be used and/or parameters of the compression protocol. For example, the message exchange or signaling may indicate (inherently or explicitly) that one compression protocol is to be used for all communications from the wireless device202tto the wireless device202rand/or vice versa. Accordingly, a device receiving packets after the message exchange or signaling is aware that the packets use the one compression protocol without further signaling.

In another example, the message exchange or signaling may indicate (inherently or explicitly) that different compression protocols are to be used for different packets communicated from the wireless device202tto the wireless device202rand/or vice versa. Accordingly, the device receiving the packets after the message exchange or signaling may look for an indicator in the packet that identifies which compression protocol is used for the packet. For example, different values of the indicator may be associated with different communication protocols. The mapping of the indicator values to the communication protocols may be inherently known by the devices (e.g., pre-programmed). Alternatively or additionally, the mapping of the indicator values to the communication protocols may be explicitly indicated via the message exchange or signaling (e.g., based on the information elements). For example, the compression request management frame and the compression response management frame may be used to setup multiple compression profiles between the wireless device202tand the wireless device202r. Each profile may be associated with a different compression protocol and identified by a numeric value. The indicator may therefore have the appropriate numeric value based on the compression protocol used for the data packet.

In some aspects, the indicator may be sent from the wireless device202tto the wireless device202ras new values for existing fields in data packets communicated between the wireless device202tand the wireless device202r. For example, the indicator may be sent as a new value for an ethertype field included in the logical link control (LLC) header, subnetwork access protocol (SNAP) header, or LLC+SNAP header, of a data packet.

In another example, the indicator may be sent as a new value for a field included in the MAC header of a data packet. In another example, a new service access point is defined for the compression protocol to be used and the indicator comprises a new value in the subnetwork access protocol (SNAP) header in the LLC+SNAP header.

FIG. 7illustrates an exemplary packet structure for a data packet700. The data packet700comprises a physical layer (PHY) header702, a MAC header704, an LLC (which may be an LLC+SNAP) header706, and a payload708. In one aspect, the indicator may be sent as a new value for an ethertype field of the LLC header706.

FIG. 8illustrates an exemplary packet structure for a data packet800. The data packet800comprises a physical layer (PHY) header802, a MAC header804, and a payload808, but does not include an LLC header. In one aspect, instead of an entire LLC header, an ethertype field may be added to the MAC header804. The indicator may be sent as a new value for the ethertype field.

FIG. 9illustrates an exemplary packet structure for a data packet900. The data packet900comprises a physical layer (PHY) header902, a MAC header904, an LLC (which may be an LLC+SNAP) header906, and a payload908. In one aspect, the indicator may be sent as a new value for a field in the MAC header904.

FIG. 10illustrates an exemplary LLC+SNAP header1000for a data packet. The LLC+SNAP header1000comprises a LLC header1002and a SNAP header1004. The LLC header1002comprises three octets1006. Further, the SNAP header1004comprises five octets1006. The first three octets of the SNAP header1004may be a three octet IEEE organizationally unique identifier (OUI). The last 2 octets may be the ethertype field that includes the indicator discussed above

In some aspects, there may be more than one session or flow of communication of packets between the wireless device202tand the wireless device202r. A different compression protocol may be defined for each of the sessions or flows using the message exchange or signaling discussed above. Further, each session or flow may have an identifier associated with the session or flow (e.g., a bit in a header for data packets of the session or flow, such as a TID). Accordingly, a wireless device202receiving a data packet of the particular session or flow can determine the compression protocol used for the data packet is the same as associated with the session or flow.

Various compression protocols that may be used according to the systems and methods described herein are further discussed below.

In one aspect, one compression protocol that can be used according to the systems and methods described herein is a ROHC over WiFi protocol. In the ROHC over WiFi protocol, some parameters may be exchanged during negotiation of use of the ROHC over WiFi protocol between the wireless device202tand the wireless device202r. Such parameters may include one or more of the following: IP compression protocol, MAX_CID (indicates the maximum value of a context identifier), MRRU (maximum reconstructed reception unit (the size of the largest reconstructed unit in octets that a decompressor is expected to reassemble from segments)), MAX_HEADER (largest header size in octets that may be compressed, and ROHC profile. The parameters may be exchanged according to negotiation discussed above. In another aspect, existing network discovery protocols (e.g., address resolution protocols) that are performed as part of ROHC setup is used to exchange the parameters, such as by including the parameters in ROHC setup messages. These parameters may therefore not be included in a compressed header for packets transmitted using the ROHC over WiFi protocol. The compressed header may include other information that is used along with the parameters to decode the packets.

In another aspect, another compression protocol that can be used according to the systems and methods described herein is a flow based header compression protocol. In the flow based header compression protocol, semi-static or static parameters may be exchanged during negotiation of use of the flow based header compression protocol between the wireless device202tand the wireless device202r. Such semi-static or static parameters may be different for each IP flow (which may be defined by at least a source and destination address for packets of the flow) between the wireless device202tand the wireless device202r. Such semi-static or static parameters may include fields from one or more of the following header fields: IPv4, IPv6, TCP, UDP, LLC/SNAP, App headers (e.g., http, etc.). In IPv4, the semi-static or static parameters may include one or more of the following fields: version, internet header length (IHL) differentiated services code point (DSCP), protocol, header checksum, source address, and destination address. In IPv6, the semi-static or static parameters may include one or more of the following fields: version, traffic class, flow label, source address, and destination address. In TCP, the semi-static or static parameters may include one or more of the following fields: source port, destination port, and reserved. In UDP, the semi-static or static parameters may include one or more of the following fields: source port and destination port.

The parameters may be exchanged according to negotiation discussed above. In another aspect, existing network discovery protocols (e.g., address resolution protocols) that are performed as part of setup are used to exchange the parameters, such as by including the parameters in setup messages. These parameters may therefore not be included in a compressed header for packets transmitted using the flow based header compression protocol. The compressed header may include other information (e.g., dynamic fields of the header fields that change between packets more often than the parameters) that is used along with the parameters to decode the packets. In IPv4, the dynamic fields may include one or more of the following fields: explicit congestion notification (ECN), total length, identification, flags, fragment offset, time to live (TTL) and options. In IPv6, the dynamic fields may include one or more of the following fields: payload length, next header, and hop limit. In TCP, the dynamic fields may include one or more of the following fields: control bits, sequence number, acknowledgement number, ECN, data offset, window, and checksum. In UDP, the dynamic fields may include one or more of the following fields: length and checksum.

In another aspect, another compression protocol that can be used according to the systems and methods described herein is a modified 6LoWPAN over WiFi protocol. In the modified 6LoWPAN over WiFi protocol, some parameters may be exchanged during negotiation of use of the modified 6LoWPAN over WiFi protocol between the wireless device202tand the wireless device202r. Other parameters may be inherently known and not exchanged, such as a MAC identifier. The parameters may be exchanged according to negotiation discussed above. In another aspect, existing network discovery protocols (e.g., address resolution protocols) that are performed as part of setup is used to exchange the parameters, such as by including the parameters in setup messages. These parameters may therefore not be included in a compressed header for packets transmitted using the modified 6LoWPAN over WiFi protocol. The compressed header may include other information that is used along with the parameters to decode the packets.

FIG. 3illustrates an aspect of a method300for negotiating use of a compression protocol. The method300may be used to negotiate which compression protocol(s) are to be used for particular communications between the wireless device202tand the wireless device202ras discussed above. Although the method300is described below with respect to elements of the wireless device202t, those having ordinary skill in the art will appreciate that other components may be used to implement one or more of the steps described herein.

At block302, the wireless device202tselects one or more compression protocols to be used for communication between the wireless device202tand the wireless device202r. Next, at block304, the wireless device202tsends information to the wireless device202rindicating the selected compression protocol(s). Optionally, along with or separate from the information indicating the selected compression protocol(s), the wireless device202tsends parameters related to the selected compression protocol(s). Continuing, at a block306, the wireless device202rsends and the wireless device202treceives a response acknowledging receipt of the information and optionally the parameters.

FIG. 4is a functional block diagram of another exemplary wireless device400that may be employed within the wireless communication system100. The device400comprises a selecting module402for selecting the one or more communication protocols to be used for communication between the wireless device400and the wireless device202r. The selecting module402may be configured to perform one or more of the functions discussed above with respect to the block302illustrated inFIG. 3. The selecting module402may correspond to one or more of the processor204and the DSP220. The device400further comprises a transmitting module404for transmitting information to the wireless device202rindicating the selected compression protocol(s) and optionally parameters. The transmitting module404may be configured to perform one or more of the functions discussed above with respect to the block304illustrated inFIG. 3. The transmitting module404may correspond to the transmitter210. The device400further comprises a receiving module406for a receiving a response acknowledging receipt of the information and optionally the parameters. The receiving module406may be configured to perform one or more of the functions discussed above with respect to the block306illustrated inFIG. 3. The receiving module406may correspond to the receiver212.

FIG. 5illustrates an aspect of a method500for communicating data packets having compressed headers using a compression protocol. Although the method500is described below with respect to elements of the wireless device202r, those having ordinary skill in the art will appreciate that other components may be used to implement one or more of the steps described herein.

At block502, a wireless communication comprising the packet is received at the wireless device202rafter negotiation of a compression protocol.

Subsequently, at block504, the data packet is processed according to the compression protocol indicated (inherently or expressly) in the data packet and/or parameters received during the negotiation.

FIG. 6is a functional block diagram of another exemplary wireless device600that may be employed within the wireless communication system100. The device600comprises a receiving module602for wirelessly receiving a data packet. In some aspects, the packet is compressed using a compression protocol. The receiving module602may be configured to perform one or more of the functions discussed above with respect to the block502illustrated inFIG. 5. The receiving module602may correspond to the receiver212. The device600further comprises a processing module604for processing the packet according to the compression protocol indicated (inherently or expressly) in the data packet and/or parameters received during the negotiation. The processing module604may be configured to perform one or more of the functions discussed above with respect to the block504illustrated inFIG. 5. The processing module604may correspond to one or more of the processor204, the signal detector218, and the DSP220.

As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like. Further, a “channel width” as used herein may encompass or may also be referred to as a bandwidth in certain aspects.