Encryption of the scheduled uplink message in random access procedure

Systems and methodologies are described that facilitate employing a random access procedure that leverages encrypted and/or unencrypted data in a scheduled uplink message. A random access preamble can be sent from an access terminal to a base station, and a random access response can be sent from the base station to the access terminal. A scheduled transmission message can be sent from the access terminal to the base station based upon a grant included in the random access response. When contention based random access is employed, the scheduled transmission message or a portion thereof can be unencrypted. Further, non-security-critical information can be sent in an unencrypted manner in the scheduled transmission message, while security-critical information can be encrypted for transmission (e.g., included in an encrypted portion of the scheduled transmission message and/or transmitted in a subsequent encrypted normal scheduled transmission message).

BACKGROUND

The following description relates generally to wireless communications, and more particularly to controlling encryption of uplink messages in a random access procedure in a wireless communication system.

Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data can be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources (e.g., bandwidth, transmit power, . . . ). For instance, a system can use a variety of multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing (OFDM), and others.

Generally, wireless multiple-access communication systems can simultaneously support communication for multiple access terminals. Each access terminal can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to access terminals, and the reverse link (or uplink) refers to the communication link from access terminals to base stations. This communication link can be established via a single-in-single-out, multiple-in-single-out or a multiple-in-multiple-out (MIMO) system.

MIMO systems commonly employ multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NTtransmit and NRreceive antennas can be decomposed into Ns independent channels, which can be referred to as spatial channels, where NS≦{NT,NR}. Each of the NSindependent channels corresponds to a dimension. Moreover, MIMO systems can provide improved performance (e.g., increased spectral efficiency, higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.

MIMO systems can support various duplexing techniques to divide forward and reverse link communications over a common physical medium. For instance, frequency division duplex (FDD) systems can utilize disparate frequency regions for forward and reverse link communications. Further, in time division duplex (TDD) systems, forward and reverse link communications can employ a common frequency region so that the reciprocity principle allows estimation of the forward link channel from reverse link channel.

Wireless communication systems oftentimes employ one or more base stations that provide a coverage area. A typical base station can transmit multiple data streams for broadcast, multicast and/or unicast services, wherein a data stream may be a stream of data that can be of independent reception interest to an access terminal. An access terminal within the coverage area of such base station can be employed to receive one, more than one, or all the data streams carried by the composite stream. Likewise, an access terminal can transmit data to the base station or another access terminal.

An access terminal can utilize a random access procedure to gain access to a system (e.g. to obtain allocation of a communications channel and/or associated resources, . . . ). For instance, the random access procedure can be used for initial access to the system, handover from a source base station to a target base station, uplink timing synchronization for data transfer, and the like. Typically, an access terminal sends a random access preamble on the uplink when the access terminal desires to gain access to the system. A base station can receive the random access preamble and respond with a random access response sent over the downlink. Based upon the random access response, the access terminal can attempt to send a scheduled transmission over the uplink to the base station. However, in the case of contention based random access, the base station can be unaware of an identity of the access terminal attempting to transmit the scheduled transmission. Hence, conventional techniques oftentimes fail to account for the base station being unable to determine an identity of a source from which the scheduled transmission originates, which can be particularly problematic when such scheduled transmission is encrypted.

SUMMARY

In accordance with one or more embodiments and corresponding disclosure thereof, various aspects are described in connection with facilitating employment of a random access procedure that leverages encrypted and/or unencrypted data in a scheduled uplink message. A random access preamble can be sent from an access terminal to a base station, and a random access response can be sent from the base station to the access terminal. A scheduled transmission message can be sent from the access terminal to the base station based upon a grant included in the random access response. When contention based random access is employed, the scheduled transmission message or a portion thereof can be unencrypted. Further, non-security-critical information can be sent in an unencrypted manner in the scheduled transmission message, while security-critical information can be encrypted for transmission (e.g., included in an encrypted portion of the scheduled transmission message and/or transmitted in a subsequent encrypted normal scheduled transmission message).

According to related aspects, a method that facilitates employing a random access procedure in a wireless communication environment is described herein. The method can include transmitting a random access preamble to a base station. Further, the method can comprise receiving a random access response from the base station based upon the random access preamble. Moreover, the method can include transmitting a scheduled transmission message, which includes at least a portion that is unencrypted, to the base station as granted by the random access response when employing contention based random access.

Another aspect relates to a wireless communications apparatus. The wireless communications apparatus can include a memory that retains instructions related to transmitting a random access preamble to a base station for at least one of initial access, re-entry from non-synchronized state, or handover from a source base station to the base station, receiving a random access response from the base station based upon the random access preamble, transmitting a scheduled transmission message, which includes at least a portion that is unencrypted, to the base station as granted by the random access response when employing contention based random access, and receiving a contention resolution message from the base station in response to the scheduled transmission message. Further, the wireless communications apparatus can include a processor, coupled to the memory, configured to execute the instructions retained in the memory.

Yet another aspect relates to a wireless communications apparatus that enables utilizing a random access procedure in a wireless communication environment. The wireless communications apparatus can include means for sending a random access preamble that includes a common random access signature to a base station when employing contention based random access. Moreover, the wireless communications apparatus can include means for obtaining a random access response from the base station based upon the random access preamble. Further, the wireless communications apparatus can include means for sending a scheduled transmission including at least an unencrypted portion to the base station as granted by the random access response when employing contention based random access.

Still another aspect relates to a computer program product that can comprise a computer-readable medium. The computer-readable medium can include code for transmitting a random access preamble to a base station. Further, the computer-readable medium can include code for receiving a random access response from the base station based upon the random access preamble. Moreover, the computer-readable medium can comprise code for transmitting a scheduled transmission including at least an unencrypted portion to the base station as granted by the random access response when employing contention based random access.

In accordance with another aspect, an apparatus in a wireless communication system can include a processor, wherein the processor can be configured to transmit a random access preamble to a base station. The processor can also be configured to receive a random access response from the base station based upon the random access preamble. Further, the processor can be configured to transmit a scheduled transmission including at least an unencrypted portion to the base station as granted by the random access response when employing contention based random access.

According to other aspects, a method that facilitates deciphering data obtained during a random access procedure in a wireless communication environment is described herein. The method can include receiving a random access preamble from an access terminal. Further, the method can include transmitting a random access response to the access terminal based upon the random access preamble. The method can also comprise receiving a scheduled transmission message, which includes at least a portion that is unencrypted, from the access terminal when employing contention based random access. Moreover, the method can include recognizing an identity of the access terminal based upon information included in the portion of the scheduled transmission message that is unencrypted when employing contention based random access.

Yet another aspect relates to a wireless communications apparatus that can include a memory that retains instructions related to receiving a random access preamble from an access terminal, transmitting a random access response to the access terminal based upon the random access preamble, receiving a scheduled transmission message, which includes at least a portion that is unencrypted, from the access terminal when employing contention based random access, recognizing an identity of the access terminal based upon information included in the portion of the scheduled transmission message that is unencrypted when employing contention based random access, and determining a security context associated with the access terminal based upon the recognized identity of the access terminal. Further, the wireless communications apparatus can comprise a processor, coupled to the memory, configured to execute the instructions retained in the memory.

Another aspect relates to a wireless communications apparatus that enables employing a random access procedure in a wireless communication environment. The wireless communications apparatus can include means for obtaining a scheduled transmission message including at least an unencrypted portion from the access terminal when employing contention based random access. The wireless communications apparatus can further include means for recognizing an identity of the access terminal based upon information included in the unencrypted portion of the scheduled transmission message. The wireless communications apparatus can also include means for retrieving a security context associated with the access terminal based upon the recognized identity of the access terminal. Moreover, the wireless communications apparatus can include means for deciphering an encrypted, normal scheduled transmission message or encrypted portion of the scheduled transmission message that includes the unencrypted portion received from the access terminal based upon the retrieved security context.

Still another aspect relates to a computer program product that can comprise a computer-readable medium. The computer-readable medium can include code for obtaining a scheduled transmission message including at least an unencrypted portion from the access terminal when employing contention based random access. The computer-readable medium can also include code for recognizing an identity of the access terminal based upon information included in the unencrypted portion of the scheduled transmission message. The computer-readable medium can further include code for retrieving a security context associated with the access terminal based upon the recognized identity of the access terminal. Moreover, the computer-readable medium can include code for deciphering an encrypted, normal scheduled transmission message or encrypted portion of the scheduled transmission message that includes the unencrypted portion received from the access terminal based upon the retrieved security context.

In accordance with another aspect, an apparatus in a wireless communication system can include a processor, wherein the processor can be configured to receive a scheduled transmission message including at least an unencrypted portion from the access terminal when employing contention based random access; recognize an identity of the access terminal based upon information included in the unencrypted portion of the scheduled transmission message; retrieve a security context associated with the access terminal based upon the recognized identity of the access terminal; and decipher an encrypted, normal scheduled transmission message or encrypted portion of the scheduled transmission message that includes the unencrypted portion received from the access terminal based upon the retrieved security context.

DETAILED DESCRIPTION

The techniques described herein can be used for various wireless communication systems such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single carrier-frequency division multiple access (SC-FDMA) and other systems. The terms “system” and “network” are often used interchangeably. A CDMA system can implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and other variants of CDMA. CDMA2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA system can implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA system can implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) is an upcoming release of UMTS that uses E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the uplink.

Single carrier frequency division multiple access (SC-FDMA) utilizes single carrier modulation and frequency domain equalization. SC-FDMA has similar performance and essentially the same overall complexity as those of an OFDMA system. A SC-FDMA signal has lower peak-to-average power ratio (PAPR) because of its inherent single carrier structure. SC-FDMA can be used, for instance, in uplink communications where lower PAPR greatly benefits access terminals in terms of transmit power efficiency. Accordingly, SC-FDMA can be implemented as an uplink multiple access scheme in 3GPP Long Term Evolution (LTE) or Evolved UTRA.

Furthermore, various embodiments are described herein in connection with an access terminal. An access terminal can also be called a system, subscriber unit, subscriber station, mobile station, mobile, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, user device, or user equipment (UE). An access terminal can be 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, computing device, or other processing device connected to a wireless modem. Moreover, various embodiments are described herein in connection with a base station. A base station can be utilized for communicating with access terminal(s) and can also be referred to as an access point, Node B, Evolved Node B (eNodeB) or some other terminology.

Referring now toFIG. 1, a wireless communication system100is illustrated in accordance with various embodiments presented herein. System100comprises a base station102that can include multiple antenna groups. For example, one antenna group can include antennas104and106, another group can comprise antennas108and110, and an additional group can include antennas112and114. Two antennas are illustrated for each antenna group; however, more or fewer antennas can be utilized for each group. Base station102can additionally include a transmitter chain and a receiver chain, each of which can in turn comprise a plurality of components associated with signal transmission and reception (e.g., processors, modulators, multiplexers, demodulators, demultiplexers, antennas, etc.), as will be appreciated by one skilled in the art.

Base station102can communicate with one or more access terminals such as access terminal116and access terminal122; however, it is to be appreciated that base station102can communicate with substantially any number of access terminals similar to access terminals116and122. Access terminals116and122can be, for example, cellular phones, smart phones, laptops, handheld communication devices, handheld computing devices, satellite radios, global positioning systems, PDAs, and/or any other suitable device for communicating over wireless communication system100. As depicted, access terminal116is in communication with antennas112and114, where antennas112and114transmit information to access terminal116over a forward link118and receive information from access terminal116over a reverse link120. Moreover, access terminal122is in communication with antennas104and106, where antennas104and106transmit information to access terminal122over a forward link124and receive information from access terminal122over a reverse link126. In a frequency division duplex (FDD) system, forward link118can utilize a different frequency band than that used by reverse link120, and forward link124can employ a different frequency band than that employed by reverse link126, for example. Further, in a time division duplex (TDD) system, forward link118and reverse link120can utilize a common frequency band and forward link124and reverse link126can utilize a common frequency band.

Each group of antennas and/or the area in which they are designated to communicate can be referred to as a sector of base station102. For example, antenna groups can be designed to communicate to access terminals in a sector of the areas covered by base station102. In communication over forward links118and124, the transmitting antennas of base station102can utilize beamforming to improve signal-to-noise ratio of forward links118and124for access terminals116and122. Also, while base station102utilizes beamforming to transmit to access terminals116and122scattered randomly through an associated coverage, access terminals in neighboring cells can be subject to less interference as compared to a base station transmitting through a single antenna to all its access terminals.

A random access procedure can be utilized in system100. For instance, the random access procedure can be used by access terminals116and122for initial access, handover to and/or from base station102, timing synchronization (e.g. re-entry from non-synchronized mode, . . . ), and the like. A random access procedure typically includes transmission of a random access preamble (e.g., message1, . . . ) by an access terminal (e.g., access terminal116, access terminal122, . . . ) to base station102over the uplink, transmission of a random access response (e.g., message2, . . . ) from base station102to the access terminal over the downlink based upon the received random access preamble, and transmission of a scheduled transmission (e.g., message3, . . . ) from the access terminal to base station102over the uplink where such scheduled transmission is granted by the random access response message. As used herein, the term “message3” refers to the scheduled transmission sent by the access terminal to base station102as granted by the random access response message from base station102.

Moreover, there are two types of random access procedures that can be leveraged in system100: contention based random access and non-contention based random access. According to an illustration, in contention based random access, two or more access terminals116,122can transmit random access preambles to base station102at a substantially similar time over a shared resource (e.g., channel) while contending for system access. However, base station102typically is unable to identify access terminals116,122that transmit these random access preambles (e.g., a common random access signature can be sent as at least part of the random access preambles from more than one access terminal116,122). Base station102can send a random access response over the downlink based upon a received random access preamble, and obtain a scheduled transmission from an access terminal in response to the grant included in the random access response; yet, base station102may again be unable to identify the access terminal transmitting the scheduled transmission (e.g., message3, . . . ) unless an access terminal specific identifier is provided in such scheduled transmission. Moreover, in non-contention based random access, an access terminal specific random access signature can be provided to, determined by, etc. an access terminal prior to sending the random access preamble, and this access terminal specific random access signature can be transmitted by the access terminal (e.g., as at least part of the random access preamble, message1in a random access procedure, . . . ) to base station102. Thus, upon receiving the access terminal specific random access signature in non-contention based random access, base station102can identify the access terminal from which the random access signature was sent. Further, this identification related information can be used by base station102to identify a source of a received scheduled transmission (e.g., message3, . . . ) that is responsive to a random access response sent by base station102.

According to an illustration, when contention based random access is employed, the scheduled transmission (e.g., message3, . . . ) can be unencrypted. Pursuant to another example, when contention based random access is utilized, at least a portion of the scheduled transmission message (e.g., message3, . . . ) can be unencrypted. Sending an unencrypted message3or a portion of such message3unencrypted can stem from the network (e.g., base station102, . . . ) being unable to determine which access terminal transmitted the message3upon receipt. Rather, contents of message3can be evaluated to recognize the associated source of such message. This evaluation is performed upon unencrypted data (e.g., unencrypted message3or unencrypted portion thereof) since base station102is unable to decipher an encrypted message without knowing the identity of the access terminal transmitting the encrypted message. In non-contention based random access, this limitation does not exist. Accordingly, when contention based random access is employed, an access terminal can send non-security-critical information (e.g., access terminal identifier, message discriminator, . . . ) in the unencrypted scheduled transmission message (e.g., message3, . . . ) and/or unencrypted portion of a scheduled transmission message (e.g., message3, . . . ). Further, the access terminal can transmit security-critical information in a disparate, encrypted message and/or an encrypted portion of the scheduled transmission message (e.g., message3, . . . ).

Now turning toFIG. 2, illustrated is a system200that controls encryption of uplink messages in a random access procedure. System200includes an access terminal202and a base station204; however, it is to be appreciated that system200can include any number of access terminals similar to access terminal202and/or any number of base stations similar to base station204. Access terminal202and base station204can each transmit and/or receive information, signals, data, instructions, commands, bits, symbols, and the like.

Access terminal202can further include a random access requester206, an unencrypted message generator208and an encrypted message generator210. Moreover, base station204can include a random access grantor212, a message source identifier214, and a security context determiner216. Random access requester206transmits a random access preamble to base station204. In case of contention based random access, random access requester206can send a generic random access signature as at least part of the random access preamble. Further, in case of non-contention based random access, random access requester206can transmit a particular random access signature from a set of random access signatures as at least part of the random access preamble. For instance, the particular random access signature can be assigned to access terminal202, while at least one disparate random access signature from the set can be allocated to at least one disparate access terminal (not shown). According to another illustration, it is contemplated that random access requester206can determine the particular random access signature to employ from the set when operating in a non-contention based random access mode. The particular random access signature can be a dedicated signature that includes a bit pattern unique to access terminal202(e.g., other access terminals (not shown) will not use this dedicated signature, . . . ).

By way of another illustration, random access requester206(and/or access terminal202generally) can determine whether contention based random access or non-contention random access is being utilized in system200. For instance, random access requester206can identify the type of random access procedure being used based upon whether the random access procedure is being employed for initial access, re-entry from non-synchronized mode, handover, and so forth (e.g., the type of random access procedure can be predetermined based upon the use of such procedure, . . . ). However, the claimed subject matter is not limited to the foregoing.

Random access requester206can transmit a random access preamble on the uplink whenever access terminal202desires to access the system (e.g., if access terminal202has data to send, if access terminal202is paged by the system, if access terminal202receives a handover command to transition from a source base station to a target base station, . . . ). A random access preamble can also be referred to as an access request, an access signature, an access probe, a random access probe, a signature sequence, a Random Access Channel (RACH) signature sequence, etc. The random access preamble can include various types of information and can be sent in various manners.

Further, base station204can receive the random access preamble and random access grantor212can respond by sending a random access response to access terminal202. A random access response can also be referred to as an access grant (AGCH), an access response, etc. The random access response can carry various types of information and can be sent in various manners. For instance, the random access response can include control channel resources, uplink resources, control information, and so forth for access terminal202. By way of illustration, the control channel resources can include Channel Quality Indicator (CQI) resources used to send CQI on the uplink by access terminal202, power control resources used to send power control corrections on the downlink to access terminal202, and so forth. Moreover, the control information can include timing information used to adjust transmit timing of access terminal202, power control corrections used to adjust transmit power of access terminal202, and the like.

Access terminal202can receive the random access response sent by random access grantor212of base station204. The random access response can grant uplink resources to be used by access terminal202. Moreover, access terminal202(e.g., unencrypted message generator208, encrypted message generator208, a grant evaluator (not shown) included in access terminal202, . . . ) can recognize the uplink resources granted to access terminal202in the random access response. Thereafter, unencrypted message generator208and/or encrypted message generator210can yield uplink messages or portions of uplink messages that can be sent from access terminal202to base station204. For instance, granted uplink resources can be utilized to transmit a message3yielded by unencrypted message generator208and/or encrypted message generator210.

According to an example, when contention based random access is employed, unencrypted message generator208can yield an unencrypted message3for transmission to base station204. The unencrypted message3can be transmitted to base station204rather than an encrypted message since the network (e.g., base station204, . . . ) can lack knowledge of the originator of message3(e.g., message source identifier214can be unable to determine an identity of access terminal202from a random access preamble sent over the uplink by random access requester206of access terminal202when using contention based random access, . . . ). If base station204is unaware of the originator of message3and message3were to be encrypted, base station204would not know which security configuration to apply in order to decrypt such encrypted message (e.g., base station204would be unable to decipher the encrypted message3when using contention based random access, . . . ). Thus, access terminal202cannot apply encryption for the uplink message3transmitted in the contention based random access even if Radio Resource Control (RRC) security is active. Rather, access terminal202can send message3unencrypted due to the above limitations under various scenarios including, but not limited to, transmission of handover complete in a target cell, transmission of handover failure in a source cell, uplink timing synchronization for data transfer, and so forth.

Following this example, unencrypted message generator208can yield an unencrypted message (e.g., unencrypted message3, . . . ) that includes information, parameters, etc. that need not be ciphered. For instance, the unencrypted message built by unencrypted message generator208can include a temporary identifier such as a Cell Radio Network Temporary Identifier (C-RNTI) corresponding to access terminal202; however, it is to be appreciated that any differing type of identifier can be used instead of or in addition to the C-RNTI. Moreover, unencrypted message generator208can determine disparate information, parameters, etc. (e.g., non-security-critical information, . . . ) that can be transmitted as part of the unencrypted uplink message (e.g., unencrypted message3, . . . ). Further, security-critical information can be included in encrypted message(s) yielded by encrypted message generator210and transmitted after random access in accordance with this example. Additionally, message3can be transmitted by access terminal202via using Radio Link Control—Transparent Mode (RLC-TM).

By sending an unencrypted message3yielded from unencrypted message generator208per the aforementioned example, message source identifier214can evaluate the unencrypted message3to determine that access terminal202transmitted such unencrypted message3. Message source identifier214can similarly analyze at least one disparate unencrypted message3sent from at least one disparate access terminal (not shown) to identify the corresponding source(s). For instance, the unencrypted message3yielded by unencrypted message generator208and sent by access terminal202can include the temporary identifier (e.g., C-RNTI, . . . ) associated with access terminal202. Further, message source identifier214can analyze this temporary identifier to recognize that such identifier corresponds to access terminal202.

Upon message source identifier214identifying the source of the unencrypted message, security context determiner216can recognize a security context associated with the identified source. For example, when message source identifier214determines access terminal202to be the source of an unencrypted message3, security context determiner216can identify, retrieve, generate, etc. the security context corresponding to access terminal202. By way of illustration, base station204may have previously associated access terminal202with a given security context while access terminal202was in connected mode at an earlier time, and this given security context can be retained in memory associated with base station204for later retrieval when the random access procedure is effectuated. Alternatively, under the handover scenario, the security context associated with access terminal202can be obtained from a disparate base station (not shown) when access terminal202is sent a handover command from the disparate base station to initiate handover to base station204. The security context as recognized can thereafter be utilized to decipher encoded message(s) generated by encrypted message generator210and sent by access terminal202.

Moreover, message source identifier214and/or base station204in general can send a contention resolution message (e.g., message4, . . . ) to access terminal202upon determining an identity of the source of the unencrypted message3. Thereafter, encrypted message generator210can yield a normal scheduled encrypted transmission that can be sent over the uplink. Moreover, it is contemplated that encrypted message generator210can utilize substantially any type of encryption technique(s). Further, the security context corresponding to access terminal202as recognized by security context determiner216can be leveraged by base station204to decrypt encrypted messages yielded by encrypted message generator210and sent over the uplink.

By way of another illustration, when non-contention based random access is employed, message source identifier214can identify access terminal202as the source of a random access preamble when transmitted by random access requester206of access terminal202. For instance, message source identifier214can recognize a given access terminal specific random access signature included in the random access preamble as being associated with access terminal202. Thus, access terminal202can send an encrypted message3yielded by encrypted message generator210over the uplink to base station204since security context determiner216of base station204can identify a security context associated with access terminal202to be used for decryption based upon the random access preamble (e.g., rather than based upon message3as is the case for contention based random access). In an aspect, access terminal202can send an encrypted RRC message yielded by encrypted message generator210when possible (e.g., in non-contention based random access, message3is encrypted if security is active, . . . ). As opposed to the contention based random access, access terminal202does not have a specific restriction as to what it can send in message3under the non-contention based random access scenario. Thus, access terminal202can apply different restrictions (e.g., perform different actions, . . . ) depending on the type of random access procedure being utilized. However, the claimed subject matter is not limited to the aforementioned examples.

Now referring toFIG. 3, illustrated is an example signaling diagram300of a basic random access procedure. The random access procedure can be effectuated between an access terminal (e.g., access terminal202ofFIG. 2, . . . ) and a base station (e.g., base station204ofFIG. 2, . . . ). At302, the access terminal transmits a random access preamble to the base station. The random access preamble can be referred to as message1. At304, the base station transmits a random access response to the access terminal. The random access response can be referred to as message2. At306, the access terminal transmits a scheduled transmission to the base station in accordance with a grant provided by the random access response. The scheduled transmission can be referred to as message3. Further, the scheduled transmission can be transmitted with Radio Link Control—Transparent Mode (RLC-TM). At308, the base station transmits a contention resolution message to the access terminal. The contention resolution message can be referred to as message4. Further, the contention resolution message can signify an end to the random access procedure.

Turning toFIG. 4, illustrated is an example signaling diagram400of uplink Radio Resource Control (RRC) message transmission by a non-synchronized access terminal. Signaling diagram400illustrates use of contention based random access for re-entry by the access terminal from a non-synchronized mode. At402, the access terminal transmits a random access preamble to a serving base station. For instance, a common random access signature can be included as at least part of the random access preamble, and thus, the serving base station can be unable to determine the source of the random access preamble. At404, a random access response can be sent by the serving base station to the access terminal. The random access response can be responsive to the random access preamble and/or can provide an uplink grant to the access terminal.

At406, the access terminal can utilize the uplink grant to transmit message3, which is unencrypted, to the serving base station. By way of example, message3can include an identifier corresponding to the access terminal. Further, message3can indicate to the serving base station that the procedure is for uplink data, message transmission, etc. (e.g., message3can include a message discriminator, . . . ). At408, in response to message3, the serving base station can send a contention resolution message to the access terminal. For instance, the contention resolution message can include another uplink grant for the access terminal. Moreover, the contention resolution message can indicate to the access terminal that re-entry to synchronized mode has been completed and/or that the access terminal can employ encryption for subsequent uplink transmissions (e.g., the contention resolution message can signify an end to the random access procedure, . . . ). At410, the access terminal transmits a normal scheduled transmission message, which is encrypted, to the serving base station. For instance, the access terminal can utilize the uplink grant included in the contention resolution message for sending this encrypted message. In contrast to unencrypted message3, which can include the identifier related to the access terminal and/or an indicator as to the type of data to be transmitted by the access terminal, the encrypted, normal scheduled transmission message can be an actual RRC message (e.g., measurement report, including security-critical information, . . . ). Moreover, subsequent scheduled uplink transmissions from the access terminal to the serving base station while the access terminal remains in synchronized mode can similarly be encrypted.

With reference toFIG. 5, illustrated is an example signaling diagram500showing a handover scenario. Handover can be effectuated such that an access terminal transitions from being served by a source base station to being served by a target base station. The handover can involve a security configuration change, which can cause the access terminal to send critical security related information to the target base station.

At502, a handover command can be transmitted by the source base station to the access terminal. The handover command can initiate the access terminal to handover to the target base station. Further, although not shown, it is contemplated that the source base station can interact with the target base station prior to the access terminal beginning the random access procedure. For instance, the source base station can employ such interaction to transmit a security context associated with the access terminal to the target base station.

At504, the access terminal transmits a random access preamble to the target base station in response to receiving the handover command from the source base station. Since contention based random access can be employed, the target base station can be unable to determine an identity of the source of the random access preamble. At506, a random access response can be transmitted from the target base station to the access terminal. At508, the access terminal transmits an unencrypted message3to the target base station in response to the received random access response. The unencrypted message3can be used by the access terminal for transmission of non-security-critical information (e.g., non-critical handover complete information, an identifier related to the access terminal such as a C-RNTI, a message discriminator, . . . ). At510, the target base station transmits a contention resolution message to the access terminal. At512, the access terminal sends a normal scheduled transmission, which is encrypted, to the target base station. For instance, this encrypted, normal scheduled transmission can include security-critical information (e.g., handover complete critical information, . . . ).

As shown in the examples fromFIGS. 4 and 5, in contention based random access, message3can be unencrypted. Moreover, the access terminal can transmit non-critical information with the message3that is unencrypted. Further, the access terminal can utilize another message (e.g., normal scheduled transmission at410or512, . . . ) to transmit information that needs encryption after the contention based random access procedure. Moreover, in non-contention based random access, message3can be encrypted if security is active. Accordingly, the access terminal can perform different actions depending on type of random access procedure (e.g., encrypt or decrypted message3as a function of random access procedure type, include or exclude an identifier in message3as a function of random access procedure type, control information included in message3based upon the random access procedure type, delay security-critical information to be included in an encrypted message based upon the random access procedure type, . . . ). Although the foregoing examples describe the entirety or most of message3being unencrypted for contention based random access, it is contemplated that a portion of message3can be unencrypted while a remainder of message3can be encrypted as described in the below examples.

Referring toFIG. 6, illustrated is a system600that sends encrypted and/or unencrypted messages as part of a random access procedure. System600includes access terminal202and base station204, where access terminal202can include random access requester206, unencrypted message generator208, and encrypted message generator210and base station204can include random access grantor212, message source identifier214, and security context determiner216. Although not shown, it is to be appreciated that system600can include any number of additional access terminals similar to access terminal202and/or any number of additional base stations similar to base station204.

According to an example, access terminal202can transmit a message3to base station204as part of a random access procedure as described herein. When contention based random access is employed, the message3sent by access terminal202can include an unencrypted portion (e.g., yielded by unencrypted message generator208) and an encrypted portion (e.g., yielded by encrypted message generator210). Access terminal202can include a message concatenater602that can combine the unencrypted portion provided by unencrypted message generator208and the encrypted portion provided by encrypted message generator210to yield the message3. Further, the unencrypted portion of message3generated by unencrypted message generator208can include an identifier corresponding to access terminal202, which can be used by message source identifier214to recognize access terminal202as the source of message3. Thereafter, security context determiner216can recognize the security context associated with access terminal202based upon the determined identity, and the security context can be employed to decipher the encrypted portion of message3(as well as subsequent encrypted message(s)) yielded by the encrypted message generator210and sent by access terminal202to base station204over the uplink.

Further, Radio Link Control—Unacknowledged Mode (RLC-UM) and/or Radio Link Control—Acknowledged Mode (RLC-AM) can be used in message3. RLC-UM does not provide feedback from the receiver side, whereas RLC-AM uses an acknowledgement from the receiver side (e.g., if an acknowledgement is not obtained at the transmitter side, then the transmitter can resend the packet(s), . . . ). Moreover, RLC-AM supports segmentation as described below. It is noted that except for the first RRC message at the LTE_IDLE to LTE_ACTIVE state transition, it is possible for access terminal202to use RLC-UM and RLC-AM in message3. Accordingly, access terminal202can use non-transparent mode RLC for sending non-security-critical information, which is unencrypted. Additionally, message concatenater602can concatenate encrypted information within message3.

It may complicate network behavior if access terminal202uses RLC-AM before message source identifier214identifies access terminal202as being the originator of message3due to RLC-AM having the context for access terminal202. Thus, access terminal202can use RLC-UM with a special length indicator for the first RRC message for this reason since RLC-UM provides information on the RLC Protocol Data Unit (PDU) size. Moreover, it is contemplated that RLC-TM can be used if Medium Access Control (MAC) provides the size information for the RLC-TM PDU. Further, the normal RRC message that follows can use RLC-AM.

Encrypted message generator210can further include a segmenter604. Since the size of message3can be limited, an encrypted message (e.g., RRC message, . . . ) yielded by encrypted message generator210may be unable to fit in the encrypted portion of message3. Thus, segmenter604can segment this encrypted message (e.g., RRC message, . . . ) into separate parts, thereby enabling access terminal202to transfer a part of the encrypted message in the encrypted portion of message3and the remaining part of the encrypted message in a normal scheduled transmission.

Base station204can further include a buffer606. Buffer606can be utilized to retain the encrypted portion of message3and onwards until the first unencrypted portion of message3is processed at the RRC layer in the network. Thus, the Packet Data Convergence Protocol (PDCP) layer in the network can be a stop and wait protocol at least for message3. Thus, the above can enable transmission of message3with RLC-TM with rules on what access terminal202can transmit and no special handling for the RRC message transmission for subsequent RRC messages. Hence, there can be a reduction in Control-plane (C-plane) latency.

Further, in case of non-contention based random access, the random access requester206can send a random access preamble that allows message source identifier214(e.g., network, . . . ) to identify access terminal202. It is therefore possible for access terminal202to encrypt the entirety of message3and for the network to use the correct security configuration for message3. Moreover, as opposed to the contention based random access, access terminal202is not imposed a specific restriction as to what it can send in message3in this scenario.

According to an example, access terminal202can behave differently depending on the type of random access procedure (e.g., contention based versus non-contention based); however, the claimed subject matter is not so limited. For instance, where the entirety of message3is unencrypted for contention based random access per the example described in connection withFIGS. 2,4, and5, sending security critical information in message3in non-contention based random access can reduce C-plane latency compared to contention based random access. Under such scenario, allowing access terminal202to implement different behaviors as a function of random access procedure type can reduce latency for the non-contention based random access case. Following the example where message3includes an unencrypted portion and an encrypted portion as described inFIG. 6, different behaviors for contention based random access and non-contention based random access may or may not be utilized.

Now turning toFIG. 7, illustrated is an example signaling diagram700of a random access procedure that communicates encrypted and unencrypted information in message3. Signaling diagram700depicts use of random access by an access terminal to re-enter synchronized mode from non-synchronized mode. However, it is to be appreciated that signaling similar to the below description can be utilized in conjunction with handover from a source base station to a target base station (e.g., signaling described in diagram700can be effectuated between the target base station and the access terminal upon the access terminal receiving a handover command from the source base station as shown inFIG. 5, . . . ).

At702, a random access preamble can be transmitted from the access terminal to the serving base station. At704, a random access response can be transmitted by the serving base station to the access terminal. At706, message3can be transmitted from the access terminal to the serving base station. Message3can include an unencrypted portion and an encrypted portion. The unencrypted portion can include an identifier (e.g., C-RNTI, . . . ) associated with the access terminal, a message discriminator, a special length indicator for the unencrypted portion of message3, and so forth. For instance, the unencrypted portion can be sent using RLC-UM. According to another illustration, the unencrypted portion can be transmitted using RLC-TM. By way of further example, a MAC layer PDU can be used for the unencrypted portion of message3. Further, an RRC message that includes security-critical information such as a measurement report (or a portion thereof) can be transmitted in the encrypted portion of message3. The encrypted portion can be sent using RLC-AM, which supports segmentation. For instance, this measurement report can be segmented such that a first part of the measurement report can be concatenated with the unencrypted portion and sent as message3, while a remainder of the measurement report can be sent in subsequent uplink transmission(s). At708, a contention resolution message can be transmitted by the serving base station to the access terminal. At710, a normal scheduled transmission, which is encrypted, can be sent by the access terminal to the serving base station. This normal scheduled transmission can include the remainder of the measurement report. Moreover, the normal scheduled transmission can be sent using RLC-AM.

According to an example, signaling as shown in diagram700can be utilized for both contention based random access and non-contention based random access (e.g., message3can include an unencrypted portion and an encrypted portion for both contention based random access and non-contention based random access, . . . ). Pursuant to another illustration, signaling diagram700can be employed for contention based random access, while different signaling can be used for non-contention based random access. Following this illustration, for non-contention based random access, the entirety or most of message3can be encrypted and/or can be sent using RLC-AM rather than encrypting and/or using RLC-AM for only a portion of message3.

Referring toFIGS. 8-9, methodologies relating to utilizing encrypted and unencrypted messages for a random access procedure in a wireless communication environment are illustrated. While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts can, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein. For example, those skilled in the art will understand and appreciate that a methodology could alternatively be represented as a series of interrelated states or events, such as in a state diagram. Moreover, not all illustrated acts can be required to implement a methodology in accordance with one or more embodiments.

With reference toFIG. 8, illustrated is a methodology800that facilitates employing a random access procedure in a wireless communication environment. At802, a random access preamble can be transmitted to a base station. For instance, the random access preamble can include a random access signature that is commonly utilized by access terminals in the wireless communication environment (e.g., the common random access signature can be used for contention based random access, According to another illustration, the random access preamble can include an access terminal specific random access signature (e.g., used for non-contention based random access, . . . ). The random access preamble can be sent to the base station to begin initial access or re-entry from non-synchronized state, for instance. Per a further example, the random access preamble can be transmitted to the base station (e.g., target base station) in response to receiving a handover command from a disparate, source base station.

At804, a random access response can be received from the base station based upon the random access preamble. The random access response can provide a grant for a subsequent uplink, scheduled transmission.

At806, a scheduled transmission message, which includes at least a portion that is unencrypted, can be transmitted to the base station as granted by the random access response when employing contention based random access. According to an illustration, the unencrypted portion can include a temporary identifier (e.g. Cell Radio Network Temporary Identifier (C-RNTI), . . . ) of the access terminal from which the scheduled transmission is transmitted. The temporary identifier can enable the base station to recognize an identity of the access terminal, determine a security context associated with the access terminal, and employ such security context for decrypting subsequent uplink transmission(s) from the access terminal. Further, the unencrypted portion can include non-security-critical information (e.g. a message discriminator, . . . ). Moreover, a contention resolution message can be received from the base station in response to the scheduled transmission message.

According to an example, all or substantially most of the scheduled transmission message can be unencrypted when employing contention based random access. Moreover, this scheduled transmission message can be transmitted with Radio Link Control—Transparent Mode (RLC-TM); however, the claimed subject matter is not so limited. Further, a subsequent normal scheduled transmission message, which is encrypted, can be sent to the base station after receiving the contention resolution message from the base station. This subsequent normal scheduled transmission message can include security-critical information (e.g., critical data related to a Radio Resource Control (RRC) measurement report, handover completion, handover failure, . . . ). Further, when non-contention based random access is employed per this example, the scheduled transmission message can be encrypted. Thus, the type of random access procedure being utilized can be identified, and whether the scheduled transmission message sent in response to the grant included in the random access response is encrypted or unencrypted can vary depending on the identified type of random access procedure.

By way of another example, the scheduled transmission message can include the unencrypted portion and an encrypted portion when employing contention based random access. Thus, the unencrypted portion and the encrypted portion can be concatenated within the scheduled transmission message. For instance, the unencrypted portion can be transmitted with Radio Link Control—Unacknowledged Mode (RLC-UM) or RLC-TM while the encrypted portion can be transmitted with Radio Link Control—Acknowledged Mode (RLC-AM). Further, the unencrypted portion can include non-security-critical information and the encrypted portion can include security-critical information (e.g., critical data related to a Radio Resource Control (RRC) measurement report, handover completion, handover failure, . . . ). The non-security-critical information, for instance, can include a special length indicator with RLC-UM. According to another illustration, the Medium Access Control (MAC) layer Protocol Data Unit (PDU) can be used in place of RLC-UM. Moreover, the security-critical information included in the encrypted portion can be segmented such that a first part is included in the encrypted portion of the scheduled transmission message and the remainder is included in at least one subsequent normal scheduled transmission message that is encrypted and sent to the base station after receiving the contention resolution message. Further, following this example, it is contemplated that similar use of the unencrypted portion and the encrypted portion for the scheduled transmission message sent in response to the grant included in the random access response can be employed when non-contention based random access is employed (e.g., similar access terminal behavior for both contention based random access and non-contention based random access). Additionally or alternatively, non-contention based random access can yield differing behavior for such scheduled transmission message whereby all or substantially most of the scheduled transmission message (e.g., message3, . . . ) is encrypted.

Turning toFIG. 9, illustrated is a methodology900that facilitates deciphering data obtained during a random access procedure in a wireless communication environment. At902, a random access preamble can be received from an access terminal. The random access preamble can include a common random access signature (e.g., for contention based random access, . . . ), and thus, the identity of the access terminal can be unable to be recognized. Further, for non-contention based random access, the random access preamble can include a random access signature that is unique to the access terminal from which the random access preamble was obtained. At904, a random access response can be transmitted to the access terminal based upon the random access preamble. At906, a scheduled transmission, which includes at least a portion that is unencrypted, can be received from the access terminal when employing contention based random access. For instance, the unencrypted portion can include an identifier of the access terminal (e.g., Cell Radio Network Temporary Identifier (C-RNTI), . . . ). By way of another illustration, for non-contention based random access, the scheduled transmission can be encrypted; however, the claimed subject matter is not so limited (e.g., similar access terminal behavior can be employed for contention based random access and non-contention based random access, . . . ). Moreover, a contention resolution message can be sent to the access terminal in response to the received, scheduled transmission. At908, an identity of the access terminal can be recognized based upon information included in the portion of the scheduled transmission that is unencrypted when employing contention based random access. Further, a security context of the access terminal can be determined based upon the recognized identity of the access terminal. Moreover, this security context can be used to decipher subsequent encrypted information obtained from the access terminal. For example, the subsequent encrypted information can be included in an encrypted portion of the scheduled transmission message (as well as a subsequent normal scheduled transmission message that is encrypted). Following this example, the encrypted portion of the scheduled transmission message (and/or the subsequent normal scheduled transmission message) can be buffered until the unencrypted portion is processed (e.g. to determine the identity of the access terminal, . . . ). According to another example, the subsequent encrypted information can be included in a subsequent normal scheduled transmission message.

According to an example, one or methods presented above can include making inferences pertaining to determining a type of random access procedure to be employed. By way of further illustration, an inference can be made related to determining whether to alter encryption operation for message3as a function of the type of random access procedure being utilized. It will be appreciated that the foregoing examples are illustrative in nature and are not intended to limit the number of inferences that can be made or the manner in which such inferences are made in conjunction with the various embodiments and/or methods described herein.

FIG. 10is an illustration of an access terminal1000that transmits encrypted and/or unencrypted scheduled uplink messages in a wireless communication system. Access terminal1000comprises a receiver1002that receives a signal from, for instance, a receive antenna (not shown), and performs typical actions thereon (e.g. filters, amplifies, downconverts, etc.) the received signal and digitizes the conditioned signal to obtain samples. Receiver1002can be, for example, an MMSE receiver, and can comprise a demodulator1004that can demodulate received symbols and provide them to a processor1006for channel estimation. Processor1006can be a processor dedicated to analyzing information received by receiver1002and/or generating information for transmission by a transmitter1016, a processor that controls one or more components of access terminal1000, and/or a processor that both analyzes information received by receiver1002, generates information for transmission by transmitter1016, and controls one or more components of access terminal1000.

Access terminal1000can additionally comprise memory1008that is operatively coupled to processor1006and that can store data to be transmitted, received data, and any other suitable information related to performing the various actions and functions set forth herein. For instance, memory1008can store an identifier related to access terminal1000, a random access signature to include in a random access preamble, and so forth. Memory1008can additionally store protocols and/or algorithms associated with determining a type of random access procedure to employ, generating a random access preamble to transmit to a base station, generating uplink messages, concatenating encrypted and unencrypted messages, and the like.

Receiver1002is further operatively coupled to an unencrypted message generator1010and/or an encrypted message generator1012, which can be substantially similar to unencrypted message generator208ofFIG. 2and encrypted message generator210ofFIG. 2, respectively. Unencrypted message generator1010and/or encrypted message generator1012can yield a message3for transmission over an uplink to a base station. For instance, access terminal1000can transmit a random access preamble and receive a random access response based thereupon. When employing contention based random access, unencrypted message generator1010can yield at least a portion of message3for transmission over the uplink, and this portion is unencrypted. According to an example, message3can be generated by unencrypted message generator1010, and thus, can be unencrypted. Pursuant to another illustration, the unencrypted message generator1010can yield the unencrypted portion of message3, while encrypted message generator1012can yield an encrypted portion of message3. Moreover, a subsequent uplink normal scheduled transmission message can be provided by encrypted message generator1012. Further, unencrypted message generator1010can include non-security-critical information such as, for instance, an identifier related to access terminal1000, a message discriminator, etc. in the unencrypted messages, while encrypted message generator1012can include security-critical information in encrypted messages. Access terminal1000still further comprises a modulator1014and a transmitter1016that transmits the signal to, for instance, a base station, another access terminal, etc. Although depicted as being separate from the processor1006, it is to be appreciated that unencrypted message generator1010, encrypted message generator1012and/or modulator1014can be part of processor1006or a number of processors (not shown).

FIG. 11is an illustration of a system1100that evaluates unencrypted and/or encrypted scheduled messages received over an uplink during a random access procedure in a wireless communication environment. System1100comprises a base station1102(e.g., access point, . . . ) with a receiver1110that receives signal(s) from one or more access terminals1104through a plurality of receive antennas1106, and a transmitter1122that transmits to the one or more access terminals1104through a transmit antenna1108. Receiver1110can receive information from receive antennas1106and is operatively associated with a demodulator1112that demodulates received information. Demodulated symbols are analyzed by a processor1114that can be similar to the processor described above with regard toFIG. 10, and which is coupled to a memory1116that stores data to be transmitted to or received from access terminal(s)1104(or a disparate base station (not shown)) and/or any other suitable information related to performing the various actions and functions set forth herein. Processor1114is further coupled to a message source identifier1118that evaluates a received message3that includes at least an unencrypted portion from a particular one of access terminal(s)1104to recognize an identity of that particular access terminal. Such message3can be received when the particular access terminal employs a contention based random access; however, the claimed subject matter is not so limited. Message source identifier1118can be operatively coupled to a security context determiner1120that deciphers a security context corresponding to the identified, particular access terminal from which the message3was obtained. Moreover, the security context as identified can be employed to decipher subsequent encrypted scheduled uplink transmissions. It is contemplated that message source identifier1118can be substantially similar to message source identifier214ofFIG. 2and/or security context determiner1120can be substantially similar to security context determiner216ofFIG. 2. Further, message source identifier1118and/or security context determiner1120can provide information to be transmitted to a modulator1122. Modulator1122can multiplex a frame for transmission by a transmitter1126through antennas1108to access terminal(s)1104. Although depicted as being separate from the processor1114, it is to be appreciated that message source identifier1118, security context determiner1120and/or modulator1122can be part of processor1114or a number of processors (not shown).

FIG. 12shows an example wireless communication system1200. The wireless communication system1200depicts one base station1210and one access terminal1250for sake of brevity. However, it is to be appreciated that system1200can include more than one base station and/or more than one access terminal, wherein additional base stations and/or access terminals can be substantially similar or different from example base station1210and access terminal1250described below. In addition, it is to be appreciated that base station1210and/or access terminal1250can employ the systems (FIGS. 1,2,6,10-11, and13-14) and/or methods (FIGS. 8-9) described herein to facilitate wireless communication there between.

At base station1210, traffic data for a number of data streams is provided from a data source1212to a transmit (TX) data processor1214. According to an example, each data stream can be transmitted over a respective antenna. TX data processor1214formats, codes, and interleaves the traffic data stream based on a particular coding scheme selected for that data stream to provide coded data.

The modulation symbols for the data streams can be provided to a TX MIMO processor1220, which can further process the modulation symbols (e.g., for OFDM). TX MIMO processor1220then provides NTmodulation symbol streams to NTtransmitters (TMTR)1222athrough1222t. In various embodiments, TX MIMO processor1220applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

Each transmitter1222receives and processes a respective symbol stream to provide one or more analog signals, and further conditions (e.g. amplifies, filters, and upconverts) the analog signals to provide a modulated signal suitable for transmission over the MIMO channel. Further, NTmodulated signals from transmitters1222athrough1222tare transmitted from NTantennas1224athrough1224t, respectively.

At access terminal1250, the transmitted modulated signals are received by NRantennas1252athrough1252rand the received signal from each antenna1252is provided to a respective receiver (RCVR)1254athrough1254r. Each receiver1254conditions (e.g., filters, amplifies, and downconverts) a respective signal, digitizes the conditioned signal to provide samples, and further processes the samples to provide a corresponding “received” symbol stream.

An RX data processor1260can receive and process the NRreceived symbol streams from NRreceivers1254based on a particular receiver processing technique to provide NT“detected” symbol streams. RX data processor1260can demodulate, deinterleave, and decode each detected symbol stream to recover the traffic data for the data stream. The processing by RX data processor1260is complementary to that performed by TX MIMO processor1220and TX data processor1214at base station1210.

A processor1270can periodically determine which available technology to utilize as discussed above. Further, processor1270can formulate a reverse link message comprising a matrix index portion and a rank value portion.

The reverse link message can comprise various types of information regarding the communication link and/or the received data stream. The reverse link message can be processed by a TX data processor1238, which also receives traffic data for a number of data streams from a data source1236, modulated by a modulator1280, conditioned by transmitters1254athrough1254r, and transmitted back to base station1210.

At base station1210, the modulated signals from access terminal1250are received by antennas1224, conditioned by receivers1222, demodulated by a demodulator1240, and processed by a RX data processor1242to extract the reverse link message transmitted by access terminal1250. Further, processor1230can process the extracted message to determine which precoding matrix to use for determining the beamforming weights.

Processors1230and1270can direct (e.g., control, coordinate, manage, etc.) operation at base station1210and access terminal1250, respectively. Respective processors1230and1270can be associated with memory1232and1272that store program codes and data. Processors1230and1270can also perform computations to derive frequency and impulse response estimates for the uplink and downlink, respectively.

In an aspect, logical channels are classified into Control Channels and Traffic Channels. Logical Control Channels can include a Broadcast Control Channel (BCCH), which is a DL channel for broadcasting system control information. Further, Logical Control Channels can include a Paging Control Channel (PCCH), which is a DL channel that transfers paging information. Moreover, the Logical Control Channels can comprise a Multicast Control Channel (MCCH), which is a Point-to-multipoint DL channel used for transmitting Multimedia Broadcast and Multicast Service (MBMS) scheduling and control information for one or several MTCHs. Generally, after establishing a Radio Resource Control (RRC) connection, this channel is only used by UEs that receive MBMS (e.g., old MCCH+MSCH). Additionally, the Logical Control Channels can include a Dedicated Control Channel (DCCH), which is a Point-to-point bi-directional channel that transmits dedicated control information and can be used by UEs having a RRC connection. In an aspect, the Logical Traffic Channels can comprise a Dedicated Traffic Channel (DTCH), which is a Point-to-point bi-directional channel dedicated to one UE for the transfer of user information. Also, the Logical Traffic Channels can include a Multicast Traffic Channel (MTCH) for Point-to-multipoint DL channel for transmitting traffic data.

In an aspect, Transport Channels are classified into DL and UL. DL Transport Channels comprise a Broadcast Channel (BCH), a Downlink Shared Data Channel (DL-SDCH) and a Paging Channel (PCH). The PCH can support UE power saving (e.g., Discontinuous Reception (DRX) cycle can be indicated by the network to the UE, . . . ) by being broadcasted over an entire cell and being mapped to Physical layer (PHY) resources that can be used for other control/traffic channels. The UL Transport Channels can comprise a Random Access Channel (RACH), a Request Channel (REQCH), a Uplink Shared Data Channel (UL-SDCH) and a plurality of PHY channels.

The PHY channels can include a set of DL channels and UL channels. For example, the DL PHY channels can include: Common Pilot Channel (CPICH); Synchronization Channel (SCH); Common Control Channel (CCCH); Shared DL Control Channel (SDCCH); Multicast Control Channel (MCCH); Shared UL Assignment Channel (SUACH); Acknowledgement Channel (ACKCH); DL Physical Shared Data Channel (DL-PSDCH); UL Power Control Channel (UPCCH); Paging Indicator Channel (PICH); and/or Load Indicator Channel (LICH). By way of further illustration, the UL PHY Channels can include: Physical Random Access Channel (PRACH); Channel Quality Indicator Channel (CQICH); Acknowledgement Channel (ACKCH); Antenna Subset Indicator Channel (ASICH); Shared Request Channel (SREQCH); UL Physical Shared Data Channel (UL-PSDCH); and/or Broadband Pilot Channel (BPICH).

It is to be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For a hardware implementation, the processing units can be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof.

With reference toFIG. 13, illustrated is a system1300that enables utilizing a random access procedure in a wireless communication environment. For example, system1300can reside within an access terminal. It is to be appreciated that system1300is represented as including functional blocks, which can be functional blocks that represent functions implemented by a processor, software, or combination thereof (e.g., firmware). System1300includes a logical grouping1302of electrical components that can act in conjunction. For instance, logical grouping1302can include an electrical component for sending a random access preamble that includes a common random access signature to a base station when employing contention based random access1304. Further, although not shown, logical grouping1302can include an electrical component for sending a random access preamble that includes an access terminal specific random access signature to the base station when employing non-contention based random access. Moreover, logical grouping1302can include an electrical component for obtaining a random access response from the base station based upon the random access preamble1306. Further, logical grouping1302can include an electrical component for sending a scheduled transmission including at least an unencrypted portion to the base station as granted by the random access response when employing contention based random access1308. For instance, both the unencrypted portion and an encrypted portion can be sent as part of the scheduled transmission. By way of another illustration, the scheduled transmission can be unencrypted, and a subsequent normal scheduled transmission can be encrypted. Additionally, system1300can include a memory1310that retains instructions for executing functions associated with electrical components1304,1306, and1308. While shown as being external to memory1310, it is to be understood that one or more of electrical components1304,1306, and1308can exist within memory1310.

Turning toFIG. 14, illustrated is a system1400that enables employing a random access procedure in a wireless communication environment. System1400can reside at least partially within a base station, for instance. As depicted, system1400includes functional blocks that can represent functions implemented by a processor, software, or combination thereof (e.g. firmware). System1400includes a logical grouping1402of electrical components that can act in conjunction. Logical grouping1402can include an electrical component for obtaining a scheduled transmission message including at least an unencrypted portion from the access terminal when employing contention based random access1404. Further, logical grouping1402can include an electrical component for recognizing an identity of the access terminal based upon information included in the unencrypted portion of the scheduled transmission message1406. For instance, the unencrypted portion of the scheduled transmission message can include an identifier related to the access terminal. Moreover, logical grouping1402can include an electrical component for retrieving a security context associated with the access terminal based upon the recognized identity of the access terminal1408. Further, logical grouping1402can include an electrical component for deciphering an encrypted, normal scheduled transmission message or encrypted portion of the scheduled transmission message that includes the unencrypted portion received from the access terminal based upon the retrieved security context1410. Additionally, system1400can include a memory1412that retains instructions for executing functions associated with electrical components1404,1406,1408, and1410. While shown as being external to memory1412, it is to be understood that electrical components1404,1406,1408, and1410can exist within memory1412.