WO2009107093A1

WO2009107093A1 - Arrangement and approach for wireless communication frequency tracking for mobile receivers

Info

Publication number: WO2009107093A1
Application number: PCT/IB2009/050788
Authority: WO
Inventors: Ming GONG
Original assignee: Nxp B.V.
Priority date: 2008-02-26
Filing date: 2009-02-26
Publication date: 2009-09-03

Abstract

Signal processing at a wireless receiver is facilitated. According to an example embodiment of the present invention, the carrier frequency offset at a wireless receiver is estimated and used to mitigate frequency offset conditions including those often present in highly-mobile wireless receivers. An averaged symbol value is generated for a period of symbols in the wireless signal, and the averaged symbol value is used to calculate a carrier frequency offset for the wireless signal. The frequency of the wireless receiver is locked to the frequency of a wireless transmitter, using the calculated carrier frequency offset.

Description

ARRANGEMENT AND APPROACH FOR WIRELESS COMMUNICATION FREQUENCY TRACKING FOR MOBILE RECEIVERS

The present invention relates generally to communications, and more specifically, to circuits and methods for synchronizing wireless communications.

The communication of data over wireless mediums has increased tremendously in recent years. In particular, the use of mobile telephones, PDAs, media players and other mobile devices have increased dramatically. As these devices are used more and more, high demands has been placed upon the ability of these devices to communicate significant amounts of data for a variety of purposes. For example, there has been an increased demand for the use of hand-held devices in the presentation of media such as audio, images and video.

Satellite Terrestrial Interactive Multi-service Infrastructure (STiMi) is a physical scheme for China Mobile Multimedia Broadcasting that has been released as industrial standard of the State Administration of Radio Film and Television (SARFT) of the

People's Republic of China, with the index of GY/T 220.1-2006. This standard is related to the wireless communication of data such as Digital TV (DTV) to handheld mobile devices.

STiMi is based on Orthogonal Frequency Division Multiplexing (OFDM) technology. OFDM is an efficient scheme for the wideband wireless communication with moderate implementation complexity. Proper decoding of signals received using broadcasting approaches such as STiMi is generally dependent upon proper synchronization. Wireless OFDM receivers have to synchronize with a transmitter accurately in terms of carrier frequency, sampling frequency and symbol timing. However, synchronization can be difficult to achieve under a variety of operating conditions.

STiMi wireless receivers are sensitive to synchronization error related to the above issues, with such errors often involving carrier frequency offset (CFO) and symbol timing. STiMi receivers generally work in the band of 3OMHz-3OOOMHz. At relatively high frequencies, such as 2.6GHz, STiMi receivers may experience wireless channel conditions exhibiting a very large Doppler frequency for instances of high mobility, which can make carrier frequency synchronization difficult. For instance, CFO estimation under large Doppler frequency conditions is generally inaccurate and slow to respond, taking a relatively long time to converge to a carrier frequency that is without much residual CFO. The above and other issues continue to present challenges to wireless communications.

Various aspects of the present invention are directed to arrangements for and methods of processing video data in a manner that addresses and overcomes the above- mentioned issues and other issues as directly and indirectly addressed in the detailed description that follows.

According to an example embodiment of the present invention, the carrier frequency offset (CFO) of a wireless signal received at a mobile receiver is tracked and used to synchronize the receiver with a transmitter that sends the wireless signal. In one application, correlation results of symbols in the wireless signal are averaged, summed and used to calculate a CFO that is fed to a frequency lock loop.

According to another example embodiment, a carrier frequency circuit arrangement is used at a mobile wireless receiver for synchronizing and processing wireless signals sent by a wireless transmitter. The circuit arrangement includes a receiver circuit, a carrier frequency offset estimation circuit, and a frequency lock loop circuit. The receiver circuit receives a wireless signal from the wireless transmitter. The carrier frequency offset estimation circuit generates an averaged symbol value for a period of symbols in the wireless signal, and uses the averaged symbol value to calculate a carrier frequency offset for the wireless signal. The frequency lock loop circuit locks the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset.

According to another example embodiment of the present invention, Doppler effect is corrected for a satellite terrestrial interactive multi-service infrastructure (STiMi) video signal transmitted at a remote wireless transmitter and received at a highly-mobile wireless receiver device. A correlation R(i) of a cyclic preamble guard interval (CPGI) in a received STiMi signal is calculated as R(I) = T^ ^r*(j)^r,(j + ^O ,

where r_t(j) is they-th sample in an i orthogonal frequency division multiplexing (OFDM) symbol. A number L of continuous correlation results is summed as S(m). The phase of S(m) is extracted and used to calculate a carrier frequency offset (CFO) as Δ/ = — angle{S(m)} . The calculated CFO is used for locking the phase of each L

2π continuous OFDM symbol as processed at the wireless receiver to the phase of the remote wireless transmitter. The received STiMi video signal is processed, using the locked phase, and the processed video is displayed at the highly-mobile wireless receiver device.

The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Other aspects of the invention will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.

The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which: FIG. 1 shows a system for processing wireless signals in receivers susceptible to high- mobility conditions, according to an example embodiment of the present invention;

FIG. 2 shows a CFO estimation circuit and example wireless signal frame structure for a STiMi signal processed in accordance with another example embodiment of the present invention; FIG. 3 shows plots of carrier frequency offset (CFO) for the tracking performance of wireless signals processed in accordance with various example embodiments of the present invention; and

FIG. 4 is a flow diagram for a method for processing wireless signals at a mobile receiver with carrier frequency offset determination, according to another example embodiment of the present invention.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

The present invention is believed to be applicable to a variety of arrangements and approaches for wireless communications and the processing of wireless signals. While the present invention is not necessarily limited to such applications, an appreciation of various aspects of the invention is best gained through a discussion of examples in such an environment.

According to an example embodiment of the present invention, carrier frequency synchronization is effected via the estimation of the carrier frequency offset (CFO) between a transmitter and mobile receiver such as a moving hand-held device, and compensation for the CFO in signals at the receiver. With this approach, undesirable communications conditions such as those related to inaccuracies in received wireless signals and frequency variance from oscillator crystals can be addressed, facilitating the reception of wireless signals in relatively highly mobile conditions, such as those involving a receiver operating in a vehicle such as an automobile or train.

In a more particular example embodiment, correlation results from L OFDM (Orthogonal Frequency Division Multiplexing) symbols are averaged at a wireless receiver to generate a sum value for each period of OFDM symbols in a signal received from a wireless transmitter. In this context, the value L specifies a window size of a symbol averaging approach, where an output OFDM symbol is obtained when a window of L OFDM symbols are input for symbol-by-symbol averaging. The result of the averaging is used to calculate the CFO for the signal, and a frequency lock loop uses the result to synchronize the wireless receiver with the transmitter under high mobility receiver conditions. A variety of example embodiments are directed to the use of one of several approaches for estimating CFO for signals received at a mobile receiver, such as for signals provided in accordance with the Satellite Terrestrial Interactive Multi-service Infrastructure (STiMi). One such CFO estimating approach involves the exploitation of the structure of a cyclic preamble constructed in the front of an Orthogonal Frequency Division Multiplexing (OFDM) symbol to mitigate and/or avoid inter-symbol interference (ISI). The signal transmitted in the «-th OFDM is

sΛt) nN_sT_s ≤ t ≤ (n ₊ ϊ)N_sT_s , (1)

where T_s is the basic sample interval and Δ/_s is the bandwidth of the sub-carrier,

N is number of sub-carriers and Ncp is the length of the cyclic preamble, a_k is the symbol carried on the £>th sub-carrier, and the representation nN_sT_s ≤ t ≤ nN_sT_s + N_cpT_s can be referred to as the cyclic preamble. In the receiver, samples for the n-th OFDM symbol in the baseband are taken as

r_n (i) = e^j2πAf^s_n (tr h(t)] + w(t) ,_ _„ i = 0, l, ..., N_s - l , (2) where h(t) is the channel impulse response function and Af is the CFO between transmitter and receiver.

The CFO can be estimated as

(Af ) = ^-angle{ "∑ r^* (i)r(i + N)} (3)

where

[N cp-Li, Ncp-L₂-l] is the range for the accumulation, and (Af ) is the normalized CFO.

V I n

In the following discussion, the CFO mentioned is normalized by Δ/ (which is the bandwidth of a sub-carrier) unless specified otherwise. For certain STiMi applications, Δ/is 10M/4096=2.4414kHz.

When CFO is detected, the offset can be compensated with the aid of the numeric oscillator (NCO) sample by sample, e.g., using CORDIC algorithm in hardware in accordance with the following:

4H) τ_s u(i) = r(ϊ)e (4)

In many embodiments, a closed-loop feedback structure is used to deal with measurement deviation, to facilitate the compensation for CFO conditions as relative, for example, to the approach characterized in Equation 3. A frequency lock loop is used at a receiver to lock the receiver's local frequency to the frequency of a corresponding transmitter. For general information regarding signal processing, and for specific information regarding the use of a CORDIC algorithm in connection with one or more example embodiments, reference may be made to Vails, J.; Sansaloni, T.; Perez-Pascual, A.; Torres, V.; Almenar, V.; The use of CORDIC in software defined radios: a tutorial, Communications Magazine, IEEE Volume 44, Issue 9, Sept., 2006, pages 46 - 50, which is fully incorporated herein by reference. In some low mobility applications, such as for receivers in a hand-held device carried by a person walking or riding in an automobile, CFO can be estimated for each

OFDM symbol through Equation 3 above, and the result I Αf_c is fed into a low pass

filter (LPF). This approach is relative to the carrier frequency (f_c) as well as the mobility of the receiver. For each interval of an OFDM symbol, the output of the LPF is fed into a CORDIC algorithm as a controlling signal to gradually reduce or eliminate residual CFO. In this context, certain embodiments are directed to the use of such an approach for relatively low mobility conditions. For example, a mobile device can be programmed to operate as above under low mobility conditions, and to operate using an alternate approach (e.g., as described below) for high mobility conditions, with a threshold or other condition used for determining whether to operate under low or high mobility conditions. In some applications, low and high mobility conditions are detected using a global positioning system (GPS) device, a motion sensor or another motion-related device. In other applications, low and high mobility conditions are specified via user input.

Tracking is carried out under high mobility conditions using one or more of a variety of approaches, which are also amenable to implementation in low mobility conditions. In one embodiment, a STiMi scheme is used to wirelessly communicate media in a range of about 3OMHz-3OOOMHz using, for example, a UHF band such as 800MHz or an S band having a carrier frequency of about 2.6GHz. These applications are useful, for example, with time-varying wireless channels. Mobility conditions and related Doppler frequencies to which various embodiments may be applied are shown in Table 1.

Table 1 : Doppler frequency (fd) due to mobility at different carrier frequencies (f)

Referring to Table 1 above, Doppler frequency data is shown for two cases (case 1 and case 2) for mobility conditions of respectively 208km/h and 350km/h for a mobile receiver. These speeds may be relative, for example, to a mobile telephone or PDA operating in a vehicle moving at about 208km/h in case 1 (e.g., a train), or at about 350km/h in case 2 (e.g., a high-speed train). The Doppler frequency is thus related to both the carrier frequency and the speed that the wireless receiver is moving, and correspondingly affects the receiver's ability to receive and process wireless signals such as a STiMi signal.

When a wireless receiver is moving at a speed of about 208km/h (case 1), the normalized Doppler frequency is about 0.0631 at an 800MHz carrier frequency. Under such conditions, a low mobility approach such as that described above may be used to estimate CFO, or a high mobility approach as described in the following may be implemented for both low and high mobility conditions.

Again under case 1 (at 208km/h), when the carrier frequency is 2600MHz, the normalized Doppler frequency is about 0.2048. This frequency is relatively higher and can cause issues with the receipt and processing of wireless signals. In this (and similar) instances, the Doppler frequency is accounted for using one or more approaches as discussed below.

Under case 2 (at 350km/h), the wireless receiver is moving at a speed that is problematic for the accurate receipt and processing of wireless signals at carrier frequencies of both 800MHz and 2600MHz, which respectively result in Doppler frequencies of 0.1061 and 0.3453. These conditions can also be addressed using one or more of the following approaches.

Under high mobility conditions exhibiting high Doppler frequency, the estimation approach shown in Equation 3 is modified, in consideration of the following. Generally, the signal model in the time-varying channel for high mobility conditions becomes

r_n (ϊ) = e^j2πφ\\s_n (ty h(t, τ)\ + w(t)\ _t___nNsTs+ιTs i = 0, l, ..., N_s - l , (5)

where h(t, τ) is time-varying channel impulse response function. Supposing one path channel for brevity, r_n(i) = e^j2^'Q>_n (t)Oi(t) ₊ w(t) ,_ _„ i = 0, l,..., N_s - l (6) and the approach in Equation 3 becomes

Na-L₂-I

/_c ) = ^-angle{ "∑ r^*(i)r(i + N)} + Θ

= e^j2jAf^ h^* (i)h(i + N)s ^'(i)s(i + N)} + Θ

, Nc_P-L₂-X

= — angle{ Y e^j2πAf'^NT'h"(i)h(i + N)s"(i)s(i + N)} + Θ (7)

^{2π t}=Ncr-h

= — angle{ ^Cγ_j ' H y²^^NT> _e ^j2^< ⁾ _} + _Θ 2π ,=N_CP-L,

where h^*(i)h(i + N) = H_ie^{j2πΦh( )}

For a time-varying channel, the CFO estimation is influenced by the channel through the additional phase due to h^* (i)h(i + N) = H \e^{J H )} . In a time-varying channel, the added

phase ^^ h(ι) may exhibit a range of (—π, +π] , which may cause an error for CFO estimation (e.g., as much as 0.5 in one data point). In addition, the representation

2πAf_cNT exhibit a range of (-O.όπ, +0.6;r] . Calculations performed for Equation 7 are affected by phase ambiguity, in that the real summed angle may be beyond the range of (-π,+π] . This can also cause an error (e.g., as much as 1.0 in one data point). These errors are addressed as follows, in accordance with various example embodiments. According to an example embodiment, a time varying Rayleigh channel is modeled with a Jakes model as follows, with

E{h^*(i)h(i + N)} = J₀(2πf_dmi[XNT_s) . (8)

Multiple correlation results are averaged as L-\ N_cp-L₂-l

/_c ) = — angle{∑ ∑ η (i)η(i + N)} + ®

2π 1=0 I=Nc₁₁-L₁

= — angle{e^j2^^NT'e^j2>A} + Θ 2π

With large enough L (window size for averaging data), under the approach shown in

L-I Nc_P-L₂-I

Equation 8 above, the phase ^2πA of ∑ ∑ P, ^^^ h,^* (i)h,(i + N) is relatively

1=0 I=Nc_P-L₁ small. If L approaches positive infinity, the phase 2^;τΔ approach zero. These characteristics are used in estimating a CFO term that is accurate under conditions including those in which a wireless receiver is highly mobile.

In accordance with the above and a particular example embodiment, the CFO is detected by calculating a correlation R(i) of CPGI (cyclic preamble guard interval) as follows

R(i) = ^Ne∑ ^l _r;U)r,U + N) (10)

J=N_Cp-L,

Where r_t (J) is they-th sample in the i OFDM symbol and a number L of continuous correlation results are summed as S(m). The phase of S(m) is extracted and the CFO is calculated as Aj = — angle{S(m)} . The estimated CFO Δj is input for each L

2π continuous OFDM symbol.

Turning now to the figures, FIG. 1 shows a system 100 for processing wireless signals at a wireless receiver in a high-mobility environment, according to another example embodiment of the present invention. A digital front end circuit 110 receives a signal originating from a remote wireless transmitter and having a particular carrier frequency, as well as a local frequency with an added controlling signal. The signal(s) is processed using a CORDIC algorithm, such as described above, with an output presented to a CFO estimation circuit 120.

For CFO estimation, CPGI correlation is calculated at block 122 and a number of continuous correlation results are summed at 124. The phase of the summed results is determined at block 126 and used in generating a carrier frequency offset estimation Af_n. This frequency offset is used as an input for subsequently processed OFDM symbols in the incoming signal from the wireless transmitter.

FIG. 2 shows a CFO estimation circuit 210 and an example STiMi wireless signal frame structure 200 processed in accordance with another example embodiment of the present invention. The CFO estimation circuit 210 may, for example, be implemented with a circuit as shown in FIG. 1, for processing wireless signals such as the wireless signal frame 200. In this context, the following discussion may be applicable to such implementation with the system 100 and the corresponding locking loop.

The signal frame 200 is set to a time period of one second, and the frame is divided into 40 time slots, each of which is 25ms and which are respectively labeled time slot 0 (zero) through time slot 39, with ellipses illustrating certain slots for brevity. As represented at 220, each time slot includes 1 (one) beacon and 53 OFDM symbols. In every (1 second) frame, the first time slot, which is TSO (time slot zero), is exclusively used to bear control information in a control logic channel (CLCH) 230, which includes physical signaling for the other time slots and logical control information for the up layer data. Other time slots, from TSl to TS39, can be separated as groups to bear data for a service logical channel (SLCH), with example groups represented as SLCH 240-SLCH N.

The CFO estimation circuit 210 averages CPGI correlation results of L OFDM symbols (of the indicated 53 OFDM symbols at 220), and sums the averaged results for each period of L OFDM symbols. CFO is calculated using the summed results and generates an output to a lock loop for frequency synchronization with received wireless signals.

FIG. 3 shows plots of carrier frequency offset (CFO) for wireless signals processed in accordance with various example embodiments of the present invention. The CFO and related information in the plots in FIG. 3 may, for example, be generated using a system and approach as shown in FIG. 1, FIG. 2 and/or as otherwise described above. As shown, when L = 25, the error of CFO estimation is rather small and the standard deviation is also small (e.g., less than 0.2). For STiMi applications, 53 OFDM symbols together with a beacon forms a slot, which is the basic unit for service scheduling. Using an approach as shown in FIG. 2, the wireless receiver can adjust its numerically-controlled oscillator (NCO) twice per slot (e.g., as relative to the signal frame 200 in FIG. 2). This approach is useful for compensating for motion-related signal processing issues via CFO estimation. FIG. 4 is a flow diagram for a method for processing wireless signals at a mobile receiver with carrier frequency offset determination, according to another example embodiment of the present invention. At block 400, a wireless signal is received from a remote wireless transmitter. Correlation results are generated using a cyclic preamble of the incoming signal at block 410, and the results are averaged and summed at block 420. The summed value is used at block 430 to determine a carrier frequency offset that is used at block 440 in adjusting or otherwise processing incoming signals received from the remote wireless transmitter. In some embodiments, a microprocessor or microcomputer is programmed to carry out the algorithm and approach shown in FIG. 4. The approaches described above are applicable to a variety of wireless receivers, particularly to OFDM receivers, such as those for STiMi and other communications approaches. For example, in one embodiment, the above approach is implemented with the scheme described in connection with Speth, M.; Fechtel, S.A.; Fock, G.; and Meyr, H; Optimum receiver design for wireless broad-band systems using OFDM. /; Communications, IEEE Transactions on Volume 47, Issue 11, Nov. 1999 Page(s): 1668 - 1677, which is fully incorporated herein by reference.

The CFO is estimated, for two continuous OFDM symbols, with the aid of continuous pilots. The CFO information is extracted from the correlation results in the frequency domain. Using a pipeline approach, for each OFDM symbol, correlation results are accumulated and the CFO estimated from the accumulated results. The carrier frequency is modified with the estimated CFO, facilitating the reception and processing of wireless signals under high mobility conditions.

For additional information regarding wireless signal processing, and for specific information regarding approaches that may be implemented in connection with one or more example embodiments of the present invention, reference may be made to the following two references, each of which is fully incorporated herein by reference: Mobile Multimedia Broadcasting Part 1: Framing Structure, Channel Coding and Modulation for Broadcasting Channel GY/T 220.1 -2006 , Released by SARFT; and Baoguo Yang; Letaief, K.B.; Cheng, R.S.; Zhigang Cao; Timing recovery for OFDM transmission, Selected Areas in Communications, IEEE Journal on Volume 18, Issue 11, Nov. 2000 Page(s):2278 - 2291

In addition to the above, the various processing approaches described herein can be implemented using a variety of devices and methods including general purpose processors implementing specialized software, digital signal processors, programmable logic arrays, discrete logic components and fully-programmable and semi-programmable circuits such as PLAs (programmable logic arrays). For example, the above algorithms are executed on a microcomputer (a.k.a. microprocessor) in connection with certain embodiments, and as may be implemented as part of one or more of the devices shown in the figures. One such approach involves a mobile device including such a microcomputer for certain embodiments, which may be implemented to carry out the circuit functions shown in FIG. 1).

The various embodiments described above and shown in the figures are provided by way of illustration only and should not be construed to limit the invention. Based on the above discussion and illustrations, those skilled in the art will readily recognize that various modifications and changes may be made to the present invention without strictly following the exemplary embodiments and applications illustrated and described herein. For example, the approaches described herein are applicable to the communication of many different types of data, over different mediums and with many different types of devices. Correspondingly, the various applications directed to the implementation of wireless communications under the Satellite Terrestrial Interactive Multi-service Infrastructure (STiMi) broadcasting scheme may be implemented using one or more other schemes, such as those relating to audio or video broadcasting or other delivery approaches, Internet-based communications, telephony-based communications and others. Wireless channels applicable for use in connection with various example embodiments include those operating in accordance with AWGN, TU6, CT8 (China test type 8 channel, typical SFN channel), and in low CNR cases (e.g., OdB). Such modifications and changes do not depart from the true scope of the present invention, including that set forth in the following claims.

Claims

What is claimed is:

1. A carrier frequency circuit arrangement for use at a mobile wireless receiver for synchronizing and processing wireless signals sent by a wireless transmitter, the circuit arrangement comprising: a receiver circuit to receive a wireless signal from the wireless transmitter; a carrier frequency offset estimation circuit to generate an averaged symbol value for a period of symbols in the wireless signal, and use the averaged symbol value to calculate a carrier frequency offset for the wireless signal; and a frequency lock loop circuit to lock the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset.

2. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit calculates a carrier frequency offset to compensate for the carrier frequency offset of the mobile wireless receiver at a receiver speed that exceeds about 200km/hr.

3. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit calculates a carrier frequency offset to compensate for Doppler effect at the mobile wireless receiver due to movement of the mobile receiver.

4. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit generates an averaged symbol value for a period of symbols in the wireless signal by averaging and summing CPGI (cyclic preamble guard interval) correlation results of a set of symbols.

5. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit uses the averaged symbol value to calculate a carrier frequency offset for the wireless signal by extracting the phase of the averaged symbol value, calculating the carrier frequency offset using the extracted phase and using the extracted phase to calculate the carrier frequency offset.

6. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit generates an averaged symbol value for a period of symbols in the wireless signal by averaging and summing CPGI (cyclic preamble guard interval) correlation results of a set of symbols, and uses the averaged symbol value to calculate a carrier frequency offset for the wireless signal by extracting the phase of the averaged and summed CPGI (cyclic preamble guard interval) correlation results and using the extracted phase to calculate the carrier frequency offset.

7. The circuit arrangement of claim 1, wherein the frequency lock loop circuit locks the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset by inputting the calculated carrier frequency offset for processing each symbol in the period of symbols.

8. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit generates an averaged symbol value for a period of symbols in the wireless signal by averaging and summing CPGI (cyclic preamble guard interval) correlation results of a set of symbols, and uses the averaged symbol value to calculate a carrier frequency offset for the wireless signal by extracting the phase of the averaged and summed CPGI (cyclic preamble guard interval) correlation results and using the extracted phase to calculate the carrier frequency offset, and the frequency lock loop circuit locks the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset by inputting the calculated carrier frequency offset for processing each symbol in the period of symbols.

9. The circuit arrangement of claim 1, wherein the carrier frequency offset estimation circuit calculates the carrier frequency offset by dividing the phase angle of the averaged symbol value by 2π.

10. The circuit arrangement of claim 1, further including a mobile hand-held device that displays video received by the receiver circuit.

11. For use at a mobile wireless receiver, a method for synchronizing and processing wireless signals sent by a wireless transmitter, the method comprising: receiving a wireless signal from the wireless transmitter; generating an averaged symbol value for a period of symbols in the wireless signal; using the averaged symbol value to calculate a carrier frequency offset for the wireless signal; and locking the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset.

12. The method of claim 11, wherein using the averaged symbol value to calculate a carrier frequency offset for the wireless signal includes calculating a carrier frequency offset for the mobile wireless receiver when the receiver exceeds a speed of about 200km/hr.

13. The method of claim 11, wherein using the averaged symbol value to calculate a carrier frequency offset for the wireless signal includes calculating a carrier frequency offset to compensate for Doppler effect at the mobile wireless receiver due to movement of the mobile receiver.

14. The method of claim 11, wherein generating an averaged symbol value for a period of symbols in the wireless signal includes averaging and summing CPGI (cyclic preamble guard interval) correlation results of a set of symbols.

15. The method of claim 11, wherein using the averaged symbol value to calculate a carrier frequency offset for the wireless signal includes extracting the phase of the averaged symbol value, calculating the carrier frequency offset using the extracted phase and using the extracted phase to calculate the carrier frequency offset.

16. The method of claim 11 , wherein generating an averaged symbol value for a period of symbols in the wireless signal includes averaging and summing CPGI (cyclic preamble guard interval) correlation results of a set of symbols, and using the averaged symbol value to calculate a carrier frequency offset for the wireless signal includes extracting the phase of the averaged and summed CPGI (cyclic preamble guard interval) correlation results and using the extracted phase to calculate the carrier frequency offset.

17. The method of claim 11, wherein locking the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset includes inputting the calculated carrier frequency offset for processing each symbol in the period of symbols.

18. The method of claim 11 , wherein generating an averaged symbol value for a period of symbols in the wireless signal includes averaging and summing CPGI (cyclic preamble guard interval) correlation results of a set of symbols, using the averaged symbol value to calculate a carrier frequency offset for the wireless signal includes extracting the phase of the averaged and summed CPGI (cyclic preamble guard interval) correlation results and using the extracted phase to calculate the carrier frequency offset, and locking the frequency of the wireless receiver to the frequency of the wireless transmitter using the calculated carrier frequency offset includes inputting the calculated carrier frequency offset for processing each symbol in the period of symbols.

19. The method of claim 11, wherein using the averaged symbol value to calculate a carrier frequency offset for the wireless signal includes calculating the carrier frequency offset by dividing the phase angle of the averaged symbol value by 2π.

20. A method for correcting Doppler effect for a satellite terrestrial interactive multiservice infrastructure (STiMi) video signal transmitted at a remote wireless transmitter and received at a highly-mobile wireless receiver device, the method comprising: calculating a correlation R(i) of a cyclic preamble guard interval (CPGI) in a

received STiMi signal as R(i) = ^ ^r*(j)^r, (J + N) _> where η (j) is they-th sample in

an i orthogonal frequency division multiplexing (OFDM) symbol; summing a number L of continuous correlation results as S(m); extracting the phase of S(m); calculating a carrier frequency offset (CFO) as Δj _m = — angle {S(m)} ;

2π using the calculated CFO for locking the phase of each L continuous OFDM symbol as processed at the wireless receiver to the phase of the remote wireless transmitter; and processing the received STiMi video signal, using the locked phase, and displaying the processed video at the highly-mobile wireless receiver device.